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ECMA-236 — 3,81 mm wide magnetic tape cartridge for information interchange - Helical scan recording - DDS-3 format using 125 m length tapes (June 1996)

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ecma, standard, ecma international, specification, ecma-236, ecma 236, 236, wide, magnetic, tape, cartridge, for, information, interchange, helical, scan, recording, dds-3, format, using, 125, length, tapes

Standard ECMA-236 J une 1 9 9 6

Standardizing

Information

and

Communication

Systems

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DDS-3 Format using 125 m Length Tapes

P h o n e : + 4 1 2 2 8 4 9 . 6 0 . 0 0 - F a x : + 4 1 2 2 8 4 9 . 6 0 . 0 1 - U R L : h t t p : / / www. e c m a . c h - I n t e r n e t : h e l p d e s k @ e c m a . c h

Standard ECMA-236 J une 1 9 9 6

Standardizing

Information

and

Communication

Systems

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DDS-3 Format using 125 m Length Tapes

P h o n e : + 4 1 2 2 8 4 9 . 6 0 . 0 0 - F a x : + 4 1 2 2 8 4 9 . 6 0 . 0 1 - U R L : h t t p : / / www. e c m a . c h - I n t e r n e t : h e l p d e s k @ e c m a . c h MB - ECMA-236.DOC - 13.08.96 09,45

Brief History ECMA have produced a series of ECMA Standards for cassettes and cartridges containing magnetic tapes of different width and characteristics. Of these, the following relate to helical scan recording. ECMA-139 (1990)

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DDS format

ECMA-145 (1990)

8 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording

ECMA-146 (1990)

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DATA/DAT Format

ECMA-150 (1991)

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DDS-DC Format using 60 m and 90 m Length Tapes, 2nd Edition

ECMA-169 (1992)

8 mm Wide Magnetic Tape Cartridge, Dual Azimuth Format for Information Interchange- Helical Scan Recording

ECMA-170 (1992)

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DDS Format using 60 m and 90 m Length Tapes

ECMA-171 (1992)

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DATA/DAT-DC Format using 60 m and 90 m Length Tapes

ECMA-198 (1995)

3,81 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DDS-2 Format using 120m Length Tapes

ECMA-210 (1994)

12,65 mm Wide Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording - DATA-D3-1 Format

All previously issued Standards for the family of DDS cartridges have been adopted by ISO/IEC under the fast-track procedure as International Standards. This ECMA Standard specifies a magnetic tape cartridge, based on the features of ECMA-198, which offers an increase in data capacity. The primary changes to the recorded format are a doubling of the linear recording density and an increase in the proportion of a recorded track that is available for user data. Together, these provide three times the data capacity, compared with DDS-2, for a cartridge of a given tape length. The DDS-3 format, when recorded on a 3,81 mm wide tape the length of which is 125 metres, will provide a storage capacity of 12 Gigabytes of uncompressed user data or typically 24 to 36 Gigabytes of compressed user data. It is not a requirement for compliance to this ECMA Standard that a DDS-3 drive also reads and writes either the DDS format, the DDS-DC format or the DDS-2 format. Nor is it a requirement for compliance to this ECMA Standard that a drive compresses data and records it in entities on the tape, or that a drive decompresses data contained within such entities. A recorded cartridge of the 3,81 mm wide magnetic tape family of cartridges has a single recorded format thereon, i.e. either DDS or DDS-DC or DDS-2 or DDS-3, and therefore a single track density and linear bit density. The tape’s thickness, its magnetic coating and the recorded format are indicated by the combination of the states of the Recognition Holes on the cartridge case.

This ECMA Standard has been adopted by the ECMA General Assembly of June 1996.

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Table of contents 1 Scope

2 Conformance

2.1 Magnetic tape cartridge 2.2 Generating drive 2.3 Receiving drive

1 1 1

3 References

4 Definitions

4.1 Absolute Frame Number (AFN) 4.2 a.c. erase 4.3 Access Point 4.4 algorithm 4.5 Area ID 4.6 Average Signal Amplitude 4.7 azimuth 4.8 back surface 4.9 byte 4.10 cartridge 4.11 Channel bit 4.12 Codeword 4.13 Data Format ID 4.14 Early Warning Point (EWP) 4.15 End of Data (EOD) 4.16 Entity 4.17 Error Correcting Code (ECC) 4.18 flux transition position 4.19 flux transition spacing 4.20 Fragment 4.21 Frame 4.22 Housekeeping Frame 4.23 Logical Beginning of Tape (LBOT) 4.24 magnetic tape 4.25 Master Standard Amplitude Calibration Tape 4.26 Master Standard Reference Tape 4.27 Optimum Recording Field 4.28 Partition Boundary 4.29 Physical Beginning of Tape (PBOT) 4.30 Physical End of Tape (PEOT) 4.31 physical recording density 4.32 pre-recording condition 4.33 processing 4.34 processed data 4.35 Processed Record 4.36 Processed Record Sequence 4.37 record 4.38 Reference Recording Field 4.39 reprocessing 4.40 Secondary Standard Amplitude Calibration Tape 4.41 Secondary Standard Reference Tape 4.42 Separator Mark

2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5

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4.43 Standard Reference Amplitude 4.44 Tape Reference Edge 4.45 Test Recording Current 4.46 track 4.47 unprocessed data 4.48 Unprocessed Record 4.49 Virtual End of Tape (VEOT)

5 5 5 5 5 5 5

5 Conventions and Notations

6 Acronyms

7 Environment and safety

7.1 Testing environment 7.2 Operating environment 7.3 Storage environment 7.4 Transportation 7.5 Safety 7.6 Flammability

6 6 6 6 6 6

Section 2 - Requirements for the case

8 Dimensional and mechanical characteristics of the case

8.1 General 8.2 Overall dimensions 8.3 Loading grip 8.4 Holding areas 8.5 Notches of the lid 8.6 Lid dimensions 8.7 Optical detection of the beginning and end of tape 8.8 Bottom side

7 7 8 8 8 8 9 9

8.8.1 Locking mechanism of the slider 8.8.2 Access holes 8.8.3 Recognition, sub-datums, and write-inhibit holes 8.8.4 Datum holes 8.8.5 Access room for tape guides 8.8.6 Holes for accessing the hubs 8.8.7 Internal structure of the lower half 8.8.8 Light path 8.8.9 Support Areas 8.8.10 Datum Areas 8.8.11 Relationship between Support and Datum Areas and Reference Plane Z

10 10 10 12 12 12 13 14 14 14 14

8.9 Hubs 8.10 Attachment of leader and trailer tapes 8.11 Interface between the hubs and the drive spindles 8.12 Opening of the lid 8.13 Release of the hub locking mechanism 8.14 Label areas 8.15 Requirement for autoloaders

14 15 15 15 15 16 16

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Section 3 - Requirements for the unrecorded tape

9 Mechanical, physical and dimensional characteristics of the tape

9.1 Materials 9.2 Tape length

28 28

9.2.1 Length of magnetic tape 9.2.2 Length of leader and trailer tapes 9.2.3 Length of splicing tapes

28 28 28

9.3 Tape width

9.3.1 Width of magnetic tape 9.3.2 Width of leader and trailer tapes 9.3.3 Width and position of splicing tape 9.3.4 Edge weave

28 28 28 28

9.4 Discontinuities 9.5 Tape thickness

29 30

9.5.1 Thickness of magnetic tape 9.5.2 Thickness of leader and trailer tape 9.5.3 Thickness of splicing tape

30 30 30

9.6 Longitudinal curvature 9.7 Cupping 9.8 Coating adhesion 9.9 Layer-to-layer adhesion 9.10 Tensile strength

30 30 30 31 31

9.10.1 Breaking strength 9.10.2 Yield strength

31 31

9.11 Residual elongation 9.12 Flexural rigidity 9.13 Electrical resistance of coated surfaces 9.14 Light transmittance of the tape 9.15 Media Recognition System (MRS)

31 32 32 33 33

10 Magnetic recording characteristics

10.1 Optimum Recording Field 10.2 Signal Amplitude 10.3 Resolution 10.4 Overwrite 10.5 Ease of erasure 10.6 Tape quality

35 35 35 35 35 36

10.6.1 Missing pulses 10.6.2 Missing pulse zone

36 36

10.7 Signal-to-Noise Ratio (SNR) characteristic

Section 4 - Requirements for an interchanged tape

11 Format

11.1 General 11.2 Basic Groups

37 37

11.2.1 Entity 11.2.2 Group Information Table 11.2.3 Block Access Table (BAT)

38 39 41

11.3 Sub-Groups

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11.3.1 G1 Sub-Group 11.3.2 G2 Sub-Group - randomizing 11.3.3 G3 Sub-Group 11.3.4 G4 Sub-Group 11.3.5 Main Data Fragment 11.3.6 Summary of the transformation of a Basic Group

44 44 45 46 50 52

11.4 Sub code Information

11.4.1 Pack Item Number 0 11.4.2 Pack Item Number 1 11.4.3 Pack Item Number 2 11.4.4 Pack Item Number 3 11.4.5 Pack Item Number 4 11.4.6 Pack Item Number 5 11.4.7 Pack Item Number 6 11.4.8 Pack Item Number 7 11.4.9 Pack Item Number 8 11.4.10 Pack Item Number 9 11.4.11 Pack Item Number 10 11.4.12 Pack Item Number 11 11.4.13 Pack Item Number 12 11.4.14 Pack Item Number 13 11.4.15 Pack Item Number 14 11.4.16 Pack Item Number 15

52 52 53 53 53 54 54 55 55 56 56 56 57 57 58 58

11.5 Sub code location

11.5.1 Sub code Pack Items on a Single Data Space tape 11.5.2 Sub code Pack Items on a partitioned tape

59 59

12 Method of recording

12.1 Physical recording density 12.2 Long-term average bit cell length 12.3 Short-term average bit cell length 12.4 Rate of change 12.5 Bit shift 12.6 Read signal amplitude 12.7 Maximum recorded levels

59 59 59 59 59 59 60

13 Track geometry

13.1 Track configuration 13.2 Average track pitch 13.3 Variations of the track pitch 13.4 Track width 13.5 Track angle 13.6 Track edge linearity 13.7 Track length 13.8 Ideal tape centreline 13.9 Azimuth angles

60 60 61 61 61 61 61 61 61

14 Recorded patterns

14.1 Recorded Main Data Fragment 14.2 Preamble Zone, Margin Zones

61 61

15 Format of a track

15.1 Format of a track 15.2 Positioning accuracy

61 62

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15.3 Tracking scheme

16 Layout of a Single Data Space tape

16.1 Device Area 16.2 Reference Area 16.3 Position Tolerance Band No. 1 16.4 System Area

63 63 63 63

16.4.1 System Preamble 16.4.2 System Log 16.4.3 System Postamble 16.4.4 Position Tolerance Band No. 2 16.4.5 Vendor Group Preamble

64 64 64 64 64

16.5 Data Area

16.5.1 Vendor Group 16.5.2 Recorded Data Group 16.5.3 ECC3 16.5.4 Repeated Frames 16.5.5 Appending and overwriting

64 64 65 65 66

16.6 EOD Area 16.7 Post-EOD Area 16.8 Early Warning Point - (EWP) 16.9 Initialization

67 67 68 68

17 Layout of a partitioned tape

17.1 Overall magnetic tape layout

17.1.1 Device Area 17.1.2 Partition 1 17.1.3 Partition 0

69 69 70

17.2 Area ID 17.3 System Area Pack Items No. 3 and No. 4 17.4 Empty partitions

71 71 71

17.4.1 Empty partition 1 17.4.2 Empty partition 0

71 71

17.5 Initialization of partitioned tapes

18 Housekeeping Frames

18.1 Amble Frames 18.2 System Log Frames 18.3 Tape Management Frames

71 72 72

Annexes A - Measurement of the light transmittance of the prisms

B - Measurement of light transmittance of tape and leaders

C - Measurement of Signal-to-Noise Ratio

D - Method for determining the nominal and the maximum allowable recorded levels

E - Representation of 8-bit bytes by 10-bit patterns

F - Measurement of bit shift

G - Measurement of track edge linearity

H - Recognition Holes

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J - Means to open the lid

101

K - Recommendations for transportation

103

L - Read-After-Write.

105

M - Example of the content of a Basic Group No. 0.

107

N - Generating and Receiving Drives.

109

Scope This ECMA Standard specifies the physical and magnetic characteristics of a 3,81 mm wide magnetic tape cartridge to enable physical interchangeability of such cartridges between drives. It also specifies the quality of the recorded signals, the recording method and the recorded format - called Digital Data Storage (DDS) - thereby allowing data interchange between drives by means of such magnetic tape cartridges. Information interchange between systems also requires, at a minimum, agreement between the interchange parties upon the interchange code(s) and the specifications of the structure and labelling of the information on the interchanged cartridge. Under information interchange circumstances in which a processing algorithm, e.g. for lossless data compression as specified in ECMA-151, is applied to the host data prior to recording on the tape and a complementary reprocessing algorithm is applied after the data is read from the tape, agreement upon these by the interchange parties is also required.

2 2.1

Conformance Magnetic tape cartridge A tape cartridge shall be in conformance with this ECMA Standard if it meets all the mandatory requirements specified herein. The tape requirements shall be satisfied throughout the extent of the tape. For each recorded Entity any algorithm for lossless data compression used for processing the data therein shall have been registered, and according to ISO/IEC 11576 the corresponding numerical identifier shall be recorded in Byte No. 3 of the Entity Header.

2.2

Generating drive A drive generating a magnetic tape cartridge for interchange shall be in conformance with this ECMA Standard if all recordings on the tape meet the mandatory requirements of this ECMA Standard, and if either or both methods of appending and overwriting are implemented. A claim of conformance shall state which of the following optional features are implemented and which are not − the performing of a Read-After-Write check and the recording of any necessary repeated frames; − the generation of ECC3 Frames. In addition a claim of conformance shall state − whether or not one, or more, registered algorithm(s) are implemented within the system and are able to process data received from the host prior to collecting the data into Basic Groups, and − the algorithm registration identification number(s) of the implemented algorithm(s).

2.3

Receiving drive A drive receiving a magnetic tape cartridge for interchange shall be in conformance with this ECMA Standard if it is able to handle any recording made on the tape according to this ECMA Standard. In particular it shall − be able to recognize repeated frames and to make available to the host, data and Separator Marks from only one of these frames; − be able to recognize an ECC3 frame, and ignore it if the system is not capable of using ECC3 check bytes in a process of error correction; − be able to recognize processed data within an Entity, identify the algorithm used, and make the algorithm registration number available to the host; − be able to make processed data available to the host. In addition a claim of conformance shall state − whether or not the system is capable of using ECC3 check bytes in a process of error correction; − whether or not one or more reprocessing algorithm(s) are implemented within the system, and are able to be applied to processed data prior to making such data available to the host; − the algorithm registration number(s) of the processing algorithm(s) for which a complementary reprocessing algorithm is implemented.

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References ISO/R 527:1966

Plastics - Determination of tensile properties.

ISO 1302:1992

Technical Drawings - Method of indicating surface texture on drawings.

ISO/IEC 11576:1994

Information technology - Procedure for the registration of algorithms for the lossless compression of data.

ECMA-129 (1994)

Information Technology Equipment - Safety

Definitions For the purposes of this ECMA Standard the following definitions apply.

4.1

Absolute Frame Number (AFN) A sequence number, encoded in the Frame.

4.2

a.c. erase A process of erasure utilising magnetic fields of decaying intensity.

4.3

Access Point A point, at the start of a Processed Record Sequence, at which the presentation of Codewords to a reprocessing algorithm is required to start, regardless of whether the data of interest in a retrieval operation starts at that point or at a subsequent point.

4.4

algorithm A set of rules for transforming the logical representation of data.

4.5

Area ID An identifier defining the area of the tape and specifying the types of Frame written.

4.6

Average Signal Amplitude The average peak-to-peak value of the output signal from the read head at the fundamental frequency of the specified physical recording density over a minimum of 7,8 mm of track, exclusive of missing pulses.

4.7

azimuth The angular deviation, in degrees, minutes and seconds of arc, made by the mean flux transition line with the line normal to the centreline of the recorded track.

4.8

back surface The surface of the tape opposite to the magnetic coating which is used to record data.

4.9

byte An ordered set of bits acted upon as a unit.

4.10

cartridge A case containing magnetic tape stored on twin hubs.

4.11

Channel bit A bit after 8-10 transformation.

4.12

Codeword A word which is generated by a processing algorithm. The number of bits in a Codeword is variable, and is not defined by this Standard.

4.13

Data Format ID An identifier specifying which data format is being used on the tape.

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4.14

Early Warning Point (EWP) A point along the length of the tape at which warning is given of the approach, in the forward direction of tape motion, of the Partition Boundary or of the Physical End of Tape.

4.15

End of Data (EOD) The point on the tape at the end of the group which contains the last user data.

4.16

Entity A unit of recorded data, comprising an Entity header and a Processed Record Sequence.

4.17

Error Correcting Code (ECC) A mathematical computation yielding check bytes used for the detection and correction of errors.

4.18

flux transition position That point which exhibits maximum free-space flux density normal to the tape surface.

4.19

flux transition spacing The distance along a track between successive flux transitions.

4.20

Fragment A collection of bytes which are treated as a unit for recording, readback and error correction purposes.

4.21

Frame A pair of adjacent tracks with azimuths of opposite polarity, in which the track with the positive azimuth precedes that with the negative azimuth.

4.22

Housekeeping Frame A Frame which contains no user data and which is identified as such by the values in the data fields therein.

4.23

Logical Beginning of Tape (LBOT) The point along the length of the tape where a recording of data for interchange commences.

4.24

magnetic tape A tape which will accept and retain the magnetic signals intended for input, output and storage purposes on computers and associated equipment.

4.25

Master Standard Amplitude Calibration Tape A pre-recorded tape on which the standard signal amplitudes have been recorded in the tracks of positive azimuth, 21,0 µm wide, recorded at a track pitch of 27,2 µm, on an a.c. erased tape. NOTE 1 The tape is recorded with the nominal physical recording densities of 4 499,8 ftpmm, 2 999,9 ftpmm, 1 999,9 ftpmm and 1 499,9 ftpmm. NOTE 2 The Master Standard Amplitude Calibration Tape has been established by Reliability Centre for Electronic Components of Japan (RCJ).

4.26

Master Standard Reference Tape A tape selected as the standard for Reference Recording Field, Signal Amplitude, Resolution, Overwrite and Signalto-Noise Ratio. NOTE The Master Standard Reference Tape has been established by RCJ.

4.27

Optimum Recording Field In the plot of Average Signal Amplitude against the recording field at the physical recording density of 2 999,9 ftpmm, the field that causes the maximum Average Signal Amplitude.

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4.28

Partition Boundary The point along the length of a magnetic tape at which partition 1 ends and partition 0 commences.

4.29

Physical Beginning of Tape (PBOT) The point where the leader tape is joined to the magnetic tape.

4.30

Physical End of Tape (PEOT) The point where the trailer tape is joined to the magnetic tape.

4.31

physical recording density The number of recorded flux transitions per unit length of track, expressed in flux transitions per millimetre (ftpmm).

4.32

pre-recording condition The recording levels above which a tape intended for interchange shall not previously have been recorded.

4.33

processing The use of an algorithm to transform host data into Codewords.

4.34

processed data A sequence of Codewords which results from the application of processing to data.

4.35

Processed Record A sequence of Codewords which results from the application of processing to an Unprocessed Record.

4.36

Processed Record Sequence A sequence of one or more Processed Records which starts on an 8-bit boundary and ends on a subsequent 8-bit boundary.

4.37

record Related data treated as a unit of information.

4.38

Reference Recording Field The Optimum Recording Field of the Master Standard Reference Tape.

4.39

reprocessing The use of an algorithm to transform Codewords into data as required by the host.

4.40

Secondary Standard Amplitude Calibration Tape A tape pre-recorded as defined for the Master Standard Amplitude Calibration Tape; the outputs are known and stated in relation to those of the Master Standard Amplitude Calibration Tape. NOTE Secondary Standard Amplitude Calibration Tapes can be ordered from RCJ, 1-1-12 Hachiman-cho, Higashikurume, Tokyo 203, Japan, under Part Number JCM 6130. In principle such tapes will be available until the year 2007. However, by agreement between ECMA and RCJ, this period may be shortened or extended to take into account the demand for such Secondary Standard Amplitude Calibration Tapes. It is intended that these be used for calibrating tertiary reference tapes for use in routine calibration.

4.41

Secondary Standard Reference Tape A tape the performance of which is known and stated in relation to that of the Master Standard Reference Tape. NOTE Secondary Standard Reference Tapes can be ordered from RCJ, 1-1-12 Hachiman-cho, Higashikurume, Tokyo 203, Japan, under Part Number JRM 6130. In principle such tapes will be available until the year 2007. However, by agreement between ECMA and RCJ, this period may be shortened or extended to take into account the demand for such Secondary Standard Reference Tapes. It is intended that these be used for calibrating tertiary reference tapes for use in routine calibration.

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4.42

Separator Mark A record containing no user data, which is used to separate data.

4.43

Standard Reference Amplitude The Average Signal Amplitude from the tracks of positive azimuth of the Master Standard Amplitude Calibration Tape at a specified physical recording density.

4.44

Tape Reference Edge The bottom edge of the tape when viewing the recording side of the tape, with the PEOT to the observer's right.

4.45

Test Recording Current The current that produces the Reference Recording Field.

4.46

track A diagonally positioned area on the tape along which a series of magnetic signals may be recorded.

4.47

unprocessed data Data which has not been subjected to processing.

4.48

Unprocessed Record A record of unprocessed data, comprising an integral number of bytes.

4.49

Virtual End of Tape (VEOT) The point along the length of the magnetic tape within partition 1 which defines the end of the part of partition 1 which is usable for recording data for interchange.

Conventions and Notations A measured value is rounded off to the least significant digit of the corresponding specified value. This implies that, for example, a specified value of 1,26 with a positive tolerance of +0,01 and a negative tolerance of -0,02 allows a range of measured values from 1,235 to 1,275. The setting of a bit is denoted by ZERO or ONE. Bit patterns and numbers in binary notation are represented by strings of 0s and 1s. Within such strings, X may be used to indicate that the setting of a bit is not specified within the string. Bit patterns and numbers in binary notation are shown with the most significant bit to the left and the least significant bit to the right. The most significant bit of an 8-bit byte is denoted by b8 and the least significant by b1. The names of basic elements, e.g. specific fields, are given with a capital initial letter.

Acronyms AEWP AFN BAT DF-ID ECC EOD EWP GIT LBOT LSB LF-ID MRS MSB MSRT

After Early Warning Point Absolute Frame Number Block Access Table Data Format Identifier Error Correcting Code End of Data Early Warning Point Group Information Table Logical Beginning of Tape Least Significant Byte Logical Frame Identifier Media Recognition System Most Significant Byte Master Standard Reference Tape

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PBOT PEOT RAW SNR VEOT

7 7.1

Physical Beginning of Tape Physical End of Tape Read-After-Write Signal-to-Noise Ratio Virtual End of Tape

Environment and safety Testing environment Tests and measurements made on the tape cartridge to check the requirements of this ECMA Standard shall be carried out in the following ambient conditions of the air immediately surrounding the drive : temperature relative humidity conditioning period before testing

7.2

: 23 °C ± 2 °C : 40 % to 60 % : 24 h

Operating environment Cartridges used for data interchange shall be capable of operating under the following conditions, as measured within 10 mm of the tape exit from the drum of the generating or receiving drive : temperature relative humidity wet bulb temperature

: 15 °C to 55 °C : 10 % to 80 % : 26 °C max.

There shall be no deposit of moisture on or in the cartridge. The above conditions include any temperature rise that may occur while operating the drive. Conditioning before operating: If a cartridge has been exposed during storage and/or transportation to a condition outside the above values, before use the cartridge shall be conditioned in the operating environment for a time at least equal to the period during which it has been out of the operating environment, up to a maximum of 24 h. NOTE Rapid variations of temperature should be avoided.

7.3

Storage environment For long-term or archival storage of cartridges the following conditions shall be observed: temperature relative humidity wet bulb temperature

: 5 °C to 32 °C : 20 % to 60 % : 26 °C max.

The stray magnetic field at any point on the tape shall not exceed 4 000 A/m. There shall be no deposit of moisture on or in the cartridge.

7.4

Transportation Recommended limits for the environment to which a cartridge may be subjected during transportation, and the precautions to be taken to minimize the possibility of damage, are provided in annex K.

7.5

Safety The cartridge and its components shall satisfy the requirements of ECMA-129.

7.6

Flammability The cartridge and its components shall be made from materials, which if ignited from a match flame, do not continue to burn in a still carbon dioxide atmosphere.

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Section 2 - Requirements for the case 8 8.1

Dimensional and mechanical characteristics of the case General The case of the cartridge shall comprise − − − −

an upper half, a lower half, a slider movably mounted on the lower half, a lid pivotally mounted on the upper half.

In the drawings, using third angle projection, an embodiment of the cartridge is shown as an example. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figures 19, 20 Figures 21, 22 Figure 23 Figure 24

is a perspective view of the cartridge seen from top. is a perspective view of the cartridge seen from bottom. is a partial view of the rear side. is a schematic view showing the Reference Planes X, Y and Z. shows the front side. shows the top side with the lid in closed position. shows the left side. shows the top side with the lid in open position. shows the left side with the lid in open position. shows the bottom side with the lid and the slider in closed position. shows the bottom side with the lid and the slider in open position. is a view from the top of the inside of the lower half with the upper half removed. is a view of the bottom half with the lid and the slider in open position. is a view of the left side with the lid and the slider in open position. is a top view of a hub. is a side view of a hub with partial cross-section. is a partial cross-section through a hub and both halves of the case showing the interface with the drive spindle. shows at a larger scale the lid in the open position. show at a larger scale the functional relationship between the lid and the locking mechanism of the hubs. show the label areas on the top and the rear side. shows both corners of the bottom side, for autoloaders shows the slider bowdown, for autoloaders.

The dimensions are referred to three orthogonal Reference Planes X, Y and Z (figure 4). Plane X is perpendicular to Plane Z and passes through the centres of both the circular and elongated Datum Holes, revealed when the slider is opened (see 8.8.4 and figure 11). Plane Y is perpendicular to Plane X and Plane Z and passes through the centre of the circular Datum Hole. Plane Z is the plane on which the slider moves (see figure 7).

8.2

Overall dimensions (figures 6 and 7) The overall dimensions of the case with the lid in the closed position shall be l1 = 73,0 mm ± 0,3 mm l2 = 54,0 mm ± 0,3 mm l3 = 10,5 mm ± 0,2 mm Where the shell meets the lid on the top side of the cartridge, the angle of the chamfer shall be θ = 45° ñ 8°

(see figure 21)

The edges formed by the rear side and the left and right sides shall be rounded off with a radius r1 = 1,0 mm ± 0,5 mm

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The two edges of the lid shall be rounded off with a radius r2 = 0,5 mm max.

8.3

Loading grip (figure 6) The top side shall have a loading grip for loading and positioning the cartridge into the drive. The position and dimensions of the loading grip shall be l4 = 25,5 mm ± 0,2 mm l5 = 11,0 mm ñ 1,0 mm l6 = 5,0 mm ± 0,2 mm l7 = 2,3 mm ñ 0,3 mm The depth of the loading grip below the surface of the top side shall be + 0,2 mm

0,5 mm - 0,0 mm

8.4

Holding areas (figure 6) The two areas shown shaded in figure 6 shall be the areas along which the cartridge shall be held down when inserted in the drive. Their positions and dimensions shall be l8 = 6,0 mm ± 0,1 mm l9 = 5,0 mm ± 0,1 mm

8.5

Notches of the lid (figures 5 and 8) The lid shall have two pairs of notches. The first pair of notches, the slider lock release notches, allows elements of the drive to release the locking mechanism of the slider. The positions and dimensions of these notches shall be l10 = 0,4 mm max. l11 = 3,0 mm min. l12 = 1,2 mm ± 0,1 mm l13 = 49,8 mm ± 0,2 mm The second pair of notches, the slider movement notches, allows elements of the drive to move the slider from the closed to the open position (see also 8.8.1). The positions and dimensions of these notches shall be l11 = 3,0 mm min. l14 = 0,9 mm min. l15 = 7,5 mm ± 0,1 mm l16 = 36,00 mm ± 0,15 mm

8.6

Lid dimensions (figures 6 to 8) The lid is shown in the closed position in figures 6 and 7. Its dimensions shall be l17 = 1,2 mm ± 0,1 mm l18 = 6,8 mm ± 0,4 mm l19 = 1,1 mm ± 0,1 mm l20 = 2,0 mm ± 0,1 mm l21 = 6,4 mm ± 0,2 mm l22 = 1,5 mm ± 0,1 mm r3 = 6,8 mm ± 0,4 mm

- 9 -

The lid shall have a chamfer of 45° by l23 = 1,5 mm ± 0,1 mm There shall be a dimensional relationship between the height l24 shown in figure 7, which includes the slider and the upper half, and the height l25 of the lid. When a vertical force of 1 N is exerted on the upper half the following condition shall be met. l24 = 10,5 mm ± 0,2 mm l25 ≤ l24 When no force is exerted l24 = 10,9 mm max. In figure 8 the lid is shown in the open position. The distance from the front edge of the lid to the rear side shall be l26 = 55,5 mm ± 0,3 mm.

8.7

Optical detection of the beginning and end of tape (figures 9 and 12) Means for the optical detection of the beginning and end of tape shall be provided. These shall consist of a pair of windows on the left and right sides of the case (see also figure 18). The design of these windows allows this detection for two different drive designs: − either a light source and a detector are provided in the drive on each side of the cartridge, in which case the light enters the case through the upper windows, falls on a prism (see section A-A) mounted inside the case, which reflects this light so that it goes through the tape and falls on the detector through the lower window; the light transmittance of the prism shall be greater than 50% of that of a reference prism when measured as specified in annex A, − or, the light of a light source within the drive passes through the tape from inside the cartridge and falls through the lower windows onto the detectors placed on each side of the case. The positions and dimensions of these windows allow the cartridge to be used with drives implementing either system, they shall be l27 = 6,20 mm ± 0,10 mm l28 = 7,65 mm ± 0,10 mm + 0,20 mm

l29 = 1,50 mm

- 0,00 mm

l30 = 3,9 mm ± 0,1 mm l31 = 1,8 mm ± 0,1 mm l32 = 7,0 mm ± 0,2 mm l33 = 2,5 mm min. Dimension l32 specifies the position of the rear edge of the windows relative to Reference Plane X. Dimension l33 shall be measured relative to this rear edge.

8.8

Bottom side The bottom side is shown in figure 10 with the lid and the slider in the closed position and in figure 11 with both in the open position. The dimension l34 of the bottom half, l35 of the slider and l36 of the lid shall satisfy the following conditions l34 = 73,0 mm ± 0,3 mm l35 ≤ l34 l36 ≤ l34

- 10 -

8.8.1

Locking mechanism of the slider (figure 10) The cartridge shall have a locking mechanism for the slider which locks it in the closed and open positions. The design of this mechanism is not specified by this ECMA Standard, except for the different forces acting on the slider, and for its detent. The slider shall be spring-loaded by a spring holding it in the closed position when it is unlocked. The force required to operate the slider shall not exceed 2 N. The slider shall have two grooves with an opening at each end. The detent of the locking mechanism shall protrude through these openings so as to hold the slider in both open and closed positions. The detent shown in cross-section C-C is only an example of implementation. The grooves are parallel to Reference Plane Z and aligned with the slider lock release notches of the lid. The positions and dimensions of the grooves and of the openings for the detent of the locking mechanism when the slider is in the closed position shall be l37 = 1,2 mm ± 0,1 mm l38 = 49,8 mm ± 0,2 mm l39 = 10,0 mm ± 0,1 mm + 0,5 mm

l40 = 2,0 mm

- 0,0 mm

l41 = 3,0 mm min. l42 = 1,5 mm min. l43 = 0,8 mm ± 0,1 mm + 0,5 mm

l44 = 0,8 mm

- 0,1 mm

λ = 45° min. l45 = 0,65 mm ± 0,05 mm The position and dimensions of the openings for the detent when the slider is held in the open position are determined by l39, l40, l43 and l44. In the closed position of the slider, the maximum force to be exerted on the detent in a direction perpendicular to Reference Plane Z and over a stroke of 0,65 mm shall be 0,5 N max. In the open position of the slider the holding force shall be 0,3 N min. 8.8.2

Access holes (figure 10) The slider shall have two circular access holes (see section B-B) which, in the open position of the slider, allow penetration of the drive spindles into the hubs. The diameters of these access holes shall be d1 = 10,0 mm ± 0,2 mm d2 = 12,0 mm max. These access holes shall have a chamfer of depth 0,5 mm ñ 0,2 mm.

8.8.3

Recognition, sub-datums, and write-inhibit holes (figure 11) The bottom half shall have a number of holes on an edge at its rear. This edge shall be defined by l46 = 45,2 mm ± 0,2 mm l47 = 49,2 mm ± 0,2 mm The centres of these holes lie on a line perpendicular to Reference Plane Y at a distance from Reference Plane X of l48 = 47,2 mm ± 0,2 mm

- 11 -

8.8.3.1

Recognition Holes (figures 10 and 11) There shall be four Recognition Holes numbered from 1 to 4 as shown in figure 10. Their positions and dimensions shall be d3 = 2,5 mm ± 0,1 mm l49 = 1,0 mm ± 0,1 mm l50 = 56,0 mm ± 0,3 mm l51 = 4,0 mm ± 0,1 mm l52 = 1,0 mm ± 0,1 mm l53 = 3,0 mm min. All Recognition Holes shall have the cross-section shown in cross-section F-F in figure 11 for Recognition Hole No. 1. One of the two cross-sections F-F shows a Recognition Hole closed by means of a plug, the other shows it with the plug punched out. These plugs shall withstand an applied force of 0,5 N max. without being punched out. Recognition Holes No. 1 and No. 3 shall be open. Recognition Holes No. 2 and No. 4 shall be closed. Other combinations of the states of the Recognition Holes No. 1, No. 2, No. 3 and No. 4 are reserved for other applications (see annex H).

8.8.3.2

Write-inhibit Hole (figure 11) The position and dimensions of the Write-inhibit Hole shall be d4 = 2,5 mm ± 0,1 mm l50 = 56,0 mm ± 0,3 mm When the Write-inhibit Hole is open recording on the tape is inhibited, when it is closed recording is enabled. The Write-inhibit Hole shall have the cross-section shown in cross-section F-F in figure 11 for Recognition Hole No. 1. One of the two cross-sections F-F shows the hole closed by means of a plug, the other shows it with the hole punched out. These plugs shall withstand an applied force of 0,5 N max without being punched out. The case may have a movable element allowing the Write-inhibit Hole to be opened and closed. If present, this element shall be such that the state of Write-inhibit Hole is visible (see figure 3 as an example). Such an element shall be neither broken nor moved by a force smaller than 0,5 N. Regardless of whether a plug or a movable element is used to select the open and closed states of the Writeinhibit Hole, the following dimensions from cross-section F-F shall define the closed and open states, respectively. l52 = 1,0 mm ± 0,1 mm l53 = 3,0 mm min.

8.8.3.3

Sub-datum holes (figure 11) These holes are used to position the cartridge in the drive. Their position and dimensions shall be as follows. The hole seen below the Write-inhibit Hole in figure 11 shall have an elongated form and the same crosssection E-E as shown for the other hole. l54 = 45,5 mm ± 0,2 mm + 0,1 mm

l55 = 3,5 mm

- 0,0 mm + 0,05 mm

l56 = 2,50 mm

- 0,00 mm

- 12 -

The position and dimensions of the other Sub-datum hole shall be + 0,05 mm

d5 = 2,50 mm

- 0,00 mm

d6 = 1,0 mm min. l57 = 5,5 mm ± 0,1 mm l58 = 2,0 mm min. l59 = 1,2 mm min. The edge of both Sub-datum Holes shall have a chamfer of 0,2 mm ± 0,1 mm. 8.8.4

Datum holes (figure 11) The lower half has two Datum Holes also used to position the cartridge within the drive. One of them has an elongated form, the other is circular. Cross-section D-D shown for the latter also applies to the former. Their positions and dimensions shall be l60 = 51,0 mm ± 0,1 mm + 0,05 mm

l61 = 2,80 mm

- 0,00 mm + 0,1 mm

l62 = 3,5 mm

- 0,0 mm

l63 = 3,0 mm min. + 0,05 mm

d7 = 2,80 mm

- 0,00 mm

The upper edge of both Datum Holes shall have a chamfer of 0,2 mm ± 0,1 mm. 8.8.5

Access room for tape guides (figure 11) When the cartridge is inserted into the drive, tape guides in the drive pull out the tape toward the heads of the drive. The shape and dimensions of the access room provided by the cartridge for these tape guides shall be (see also 8.8.7.5): l64 = 3,1 mm max. l65 = 5,6 mm min. l66 = 11,0 mm max. + 0,7 mm

l67 = 7,0 mm

- 0,0 mm

l68 = 6,7 mm min. α = 45° ± 1° l69 = 47,9 mm min. + 0,00 mm

l70 = 3,30 mm 8.8.6

- 0,15 mm

Holes for accessing the hubs (figure 11) The lower half has two holes through which the spindles of the drive can access the hubs when the slider is in the open position. The positions and dimensions of these holes shall be

- 13 -

d8 = 9,0 mm ± 0,1 mm l71 = 29,00 mm ± 0,15 mm l72 = 10,5 mm ± 0,1 mm l73 = 30,0 mm ± 0,1 mm 8.8.7

Internal structure of the lower half (figure 12) In figure 12 the different elements of the inside of the lower half are shown. There shall be a locking mechanism for the hubs to prevent them from rotating when the lid is in the closed position. The design of this locking mechanism is not specified by this ECMA Standard, thus it is not shown in figure 12. Locking and unlocking of the hubs shall depend upon the position of the lid as specified in 8.13.

8.8.7.1

Diameter of the wound tape The diameter of the tape wound on a hub shall be d9 = 36,5 mm max.

8.8.7.2

Tape wind The magnetic surface of the tape shall face outwards.

8.8.7.3

Tape motion The forward direction of tape motion is from the left side of the cartridge to its right side (see figures 1 and 2).

8.8.7.4

Guide posts The tape shall pass around two guide posts in the cartridge, the axes of which are perpendicular to Reference Plane Z and pass through the centres of the Datum Holes. The positions and dimensions of these guide posts shall be − their positions are determined by those of the centres of the Datum Holes, − their cross-section shall be circular with a radius r4 = 3,0 mm ± 0,1 mm over an angle of 180° in clockwise sense starting at angle ρ = 45° ± 1° − their cross-section over the other half of 180° is not specified by this ECMA Standard.

8.8.7.5

Position of the tape in the case (view A) When the tape runs from one guide post to the other it shall remain between two planes parallel to Reference Plane Z. The distance of these planes from Reference Plane Z shall be l74 = 1,4 mm min. l75 = 6,4 mm max. The design centre for the position of the tape centreline is l76 = 3,9 mm The height of the access room specified in 8.8.5 for the tape guides shall be + 0,6 mm

l77 = 8,0 mm 8.8.7.6

- 0,0 mm

Tape path zone When the cartridge is inserted into the drive, the tape is pulled outside the case by tape guides as mentioned above. It is then no longer in contact with the guide posts. The tape path zone of the case is the zone in which the tape must be able to move freely. This zone is defined by

- 14 -

l78 = 5,5 mm ± 0,1 mm l79 = 56,5 mm ± 0,3 mm l80 = 8,0 mm ± 0,2 mm 8.8.8

Light path (figure 12) As specified in 8.7 there is a lower window in the right and left sides of the case through which light having passed through the tape can pass and fall onto a detector of the drive. In order to ensure that the corresponding light path is not obstructed by inner elements of the case, its configuration in this zone shall be as follows. The position and dimensions of the lower window are specified by l30 and l31 (see figure 9). The dimensions l81 = 1,5 mm max. l82 = 5,0 mm min. ensure that no elements of the case obstruct the light path.

8.8.9

Support Areas (figure 13) When the cartridge is inserted into the drive and held in position by forces perpendicular to Reference Plane Z acting on the Holding Areas (see 8.4), it shall be supported by three Support Areas A', B', C' on its bottom side, shown shaded in figure 13. The position and dimensions of these areas shall be as follows. − Areas A' and B' are not specified by this ECMA Standard because they depend on parts of the lower half for which this ECMA Standard does not specify requirements. − Area C' shall be defined by l83 = 1,0 mm ± 0,1 mm l84 = 49,0 mm ± 0,3 mm

8.8.10

Datum Areas (figure 13) There shall be two annular Datum Surfaces A and B and one circular such surface C. All three Datum Areas shall lie in Reference Plane Z. Their position and dimensions shall be − Datum Area A shall be centred on the intersection of Reference Planes X, Y and Z, its inner diameter shall be d7 (see 8.8.4 and figure 11), its outer diameter shall be d10 = 5,0 mm ± 0,1 mm − Datum Area B shall be centred on the intersection of Reference Planes X and Z at a distance l60 (see 8.8.4 and figure 11) from the centre of Datum Area A. Its inner dimensions shall be l61 and l62, its outer diameter shall be d10. − Datum Area C shall be centred on a point defined by l85 = 42,0 mm ± 0,3 mm l86 = 25,5 mm ± 0,3 mm Its diameter shall be d10.

8.8.11

Relationship between Support and Datum Areas and Reference Plane Z (figure 14) Support Area A' shall be coplanar with Datum Area A within 0,1 mm. Support Area B' shall be coplanar with Datum Area B within 0,1 mm. Support Area C' shall be parallel to Reference Plane Z within 0,1 mm. It shall be at a distance l87 = 1,10 mm ± 0,05 mm from Reference Plane Z.

8.9

Hubs (figures 15 and 16) The dimensions of the hubs shall be

- 15 -

+ 0,08 mm

d11 = 6,60 mm

- 0,00 mm + 0,0 mm

d12 = 8,8 mm

- 0,1 mm

d13 = 15,00 mm ± 0,05 mm β = 60° ± 1° γ = 45° ± 1° + 0,1 mm

l88 = 2,5 mm

- 0,0 mm + 0,20 mm

l89 = 2,60 mm

- 0,00 mm

The two cylindrical surfaces with diameters d11 and d13 shall be co-axial within 0,05 mm. The torque necessary to rotate the hub with a partially or fully wound tape shall be 0,000 2 N⋅m max.

8.10

Attachment of leader and trailer tapes The method of attachment of the leader and trailer tapes to the hubs shall be such that when subjected to a force of 5 N max. they will not become detached from the hubs.

8.11

Interface between the hubs and the drive spindles (figure 17) The interface between the hubs and the spindles, shown in figure 17 in cross-section, is specified in terms of the following relationships: 1,0 mm ó (d15 - d14) ó 1,2 mm l91 - l90 = 1,3 mm max. NOTE It is expected that the top of the drive spindle will not penetrate within the hub beyond a distance ld = 7,65 mm max. above Reference Plane Z.

8.12

Opening of the lid (figure 18) When the lid is opened its lower front edge moves along an arc of a circle with radius r5 = 9,6 mm ± 0,2 mm The centre of rotation is defined by l17 and l21. The end position of the lid, i.e. when it is fully open, is defined by l92 = 10,9 mm ± 0,2 mm l93 = 0,3 mm ± 0,1 mm l94 = 6,3 mm ± 0,2 mm The force F required to open the lid shall not exceed 1,2 N. It shall be applied at a distance l95 = 5,0 mm ± 0,1 mm measured parallel to Reference Plane Z from the centre of rotation of radius r5 (see also annex J).

8.13

Release of the hub locking mechanism (figures 19 and 20) As mentioned in 8.8.7 the design of the locking mechanism for the hubs is not specified by this ECMA Standard, except that it shall be connected to the lid so that the hubs are locked or unlocked as a function of the angular position of the lid. When the lid rotates from the closed to the open position (clockwise as seen in figures 19 and 20) the hubs shall remain locked as long as the lid has not reached the position defined by:

- 16 -

l96 = 7,0 mm l97 = 7,5 mm ± 0,2 mm as shown in figure 19. The hubs shall be completely released as soon as the lid has reached the position defined by: l98 = 10,3 mm l99 = 6,6 mm ± 0,2 mm as shown in figure 20.

8.14

Label areas (figures 21 and 22) On the top and rear sides of the case there shall be an area on which adhesive labels can be placed. Separate labels shall be used on the top and rear sides of the case. The dimensions of these areas shall be l100 = 5,2 mm min. l101 = 39,4 mm max. l102 = 8,8 mm max. r6

8.15

= 0,5 mm min.

Requirement for autoloaders (figures 23 and 24) To allow use with autoloaders, the channel from the Z Datum to the l87 dimension shall be clear. Within this channel, the dimensions of the corners and edges shown in figure 23 shall be l87 = 1,10 mm ± 0,05 mm r7 = 0,3 mm max. or 0,3 mm max. chamfer δ = 6° max. On the sides of the cartridge, the height of the handling area above the slider recess as shown in figure 23 shall be l103 = 5,4 mm ñ 0,5 mm On the bottom of the cartridge, the slider bowdown as shown in figure 24 shall be l104 = 0,6 mm max.

Rear Side

Left Side

Recognition holes No.1 to 3

Top Side

Sub-datum holes

Loading grip

Figure 2 - Bottom view.

Bottom Side

Front Side

Right Side

Front Side

Lid

Left side

Recognition hole No.4

Figure 1 - Top view.

Write-inhibit hole

Bottom Side

Slider

Sub-datum holes

Right Side

Lower half

Upper half

Rear Side

Figure 4 - Reference planes X, Y, Z.

Figure 3 - Partial view of the rear side.

Rear Side

Write-inhibit Indicator

Right Side

- 18 -

l2 l10

r1 AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAA

l11 l11 l 14

l13

l16

l5 l7 l4

l11 l 15

l6 Y

l12 l11 AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAA AAAA

l10

Z Figure 5 - Front side, lid closed

Figure 6 - Top side, lid closed

l17 l18 l19

l20 l25

l24 l21

l23 l22 X

Figure 7 - Left side, lid closed

- 19 -

Prism A

AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA

A l 26

Z l30

Figure 8 - Top side, Lid open

l28 Section A-A

X l27 l29

l29 l28

l30 l31 l33 l32

Figure 9 - Left side, Lid open

- 20 -

l39

(4) l41

C l40 B

l35

l34

l38

C (3) (2) (1)

l40

l37

l41

l39 X

l39

l42

l45 λ

l43 l44

Section B-B

Figure 10 - Bottom side, lid closed

Section C-C

l36

- 21 -

l71

l70

l51

l61 l56

l62

l55

l68 l67

l50

l60

l54 l73

l69 l65 d5

l72

l66

l57

l49 l51

l 64 D

l51

d7 F

F l46 l48 l47

Section D-D

l63

l58

l59

l52

l53

AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA

AAAAAAAAA AAAAAAAA AAAAA AAAA AAAAAAAAA A AAAA AAAAAAAA AAAAA A AAAA AAAA A AAAAAAAA AAAAA AAAA AAAAAAAAA A AAAA AAAA AAAAAAAA AAAAA A AAAA A AAAAAAAA AAAAA A AAAA

d6 Section E-E

Section F-F

Figure 11 - Bottom side, lid open

Section F-F (punched out)

- 22 -

G X

Tape path zone

r4 FWD

Take up

l79

Supply

FWD

l78 r4 Tape path zone

l80

Light path (direct)

Light path (prism)

l75

l30

l76 l74

l77

l31 AAAA AAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAAAAAA AAAA AAAA

View A

AAAAAA AAAA AAAAAA AA AAAA AA AAAAAA AA AAAA AAAAAA AAAA AAAAAA AA AAAA AA AAAAAA AA AAAA AAAAAA AAAA AAAAAA AA AAAA AA AAAAAA AA AAAA AAAAAA AA AAAA

Tape

l81 l82 Section G-G

Figure 12 - Inside view of the lower half

- 23 -

B' B

d 10

AAAAAAAAAAA AAAAAAAA AAAAAAA AAAA AAAAAAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAA AAA AAAAAAAA AAAAAAA AAA AAAA

C' AAAAAAAAAAA AAAAAAAA AAAAAAA AAAA AAAAAAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAA AAA AAAAAAAA AAAAAAA AAA AAAA

l84

d 10 l 86 Y AAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAAA AAAAAAAA AAAAAAA AAA AAAA AAA

l 83

A d 10

l85

Figure 13 - Bottom side, lid and slider in open position

Z l 87

Figure 14 - Left side, lid open

- 24 -

d11

d12

l89

View B

β Figure 15 - Top view of a hub

d13

l90

l88

Figure 16 - Side view of a hub

Reel Spindle

AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAA AAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA A AAAAAAAAAAAAAAAAAAAAAAAA AAAA AAAA AAAA AAAA A AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA A AAAAAAAAAAAAAAAAAAAAAAAA AAAA AAAA AAAA AAAA A AAAAAAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAA AAAA AAAAAAAAAAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA A AAAAAAAAAAAAAAAAAAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAAAAAAAAAA AAAA AAAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAA A AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAAAAAA AAAAAAAA AAAAAAAA AAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAA A AAAA AAAA AAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAA AAAA AAAA AAAA AAAA A AAAA AAAA AAAA AAAA A AAAAAAAA AAAAAAAA AAAAAAAA AAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAA A AAAA AAAA AAAA AAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAA A AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA A AAAAAAAA AAAAAAAAAAAA AAAAA AAAAAAAA AAAAAAAAAAAA AAAAA AAAA AAAA AAAAAAAAAAAA AAAAAAAAAA AAAAAAAAAAAA AAAAAAAAA A AAAA AAAA AAAA AAAA A AAAA AAAA AAAA AAAA AAAAAAAA AAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAAAAA AAAAAA AAAAAAAA AAAAAAAA AAAAAAAA AAAAA A AAAA AAAA AAAAAAA AAA AAAA AAAA AAAA AAAA AAAA AAAA AAA AAAA A AAAA AAAAAAAA AAAAAAAA AAAA AAAA AAAA AAAA AAAA AAAAAAA AAAAAA AAAAAAAA AAAAAAAA AAAAAAAAAAAA A AAAA AAAA AAAAAAA AAAA AAAA AAAA AAAA AAAA AAAA AAA AAAA AAAAAAAAAAAA AAAA AAAA AAAA AAA AAAAAAAAAAAA AAAAA AAAAAAAAAAA AAA AAAA AAAA AAAA AAAA AAAA AAA AAAA AAAA AAAA AAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAA AAAAAAAA AAAAAAA AAA

Z d14 d15

Figure 17 - Interface with the drive spindle

l91

- 25 -

l 94

AAAAAAAA AAAAAAAA AAAAAA AA AAAA AAAAAAAA AAAAAAAAAA AA AAAA AAAAAAAAAAAA AAAAAA AAAA AAAAAAAA AAAAAAAA AAAAAA AA AAAA AAAA AAAA AAAAAAAA AAAAAAAA AAAAAA AA AAAA AA AAAAAAAA AAAAAAAA AAAAAA AA AAAA

l93

l92 l21

l 17

Z l95

X Figure 18 - Lid in completely open position

l 99

l 97

l 98

l 96

Z X Figure 19 - Extreme position of the lid for which the hubs are still locked

X Figure 20 - Minimum position of the lid for which the hubs are completely unlocked

- 26 -

l1 0 1

l1 0 0

l1 0 0 θ

Section H-H Figure 21 - Top side, label area

l1 0 2

Figure 22 - Rear side, label area

- 27 -

l103

A B

Z l87 r7

Detail A

r7 B

Detail B

Figure 23 - Bottom side, both corners

l104 Z

Figure 24 - Front side, slider bowdown

- 28 -

Section 3 - Requirements for the unrecorded tape 9

Mechanical, physical and dimensional characteristics of the tape

9.1

Materials The recordable area of the tape shall consist of an aromatic polyamide base material (or equivalent) coated on one side with a strong yet flexible layer of ferromagnetic material. The back surface may be coated. There shall be a leader tape between the take-up hub and PBOT. There shall be a trailer tape between PEOT and the supply hub. The leader and trailer tapes shall consist of a translucent length of the same or equivalent base material without the ferromagnetic coating and the back coating. The leader and trailer tapes shall each be attached to the magnetic tape by means of a length of splicing tape which extends over each such joint. The splicing tape shall consist of polyethylene terephthalate (or equivalent), coated on one side with an acrylic (or equivalent) adhesive material.

9.2 9.2.1

Tape length Length of magnetic tape The length of tape between PBOT and PEOT shall be in the range 10 m to 125 m.

9.2.2

Length of leader and trailer tapes The length of the leader and trailer tapes shall be 60 mm ± 5 mm. The joints between the leader and trailer tapes and the magnetic tape shall be perpendicular to the Tape Reference Edge within 10°.

9.2.3

Length of splicing tapes The splicing tapes shall extend for a distance of not less than 6,0 mm and not more than 7,0 mm over the leader and trailer tapes. Their extents over the magnetic tape shall be not less than 4,0 mm and not more than 10,0 mm.

9.3 9.3.1

Tape width Width of magnetic tape The width of the magnetic tape shall be 3,800 mm ± 0,005 mm The width shall be measured across the tape from edge to edge when the tape is under a tension of 0,10 N max ± 0,01 N and is lying flat between glass slides.

9.3.2

Width of leader and trailer tapes The width of the leader and trailer tapes shall be + 0,00 mm

3,81 mm

− 0,02 mm

The width shall be measured across the tape from edge to edge when the tape is under a tension of 0,10 N ± 0,01 N and is lying flat between glass slides. 9.3.3

Width and position of splicing tape The width of the splicing tape and its position across the width of the leader, trailer and magnetic tapes shall be such that the bottom edge of the splicing tape shall be no more than 0,60 mm from the bottom edges of the other tapes and the top edge of the splicing tape shall be no more than 0,60 mm from their top edges. Neither edge of the splicing tape shall extend beyond the edges of the leader, trailer and magnetic tapes.

9.3.4

Edge weave The deviation of the Tape Reference Edge from the calculated edge position over a sample length of 50 mm shall be not more than 3,5 µm. Procedure 1) Place a 450 mm sample under a tension of 0,050 N ± 0,005 N.

- 29 -

2) Using a calibrated edge position sensor (see figure 25), with an accuracy of ± 0,5 µm or better, take measurements at 0,25 mm intervals along 250 mm of the Tape Reference Edge of the sample. 3) Using the edge position data for the first length of 50 mm, calculate the length’s edge position using linear regression analysis (see figure 26) 4) Determine the maximum deviation of the edge measurements within that length from the calculated edge position (see figure 26). 5) Move the start position for the calculation of the next 50 mm length by an interval of 0,25 mm. 6) Repeat steps 3), 4) and 5) for successive 50 mm lengths along 250 mm of the Tape Reference Edge. 7) The edge weave is the average of the 801 values from step 4). Edge Position Sensor

Tape Flanged Guide

250 mm 0,050 N

0,050 N Figure 25 - Measurement of edge weave

Tape Reference Edge

Maximum Deviation Calculated Edge Position

50 mm

Figure 26 - Edge weave

9.4

Discontinuities Between PBOT and PEOT there shall be no discontinuities in the magnetic tape such as those produced by tape splicing or perforations.

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9.5 9.5.1

Tape thickness Thickness of magnetic tape The thickness of the magnetic tape at any point shall be 6,9 µm

9.5.2

+ 0,0 µm − 0,8 µm

Thickness of leader and trailer tape The thickness of the leader and trailer tapes at any point shall be between 11 µm and 17 µm.

9.5.3

Thickness of splicing tape The thickness of the splicing tape at any point shall be 27 µm max.

9.6

Longitudinal curvature The radius of curvature of the edge of the tape shall not be less than 33 m. Procedure: Allow a 1 m length of tape to unroll and assume its natural curvature on a flat smooth surface. Measure the deviation from a 1 m chord. The deviation shall not be greater than 3,8 mm. This deviation corresponds to the minimum radius of curvature of 33 m if measured over an arc of a circle.

9.7

Cupping The departure across the width of tape from a flat surface shall not exceed 0,5 mm. Procedure: Cut a 1,0 m ± 0,1 m length of tape. Condition it for a minimum of 3 h in the test environment by hanging it so that both surfaces are freely exposed to the test environment. From the centre portion of the conditioned tape cut a test piece of 25 mm length. Stand the test piece on its end in a cylinder which is at least 25 mm high with an inside diameter of 4,1 mm ± 0,2 mm. With the cylinder standing on an optical comparator measure the cupping by aligning the edges of the test piece to the reticle and determining the distance from the aligned edges to the corresponding surface of the test piece at its centre.

9.8

Coating adhesion The force required to peel any part of the coating from the tape base material shall not be less than 0,05 N. Procedure (see figure 27): Take a test piece of the tape approximately 380 mm long and scribe a line through the recording coating across the width of the tape 125 mm from one end. Using a double-sided pressure sensitive tape, attach the full width of the test piece to a smooth metal plate, with the recording surface facing the plate, as shown in the figure below. Fold the test piece over 180°, attach the metal plate and the free end of the test piece to the jaws of a universal testing machine and set the speed of the jaw separation to 254 mm per min. Note the force at which any part of the coating first separates from the base material. If this is less than 0,05 N, the tape has failed the test. If the test piece peels away from the double-sided pressure sensitive tape before the force exceeds 0,05 N, an alternative type of doublesided pressure sensitive tape shall be used. If the back surface of the tape is coated, repeat the procedure for the back coating

- 31 -

Recording surface

Scribed line

125 mm

Pressure-sensitive tape

ECMA-93-120-A

Figure 27 - Measurement of coating adhesion

9.9

Layer-to-layer adhesion There shall be no tendency for the test piece to stick or for the coating to peel. Procedure: Attach one end of a test piece of magnetic tape of length 1 m to the surface of a glass tube of diameter 36 mm. Wind the tape on to the tube at a tension of 1,1 N. Store the wound test piece in a temperature of 45 °C ± 3 °C and a relative humidity of 80 % for 4 h. Store for a further 24 h in the Testing Environment. Apply a force of 0,1 N to the free end of the test piece and allow it to unwind slowly.

9.10

Tensile strength Measurements shall be made in accordance with ISO/R 527 The length of the magnetic tape test piece shall be 200 mm. The length of the leader tape test piece shall be 50 mm. The length of the trailer tape test piece shall be 50 mm. The rate of elongation for all tensile tests shall be 100 mm/min - ISO/R 527, Rate D.

9.10.1

Breaking strength The breaking strength of the magnetic tape shall be 6,0 N min. The breaking strengths of the leader and trailer tapes shall each be 5,0 N min. The breaking strength of the splice shall be 5,0 N min. Procedure: Load the test piece until the breaking point is reached. The force required to reach that point is the breaking strength.

9.10.2

Yield strength The yield strength is the force required to produce a 3 % elongation of the tape. The yield strength shall be 4,5 N min.

9.11

Residual elongation The residual elongation, expressed as a percentage of the original length, shall be less than 0,03 %. Procedure: Measure the original length of a test piece of approximately 1 m with an applied tensile force of less than 0,05 N. For 3 minutes, apply an additional force of 0,8 N. Remove the additional force and measure the length of the test piece after a further 3 min.

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9.12

Flexural rigidity The flexural rigidity of the tape in the longitudinal direction shall be between 0,000 7 N·mm2 and 0,001 4 N·mm2. For the base material, the Young's modulus in the transverse direction shall be greater than or equal to the value in the longitudinal direction. Procedure: Clamp a 180 mm test piece in a universal testing machine, allowing a 100 mm separation between the machine jaws. Set the jaw separation speed at 5 mm per minute. Plot force against distance. Calculate the flexural rigidity using the slope of the curve between 0,5 N and 1,5 N. The calculation is: 3

δF / WT δL / L

WT 12

Flexural Rigidity = EI where: δF T W δL/L E

9.13

change in force in newtons measured thickness in millimetres measured width in millimetres change in sample length between the jaws divided by the original length between the jaws Young's modulus in newtons per square millimetre

Electrical resistance of coated surfaces The electrical resistance of the recording surface of the magnetic tape, measured on any square area of tape, shall be within the ranges 105 Ω to 5 x 108 Ω for non-back coated tape 105 Ω to 5 x 1012 Ω for back-coated tape The electrical resistance of the back-coating, if present, measured on any square area of tape, shall be less than 9 x 108 Ω. Procedure (see figure 28): Condition a test piece of tape in the Test Environment for 24 h. Position the test piece over two 24-carat gold-plated semicircular electrodes having a radius r = 10 mm and a finish of at least N4, so that the recording surface is in contact with each electrode. The electrodes shall be placed parallel to the ground and parallel to each other and at a distance d = 3,81 mm between their centres. Apply a force F of 0,25 N to each end of the test piece. Apply a d.c. voltage of 100 V ± 10 V across the electrodes and measure the resulting current flow. From this value determine the electrical resistance. Repeat for a total of five positions along the test piece and average the five resistance readings. For back-coated tape repeat the procedure with the back-coating in contact with the electrodes.

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ECMA-93-0122-A

Figure 28 - Measurement of electrical resistance When mounting the test piece ensure that no conducting paths exist between the electrodes except that through the coating under test. NOTE Particular attention should be given to keeping surfaces clean.

9.14

Light transmittance of the tape The light transmittance of the magnetic tape shall be less than, or equal to, 5 %. The light transmittance of the leader and trailer tapes shall be greater than, or equal to, 60 %. The method for measuring light transmittance is given in annex B.

9.15

Media Recognition System (MRS) A pattern of alternating clear and opaque stripes shall exist along the entire length of the splicing tape at PBOT. Each stripe shall extend across the entire width of the splicing tape (see figure 29). The splicing tape at PEOT may be clear or consist of the pattern of alternating stripes. The boundaries between adjacent stripes shall be perpendicular to the Tape Reference Edge to within 10°. The length of each opaque stripe and of each clear stripe, measured parallel to the Tape Reference Edge, shall be 1,50 mm ± 0,20 mm, including the effects of any deviation from parallelism between such boundaries. It is not required that either end of the splicing tape coincide with any particular point along the length of either an opaque stripe or a clear stripe. It is not required that the joint between leader and magnetic tape coincide with any particular point along the length of either an opaque stripe or a clear stripe. The light transmittance through the combination of the opaque stripes and the leader tape shall be less than, or equal to, 5 %. The light transmittance through the combination of the clear stripes and the leader tape shall not be less than 60 %. The method for measuring light transmittance is given in annex B.

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Opaque stripe 1,50 mm + 0,20 mm

1,50 mm + 0,20 mm

Clear stripe

Magnetic tape Leader tape

90° + 10° Tape Reference Edge

Splicing tape

+ 0,0 mm

10,0 mm

+ 1,0 mm

6,0 mm

- 6,0 mm

- 0,0 mm

Figure 29 - Splicing tape at PBOT

Magnetic recording characteristics The magnetic recording characteristics shall be defined by the testing requirements given below. When performing these tests, the output or resultant signal shall be measured on a read-while-write pass for both a tape calibrated to the Master Standard Reference Tape and the tape under test, on the same equipment. The following conditions shall apply to the testing of all magnetic recording characteristics, unless otherwise stated. tape condition

: a.c. erased to a level of less than 0,1 % of the Average Signal Amplitude at 2 999,9 ftpmm

head/tape interface

: set up and conditioned to nullify the effects of differences in thickness and flexural rigidity between tapes which meet the requirements of this ECMA Standard and those of other ECMA Standard(s), e.g. ECMA-170 for DDS and ECMA-198 for DDS-2. This may be achieved, for example, by running for a sufficient time with media that meets the requirements of clause 9 of this ECMA Standard.

diameter of scanner

: 30,00 mm

+ 0,01

- 0,00

rotational speed of scanner

: 2000,0 rpm ± 0,2 rpm

tape speed

: 8,15 mm/s ± 0,03 mm/s

tape tension

: 0,07 N ± 0,02 N, measured at the input to the scanner

test tracks

: positive azimuth; the gaps in the heads shall make an angle of 20° 00’ ± 12’ with the axis of the scanner

write gap length

: 0,25 µm ± 0,03 µm

read gap length

: 0,20 µm ± 0,05 µm

recording current

: Test Recording Current

recording waveform

: square wave

read track width

: in the range of 5 µm to 15 µm

- 35 -

10.1

write track width

: equal to, or greater than, the read track width but 24 µm max.

read head height setting

: during a read-while-write pass, all of the read head track shall be within the boundaries of the written track

read output level

: taken at the appropriate fundamental frequency only

Optimum Recording Field The Optimum Recording Field shall be between 89 % and 112 % of the Reference Recording Field. Traceability to the Reference Recording Field is provided by the calibration factor supplied with each Secondary Standard Reference Tape.

10.2

Signal Amplitude The Average Signal Amplitude at the physical recording density of 4 499,8 ftpmm shall be between 89 % and 142 % of that for the Master Standard Reference Tape. The Average Signal Amplitude at the physical recording density of 1 499,9 ftpmm shall be between 89 % and 142 % of that for the Master Standard Reference Tape. Traceability to the Average Signal Amplitudes of the Master Standard Reference Tape is provided by the calibration factors supplied with each Secondary Standard Reference Tape.

10.3

Resolution The ratio of the Average Signal Amplitude at the physical recording density of 4 499,8 ftpmm to that at the physical recording density of 1 499,9 ftpmm shall be between 84 % and 119 % of the same ratio for the Master Standard Reference Tape. Traceability to the resolution for the Master Standard Reference Tape is provided by the calibration factors supplied with each Secondary Standard Reference Tape.

10.4

Overwrite Overwrite is the ratio of the Average Signal Amplitude of the residual of a low density recording after overwriting at a higher density to the Average Signal Amplitude of the original low density recording. Traceability to the overwrite ratios for the Master Standard Reference Tape is provided by the calibration factors supplied with each Secondary Standard Reference Tape. Procedure First, a.c. erase the tape. Record at the physical density of 1 499,9 ftpmm and measure the Average Signal Amplitude. Overwrite at the physical recording density of 5 999,7 ftpmm and measure the Average Signal Amplitude of the residual 1 499,9 ftpmm signal. Repeat for the Secondary Standard Reference Tape. Requirement The ratio Residual Average Signal Amplitude at 1 499,9 ftpmm after overwriting

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Average Signal Amplitude of the original recording at 1 499,9 ftpmm shall be less than 119 % of the same ratio for the Master Standard Reference Tape.

10.5

Ease of erasure When a tape has been recorded at 1 499,9 ftpmm with the Test Recording Current and then passed through a longitudinal steady erasing field of 290 000 A/m, any remaining signal shall not exceed 3 % of the Standard Reference Amplitude for that density. The erasing field shall be reasonably uniform, for example, the field in the middle of a solenoid. This measurement shall be made with a band pass filter passing at least the first three harmonics.

- 36 -

10.6 10.6.1

Tape quality Missing pulses A missing pulse is a loss of read signal amplitude. A missing pulse exists when the base-to-peak read signal is 50 %, or less, of half the Average Signal Amplitude for the recording density of 2 999,9 ftpmm on the same tape.

10.6.2

Missing pulse zone A missing pulse zone shall commence with a missing pulse and end when 5 consecutive flux transitions, which are not missing pulses, have been detected or when a length of 0,277 mm of track has been measured. If a missing pulse continues for a distance exceeding 0,277 mm, a further missing pulse zone shall result. A missing pulse zone does not continue from one track to the next. The missing pulse zone rate shall be less than one in 1,4 x 105 flux transitions and applies to both positive and negative azimuth tracks.

10.7

Signal-to-Noise Ratio (SNR) characteristic The Signal-to-Noise Ratio is the average rms read signal amplitude divided by the average integrated rms noise amplitude, and expressed in decibels. Average rms read signal amplitude dB

SNR = 20 log Average integrated rms noise amplitude Requirement

The SNR for the tape under test (SNRtape) shall be better than -2 dB relative to the SNR for the Master Standard Reference Tape (SNRMSRT) when measured according to the procedure defined in annex C. Traceability to the SNRMSRT Reference Tape.

is provided by the calibration factor supplied with each Secondary Standard

- 37 -

Section 4 - Requirements for an interchanged tape 11 11.1

Format General The smallest collection of data supported by the format is a record. A record is the smallest distinct set of data bytes supplied, e.g. from a host, for processing and recording by a tape drive system, and the smallest distinct set of data to be read from tape, reprocessed and made available, e.g. to a host, by a tape drive system. Two types of record are supported, namely Processed Records and Unprocessed Records. A recorded tape shall contain Unprocessed Records or Processed Records or both. It may also contain Separator Marks. Processed Records are contained within logical objects which are referred to, by this ECMA Standard, as Entities. Separator Marks may be used by the host to indicate the logical separation(s) of the data within a structuring scheme. Entities, Unprocessed Records and Separator Marks are collected into groups. An index within each group describes that group's contents. A series of transformations, namely randomizing, interleaving, blocking, the generation and inclusion of two Reed-Solomon error correcting codes, and the translation of bytes to Channel Bits, is applied to each group prior to recording. A third Reed-Solomon error correcting code may be applied to the group; in this case, the resulting bytes are transformed and recorded in a frame that follows the group on the tape. Each group is recorded on a set of tracks. The part of each track in which the user data, Separator Marks and associated information are recorded is called the Main Data Zone of the track. Information about the contents of the group, the location of the track(s) and the contents of the track(s) is recorded in the headers of the fragments which are included in the Main Data Zone. In the following description all operations on the data received from the host computer, including the use of error detecting and correcting codes, but excluding processing, are described. Then the method of recording on the tape and the tape layout itself is described. However, because of the inherent characteristics of this format, where required, advance references to the tape layout will also be made in the course of the description of the operations on the data.

11.2

Basic Groups The data to be recorded shall be grouped in Basic Groups of 384 296 bytes. Each Basic Group shall be identified by a running number allocated consecutively starting with zero. In each Basic Group the bytes are identified by a running number from 1 to 384 296. The structure of Basic Group No. 0 is not specified by this ECMA Standard. The data for this group is generated by the tape system (see annex M). It is recorded as the Vendor Group (see 16.5.1). Data and Separator Marks received from the host computer shall be grouped in the Basic Groups following Basic Group No. 0 starting with Basic Group No. 1. These Basic Groups shall be structured as follows. NOTE In this ECMA Standard, there are two types of Separator Marks which are referred to as Separator 1 and Separator 2. Some other standards, e.g. those which define an interface between a tape drive and a host computer, use the terms "file mark" and "set mark" to denote Separator Marks. It is strongly recommended that Separator 1 be equated to file mark and Separator 2 be equated to set mark.

- 38 -

384 262 Byte No.

1, 2, 3, ... Entities and/or Unprocessed Records

..., 384 261

384 296

Block Access Table

Group Information Table 35 bytes

384 296 bytes Figure 30 - Structure of a Basic Group Data, which comprises entities and/or Unprocessed Records, shall progress into the Basic Group from left to right (see figure 30). At the same time a part of the Basic Group, called the Block Access Table (BAT), shall progress from right to left. The Group Information Table (GIT) shall occupy the last 35 bytes of the Basic Group. 11.2.1 11.2.1.1

Entity Content An Entity shall comprise an Entity header and a Processed Record Sequence. The Entity header shall be 8 bytes in length and shall precede the Processed Record Sequence. All Processed Records in an Entity shall be the result of applying the same processing algorithm to Unprocessed Records of equal length. An Entity may span Basic Groups, provided that all of the Entity header and the first 8 bits of the Processed Record Sequence are within the same Basic Group. In the case where an Entity spans Basic Groups, the parts thereof, within each Basic Group, are known as partial Entities. A partial Entity is either a start part, a middle part or a last part of the whole Entity - see 11.2.3.1.2, 11.2.3.1.3, 11.2.3.1.4. Within a spanned Entity, there shall be at most one Processed Record in the total set of partial Entities which are the middle part(s) (if any) and last part of that Entity, i.e. there may be a part or all of one Processed Record in that set. The Processed Record Sequence within an Entity may also include Processed Records other than those containing data for interchange. In such a case, all of the Processed Records which do not contain data for interchange shall be located after the last Processed Record which does contain data for interchange. When reading such an Entity, the receiving system shall skip over those Processed Records which do not contain data for interchange. The number of such Processed Records need not be an integer. This condition may arise, for example, as a result of an overwrite operation starting within a previously-recorded Processed Record Sequence.

11.2.1.2

Access Points An Entity shall contain zero or one Access Point. If present, it shall be located at the start of the first Processed Record in the Entity. The presence of an Access Point shall be indicated by a non-0 value of Byte No. 3 of the Entity header (see 11.2.1.3). An Access Point shall be relevant to processed data in that Entity; it may also be relevant to processed data in subsequent entities. There may be an Access Point in any entire Entity or start part partial Entity. If there is one, or more, entire entities in a Basic Group, there shall be an Access Point in the first entire Entity. If there are no entire entities in a Basic Group, but there is a start part partial Entity in that Basic Group, the start part partial Entity shall contain an Access Point. There shall be an Access Point at the start of the first Processed Record of the first Entity following − − − −

LBOT, a Separator Mark, an Unprocessed Record , a change of algorithm,

- 39 -

− an Entity including also Processed Records other than those containing data for interchange. 11.2.1.3

Entity header Byte No. 1 is the first byte in the header, and Byte No. 8 is the last byte in the header, i.e. is adjacent to the Processed Record Sequence. Within a byte, bit 1 shall be the lowest-numbered bit and shall be the least significant, and bit 8 shall be the highest-numbered bit and shall be the most significant. The Entity header shall have the following layout: Byte No. 1

bits 1 to 4 shall specify, in binary notation, the length of the Entity header in bytes, viz. eight. bits 5 to 8 shall be set to ZERO.

Byte No. 2

all bits shall be set to ZERO.

Byte No. 3

shall specify in binary notation: − either the value 0, indicating that there is no Access Point within the Entity, or − any other value, indicating that there is an Access Point within the Entity, and specifying the identifier of the registered algorithm according to ISO/IEC 11576. This format supports only those registered algorithms which have an identifier in the range 2 to 254. The value 255 in this byte indicates that the algorithm used is not registered.

11.2.2

Bytes No. 4 to 6

shall specify in binary notation the length in bytes of the Unprocessed Record which was transformed by processing into the first Processed Record of the Entity (see 11.2.1.1, 2nd paragraph). This length shall not equal 0. Byte No. 4 shall be the most significant, Byte No. 6 shall be the least significant.

Bytes No. 7 and 8

shall specify in binary notation the number of Processed Records in the Entity which contain data for interchange. This number shall not equal 0. Byte No. 7 shall be more significant than Byte No. 8.

Group Information Table The Group Information Table shall have the following layout.

- 40 -

Table 1 - Group Information Table Byte positions 384 296 to 384 294 384 293 to 384 291 384 290 to 384 288 384 287 to 384 285 384 284 to 384 282 384 281 to 384 279 384 278 and 384 276 384 275 to 384 272 384 271 to 384 268 384 267 to 384 265 384 264 to 384 262

Length in bytes

Name of the field

Group Number of the previous Separator 2

Count of Separator 2s

Group Number of the previous Separator 1

Count of Separator 1s

Group Number of the previous record

Count of records in the current Basic Group

Separator 2 count

Separator 1 count

Record count

Block Access Table count

Group Number

Within each field of table 1 the most-significant byte shall be in the lowest-numbered byte position and the leastsignificant byte shall be in the highest-numbered byte position. 11.2.2.1

Group number of the previous Separator 2 field This field shall be a 3-byte field. It shall specify in binary notation the running number of the previous Basic Group which contains the last written Separator 2. If no such Basic Group exists, this field shall be set to all ZEROs.

11.2.2.2

Count of Separator 2s field This field shall be a 3-byte field. It shall specify in binary notation the number of Separator 2s written in the current Basic Group.

11.2.2.3

Group number of the previous Separator 1 field This field shall be a 3-byte field. It shall specify in binary notation the running number of the previous Basic Group which contains the last written Separator 1. If no such Basic Group exists, this field shall be set to all ZEROs.

- 41 -

11.2.2.4

Count of Separator 1s field This field shall be a 3-byte field. It shall specify in binary notation the number of Separator 1s written in the current Basic Group.

11.2.2.5

Group number of the previous record field This field shall be a 3-byte field. It shall specify in binary notation the running number of the highestnumbered previous Basic Group in which a Separator Mark, an Access Point or the beginning of an Unprocessed Record occurred. If no such Basic Group exists, this field shall be set to all ZEROs.

11.2.2.6

Count of records in the current Basic Group field This field shall be a 3-byte field. It shall specify in binary notation the sum of the following: − the number of Separator Mark entries in the BAT (see 11.2.3) of the current Basic Group − the number of Total Count of Unprocessed Record entries in the BAT of the current Basic Group − the number of entire Unprocessed Record entries in the BAT of the current Basic Group − the sum of the numbers in Bytes No. 7 and No. 8 of the Entity headers of all entities for which there is an entire Entity entry in the BAT of the current Basic Group, − the value which is 1 less than the number in Bytes No. 7 and No. 8 of the Entity header of the Entity for which there is a start part of Entity entry in the BAT of the current Basic Group, if such an entry exists, − the number of Total Count of Entity entries in the BAT of the current Basic Group.

11.2.2.7

Separator 2 count field This field shall be a 3-byte field. It shall specify in binary notation the number of Separator 2s written since the LBOT including those in the current Basic Group.

11.2.2.8

Separator 1 count field This field shall be a 4-byte field. It shall specify in binary notation the number of Separator 1s written since the LBOT including those in the current Basic Group.

11.2.2.9

Record count field This field shall be a 4-byte field. It shall specify in binary notation the sum of the numbers in the Count of records in the current Basic Group fields of the GITs of all Basic Groups since LBOT, up to and including the current Basic Group.

11.2.2.10 Block Access Table count field This field shall be a 3-byte field. It shall specify in binary notation the number of entries in the Block Access Table. 11.2.2.11 Group Number field This field shall be a 3-byte field. It shall specify in binary notation the running number of the current Basic Group. 11.2.3

Block Access Table (BAT) The BAT shall contain one or more entries for each Entity, Unprocessed Record and Separator Mark of the Basic Group. Entities and Unprocessed Records not entirely contained in the Basic Group shall also be identified by one or more entries. The first entry shall be written immediately before the Group Information Table, in byte positions 384 258 to 384 261. Each entry shall be a 4-byte field, structured as shown in figure 31. The 1st byte shall be in the lowest-numbered byte position and the 4th byte shall be in the highest-numbered byte position.

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Entry of the Block Access Table Flag Byte

Count

1st byte b8

2nd byte b3

(MSB)

3rd byte

4th byte (LSB)

Figure 31 - Block Access Table Depending on the setting of the Flag Byte, the 3-byte Count field shall express in binary notation a number not greater than 224-1 as specified below. This Standard specifies twelve settings of the Flag Byte. Other settings are prohibited by this Standard. 11.2.3.1 11.2.3.1.1

Block Access Table entries, setting of the Flag Bytes 0111X011 : Entire Entity This entry relates to an Entity and shall specify that the Entity starts and ends in the current Basic Group. The count field shall specify the number of bytes in the Entity.

11.2.3.1.2

0101X010 : Start part of Entity This entry relates to an Entity and shall specify that the Entity starts in the current Basic Group and ends in a subsequent Basic Group. The count field shall specify the number of bytes in the partial Entity which is in the current Basic Group.

11.2.3.1.3

0101X000 : Middle part of Entity This entry relates to an Entity and shall specify that the Entity starts in a previous Basic Group and ends in a subsequent Basic Group. The count field shall specify the number of bytes in the partial Entity which is in the current Basic Group.

11.2.3.1.4

0111X000 : Last part of Entity This entry relates to an Entity and shall specify that the Entity starts in a previous Basic Group and ends in the current Basic Group. The count field shall specify the number of bytes in the partial Entity which is in the current Basic Group. This entry shall be immediately followed in the BAT of the current Basic Group by an entry for Total Count of Entity.

11.2.3.1.5

0001X001 : Total Count of Entity This entry relates to the same Entity as that of the immediately preceding entry for last part of Entity. The count field shall specify the total number of bytes in the Entity.

11.2.3.1.6

0110X011 : Entire Unprocessed Record This entry relates to an Unprocessed Record and shall specify that the record starts and ends in the current Basic Group. The count field shall specify the number of bytes of the record.

11.2.3.1.7

0100X010 : Start part of Unprocessed Record This entry relates to an Unprocessed Record and shall specify that the record starts in the current Basic Group and ends in a subsequent Basic Group. The count field shall specify the number of bytes in that part of the record which is in the current Basic Group.

11.2.3.1.8

0100X000 : Middle part of Unprocessed Record This entry relates to an Unprocessed Record and shall specify that the record starts in a previous Basic Group and ends in a subsequent Basic Group. The count field shall specify the number of bytes in that part of the record which is in the current Basic Group.

11.2.3.1.9

0110X000 : Last part of Unprocessed Record This entry relates to an Unprocessed Record and shall specify that the record starts in a previous Basic Group and ends in the current Basic Group. The count field shall specify the number of bytes in that part of the record which is in the current Basic Group.

- 43 -

11.2.3.1.10 0000X001 : Total Count of Unprocessed Record This entry relates to an Unprocessed Record and shall specify − if this entry is preceded by a Last part of Unprocessed Record entry, the count field shall specify the total number of bytes of the Unprocessed Record ; − if the last two entries of the BAT of the previous Basic Group are a Last part of Unprocessed Record entry and a skip entry (see 11.2.3.1.12), this entry shall be the first entry of the BAT of the current Basic Group. The count field shall specify the total number of bytes of the Unprocessed Record . 11.2.3.1.11 0000X111 : Separator Mark This entry shall specify that the record is a Separator record. The count field shall specify the number zero if the record is a Separator 1 record and the number one if the record is a Separator 2 record. 11.2.3.1.12 1000X000 : Skip There shall be a Skip entry as the last entry of the Block Access Table of each Basic Group. This entry indicates that the last byte of user data in the current Basic Group has been reached. The count field shall specify the remaining number of bytes in the Basic Group. Thus the minimum number that can be specified by the count field shall be the number of bytes of the BAT plus 35. 11.2.3.1.13 Count fields The sum of the numbers specified in the count fields of those of the types of entry in the following list which are present in the Block Access Table shall be 384 296. The list comprises: Skip, entire Unprocessed Record , start part of Unprocessed Record , middle part of Unprocessed Record , last part of Unprocessed Record , entire Entity, start part of Entity, middle part of Entity, last part of Entity. 11.2.3.1.14 Bit b4 - After Early Warning Point (AEWP) In each of the entries specified in 11.2.3.1.1 to 11.2.3.1.12 the fourth bit, the After Early Warning Point bit, is indicated as indifferent as far as the meaning of the entry is concerned. Its setting shall be as follows − before EWP (see 16.8 and 17.1.2.4) it shall be set to ZERO; − after EWP it shall be set to ONE in the current entry and all following BAT entries of the current Basic Group and in all BAT entries of all following Basic Groups. 11.2.3.2

Valid sequences of entries of the Block Access Table These are specified by table 2, in which states and actions are described within rectangles, and the entries (as designated by the setting of the Flag Byte) are described within ellipses. The terms "spanned Entity" and "spanned Unprocessed Record " designate respectively an Entity or Unprocessed Record which starts in one Basic Group and ends in a subsequent Basic Group. Table 2 shows only those entries which are valid as the next entry to be encountered in each state or after each action. All other entries are invalid. Note that a special case is permitted, for spanned Unprocessed Records only, in which the total count of Unprocessed Record entry may be placed as the first item in the Block Access Table of the subsequent Basic Group.

- 44 -

Table 2 - Valid sequences of entries in the Block Access Table Start first group

Start part of Unprocessed Record

Start spanned Unproc Record

Skip

Start part of Entity Start spanned Entity Separator Mark

Move to next group

Skip

Last part of Unproc Record

Middle part of Unproc Record

Entire Unprocessed Record

Move to next group

Entire Entity

Middle part of Entity

Last part of Entity

Continue spanned Entity

End spanned Entity

Skip

Total count of Entity

Cont. spanned Unproc Record

End spanned Unproc Record

Skip

Move to next group

Skip

Total count of Unproc Record

Move to next group if any else exit

Item complete

11.3

Sub-Groups

11.3.1

G1 Sub-Group When a Basic Group has been completed, it shall be split into 22 G1 Sub-Groups of 17 468 bytes numbered from 0 to 17 467. Each G1 Sub-Group shall have a running number in the range 1 to 22.

Byte No. →

0,1 ... 17 467

1st G1

2nd G1

3rd G1

4th G1

...

22nd G1

17 468 bytes

...

17 468 bytes

384 296 bytes

Figure 32 - G1 Sub-Groups 11.3.2

G2 Sub-Group - randomizing The bytes of each G1 Sub-Group shall be submitted to an Exclusive OR operation together with a sequence of bits which is the output of the shift register shown in figure 33. Before each G1 Sub-Group, the shift register shall be set as shown.

- 45 -

Preset value

+ Bit clock

Input data

Output

ECMA-95-0089-A

Figure 33 - Shift register For each byte the least significant bit, i.e. bit b1 is input first. The logical operators are Exclusive ORs. The result of this operation is a G2 Sub-Group in which all bytes are numbered from D0 to D17 467. Their sequence is the same as before the randomizing operation, i.e. as in the G1 Sub-Group. 11.3.3

G3 Sub-Group Each G2 Sub-Group of 17 468 bytes shall be re-arranged into a G3 Sub-Group of 17 472 bytes. Bytes D0 to D8 733 of a G2 Sub-Group are grouped in a track A of the G3 Sub-Group. Bytes D8 734 to D17 467 are grouped in a track B of the G3 Sub-Group. In each track the bytes are allocated to a lower or an upper byte as follows (see figure 34). Even numbered bytes are allocated to a lower byte of the G3 Sub-Group. Odd numbered bytes are allocated to an upper byte of the G3 Sub-Group. Thus, each track contains 4 367 byte pairs. Each byte pair is allocated to a word of the track, starting with word No. 1. The first word of the track, word No. 0, contains a 2-byte header.

Track name

Byte name

lower

Bit number Header

B lower

upper

8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1

8 76 5 4 3 2 1

8 7 6 5 4 3 2 1

0 0 0 0

DF-ID

upper

LF-ID

DF-ID

LF-ID

D8 734

D8 735

D8 736

D8 737

D8 738

D8 739

. . .

4 366

D8 730

D8 731

D17 464

D17 465

4 367

D8 732

D8 733

D17 466

D17 467

Word number Figure 34 - G3 Sub-Group

- 46 -

11.3.3.1

Header Word No. 0 constitutes a 6-field header.

11.3.3.1.1

Data format ID (DF-ID) In both tracks, this field shall be a 4-bit field. It shall be set to 0010.

11.3.3.1.2

Bits 5-8 of the lower byte of both tracks These bits shall be set to all ZEROs.

11.3.3.1.3

Logical Frame ID (LF-ID) In both tracks this field shall be an 8-bit field. Bits 6 to 1 shall express in binary notation the Logical Frame Number, which is the running number of the G1 Sub-Group. −

if bits 6 to 1 express a number in the range 1 to 21: . .

−

bit 7 shall be set to ZERO, and bit 8 shall be set to ZERO

if bits 6 to 1 express the number 22: . .

bit 7 shall be set to ZERO, and bit 8 shall be set to: ♦ ♦

−

ZERO to indicate that there is a 23rd Sub-Group containing the check bytes of the ECC3 (see 16.5.3), or ONE, to indicate that there is no such 23rd Sub-Group

if bits 6 to 1 express the number 23 . .

bit 7 shall be set to ONE, and bit 8 shall be set to ONE

thus indicating that the Sub-Group contains the check bytes of the ECC3, and that the Sub-Group is the last of the sequence. 11.3.3.1.4

Byte identification Each byte of a G3 Sub-Group is now identified by − − −

its track (A or B) its byte name (lower or upper) its word number (from 0 to 4 367)

Thus, the following notation is introduced.

11.3.4

Ail Aiu

indicates the byte identified by the lower byte of track A in the i-th word.

Bil

indicates the byte identified by the lower byte of track B in the i-th word.

Biu

indicates the byte identified by the upper byte of track B in the i-th word.

indicates the byte identified by the upper byte of track A in the i-th word.

G4 Sub-Group Each G3 Sub-Group shall be transformed into a G4 Sub-Group consisting of two twin arrays as follows. A Sign, a Fragment Number and a Serial Number shall be allocated to each byte using the following formulae. Sign :

( −1) a

i (mod 78) + 9 i i Serial number : (2( u + int )) − (int ) (mod 2) 78 78 Fragment number :

where int

= indicates the integer part of the quotient

- 47 -

= 0 to 4 367

= 0 for the Aiu and Ail bytes

= 1 for the Biu and Bil bytes

= 0 for the Aiu and Biu bytes

= 1 for the Ail and Bil bytes

Processing a G3 Sub-Group in this way yields twin arrays PLUS and MINUS in which each byte is identified by its Fragment Number (from 0 to 95) and its Serial Number (from 0 to 123). Bytes from track A are placed in the array PLUS. Bytes from track B are placed in the array MINUS. Array PLUS 0

9 10 11 12

83 84 85 86 87

93 94 95

83 84 85 86 87

93 94 95

0 1 . . . . . . . . 112 . 123

Array MINUS 0

9 10 11 12

0 1 . . . . . . . . 112 . 123

Figure 35 - Twin arrays of a G4 Sub-Group before C1 and C2 computation

- 48 -

Applying the above formulae to the bytes of a G3 Sub-Group leaves a number of positions unoccupied in both arrays. These positions, shown shaded in figure 35, are: −

all bytes having Serial Numbers in the range 112 to 123 in all Fragments having a Fragment Number in the range 9 to 86,

−

all bytes in all Fragments having a Fragment Number in the range 0 to 8 or in the range 87 to 95.

The bytes to be allocated to these positions shall be obtained by computing ECC bytes obtained from two error detection and correction codes C1 and C2 computed over the bytes already allocated into the two twin arrays. The C2 bytes shall be computed for the byte positions with Serial Numbers in the range 0 to 111 in each Fragment having a Fragment Number in the range 0 to 8 or in the range 87 to 95 from the bytes with the same Serial Number in all the other Fragments. The C1 bytes shall then be computed for byte positions with Serial Numbers in the range 112 to 123 in all Fragments from all the other bytes in the same Fragment. In Fragments with a Fragment Number in the range 0 to 8 or in the range 87 to 95, these C1 bytes shall be computed from the C2 bytes previously computed. These two computations yield the bytes for the byte positions indicated by the shaded portions of the two twin arrays of figure 32. − C1 shall be a GF (28) Reed-Solomon Code (62, 56, 7) − C2 shall be a GF (28) Reed-Solomon Code (32, 26, 7) Calculation in a GF (28) shall be defined by : G (x) = x8 + x4 + x3 + x2 + 1 A primitive element à in GF (28) is 00000010. The interleave depth of C1 shall be two bytes, that of C2 shall be three Fragments. The ECC bytes shall satisfy : HP × V P = 0 HQ × V Q = 0 The generator polynomials shall be :

( i) i G ( x) = ∏ ( x − α ) i =0 ()

i =5

GP x = ∏ x − α i =0 i =5

 1  α 61  α 122 HP =  183 α α 244  50  α

1 1 60 α α 59 α 120 α 118 α 180 α 177 α 240 α 236 α 45 α 40

... ... ... ... ... ...

1 1 2 α α α4 α2 α6 α3 α8 α 4 α 10 α 5

1 1 1  1 1  1

NOTE The last row of Hp may be equivalently written as [α305 α300 α295 ..... α10 α5 α1]. The identity α255= 1 has been used to simplify the matrix elements.

- 49 -

 1  α 31   α 62 HQ =  93 α α 124  155 α

1 α 29 α 60 α 90 α 120 α 150

1 α 28 α 58 α 87 α 116 α 145

... ... ... ... ... ...

1 α2 α4 α6 α8 α 10

  Q m ,n   D k ,l      Q m + 3 ,n   D k ,l + 2   Q m + 6 ,n   D k ,l + 4       D m + 9 ,n   D k ,l + 6   D  D  m + 1 2 ,n   k ,l + 8   D m + 1 5 ,n   D k ,l + 1 0       D m + 1 8 ,n   D k ,l + 1 2   D  D  m + 2 1 ,n   k ,l + 1 4   D m + 2 4 ,n   D k ,l + 1 6       D m + 2 7 ,n   D k ,l + 1 8   D  D  m + 3 0 ,n   k ,l + 2 0   D m + 3 3 ,n   D k ,l + 2 2       D m + 3 6 ,n   D k ,l + 2 4   D m + 3 9 ,n   D k ,l + 2 6       D m + 4 2 ,n   D k ,l + 2 8   D  D  m + 4 5 ,n   k ,l + 3 0  VP =   VQ =  D m + 4 8 ,n       D m + 5 1 ,n   D k ,l + 9 4   D  D  m + 5 4 ,n   k ,l + 9 6   D m + 5 7 ,n   D k ,l + 9 8       D m + 6 0 ,n   D k ,l + 1 0 0   D  D k ,l + 1 0 2   m + 6 3 ,n     D m + 6 6 ,n   D k ,l + 1 0 4     D  D m + 6 9 ,n   k ,l + 1 0 6   D m + 7 2 ,n   D k ,l + 1 0 8       D m + 7 5 ,n   D k ,l + 1 1 0   D  P  m + 7 8 ,n   k ,l + 1 1 2   D m + 8 1 ,n   Pk ,l + 1 1 4       D m + 8 4 ,n   Pk ,l + 1 1 6   Q  P  m + 8 7 ,n   k ,l + 1 1 8   Q m + 9 0 ,n   Pk ,l + 1 2 0       Pk ,l + 1 2 2   Q m + 9 3 ,n 

1 α α2 α3 α4 α5

1 1  1  1 1  1

- 50 -

where Pi,j = C1 bytes Qi,j = C2 bytes i = Fragment Number j

= Serial Number

For C1: k = 0, 1, ..., 95 l = 0,1 if k = 0, 1, ..., 8 or k = 87, 88, ..., 95, then Dij in VP is read as Qij For C2: m = 0, 1, 2 n = 0, 1, ..., 111 11.3.5

Main Data Fragment Each Fragment of a G4 Sub-Group shall be transformed into a 132-byte Main Data Fragment by prefixing an 8-byte header. The byte of the header which contains the Fragment ID field shall be the first byte of the Main Data Fragment. b8 Fragment Header

Fragment ID Area ID

Frame Number

Sub code byte No. 0 (SC0) Sub code byte No. 1 (SC1) Sub code byte No. 2 (SC2) Sub code byte No. 3 (SC3) Header parity byte No. 0 (FHP0) Header parity byte No. 1 (FHP1) Byte with Serial Number 0 Byte with Serial Number 1 . Fragment

bytes from

a G4

Sub-Group

. . Byte with Serial Number 122 Byte with Serial Number 123

Figure 36 - Main Data Fragment

- 51 -

11.3.5.1 Fragment Header 11.3.5.1.1

Fragment ID The Fragment ID field shall specify in binary notation the Fragment Number, from 0 to 95, of the current Fragment.

11.3.5.1.2

Area ID The Area ID shall identify the current area of the tape. See 16. The field settings shall be as follows 0000 : Device Area X001: Reference Area X010: System area X100: Data Area X101: EOD Area Other settings of this field are prohibited by this ECMA standard. For a tape with a Single Data Space (see 16), bit X shall be set to ONE. For a tape with two partitions (see 17), bit X shall be ONE for Partition 0 and shall be ZERO for Partition 1.

11.3.5.1.3

Frame Number The Frame Number shall specify in binary notation a running number which shall be incremented (mod 16) between consecutive frames. Repetitions and discontinuities are allowed at append points (see 16.5.5) and within the Position Tolerance Bands (see 16.3 and 16.4.4).

11.3.5.1.4

Sub code Four bytes of the Fragment Header shall be used to contain Sub code information. See 11.4.

11.3.5.1.5

Fragment Header Parity The Fragment Header parity bytes shall be computed using an extended Reed-Solomon Code. Calculation in a GF (28) shall be defined by : G (x) = x8 + x4 + x3 + x2 + 1 A primitive element à in GF (28) is 00000010. The Fragment Header parity bytes shall satisfy : HS × V S = 0 1 HS =  5 α

0  1

FH0    FH1    SC0    SC1  VS =   SC2  SC3    FHP0   FHP1

where FH0 is the byte of the header which contains the Fragment ID field and FH1 is the byte of the header which contains the Area ID and Frame Number fields.

- 52 -

11.3.6

Summary of the transformation of a Basic Group Each Basic Group has been transformed into 22 G4 Sub-Groups. Each G4 Sub-Group consists of two arrays of 96 Fragments each. Each of these Fragments has been transformed into a Main Data Fragment. Thus a Basic Group is transformed into 22 x 2 x 96 = 4 224 Main Data Fragments before being recorded on the tape.

11.4

Sub code Information The Sub code information shall be embedded along each track within the Fragment Headers. It shall specify − − − − − −

the running number of the Basic Group, the number of Separator 1's written since the LBOT the number of Separator 2's written since the LBOT the number of Records written since the LBOT information about the track contents information about the history of the tape

Sub code information shall be arranged as 4-byte Pack Items. The identification number of the Pack Item contained within each Fragment Header shall be calculated as Fragment ID mod 8 or Fragment ID mod 16. See 11.5.

11.4.1

Pack Item Number 0 b8

SC 0

Group Number (MSB)

SC 1

Group Number

SC 2

Group Number (LSB)

SC 3

LF-ID

Figure 37 - Pack Item Number 0 11.4.1.1

SC 0,1,2 These bytes shall specify in binary notation the Group Number recorded in the Group Information Table (see 11.2.2).

11.4.1.2

SC 3 This byte shall have the same setting as the Logical Frame ID of the G1 Sub-Group (see 11.3.3.1.3) to which this Pack Item refers.

11.4.2

Pack Item Number 1

SC 0

Separator 1 Count (MSB)

SC 1

Separator 1 Count

SC 2

Separator 1 Count

SC 3

Separator 1 Count (LSB)

Figure 38 - Pack Item Number 1 11.4.2.1

SC 0,1,2,3 These bytes shall specify the Separator 1 Count recorded in the Group Information Table (see 11.2.2).

- 53 -

11.4.3

Pack Item Number 2

SC 0

Separator 2 Count (MSB)

SC 1

Separator 2 Count

SC 2

Separator 2 Count (LSB)

SC 3

Set to all ZEROs

DF-ID

Figure 39 - Pack Item Number 2 11.4.3.1

SC 0,1,2 These bytes shall specify the Separator 2 Count as recorded in the Group Information Table (see 11.2.2).

11.4.3.2

SC 3 Bits b1 to b4 of this byte shall have the same setting as the Data Format ID of the current G3 Sub Group 11.3.3.1.1). Bits b5 to b8 shall be set to all ZEROs.

11.4.4

Pack Item Number 3

SC 0

Record Count (MSB)

SC 1

Record Count

SC 2

Record Count

SC 3

Record Count (LSB)

Figure 40 - Pack Item Number 3 11.4.4.1

SC 0,1,2,3 These bytes shall specify the Record Count recorded in the Group Information Table (see 11.2.2).

11.4.5

Pack Item Number 4

SC 0

Absolute Frame Number (MSB)

SC 1

Absolute Frame Number

SC 2

Absolute Frame Number

SC 3

Absolute Frame Number (LSB) Figure 41 - Pack Item Number 4

(see

- 54 -

11.4.5.1

SC 0,1,2,3 These bytes shall specify a running number, the Absolute Frame Number, of the current frame, starting with 1 for the first frame after LBOT.

11.4.6

Pack Item Number 5 b8

SC 0

Check Sum No. 1

SC 1

Check Sum No. 2

SC 2

Check Sum No. 3

SC 3

Check Sum No. 4

Figure 42 - Pack Item Number 5 11.4.6.1

SC 0 For each bit position of this byte the content shall be the sum (mod 2) of the corresponding bits of the upper byte of word No. 0 of track A of the G3 Sub-Group (see 11.3.3) identified by SC 3 of Pack Item No. 0 and the corresponding bits of the bytes of the G1 Sub-Group to which this Pack Item refers which have the indices D2i+1 where i = 0, 1, 2, ..., 4 366.

11.4.6.2

SC 1 For each bit position of this byte the content shall be the sum (mod 2) of the corresponding bits of the lower byte of word No. 0 of track A of the G3 Sub-Group (see 11.3.3) identified by SC 3 of Pack Item No. 0 and the corresponding bits of the bytes of the G1 Sub-Group to which this Pack Item refers which have the indices D2i where i = 0, 1, 2, ..., 4 366.

11.4.6.3

SC 2 For each bit position of this byte the content shall be the sum (mod 2) of the corresponding bits of the upper byte of word No. 0 of track B of the G3 Sub-Group (see 11.3.3) identified by SC 3 of Pack Item No. 0 and the corresponding bits of the bytes of the G1 Sub-Group to which this Pack Item refers which have the indices D2i+1 where i = 4 367, 4 368, ..., 8 733.

11.4.6.4

SC 3 For each bit position of this byte the content shall be the sum (mod 2) of the corresponding bits of the lower byte of word No. 0 of track B of the G3 Sub-Group (see 11.3.3) identified by SC 3 of Pack Item No. 0 and the corresponding bits of the bytes of the G1 Sub-Group to which this Pack Item refers which have the indices D2i where i = 4 367, 4 368, ..., 8 733.

11.4.7

Pack Item Number 6 b8

SC 0

Maximum Partition 1 AFN (MSB)

SC 1

Maximum Partition 1 AFN

SC 2

Maximum Partition 1 AFN

SC 3

Maximum Partition 1 AFN (LSB) Figure 43 - Pack Item Number 6

- 55 -

11.4.7.1

SC 0,1,2,3

11.4.7.1.1

Area ID set to 0010 These bytes shall specify in binary notation the highest Absolute Frame Number within partition 1 of a partitioned tape (see 17.1.2.1).

11.4.7.1.2

Area ID set to 1010 These bytes shall be set to all ONEs.

11.4.7.1.3

Area ID set to any other bit combination These bytes shall be set to all ZEROs.

11.4.8

Pack Item Number 7 b8

SC 0

Set to all ZEROs

SC 1

Set to all ZEROs

SC 2

Set to all ZEROs

SC 3

Set to all ZEROs

Figure 44 - Pack Item Number 7 11.4.8.1

SC 0,1,2,3 These bytes shall be set to all ZEROs.

11.4.9

Pack Item Number 8 b8

SC 0

Recorded Data Groups (MSB)

SC 1

Recorded Data Groups

SC 2

Recorded Data Groups

SC 3

Recorded Data Groups (LSB) Figure 45 - Pack Item Number 8

11.4.9.1

SC 0,1,2,3 These bytes shall specify in binary notation the number of Recorded Data Groups recorded on the tape between the penultimate and the last update of the log.

- 56 -

11.4.10

Pack Item Number 9 b8

SC 0

Total Recorded Data Groups (MSB)

SC 1

Total Recorded Data Groups

SC 2

Total Recorded Data Groups

SC 3

Total Recorded Data Groups (LSB)

Figure 46 - Pack Item Number 9 11.4.10.1 SC 0,1,2,3 These bytes shall specify in binary notation the number of Recorded Data Groups recorded following the last initialization of the tape (see 16.9 and 17.5) and prior to the last update of the log. 11.4.11

Pack Item Number 10 b8

SC 0

Recorded Data Groups Read (MSB)

SC 1

Recorded Data Groups Read

SC 2

Recorded Data Groups Read

SC 3

Recorded Data Groups Read (LSB)

Figure 47 - Pack Item Number 10 11.4.11.1 SC 0,1,2,3 These bytes shall specify in binary notation the number of Recorded Data Groups read successfully by a drive between the penultimate and the last update of the log. 11.4.12

Pack Item Number 11 b8

SC 0

Total Recorded Data Groups Read (MSB)

SC 1

Total Recorded Data Groups Read

SC 2

Total Recorded Data Groups Read

SC 3

Total Recorded Data Groups Read (LSB) Figure 48 - Pack Item Number 11

11.4.12.1 SC 0,1,2,3 These bytes shall specify in binary notation the number of Recorded Data Groups read successfully following the last initialization of the tape (see 16.9 and 17.5) and prior to the last update of the log.

- 57 -

11.4.13

Pack Item Number 12 b8

SC 0

Total Check-Read Failures (MSB)

SC 1

Total Check-Read Failures

SC 2

Total Check-Read Failures (LSB)

SC 3

Set to all ZEROs

Figure 49 - Pack Item Number 12 11.4.13.1 SC 0,1,2,3 These bytes shall specify in binary notation the number of frames that have failed a Read-After-Write check (see annex L) following the last initialization of the tape (see 16.9 and 17.5) and prior to the last update of the log. This number does not include the frames which are written between the original frame and its next rewritten occurrence. 11.4.13.2 SC 3 This byte shall be set to all ZEROs. 11.4.14

Pack Item Number 13 b8

SC 0

Total Group Read Failures (MSB)

SC 1

Total Group Read Failures

SC 2

Total Group Read Failures (LSB)

SC 3

Set to all ZEROs

Figure 50 - Pack Item Number 13 11.4.14.1 SC 0,1,2 These bytes shall specify in binary notation the number of times it has not been possible to read successfully all data in a Recorded Data Group with the use of C1 and C2 only, following the last initialization of the tape (see 16.9 and 17.5) and prior to the last update of the log. This number includes all unsuccessful attempts. 11.4.14.2 SC 3 This byte shall be set to all ZEROs.

- 58 -

11.4.15

Pack Item Number 14 b8

SC 0

Previous Check-Read Failures (MSB)

SC 1

Previous Check-Read Failures (LSB)

SC 2

Group Read Failures Read (MSB)

SC 3

Group Read Failures Read (LSB)

Figure 51 - Pack Item Number 14 11.4.15.1 SC 0,1 These bytes shall specify in binary notation the total number of frames that have failed a Read-After-Write check (see annex L) between the penultimate and the last update of the log. This number does not include the frames which are written between the original frame and its next rewritten occurence. 11.4.15.2 SC 2,3 These bytes shall specify in binary notation the number of times it has not been possible to read successfully all the data in a Recorded Data Group with the use of C1 and C2 alone, between the penultimate and the last update of the log. This number includes all unsuccessful attempts. 11.4.16

Pack Item Number 15 b8

SC 0

Load Count (MSB)

SC 1

Load Count (LSB)

SC 2

Set to all ZEROs

SC 3

Set to all ZEROs

Figure 52 - Pack Item Number 15 11.4.16.1 SC 0,1 These bytes shall specify in binary notation the number of times the tape has been loaded following the last initialization of the tape (see 16.9 and 17.5) and prior to the last update of the log. One load consists of pulling the tape from its case, wrapping the tape around the drum, positioning the tape ready for use, unwrapping the tape and returning it into the case. 11.4.16.2 SC 2,3 These bytes shall be set to all ZEROs.

11.5

Sub code location Sub code information is written within each Main Data Fragment Header. The presence or absence of some sub code Pack Items depends on the position of the frame in the overall tape layout. The location of sub code Pack Items depends on the Fragment Number (see 11.3.5.1.1). In addition, in the System Log area of a partitioned tape (see 17), the values specified by some Pack Items depend upon the value of the Absolute Frame Number (AFN).

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11.5.1

Sub code Pack Items on a Single Data Space tape Table 3 : Pack Items on a Single Data Space tape Tape Area

Pack Items All Pack Items (0 to 15). The number of the Pack Item in each Fragment Header is given by Fragment Number mod 16.

System Log (see 16.4.2) Other Areas

11.5.2

Pack Items 0 to 7. The number of the Pack Item in each Fragment Header is given by Fragment Number mod 8.

Sub code Pack Items on a partitioned tape Table 4 : Pack Items on a partitioned tape Tape Area

AFN

Pack Items

Odd

All Pack Items (0 to 15). The number of the Pack Item in each Fragment Header is given by Fragment Number mod 16. Pack Items Nos. 8 to 15 specify values which are the sums of the corresponding log values for each partition.

Even

All Pack Items (0 to 15). The number of the Pack Item in each Fragment Header is given by Fragment Number mod 16. Pack Items Nos. 8 to 15 specify values which pertain to Partition 0 only.

All

Pack Items 0 to 7. The number of the Pack Item in each Fragment Header is given by Fragment Number mod 8.

System Log in Partition 1 (see 16.4.2 and 17.1.2.2)

Other Areas

Method of recording The method of recording shall be : − a ONE is represented by a flux transition at the beginning of a bit cell; − a ZERO is represented by no flux transition in the bit cell.

12.1

Physical recording density The nominal maximum physical recording density is 5 999,7 ftpmm. The resulting nominal bit cell length is 0,166 6 µm. These values are derived from the track length (see 13.7) divided by the number of bits per track.

12.2

Long-term average bit cell length The long-term average bit cell length for each track shall be measured over 96 recorded Main Data Fragments (see 14.1). It shall be within 0,2 % of the nominal bit cell length.

12.3

Short-term average bit cell length The short-term average bit cell length, referred to a particular bit cell, shall be the average of the preceding 40 bit cells. It shall be within 0,35 % of the long-term average bit cell length for the preceding track of the same azimuth.

12.4

Rate of change The above defined short-term average bit cell length shall not change at a rate greater than 0,05 % per bit cell.

12.5

Bit shift When measured according to annex F, (|A1110| + |A0111|) / (A0100 + A0010) shall be less than 0,05.

12.6

Read signal amplitude The Average Signal Amplitude of an interchanged cartridge shall be − at 1 499,9 ftpmm, 1 999,9 ftpmm, 2 999,9 ftpmm and 4 499,8 ftpmm : between 80 % and 119 % of the respective nominal recorded levels (see annex D).

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12.7

Maximum recorded levels Recorded signals shall be erasable by overwriting. The limits imposed on the recorded levels for this reason are specified in annex D.

13 13.1

Track geometry Track configuration The helical track pattern is formed by the relationship between the direction of tape motion and the axis of rotation of a pair of heads, one of which has a positive azimuth angle and the other a negative azimuth angle. The direction of recording is away from the Tape Reference Edge. The track configuration is shown in figure 53. Negative azimuth track

Positive azimuth track

Tape motion

P Head motion

B A L

θ T Tape Reference Edge

Positive azimuth angle

Negative azimuth angle

A : Tape width B : Ideal tape centreline θ : Track angle L : Track length P : Track pitch T : Track width Figure 53 - Track configuration (view on recording surface)

13.2

Average track pitch The average track pitch, taken over any group of 30 consecutive tracks, shall be 9,053 µm ± 0,045 µm. The track pitch at a non-seamless append point (see 16.5.5.2) shall not be included in this average.

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13.3

Variations of the track pitch The change of track pitch between successive track pitches shall not exceed 2,0%, excluding the effect of an appending operation (see 16.5.5).

13.4

Track width The nominal track width shall be 9,053 µm. The measured track width shall be 9,1 µm ± 1,8 µm. This requirement shall not apply at a non-seamless append point.

13.5

Track angle The nominal angle of each track with respect to the Tape Reference Edge shall be 6° 22' 39,6".

13.6

Track edge linearity The leading edge of each track shall fall within the box defined in annex G.

13.7

Track length The length of each track shall be 23,521 mm ± 0,047 mm.

13.8

Ideal tape centreline The ideal centreline of the tape is 1,900 mm from the Tape Reference Edge.

13.9

Azimuth angles The positive azimuth angle shall be 20° 00' 39,6" ± 15' 00,0". The negative azimuth angle shall be 19° 59' 20,4" ± 15' 00,0".

Recorded patterns Each 8-bit byte of the Main Data Fragments shall be represented on the tape by a 10-bit pattern. Annex E specifies for each 8-bit byte the 10-bit pattern to be recorded. The bits of the 10-bit pattern are called Channel bits.

14.1

Recorded Main Data Fragment A Recorded Main Data Fragment shall consist of 1 330 Channel bits representing the 132 8-bit bytes of a Main Data Fragment preceded by a Sync field of 10 Channel bits with one of the following patterns: a) b)

0100010001 1100010001

Pattern a) shall be used for Q' = -1, DC = 0, Q = 1; pattern b) for Q' = 1, DC = 0, Q = 1 (see annex E). Either pattern may be used when there is no preceding pattern, and hence no value of Q'. See E.1 for the order of recording. In a track of positive azimuth, the Recorded Main Data Fragments shall represent the Main Data Fragments formed from the PLUS array of a G4 Sub-Group (see 11.3.4). In the track of negative azimuth of the same Frame, the Recorded Main Data Fragments shall represent the Main Data Fragments formed from the MINUS array of the same G4 Sub-Group. Within each track, the Recorded Main Data Fragments shall be recorded in the sequence of their Fragment Numbers.

14.2

Preamble Zone, Margin Zones These zones shall be recorded with the repeating Channel bit pattern 1010101010. See E.1 for the order of recording. There shall be no discontinuity of this pattern between Margin Zone No. 1 and the Preamble Zone.

15 15.1

Format of a track Format of a track Each track shall consist of two Margin Zones, a Preamble Zone and a Main Data Zone. In Table 5 the direction of recording is down the page.

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Table 5 - Track format Zone

15.2

Contents

Number of 10-bit patterns

Margin Zone No. 1

Margin pattern

640

Preamble Zone

Preamble pattern

Main Data Zone

Recorded Main Data Fragments

12 768

Margin Zone No. 2

Margin pattern

640

Positioning accuracy The position reference point of a track is the position, measured in the direction perpendicular to the Tape Reference Edge, of the first bit cell of Fragment Number 48, along the centreline of the track. The position reference points of all tracks, shall be 1,906 mm ± 0,027 mm from the Tape Reference Edge. The position reference point of : − all tracks within the continuum formed by a Recorded Data Group (see 16.5.2) and, at an append point (see 16.5.5), the Amble Frames which start at Frame B and precede that Recorded Data Group, and − all tracks within the continuum formed by the System Preamble, System Log and System Postamble (see 16.4), and − all tracks within the continuum formed by the Vendor Group Preamble and the Vendor Group (see 16.5.1) shall be within 4,5 µm of the mean of the position reference points of all tracks in the continuum. In addition, the mean of the position reference points of any 12 consecutive tracks within the continuum shall be within 1,0 µm of the mean of position reference points of all tracks within the continuum.

15.3

Tracking scheme This format does not include any aids specifically designed to assist a reading drive in maintaining tracking. However, the specifications of 15.2 limit the extent of the conditions that it must handle correctly.

Layout of a Single Data Space tape A magnetic tape shall be recorded as a Single Data Space tape or as a Partitioned tape. The layout of a Single Data Space tape is specified in this clause, that of a Partitioned tape in clause 17. The layout of the Single Data Space tape consists of six areas: − − − − − −

the Device Area the Reference Area the System Area the Data Area the EOD Area the Post-EOD Area

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Reference Pos. Tol. Band Area No. 1

Device Area

DEVICE PBOT

System System Preamble Log

Pos. Tol. Vendor Vendor Band Group Group Postamble Preamble No. 2

Recorded Data Group No. 1

System

REFERENCE

Recorded Data Group No. 2

DATA

SYSTEM

LBOT

350 mm ±10 mm

35 frames

30 frames

25 frames

10 frames

Last Recorded Data Group

Amble Frames

EOD Area

DATA

EOD Min. 12 frames

Minimum 450 frames

Post-EOD Area

POST-EOD

PEOT

ECMA-95-0094-A

Figure 54 - Layout of a Single Data Space tape

16.1

Device Area This area shall be the first area on the magnetic tape and shall extend from PBOT to LBOT. It shall not be used for writing data for interchange. Its length, measured parallel to the Tape Reference Edge, from PBOT to the first bit of the first block of the first recorded track of the Reference Area, shall be 350 mm ± 10 mm. It shall consist of three zones : a spin-up zone, a test zone and a guard zone. The first zone of the Device Area is a spin-up zone. It is the part of the tape which is wrapped around the drum when the tape is loaded into the drive. The spin-up zone shall be followed by a test zone available for read/write purposes. The contents of these two zones are not specified by this ECMA Standard. However, if a track in these zones complies with the track format of table 5 in 15.1 the Area ID field of all Fragment Headers shall be set to 0000. The test zone shall be followed by a guard zone of length 9 mm minimum, in which no recording is permitted.

16.2

Reference Area This area shall consist of 35 Tape Management Frames (see 18.3), of which the first starts at LBOT and has an Absolute Frame Number of 1. The Reference Area is used as the physical reference when updating the System Log.

16.3

Position Tolerance Band No. 1 This band shall have a nominal length equivalent to five Frames, with a minimum length of zero and a maximum length of 10 Frames. It is used to accommodate the positioning tolerances when updating the System Log. Discontinuities and repetitions of the Absolute Frame Number may occur in this band. The recorded signals may be ill-defined in this band.

16.4

System Area This area shall consist of the System Preamble, System Log, System Postamble, Position Tolerance Band No. 2, and the Vendor Group Preamble.

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16.4.1

System Preamble The System Preamble shall consist of 30 Tape Management Frames (see 18.3), having the Absolute Frame Numbers 41 to 70.

16.4.2

System Log The System Log shall consist of 25 System Log Frames (see 18.2), having the Absolute Frame Numbers 71 to 95. NOTE The history data in the System Log cannot be relied upon to be always accurate, because drives cannot update the log if the Write-inhibit Hole is open. It may also be destroyed during initialization (see 16.9).

16.4.3

System Postamble The System Postamble shall consist of 10 Tape Management Frames, having the Absolute Frame Numbers 96 to 105. NOTE It is recommended that the continuum comprising the System Preamble, System Log and System Postamble be written in a continuous motion when the System Log is updated.

16.4.4

Position Tolerance Band No. 2 This band shall have a nominal length equivalent to 15 Frames. Its actual length depends on the actual length of the Position Tolerance Band No. 1 and on the actual position of the first Frame of the Vendor Group Preamble, and hence may vary from 0 to 30 Frames. Discontinuities and repetitions of the Absolute Frame Number may occur in this band. The recorded signals may be ill-defined in this band.

16.4.5

Vendor Group Preamble The Vendor Group Preamble shall consist of 30 Tape Management Frames having the Absolute Frame Numbers 121 to 150. The Vendor Group Preamble shall immediately precede the Vendor Group and be contiguous with it.

16.5

Data Area This area shall consist of the Vendor Group and one or more Recorded Data Groups. A Frame in the Data Area shall be either an Amble Frame (see 18.1) or, within a Recorded Data Group, a recorded representation of a SubGroup. A Logical Frame Number is allocated to each Frame. The Logical Frame Number of an Amble Frame is zero. The Logical Frame Number of a Frame within a Recorded Data Group is the number of the Sub-Group it represents. It is expressed by bits 1 to 6 of the Logical Frame ID (see 11.3.3.1.3 and 11.4.1). The last Recorded Data Group shall be followed by at least 12 Amble Frames.

16.5.1

Vendor Group A Vendor Group is the recorded instance of Basic Group No. 0, the content of which is not specified by this ECMA Standard (see annex M). The Vendor Group is formed from the bytes of that Basic Group by applying the operations described in 11.3 and 11.4 and recording the resulting Frames. The first of these Frames shall have the Absolute Frame Number 151. In addition none or either or both of two further operations, namely ECC3 (see 16.5.3) and Repeated Frames (see 16.5.4) may be applied. No unrecorded space or physical discontinuity or seam or Absolute Frame Number discontinuity or Absolute Frame Number repetition may occur within a Vendor Group.

16.5.2

Recorded Data Group Each Recorded Data Group is a recorded instance of a Basic Group, and is formed from the data sent from a host computer by applying the operations described in clause 11 and recording the resulting Frames, one per G4 SubGroup, in the sequence of their Logical Frame Numbers (see 11.3.3.1.3). In addition, none or either or both of two further operations may be applied. These are ECC3 (see 16.5.3) and Repeated Frames (see 16.5.4). No unrecorded space or physical discontinuity or seam or Absolute Frame Number discontinuity or Absolute Frame Number repetition may occur within a Recorded Data Group.

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16.5.3

ECC3 The Error Correction Code 3 (ECC3) has the capability of correcting any two tracks which are bad in a Recorded Data Group. The ECC3 data is derived from the 22 G1 Sub-Groups of the Basic Group to form a 23rd G1 SubGroup. ECC3 shall be a GF (28) Reed-Solomon Code (46, 44, 3). Calculation in a GF (28) shall be defined by : G (x) = x8 + x4 + x3 + x2 + 1 A primitive element à in GF (28) is 00000010. The interleave depth of ECC3 shall be one track. The ECC bytes shall satisfy : HR × V R = 0 The generator polynomial shall be :

()

( i =0

...

... α

i =1

GR x = ∏ x − α  1 HR =  45 α

)

1 1  α 1

Dn,1    Dn+8734,1  Dn   ,2  Dn+8734, 2  VR =     Dn+8734, 22    Rn, 23  R   n+8734, 23 

n = 0, 1, 2, ..., 8 733 Dx,y

x = User data byte number in a G1 Sub-Group, y = G1 Sub-Group number

Rx,23

x = Parity byte number in the ECC3 G1 Sub-Group

The ECC3 G1 Sub-Group shall be transformed according to the procedures of 11.3 and 11.4 to form the recorded Main Data Fragments of the two tracks of the ECC3 Frame. 16.5.4

Repeated Frames In the Data Area, a Frame within a Recorded Data Group may be repeated by rewriting it further along the tape. The repeated Frame may be written after zero, one, two, three, four, five, six or seven other Frames have been written. Each such sequence (i.e. the original or repeated Frame and the zero, one, two, three, four, five, six or seven following Frames) can be repeated multiple times, e.g. to allow skipping over bad areas on the tape. The maximum number of instances of a sequence shall be 256, i.e. the original and up to 255 repetitions. Intermediate Frames, i.e. those Frames written between the original Frame and its next occurrence shall start with the Frame the Logical Frame Number of which is the next in the normal sequence, and shall follow the correct sequence thereafter. The correct sequence requires successive Frames to have Logical Frame Numbers which increment by one until the last Frame in the Recorded Data Group, or the ECC3 Frame if present, after which they restart from 0 (for an Amble Frame) or 1 (for the first Frame of the next Recorded Data Group). Amble Frames are allowed in this sequence, provided the limit of seven Intermediate Frames is not exceeded. The final occurrence of the repeated Frame shall be followed by the Intermediate Frames written in the correct sequence.

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16.5.5

Appending and overwriting When new data is appended to data already recorded on tape, or existing data is overwritten by new data, the point at which recording may start shall be referenced to the last Frame (Frame A in figure 55) of a Recorded Data Group. If Repeated Frames have been recorded, the relevant Frame is the last repetition of the last Frame. The smallest unit of appending or overwriting is a Recorded Data Group. NOTE After overwriting commences, all data between the current recording point and PEOT is logically inaccessible. The rules for appending and overwriting are identical. For simplicity, the following description refers only to appending. Data may be appended to the tape by either the seamless or non-seamless methods. In a seamless appending operation, the appended tracks shall form a continuous sequence with the previous tracks. No track shall be partially overwritten to the point of being unreadable nor shall any gaps be left between tracks.

1 Frame

m Amble Frames m>1

Frame number →

n+2

n+3+m

Figure 55 - Appending rules The Frames up to and including Frame A on figure 55 contain information which is to be retained. The append starts with Amble Frames at Frame B and the information at Frame C. 16.5.5.1

Seamless appending rules Rule 1. There shall be one Frame between Frame A and Frame B, i.e. if Frame A has an Absolute Frame Number (AFN) of n, then Frame B shall have an AFN of n+2. Rule 2. The Frame written between Frames A and B shall be contiguous with Frame A, i.e. no unrecorded space between A and B is permitted, nor is any discontinuity or repetition of AFNs, nor is any physical discontinuity. The Group Number of this Frame shall be greater than that of Frame A, unless this Frame is an Amble Frame (see 18.1), in which case its Group Number shall be equal to that of Frame A. The content of this Frame shall be ignored. Rule 3. There shall be a minimum of one Amble Frame between Frames B and C, i.e. if Frame B has an AFN of n+2, then Frame C shall have an AFN of n+4 minimum. No unrecorded space, physical discontinuity, or AFN discontinuity or repetition is allowed between Frames B and C. Rule 4. The position of the first track of Frame B (AFN = n+2), as measured along the length of the tape at the point shown in figure 56, shall be at a distance of x = 163,0 µm ± 26,7 µm from the first track of the Frame with AFN = n+1.

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Frame AFN =n + 1

Frame A AFN =n

Frame B AFN =n + 2

Ideal tape centreline

Tape Reference Edge

ECMA-95-0051-A

Figure 56 - Tolerance on seamless appending 16.5.5.2

Non-seamless appending rules Rule 1. The distance between Frame A and Frame B shall be sufficient for a minimum of one and a maximum of 11 Frames. No unrecorded space is permitted between Frame A and Frame B. One or more Frames between Frame A and Frame B may be ill-defined, e.g., as a result of partial overwriting at an append point. Rule 2. Discontinuities and repetitions of AFN are permitted between Frame A and Frame B, provided that, where Frame A has an AFN of n, − −

all Frames have an AFN greater than n, and Frame B has an AFN of n+2 minimum and n+12 maximum.

Rule 3. Amble Frames (see 18.1) between Frame A and Frame B shall have a value of Group Number which is equal to that of Frame A. Other Frames between Frame A and Frame B shall have a value of Group Number which is greater than that of Frame A. Rule 4. There shall be a minimum of 29 Frames between Frames B and C, i.e. if Frame B has an AFN of n+2 ≤ n' ≤ n+12, then Frame C shall have an AFN of n'+30 minimum. No unrecorded space, physical discontinuity or seam or AFN discontinuity or repetition is allowed between Frames B and C.

16.6

EOD Area The Data Area shall be followed by an EOD Area. It shall consist of a minimum of 450 Tape Management Frames (see 18.3), and shall start after the last Amble Frame in the sequence of Amble Frames which follows the last Recorded Data Group. The first Frame of the EOD Area shall be recorded at least 2 500 mm before PEOT. More than one EOD Area may exist on a tape. The EOD Area closest to LBOT shall be the only valid one for information interchange.

16.7

Post-EOD Area The EOD Area shall be followed by a Post-EOD Area which extends to PEOT. The contents of this Post-EOD Area are not defined for interchange.

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16.8

Early Warning Point - (EWP) For a new or bulk-erased tape the position of the EWP is calculated by the drive writing the tape. The calculation shall ensure that the EWP is not less than 3 000 mm before PEOT. Until data is recorded beyond the calculated EWP no indication of its position is recorded on the tape. When data is first recorded beyond the calculated EWP, the setting of the AEWP bit (see 11.2.3.1.14) changes from ZERO to ONE in the last Basic Group which is completely or partially recorded before that point. This changeover then denotes the position of the EWP when the tape is subsequently read. For a tape containing data which is being overwritten, if the point at which overwriting commenced is before the EWP as defined prior to the commencement of overwriting, a new position of the EWP is calculated by the drive currently writing the tape. The calculation shall ensure that the EWP is not less than 3 000 mm before PEOT. When data is recorded beyond this calculated EWP, the setting of the AEWP bit (see 11.2.3.1.14) changes from ZERO to ONE in the last Basic Group which is completely or partially recorded before that point. This changeover then denotes the position of the EWP when the tape is subsequently read. For a tape containing data which is being overwritten, if the AEWP bit changes from ZERO to ONE prior to the point at which overwriting commenced, the position of the EWP is denoted by that changeover, i.e. the AEWP bit is set to ONE in all overwriting groups.

16.9

Initialization Initialization is a procedure which shall be carried out before the first use of a tape cartridge for recording user data (it may be also used at other times). The procedure ensures that there shall be no unrecorded space between LBOT and the end of the Vendor Group. The extent from LBOT to the end of the Vendor Group shall be recorded as a continuum in which the Position Tolerance Bands No. 1 and No. 2 shall be recorded as Tape Management Frames (see 18.3) and shall have their nominal numbers of 5 and 15 Frames, respectively. The Frames in the Position Tolerance Band No. 1 shall have their Area ID fields set to the Reference Area ID (see 11.4.9.1.1). If an initialization pass is performed on a recorded tape, it will destroy all data thereon, including the history data in the System Log(s). NOTE The tape layout is such that a separate initialization pass on a new or bulk-erased tape is not necessary prior to the recording of the first Recorded Data Group. The Reference Area, System Area and Vendor Group can be recorded at a time immediately prior to the recording of the first Recorded Data Group.

Layout of a partitioned tape A partitioned tape provides on one magnetic tape two independent partitions, each of which has a structure and properties similar to those of the recorded parts of a Single Data Space tape. With the exception of the differences described hereafter, all of the foregoing descriptions of the recorded format shall apply to each partition of a partitioned tape.

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Partition No. 1

Device Area

Reference Area

System System Pos.Tol. Log Band Preamble No.1

Pos. Tol. System Band Postamble No.2

REFERENCE

DEVICE

Vendor Vendor Group Group Preamble

Recorded Recorded Data Group Data Group No.2 No.1

SYSTEM

DATA

LBOT

PBOT

350 mm ±10 mm

35 frames

30 frames 25 frames

10 frames

Partition No. 0

Partition No. 1 Amble Last Recorded Frames Data Group

EOD Area

Post-EOD Area

EOD

DATA

450 EOD Frames

POST-EOD

Min. 12 Min. 450. frames frames

Reference Area

Pos .Tol. Band No. 1

System Preamble

System Log

Pos. Tol. System Band Postamble No. 2

REFERENCE

VEOT

SYSTEM 30 frames

LBOT

25 frames 10 frames

Partition No. 0 Vendor Vendor Group Group Preamble

Recorded Recorded Data Group Data Group No. 1 No. 2

Last Amble Recorded Frames Data Group

DATA

SYSTEM

Post-EOD Area

EOD Area

EOD Min. 12 frames

POST-EOD

Min. 450 frames

ECMA-95-0097-A

Figure 57 - Layout of a partitioned tape

17.1

Overall magnetic tape layout The layout of a partitioned tape shall consist of the Device Area, partition 1 and partition 0, which shall be located in that order from PBOT to PEOT.

17.1.1

Device Area This area shall be identical with that of a Single Data Space tape.

17.1.2 17.1.2.1

Partition 1 Size of Partition 1 The total number of Frames in partition 1 shall be recorded in Pack Item No. 6 in the frames of the System Log of partition 1. See 11.4.7.

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17.1.2.2

System Log The contents of Pack Items Nos. 8 to 15 in each frame of the System Log shall depend on whether the Absolute Frame Number is odd or even. See 11.5.2.

17.1.2.3

Virtual End Of Tape (VEOT) The VEOT shall be a reference point at a distance equivalent to 450 Frames before the Partition Boundary. This reference point is intended for use in a manner identical with that of PEOT on a Single Data Space tape, i.e. no recording shall occur within partition 1 beyond VEOT, except during initialization (see 17.5). The space between VEOT and the Partition Boundary shall contain Tape Management Frames which are identical with those of the EOD Area of partition 1. NOTE After overwriting commences (see 16.5.5) in partition 1, all data between the current recording point and VEOT is logically inaccessible. Data in partition 0 is unaffected.

17.1.2.4

Partition 1 Early Warning Point - (EWP) Within an empty partition 1 (see 17.4) the position of the EWP is calculated by the drive writing the tape. The calculation shall ensure that the EWP is not less than 3 067 Frames before VEOT. Until data is recorded beyond the calculated EWP no indication of its position is recorded on the tape. When data is first recorded beyond the calculated EWP, the setting of the AEWP bit (see 11.2.3.1.14) changes from ZERO to ONE in the last Basic Group which is completely or partially recorded before that point. This changeover then denotes the position of the EWP when the tape is subsequently read. For a partition 1 containing data which is being overwritten, if the point at which overwriting commenced is before the EWP as defined prior to the commencement of overwriting, a new position of the EWP is calculated by the drive currently writing the tape. The calculation shall ensure that the EWP is not less than 3 067 Frames before VEOT. When data is recorded beyond this calculated EWP, the setting of the AEWP bit (see 11.2.3.1.14) changes from ZERO to ONE in the last Basic Group which is completely or partially recorded before that point. This changeover then denotes the position of the EWP when the tape is subsequently read. For a partition 1 containing data which is being overwritten, if the AEWP bit changes from ZERO to ONE prior to the point at which overwriting commenced, the position of the EWP is denoted by that changeover, i.e. the AEWP bit is set to ONE in all overwriting groups in partition 1. NOTE The length of tape occupied by 3 067 frames is approximately 500 mm.

17.1.2.5

Partition 1 EOD Area The Data Area shall be followed by an EOD Area. It shall consist of Tape Management Frames, and shall start after the last Amble Frame in the sequence of Amble Frames which follows the last Recorded Data Group. If the length of tape between the last Amble Frame and VEOT is greater than, or equal to, 450 Frames, the EOD Area shall consist of at least 450 Frames. If the length of tape between the last Amble Frame and VEOT is less than 450 Frames, the length of the EOD Area shall be equal to that length.

17.1.2.6

Partition 1 Post-EOD Area If the end of the EOD Area occurs before VEOT, it shall be followed by a Post-EOD Area which extends to VEOT. This Post-EOD Area shall consist of recorded Frames in which the Area ID (see 11.4.9.1.1) indicates partition 1, but the contents of which are not otherwise specified for interchange.

17.1.3 17.1.3.1

Partition 0 LBOT The LBOT is the Partition Boundary. The first Frame after this point shall have the Absolute Frame Number of one.

17.1.3.2

System Log Pack Item Nos. 8 to 15 shall not be recorded in the frames of the System Log. See 11.5.2.

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17.2

Area ID The most significant bit of the Area ID (see 11.4.11.1.1) shall be set to ONE for partition 0 and to ZERO for Partition 1.

17.3

System Area Pack Items No. 3 and No. 4 In the System Area of partition 0, the bytes of Pack Item No. 6 shall be set to all ONEs.

17.4

Empty partitions On a partitioned tape, of which only one partition contains Recorded Data Groups, the other partition shall be regarded as empty.

17.4.1

Empty partition 1 An empty partition 1 shall contain − − − −

a Reference Area a System Area a Data Area, comprising a Vendor Group and at least 35 Amble Frames a minimum of 3 517 Tape Management Frames identical with those of the EOD Area of partition 1.

The Vendor Group Preamble, the Data Area and the following Tape Management Frames shall form a continuum which extends to the Partition Boundary and in which no unrecorded space, physical discontinuity or seam or Absolute Frame Number discontinuity or Absolute Frame Number repetition is permitted. 17.4.2

Empty partition 0 An empty partition 0 shall contain − − − −

a Reference Area a System Area a Data Area, comprising a Vendor Group and at least 35 Amble Frames an EOD Area of length 450 Frames minimum.

The first Frame of the EOD Area shall be recorded at least 2 500 mm before PEOT. The Vendor Group Preamble, the Data Area and the EOD Area shall form a continuum in which no unrecorded space, physical discontinuity or seam or Absolute Frame Number discontinuity or Absolute Frame Number repetition is permitted.

17.5

Initialization of partitioned tapes When a new or bulk-erased tape is to be used as a partitioned tape, the recording of Recorded Data Groups starts in one partition, the other is empty. In order to define the position of the Partition Boundary, to ensure that the empty partition conforms to the requirements of 17.4, and to assist in efficient management of the tape position, it is convenient to perform an initialization pass prior to the first recording. Such initialization should write, as a continuum, empty partitions 1 and 0 as defined above. If an initialization pass is performed on a recorded tape, it may destroy all data thereon, including history data in the System Log(s).

Housekeeping Frames Housekeeping Frames do not contain any user data. The Main Data Fragments of each track shall be generated by forming a G1 Sub-Group, with a running number of 0 and in which each byte is set to all ZEROs, and then applying the procedure of 11.3 thereto. The Sub code information shall be as defined in 11.4. There are three types of Housekeeping Frames, namely Amble Frames, System Log Frames and Tape Management Frames.

18.1

Amble Frames Amble Frames are permitted only in the Data Area. Their Logical Frame Number shall be zero. The Sub code information in Pack Items No. 0, No. 1, No. 2 and No. 3 shall refer to the Basic Group which is represented by the preceding Recorded Data Group.

- 72 -

Amble Frames are not permitted within a Recorded Data Group, except within a run of Intermediate Frames (see 16.5.4), and are not permitted before the Vendor Group. An Amble Frame shall be preceded only by another Amble Frame or the last Frame of a Recorded Data Group, except at an append point (see 16.5.5.1 and 16.5.5.2).

18.2

System Log Frames System Log Frames shall be recorded within the System Area and with Absolute Frame Numbers in the range 71 to 95. All bytes of Pack Items No. 0, No. 1 and No. 3 shall be set to all ZEROs. Bytes SC0, SC1 and SC2 of Pack Item No. 2 shall be set to all ZEROs. Byte SC3 of Pack Item No. 2 shall be set as defined in 11.4.3.2.

18.3

Tape Management Frames Tape Management Frames shall be recorded only in − − − −

the Reference Area; the System area, except in the System Log; the EOD Area; between VEOT and the Partition Boundary.

All bytes of Pack Items No. 0, No. 1 and No. 3 shall be set to all ZEROs. Bytes SC0, SC1 and SC2 of Pack Item No. 2 shall be set to all ZEROs. Byte SC3 of Pack Item No. 2 shall be set as defined in 11.4.3.2.

- 73 -

Annex A (normative)

Measurement of the light transmittance of the prisms

A.1

The following description outlines the measuring equipment and measuring method to be used for measuring the light transmittance of the prisms. Transmittance is the ratio between the reading obtained from the measuring equipment with the cartridge in position and the reading obtained with a reference prism in position. Transmittance of the cartridge prism: Pc (Cartridge prism) ------------------Pr (Reference prism)

A.2

x 100 %

Radiation source An infra-red light-emitting diode (LED) with the following parameters shall be used: wavelength at peak emission: half-power bandwidth:

A.3

850 nm ± 50 nm ± 50 nm

Radiation receiver A silicon photo diode shall be used. It shall be operated in the short-circuit mode.

A.4

Optical assembly The optical assembly for testing the cartridge prisms shall be as shown in figure A.2. All surfaces shall be matt black. Both optical systems shall be calibrated using the reference prism mounted as in figure A.1. All measurements shall be made in a dark room.

A.5

A.6

Reference prism transmittance:

95 % for a wavelength of 850 nm ± 50 nm

dimensions:

see figure A.3

Measuring circuitry As described in B.2.6; switch S to be in position 0.

- 74 -

a LED PHOTO Tr.

d LED PHOT Tr.

ECMA-95-00099-A

Cartridge prism

Reference prism

ECMA-95-00598-

Figure A.1 - Reference prism a = 3,75 mm b = 13,00 mm c = 64,20 mm

Figure A.2 - Cartridge prism

d = 1,00 mm e = 13,20 mm f = 1,00 mm

6,0 6,0

6,0

ECMA-95-00100-A

Figure A.3 - Perspective view of the reference prism

- 75 -

Annex B (normative)

Measurement of light transmittance of tape and leaders

B.1

Introduction The following description outlines the general principle of the measuring equipment and measuring method to be applied when measuring the light transmittance of tape. For the purpose of this ECMA Standard "light transmittance" is defined by convention as the relationship between the reading obtained from the measuring equipment with the test piece inserted and the reading obtained when no test piece is present. The transmittance value is expressed as the percentage ratio of the two readings.

B.2

Description of the measuring equipment The equipment shall consist of − − − − −

B.2.1

the radiation source; the radiation receiver; the measuring mask; the optical path; the measuring circuitry.

Radiation source An infra-red light-emitting diode (LED) with the following parameters shall be used:

B.2.2

wavelength at peak emission

: 850 nm ± 50 nm

half-power bandwidth

: ± 50 nm

Radiation receiver A flat silicon photo diode shall be used. It shall be operated in the short circuit mode.

B.2.3

Measuring mask The measuring mask shall have a thickness of 2 mm and a circular aperture of diameter d such that the area is 80 % to 100 % of the active area of the photo diode. The surface of the mask shall be matt black. The test piece shall be held firmly against the mask to cover the aperture and to ensure that no ambient light leaks past.

B.2.4

Optical path (figure B.1) The optical path shall be perpendicular to the mask. The distance from the emitting surface of the LED to the mask shall be L=

d  mm 2 tan α

where d is in mm and α is the angle where the relative intensity of the LED is equal to, or greater than, 95% of the maximum intensity of the optical axis.

B.2.5

Finish The whole assembly shall be enclosed in a matt black case.

- 76 -

B.2.6

Measuring circuitry (figure B.2) The components of the measuring circuitry are E R LED Di A Rf0, Rf1 S V

: regulated power supply with variable output voltage : current-limiting resistor : light-emitting diode : silicon photo diode : operational amplifier : feedback resistors : gain switch : voltmeter

The forward current of the LED, and consequently its radiation power, can be varied by means of the power supply E. Di is operating in the short circuit mode. The output voltage of the operational amplifier is given by V0 = Ik x Rf where Ik is the short-circuit current of Di. The output voltage is therefore a linear function of the light intensity. Rf0 and Rf1 shall be low temperature-drift resistors with an accuracy of 1 %. The following ratio applies

Rf 0 Rf 1 B.3

1 20

Measuring method

B.3.1

Set switch S to position 0.

B.3.2

With no test piece mounted vary the supply voltage of E until voltmeter V reads full scale (100 %).

B.3.3

Mount a leader or trailer tape on the mask. The reading of the voltmeter shall be in the range 60 % to 100 %.

B.3.4

Mount a test piece of magnetic tape on the mask. Set switch S to position 1. Full deflection of the voltmeter now represents a light transmittance of 5 %.

- 77 -

Tape

2α LED

Silicon photo diode

Mask

Figure B.1 - Optical arrangement

R f0

R S R f1

LED E

A V

ECMA-93-0124-A

Figure B.2 - Measuring circuitry

Optical Axis

- 78 -

- 79 -

Annex C (normative)

Measurement of Signal-to-Noise Ratio The Signal-to-Noise Ratio shall be measured using a spectrum analyzer with a resolution bandwidth of 10 kHz. Unless otherwise stated, the test conditions are those defined in clause 10 of this ECMA Standard. C.1

A.c. erase the tape to be tested.

C.2

Record the tape at 2 999,9 ftpmm. The associated recording frequency is denoted f 1 .

C.3

Measure the rms signal amplitude by gating the sweep of the spectrum analyzer over a length of track that corresponds to an 70° ± 3° arc of scanner rotation. The centre of this arc shall be within 5° of the centre of the arc of the read head’s contact with the tape. Each sweep yields one measured value. Compute the average of 8 measured values. This is S tape . During each of the same 8 sweeps, measure the total rms noise level at frequency f2, where f2 is 1 MHz less than f1. Each sweep yields one measured value. Compute the average of 8 measured values. This is Ntotal.

C.4

Measure the rms read channel noise level at frequency f 2 over the same 70° arc, without a tape loaded but with the motors running. Each sweep yields one measured value. Compute the average of 8 measured values. This is N amp .

C.5

Compute the Signal-to-Noise Ratio for this pass, 20 log

Stape Ntape

dB, where

2 2 N tape = N total − N amp .

N amp Ntape C.6

C.7

shall be less than 0,7.

Repeat C3, C4, C5 for at least 64 passes. Take the average of the 64 Signal-to-Noise Ratios to determine the Signal-to-Noise Ratio for the tape (SNR tape ). Repeat C.1 to C.6 for the Secondary Standard Reference Tape, to give SNR MSRT . The Signal-to-Noise Ratio characteristic is SNRtape - SNRMSRT dB.

- 80 -

- 81 -

Annex D (normative)

Method for determining the nominal and the maximum allowable recorded levels (pre-recording condition) The following tests shall be carried out under the conditions defined in clause 10 of this ECMA Standard. D.1

Method for determining the Nominal Recorded Level

D.1.1

Read the section of the Secondary Standard Amplitude Calibration Tape that has been recorded at 4 499,8 ftpmm. note the read output and apply the appropriate calibration factor.

D.1.2

a.c. erase the Secondary Standard Reference Tape and record at 4 499,8 ftpmm, increasing the write current from a low value until the output on read equals, after applying the appropriate calibration factor, the value noted in D.1.1.

D.1.3

a.c. erase the interchange tape and record at 4 499,8 ftpmm with the current determined in D.1.2. The read output from this tape is the Nominal Recorded Level for the physical recording density of 4 499,8 ftpmm.

D.1.4 D.2

Repeat D.1.1 to D.1.3 for the physical recording densities of 1 499,9 ftpmm, 1999,9 ftpmm and 2 999,9 ftpmm. Method for determining the Maximum Allowable Recorded Level

D.2.1

a.c. erase the Secondary Standard Reference Tape and record at 4 499,8 ftpmm, increasing the write current until the output on read equals, after applying the appropriate calibration factor, 119 % of the value noted in D.1.1.

D.2.2

a.c. erase the interchange tape and record at 4 499,8 ftpmm with the current determined in D.2.1. The read output from this tape is the Maximum Allowable Recorded Level for the physical recording density of 4 499,8 ftpmm.

D.2.3 D.3

Repeat D.2.1 and D.2.2 for the physical recording densities of 1 499,9 ftpmm, 1 999,9 ftpmm and 2 999,9 ftpmm. Limits for the recorded levels As a history of excessive recording levels can impair the operation of the recording system used in this ECMA Standard it is necessary to prescribe limits for the recording levels to which the tape has been subjected since the last bulk erasure and for the levels used when recording a tape for interchange. These levels are, for each of the physical recording densities of 1 499,9 ftpmm, 1 999,9 ftpmm, 2 999,9 ftpmm and 4 499,8, the Maximum Allowable Recorded Level for that physical recording density. NOTE It is recommended that a tape to be used for interchange should not have been previously recorded at levels higher than its Nominal Recorded Levels at the physical recording densities of 1 499,9 ftpmm, 1 999,9 ftpmm, 2 999,9 ftpmm and 4 499,8 ftpmm.

- 82 -

- 83 -

Annex E (normative)

Representation of 8-bit bytes by 10-bit patterns

E.1

The 8-bit bytes are represented with the most significant bit to the left and the least significant bit to the right. The 10-bit patterns are represented with the bit recorded first to the left and the bit recorded last to the right.

E.2

The magnetic recording system chosen requires that the d.c. level of the recorded signals be maintained near zero. All 10-bit patterns are either balanced to d.c. level of zero or have a d.c. imbalance of 6:4 or 4:6. Each 10-bit pattern is accompanied by an indicator Q which instructs the translator which of the two alternative patterns should be selected for the next 10-bit pattern in order to maintain the lowest d.c. level.

E.3

is the d.c. information of the previous pattern.

is the d.c. information of the current pattern.

The left-hand column indicates the hexadecimal notation of the 8-bit byte for ease of search.

- 84 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(00)

00000000

0101010101

-1

(01)

00000001

0101010111

-1

0101010111

(02)

00000010

0101011101

-1

0101011101

(03)

00000011

0101011111

-1

(04)

00000100

0101001001

-1

0101001001

(05)

00000101

0101001011

-1

(06)

00000110

0101001110

-1

(07)

00000111

0101011010

-1

(08)

00001000

0101110101

-1

0101110101

(09)

00001001

0101110111

-1

(0A)

00001010

0101111101

-1

(0B)

00001011

0101111111

-1

0101111111

(0C)

00001100

0101101001

-1

(0D)

00001101

0101101011

-1

0101101011

(0E)

00001110

0101101110

-1

0101101110

(0F)

00001111

0101111010

-1

0101111010

(10)

00010000

1101010010

-1

(11)

00010001

0100010010

-1

1100010010

-2

-1

(12)

00010010

0101010010

-1

0101010010

(13)

00010011

0101110010

-1

(14)

00010100

1101110001

0101110001

-2

(15)

00010101

1101110011

-1

0101110011

-2

-1

(16)

00010110

1101110110

-1

0101110110

-2

-1

(17)

00010111

1101110010

-1

1101110010

- 85 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(18)

00011000

0101100101

-1

1101100101

-2

-1

(19)

00011001

0101100111

1101100111

-2

(1A)

00011010

0101101101

1101101101

-2

(1B)

00011011

0101101111

-1

1101101111

-2

-1

(1C)

00011100

0101111001

1101111001

-2

(1D)

00011101

0101111011

-1

1101111011

-2

-1

(1E)

00011110

0101111110

-1

1101111110

-2

-1

(1F)

00011111

0101101010

-1

1101101010

-2

-1

(20)

00100000

0111010101

-1

0111010101

(21)

00100001

0111010111

-1

(22)

00100010

0111011101

-1

(23)

00100011

0111011111

-1

0111011111

(24)

00100100

1111010001

0111010001

-2

(25)

00100101

1111010011

-1

0111010011

-2

-1

(26)

00100110

1111010110

-1

0111010110

-2

-1

(27)

00100111

0111011010

-1

0111011010

(28)

00101000

0111110101

-1

(29)

00101001

0111110111

-1

0111110111

(2A)

00101010

0111111101

-1

0111111101

(2B)

00101011

0010011011

-1

1010011011

-2

-1

(2C)

00101100

0111101001

-1

0111101001

(2D)

00101101

0111101011

-1

(2E)

00101110

0111101110

-1

(2F)

00101111

0111111010

-1

- 86 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(30)

00110000

0111010010

-1

(31)

00110001

1110010010

-1

0110010010

-2

-1

(32)

00110010

1111010010

-1

1111010010

(33)

00110011

1111110010

-1

(34)

00110100

0111110001

1111110001

-2

(35)

00110101

0111110011

-1

1111110011

-2

-1

(36)

00110110

0111110110

-1

1111110110

-2

-1

(37)

00110111

0111110010

-1

0111110010

(38)

00111000

0111000101

-1

1111000101

-2

-1

(39)

00111001

0111000111

1111000111

-2

(3A)

00111010

0111001101

1111001101

-2

(3B)

00111011

0111001111

-1

1111001111

-2

-1

(3C)

00111100

0111011001

1111011001

-2

(3D)

00111101

0111011011

-1

1111011011

-2

-1

(3E)

00111110

0111011110

-1

1111011110

-2

-1

(3F)

00111111

0111001010

-1

1111001010

-2

-1

(40)

01000000

0100010101

1100010101

-2

(41)

01000001

0100010111

-1

1100010111

-2

-1

(42)

01000010

0100011101

-1

1100011101

-2

-1

(43)

01000011

0100011111

1100011111

-2

(44)

01000100

0101010001

1101010001

-2

(45)

01000101

0101010011

-1

1101010011

-2

-1

(46)

01000110

0101010110

-1

1101010110

-2

-1

(47)

01000111

0100011010

1100011010

-2

- 87 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(48)

01001000

0100110101

-1

1100110101

-2

-1

(49)

01001001

0100110111

1100110111

-2

(4A)

01001010

0100111101

1100111101

-2

(4B)

01001011

0100111111

-1

1100111111

-2

-1

(4C)

01001100

0100101001

1100101001

-2

(4D)

01001101

0100101011

-1

1100101011

-2

-1

(4E)

01001110

0100101110

-1

1100101110

-2

-1

(4F)

01001111

0100111010

-1

1100111010

-2

-1

(50)

01010000

0100100101

-1

0100100101

(51)

01010001

0100100111

-1

(52)

01010010

0100101101

-1

(53)

01010011

0100101111

-1

0100101111

(54)

01010100

0100111001

-1

(55)

01010101

0100111011

-1

0100111011

(56)

01010110

0100111110

-1

0100111110

(57)

01010111

0100101010

-1

0100101010

(58)

01011000

0110100101

-1

(59)

01011001

0110100111

-1

0110100111

(5A)

01011010

0110101101

-1

0110101101

(5B)

01011011

0110101111

-1

(5C)

01011100

0110111001

-1

0110111001

(5D)

01011101

0110111011

-1

(5E)

01011110

0110111110

-1

(5F)

01011111

0110101010

-1

- 88 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(60)

01100000

0010010101

-1

0010010101

(61)

01100001

0010010111

-1

(62)

01100010

0010011101

-1

(63)

01100011

0010011111

-1

0010011111

(64)

01100100

1010010001

0010010001

-2

(65)

01100101

1010010011

-1

0010010011

-2

-1

(66)

01100110

1010010110

-1

0010010110

-2

-1

(67)

01100111

0010011010

-1

0010011010

(68)

01101000

0010110101

-1

(69)

01101001

0010110111

-1

0010110111

(6A)

01101010

0010111101

-1

0010111101

(6B)

01101011

0010111111

-1

(6C)

01101100

0010101001

-1

0010101001

(6D)

01101101

0010101011

-1

(6E)

01101110

0010101110

-1

(6F)

01101111

0010111010

-1

(70)

01110000

0010010010

-1

(71)

01110001

1011010010

-1

0011010010

-2

-1

(72)

01110010

1010010010

-1

1010010010

(73)

01110011

1010110010

-1

(74)

01110100

0010110001

1010110001

-2

(75)

01110101

0010110011

-1

1010110011

-2

-1

(76)

01110110

0010011110

-1

1010011110

-2

-1

(77)

01110111

0010110010

-1

0010110010

- 89 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(78)

01111000

0011100101

-1

(79)

01111001

0011100111

-1

0011100111

(7A)

01111010

0011101101

-1

0011101101

(7B)

01111011

0011101111

-1

(7C)

01111100

0011111001

-1

0011111001

(7D)

01111101

0011111011

-1

(7E)

01111110

0011111110

-1

(7F)

01111111

0011101010

-1

(80)

10000000

1010010101

-1

(81)

10000001

1010010111

-1

1010010111

(82)

10000010

1010011101

-1

1010011101

(83)

10000011

1010011111

-1

(84)

10000100

1010001001

-1

1010001001

(85)

10000101

1010001011

-1

(86)

10000110

1010001110

-1

(87)

10000111

1010011010

-1

(88)

10001000

1010110101

-1

1010110101

(89)

10001001

1010110111

-1

(8A)

10001010

1010111101

-1

(8B)

10001011

1010111111

-1

1010111111

(8C)

10001100

1010101001

-1

(8D)

10001101

1010101011

-1

1010101011

(8E)

10001110

1010101110

-1

1010101110

(8F)

10001111

1010111010

-1

1010111010

- 90 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(90)

10010000

1100100101

-1

(91)

10010001

1100100111

-1

1100100111

(92)

10010010

1100101101

-1

1100101101

(93)

10010011

1100101111

-1

(94)

10010100

1100111001

-1

1100111001

(95)

10010101

1100111011

-1

(96)

10010110

1100111110

-1

(97)

10010111

1100101010

-1

(98)

10011000

1010100101

-1

0010100101

-2

-1

(99)

10011001

1010100111

0010100111

-2

(9A)

10011010

1010101101

0010101101

-2

(9B)

10011011

1010101111

-1

0010101111

-2

-1

(9C)

10011100

1010111001

0010111001

-2

(9D)

10011101

1010111011

-1

0010111011

-2

-1

(9E)

10011110

1010111110

-1

0010111110

-2

-1

(9F)

10011111

1010101010

-1

0010101010

-2

-1

(A0)

10100000

1011010101

0011010101

-2

(A1)

10100001

1011010111

-1

0011010111

-2

-1

(A2)

10100010

1011011101

-1

0011011101

-2

-1

(A3)

10100011

1011011111

0011011111

-2

(A4)

10100100

1011001001

-1

0011001001

-2

-1

(A5)

10100101

1011001011

0011001011

-2

(A6)

10100110

0111001110

-1

0111001110

(A7)

10100111

1011011010

0011011010

-2

- 91 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(A8)

10101000

1011110101

-1

0011110101

-2

-1

(A9)

10101001

1011110111

0011110111

-2

(AA)

10101010

1011111101

0011111101

-2

(AB)

10101011

1110110010

0110110010

-2

(AC)

10101100

1011101001

0011101001

-2

(AD)

10101101

1011101011

-1

0011101011

-2

-1

(AE)

10101110

1011101110

-1

0011101110

-2

-1

(AF)

10101111

1011111010

-1

0011111010

-2

-1

(B0)

10110000

1101110101

-1

(B1)

10110001

1101110111

-1

1101110111

(B2)

10110010

1101111101

-1

1101111101

(B3)

10110011

1101111111

-1

(B4)

10110100

1101101001

-1

1101101001

(B5)

10110101

1101101011

-1

(B6)

10110110

1101101110

-1

(B7)

10110111

1101111010

-1

(B8)

10111000

1011100101

-1

1011100101

(B9)

10111001

1011100111

-1

(BA)

10111010

1011101101

-1

(BB)

10111011

1011101111

-1

1011101111

(BC)

10111100

1011111001

-1

(BD)

10111101

1011111011

-1

1011111011

(BE)

10111110

1011111110

-1

1011111110

(BF)

10111111

1011101010

-1

1011101010

- 92 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

Q pattern

10-Channel bit

(C0)

11000000

1110010101

0110010101

-2

(C1)

11000001

1110010111

-1

0110010111

-2

-1

(C2)

11000010

1110011101

-1

0110011101

-2

-1

(C3)

11000011

1110011111

0110011111

-2

(C4)

11000100

1110001001

-1

0110001001

-2

-1

(C5)

11000101

1100100011

-1

0100100011

-2

-1

(C6)

11000110

0111001011

-1

0111001011

(C7)

11000111

1110011010

0110011010

-2

(C8)

11001000

1110110101

-1

0110110101

-2

-1

(C9)

11001001

1110110111

0110110111

-2

(CA)

11001010

1110111101

0110111101

-2

(CB)

11001011

1110111111

-1

0110111111

-2

-1

(CC)

11001100

1110101001

0110101001

-2

(CD)

11001101

1110101011

-1

0110101011

-2

-1

(CE)

11001110

1110101110

-1

0110101110

-2

-1

(CF)

11001111

1110111010

-1

0110111010

-2

-1

(D0)

11010000

1101000101

-1

0101000101

-2

-1

(D1)

11010001

1101000111

0101000111

-2

(D2)

11010010

1101001101

0101001101

-2

(D3)

11010011

1101001111

-1

0101001111

-2

-1

(D4)

11010100

1101011001

0101011001

-2

(D5)

11010101

1101011011

-1

0101011011

-2

-1

(D6)

11010110

1101011110

-1

0101011110

-2

-1

(D7)

11010111

1101001010

-1

0101001010

-2

-1

- 93 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(D8)

11011000

1110100101

-1

1110100101

-1

(D9)

11011001

1110100111

-1

(DA)

11011010

1110101101

-0

1110101101

-1

(DB)

11011011

1110101111

-1

1110101111

(DC)

11011100

1110111001

-1

(DD)

11011101

1110111011

-1

1110111011

(DE)

11011110

1110111110

-1

1110111110

(DF)

11011111

1110101010

-1

1110101010

(E0)

11100000

1111010101

-1

(E1)

11100001

1111010111

-1

1111010111

(E2)

11100010

1111011101

-1

1111011101

(E3)

11100011

1111011111

-1

(E4)

11100100

1111001001

-1

1111001001

(E5)

11100101

1111001011

-1

(E6)

11100110

1111001110

-1

(E7)

11100111

1111011010

-1

(E8)

11101000

1111110101

-1

1111110101

(E9)

11101001

1111110111

-1

(EA)

11101010

1011110010

0011110010

-2

(EB)

11101011

0111001001

-1

(EC)

11101100

1111101001

-1

(ED)

11101101

1111101011

-1

1111101011

(EE)

11101110

1111101110

-1

1111101110

(EF)

11101111

1111111010

-1

1111111010

- 94 -

Q’ = -1 8-bit byte

Q’ = 1

10-Channel bit DC pattern

10-Channel bit pattern

(F0)

11110000

1101010101

-1

1101010101

(F1)

11110001

1101010111

-1

(F2)

11110010

1101011101

-1

(F3)

11110011

1101011111

-1

1101011111

(F4)

11110100

1101001001

-1

(F5)

11110101

1101001011

-1

1101001011

(F6)

11110110

1101001110

-1

1101001110

(F7)

11110111

1101011010

-1

1101011010

(F8)

11111000

1111100101

-1

0111100101

-2

-1

(F9)

11111001

1111100111

0111100111

-2

(FA)

11111010

1111101101

0111101101

-2

(FB)

11111011

1111101111

-1

0111101111

-2

-1

(FC)

11111100

1111111001

0111111001

-2

(FD)

11111101

1111111011

-1

0111111011

-2

-1

(FE)

11111110

1100100110

-1

0100100110

-2

-1

(FF)

11111111

1111101010

-1

0111101010

-2

-1

- 95 -

Annex F (normative)

Measurement of bit shift The tape to be measured shall have been written by the tape drive used for data interchange. The tape shall have been written in any mode compatible with system operation. F.1

Reading equipment The tape shall be read on any drive which supports a track linearity of 3 µm max., as defined in annex G. There are no absolute requirements placed on the output voltage of the head. However, the head design, the rotary transformer, the pre-amplifier, the head-to-tape speed and the equalizer shall be chosen so as to avoid problems due to a low signal-to-noise ratio. −

Read head gap length

0,20 µm ± 0,05 µm

angle of the head gap

The gap in the head of positive azimuth shall make an angle of + 20° 00' ± 12' with the axis of the scanner. The gap in the head of negative azimuth shall make an angle of - 20° 00' ± 12' with the axis of the scanner.

−

Head-tape contact and read channel The stability of the head-tape contact during the signal capture period (see F.2), together with the overall frequency response of the head, the rotary transformer, the pre-amplifier and the equalizer shall be sufficient to give a Signal-to-Noise ratio of better than 10 dB.

F.2

Measurement method Bit shift shall be measured using computational signal processing of a digitized record of the playback voltage waveform at the equalizer output. The signal capture period shall start with the first bit of Margin Zone No. 1 (see 15.1) and finish when at least 25 000 Channel bits of the Main Data Zone have been read. The signal processing algorithm shall perform the following steps 1) Input the digitized waveform from Margin Zone No.1 and the Preamble Zone into a timing extraction algorithm, e.g. a Fast Fourier Transform, which generates a series of fixed-interval time references for the nominal centres of the bit periods of the readback Channel bit signals from those zones. These references shall be sufficiently accurate that, when steps 2), 3) and 4) are executed, the bit error rate specified in 4) is achieved. 2) Extend this series of time references, at the same frequency and phase, into the remainder of the signal capture period. These references define the timing of the nominal centers of the bit periods of the readback Channel bit signals from the Main Data Zone. 3) Measure the playback voltage, to an accuracy of better than 2 %, at the nominal centre of each captured bit period from the Main Data Zone. 4) For each captured bit period from the Main Data Zone, deduce the state of the corresponding bit cell on the tape under test, by means of a detection method which has a bit error rate of less than 1 in 10 000. For each bit cell which is magnetized in the direction of head travel, assign to it a data value D of +1. For each bit cell which is magnetized in the direction opposite to head travel, assign to it a data value D of -1. 5) For each bit cell, form a vector of 4 elements. The elements shall be numbered 1, 2, 3 and 4. The value D3 of the third element shall be the data value D of the current bit cell. The value D4 of the fourth element shall be the data value D of the next bit cell. The values D1 and D2 respectively of the first and second elements shall be the data values D of the previous two bit cells. Thus, the vector has a vector value i which is one of a set of 16 possible vector values.

- 96 -

6) For each of the 16 vector values, compute the average Vi of the playback voltages, measured in step 3), of all bit cells whose vectors have that vector value i. 7) Arrange the voltage averages and the data values to form 16 Volterra series, one per vector value. Each series shall be as defined below : Vi

A0000

(d.c. term)

+ A0100 D2 + A0010 D3

(signal terms)

+ A1000 D1 + A0001 D4

(linear ISI terms)

+ A1100 D1 D2 + A0110 D2 D3 + A0011 D3 D4

(non-linear ISI terms)

+ A1010 D1 D3 + A0101 D2 D4 + A1001 D1 D4

(more non-linear ISI terms)

+ A1101 D1 D2 D4 + A1011 D1 D3 D4 + A1111 D1 D2 D3 D4

(more non-linear ISI terms)

+ A1110 D1 D2 D3 + A0111 D2 D3 D4

(non-linear ISI terms associated with bit shift)

8) Obtain the Volterra coefficients A0000 to A1111 by solving the 16 simultaneous equations formed in step 7). 9) The Volterra coefficients which indicate non-linear inter-symbol interference corresponding to bit shift are A1110 and A0111.

NOTE The theoretical basis for this method is described in Newby, P. and Wood, R., 1986 "The effects of Nonlinear Distortion on Class IV Partial Response" IEEE Transactions on Magnetics Volume MAG-22, Number 5, September 1986, Page 1203 and an application of this method is described in Williams, C.H., 1990 "The Measurement and Classification of Impairment for DVTR Transports" 8th Conference on Video, Audio and Data Recording IEE Conference Publication No. 319, page 67

- 97 -

Annex G (normative)

Measurement of track edge linearity

G.1

Condition The test piece shall be secured under a longitudinal tension between 0,05 N and 0,11 N.

G.2

Procedure Define a rectangular box of 21,87 mm × 4 µm with its longitudinal axis at an angle α = 6° 22' 39,6" with the Tape Reference Edge and its centre on the ideal tape centreline (see 13.8), positioned over the leading edge of the track.

G.3

Requirement Place the box, by varying its position only along the longitudinal axis of the tape, in such a position that the track’s leading edge intersects its short sides only.

Ideal tape centerline. α Figure G.1 Track edge linearity

- 98 -

- 99 -

Annex H (informative)

Recognition Holes In other applications, the case of the cartridge specified by this Standard may be loaded with different types of tape. Table H.1 indicates the combinations of states of the Recognition Holes which are defined for existing applications and are recommended for future applications. Table H.1 - Recognition Holes Recognition Hole 1 2 3 4

Tape thickness

Tape coating

Track width

Pre-recorded

Format

0 0 0 0

13 µm

Metal Particle (MP)

13,6 µm

DDS

0 0 0 1

13 µm

13,6 µm

Yes

DDS

0 0 1 0

Cleaning cartridge

0 0 1 1

13 µm

Barium Ferrite

20,4 µm

Yes

DAT

0 1 0 0

9 µm

13,6 µm

DDS

0 1 0 1

9 µm

13,6 µm

Yes

DDS

0 1 1 0

Reserved

0 1 1 1

9 µm

Barium Ferrite

20,4 µm

Yes

DAT

1 0 0 0

6,9 µm

MP+

9,1 µm

DDS-2

9,1 µm

DDS-3

1 0 0 1 1 0 1 0

Reserved 6,9 µm

MP ++

1 0 1 1

Reserved

1 1 0 0

Reserved

1 1 0 1

Reserved

1 1 1 0

Reserved

1 1 1 1

Reserved

DDS-4

1 = hole open 0 = hole closed In the rightmost column of table H.1, the terms have the following meanings: DDS

The Recorded Format is either that of ECMA-139 and ECMA-170 (i.e. DDS) or of ECMA-150 (i.e. DDS-DC)

DDS-2

The Recorded Format is that of ECMA-198.

DDS-3

The Recorded Format is as specified in this Standard, ECMA-236.

DDS-4

A future Recorded Format

DAT

The Recorded Format is that of IEC 1119-1.

- 100 -

- 101 -

Annex J (informative)

Means to open the lid

J.1

Figure J.1 shows the bottom side of the case. The two square areas defined by dimension a = 2 mm are the contact areas where the force opening the lid is to be applied.

J.2

Figure J.2 and J.3 show an example of implementation. The drive in which the cartridge is introduced has two pins positioned so that their ends lie below the two areas shown in figure J.1 when the cartridge is inserted. When the cartridge is then pushed downwards (figure J.2) the pins open the lid completely (figure J.3)

ECMA-95-00101-A

Figure J.1 - Bottom side of the case

- 102 -

ECMA-95-00102-A

Figure J.2 Intermediate position within the drive

ECMA-95-00103A

Figure J.3 Final position within the drive

- 103 -

Annex K (informative)

Recommendations for transportation K.1

Environment It is recommended that during transportation the cartridges are kept within the following conditions: temperature

: - 40 °C to 45 °C

relative humidity

: 5 % to 80 %

wet bulb temperature

: 26 °C max.

There shall be no condensation in or on the cartridge. K.2

Hazards Transportation of recorded cartridges involves three basic potential hazards.

K.2.1

Impact loads and vibrations The following recommendations should minimize damage during transportation.

K.2.2

K.2.3

Avoid mechanical loads that would distort the cartridge shape.

Avoid dropping the cartridge more than 1 m.

Cartridges should be fitted into a rigid box containing adequate shock-absorbent material.

The final box must have a clean interior and a construction that provides sealing to prevent the ingress of dirt and water.

The orientation of the cartridges within the final box should be such that the axes of the tape reels are horizontal.

The final box should be clearly marked to indicate its correct orientation.

Extremes of temperature and humidity a)

Extreme changes in temperature and humidity should be avoided whenever possible.

Whenever a cartridge is received it should be conditioned in the operating environment for a period of at least 24 h.

Effects of stray magnetic fields A nominal spacing of not less than 80 mm should exist between the cartridge and the outer surface of the shipping container. This should minimize the risk of corruption.

- 104 -

- 105 -

Annex L (informative)

Read-After-Write

Read-After-Write (RAW) is a technique by which a Frame is read immediately after being written, examined to determine if it was written successfully, and re-written if not. The unit of RAW is a Frame. The RAW technique is applicable only in the Data Area of a tape, and is not applied to Amble Frames. Where RAW is applicable, it may be applied or not applied to individual Frames, regardless of whether or not it is applied to other Frames. When a Frame is identified, during a Read-After-Write check, as having been unsuccessfully written, it is rewritten further along the tape, i.e. the original Frame is not overwritten by the re-written Frame. The primary intent of the RAW check is the detection of Frames containing errors of significant size and/or quantity, e.g. as caused by non-trivial media defects. Consequently, where RAW is applied it is not necessary that all Channel Bits be read correctly to avoid a re-write. Instead, the minimum requirement needs to be only that the quality of the recording and the quantity of correctly decoded data is such that the data of the entire Frame is recoverable with sufficient margin for reliable data interchange. The actual performance of a Frame against this requirement can be assessed in a number of ways, for example by measuring the length, severity and/or distribution of missing pulses, counting the number of errors detected by C1 and/or C2, comparing written and read checksums, comparing written and read data on a sampled or full time basis. Where a Frame has been rewritten multiple instances of it will exist. It is possible that a subsequent read will successfully recover data from more than one instance of a Frame. In such case, it is recommended that the last successfully recovered instance be used, since previous ones may have been considered unsuccessfully written.

- 106 -

- 107 -

Annex M (informative)

Example of the content of a Basic Group No. 0

Byte Position

Field Name

1-128

Name of Manufacturer

Name of the manufacturer of the drive that initialized or wrote the partition.

129-160

Model Number

Model number or identifier of the drive that initialized or wrote the partition.

161-192

Serial Number

Serial number assigned to the drive.

193-224

Revision Number

Revision numbers of drive components: 193-200 Sub-assembly 1 201-208 Sub-assembly 2 209-216 Sub-assembly 3 217-224 Sub-assembly 4

225-256

Host Interface Type and Address

Type of host interface, e.g. SCSI and connection address. 225-240 Host Interface Type 241-256 Address

257-272

Date and Time

YYMMDDHHMMSS

Date and time the partition was initialized 257-258 YY year = 1980 + YY 259-260 MM month 261-262 DD day 263-264 HH hour 265-266 MM minutes 267-268 SS seconds

273-400

Tape Label or Identifier

An indicator of the partition's content.

401-17 468

Reserved

All bytes set to all ZEROs

17 469-384 296 Manufacturer's data

Description of Contents

Not specified

Figure M.1 - Example of a Basic Group No. 0

All entries in byte positions 1 to 400 are followed by a byte set to all ZEROs and the remainder of the field is padded with bytes which are set to all ZEROs.

- 108 -

- 109 -

Annex N (informative)

Generating and Receiving Drives

Drives generating or receiving magnetic tape cartridges for interchange should be designed to operate in a way that does not inhibit or damage the magnetic tape. Characteristics that contribute to poor tape drive performance include poor tape guidance, damaged or worn recording heads, contaminated tape path components.

Printed copies can be ordered from: ECMA 114 Rue du Rhône CH-1204 Geneva Switzerland Fax: Internet:

+41 22 849.60.01 [email protected]

Files can be downloaded from our FTP site, ftp.ecma.ch, logging in as anonymous and giving your E-mail address as password. This Standard is available from library ECMA-ST as a compacted, self-expanding file in MSWord 6.0 format (file E236-DOC.EXE) and as a compacted, self-expanding PostScript file (file E236-PSC.EXE). File E236-EXP.TXT gives a short presentation of the Standard. The ECMA site can be reached also via a modem. The phone number is +41 22 735.33.29, modem settings are 8/n/1. Telnet (at ftp.ecma.ch) can also be used. Our web site, http://www.ecma.ch, gives full information on ECMA, ECMA activities, ECMA Standards and Technical Reports.

ECMA 114 Rue du Rhône CH-1204 Geneva Switzerland This Standard ECMA-236 is available free of charge in printed form and as a file. See inside cover page for instructions

ECMA-236 — 3,81 mm wide magnetic tape cartridge for information interchange - Helical scan recording - DDS-3 format using 125 m length tapes (June 1996)

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