ECMA 146 : 1ED 90

SECTION I - GENERAL
1 SCOPE
2 CONFORMANCE
   2.1 Magnetic Tape Cartridge
   2.2 Generating System
   2.3 Receiving System
3 REFERENCES
4 DEFINITIONS
   4.1 Absolute Frame Number (AFN)
   4.2 Area ID
   4.3 Automatic Track Finding (ATF)
   4.4 Average Signal Amplitude
   4.5 Azimuth
   4.6 Back Surface
   4.7 Byte
   4.8 Cartridge
   4.9 Channel Bit
   4.10 Data Format ID
   4.11 End of Data (EOD)
   4.12 End of Information (EOI)
   4.13 End of Partition (EOP)
   4.14 Error Correcting Code (ECC)
   4.15 Flux Transition Position
   4.16 Flux Transition Spacing
   4.17 Frame
   4.18 Group
   4.19 Logical Beginning of Tape (LBOT)
   4.20 Logical End of Tape (LEOT)
   4.21 Magnetic Tape
   4.22 Master Reference
   4.23 Master Standard Amplitude Calibration Tape
   4.24 Master Standard Reference Tape
   4.25 Optimum Recording Field
   4.26 Partition
   4.27 Partition Reference
   4.28 Physical Beginning of Tape (PBOT)
   4.29 Physical End of Tape (PEOT)
   4.30 Physical Recording Density
   4.31 Pre-recording Condition
   4.32 Record
   4.33 Reference Recording Field
   4.34 Secondary Standard Amplitude Calibration Tape
   4.35 Secondary Standard Reference Tape
   4.36 Separator
   4.37 Standard Reference Amplitude
   4.38 Tape Noise Amplitude
   4.39 Tape Reference Edge
   4.40 Track
5 ENVIRONMENT AND SAFETY
   5.1 Testing Environment
   5.2 Operating Environment
   5.3 Storage Environment
   5.4 Transportation
   5.5 Safety
   5.6 Flammability
SECTION II - REQUIREMENTS FOR THE CASE
6 DIMENSIONAL AND MECHANICAL CHARACTERISTICS OF THE CASE
   6.1 General
   6.2 Overall Dimensions (Fig. 6 and 7)
   6.3 Loading Grip (Fig. 6)
   6.4 Holding Areas (Fig. 6)
   6.5 Notches of the Lid (Fig. 5 and 8)
   6.6 Lid Dimensions (Fig. 6 to 8)
   6.7 Optical Detection of the Beginning and End of Tape
        (Fig. 9 and 12)
   6.8 Bottom Side (Fig. 10 and 11)
        6.8.1 Locking mechanism of the slider
        6.8.2 Access holes
        6.8.3 Recognition, Sub-datum and Write-inhibit
               holes
        6.8.4 Datum Holes
        6.8.5 Access room for tape guides
        6.8.6 Holes for accessing the hubs
        6.8.7 Internal structure of the lower half
               (Fig. 12)
        6.8.8 Light path (Fig. 12)
        6.8.9 Support Areas (Fig. 13)
        6.8.10 Datum Areas (Fig. 13)
        6.8.11 Relationship between Support and Datum Areas
               and Reference Plane Z (Fig. 14)
   6.9 Hubs (Fig. 15, 16)
   6.10 Leader and Trailer Attachment
   6.11 Interface between the Hubs and the Drive Spindles
        (Fig. 17)
   6.12 Opening of the Lid (Fig. 18)
   6.13 Release of the Hub Locking Mechanism (Fig. 19, 20)
   6.14 Label Area (Fig. 21, 22)
SECTION III - REQUIREMENTS FOR THE UNRECORDED TAPE
7 MECHANICAL, PHYSICAL AND DIMENSIONAL CHARACTERISTICS OF
   THE TAPE
   7.1 Materials
   7.2 Tape Length
        7.2.1 Length of Magnetic Tape
        7.2.2 Length of Leader and Trailer Tapes
   7.3 Tape Width
   7.4 Discontinuities
   7.5 Total Thickness
   7.6 Longitudinal Curvature
   7.7 Cupping
   7.8 Coating Adhesion
   7.9 Layer-to-Layer Adhesion
   7.10 Tensile Strength
        7.10.1 Breaking Strength
        7.10.2 Yield Strength
   7.11 Residual Elongation
   7.12 Electrical Resistance of Coated Surfaces
   7.13 Light Transmittance of Tape
8 MAGNETIC RECORDING CHARACTERISTICS
   8.1 Optimum Recording Field
   8.2 Signal Amplitude
   8.3 Resolution
   8.4 Overwrite
        8.4.1 Physical Recording Densities of 750,6 and
               3002 ftpmm
        8.4.2 Physical Recording Densities of 83,4 ftpmm
               and 1001 ftpmm
   8.5 Ease of Erasure
   8.6 Tape Quality
        8.6.1 Missing Pulses
        8.6.2 Missing Pulse Zone
   8.7 Signal-to-Noise Ratio (S/N) Characteristic
SECTION IV - REQUIREMENTS FOR AN INTERCHANGED TAPE
9 DATA/DAT FORMAT
   9.1 General
   9.2 Basic Groups
        9.2.1 Basic Groups for Group Format 0
        9.2.2 Basic Groups for Group Format 1
   9.3 Sub-Groups
        9.3.1 G1 Sub-groups
        9.3.2 G2 Sub-groups
        9.3.3 G3 Sub-groups
        9.3.4 G4 Sub-group
        9.3.5 Main Data Block
   9.4 Sub-Data Area
        9.4.1 Pack Item No. 1
        9.4.2 Pack Item No. 2
        9.4.3 Pack Item No. 3
        9.4.4 Pack Item No. 4
        9.4.5 Pack Item No. 5
        9.4.6 Pack Item No. 6
        9.4.7 Pack Item No. 7
        9.4.8 Sub Data Block
   9.5 Basic Group Structure
        9.5.1 User Data
        9.5.2 System Data
        9.5.3 Record ID List
        9.5.4 Heuristic Recovery Data Area
10 METHOD OF RECORDING
   10.1 Physical Recording Density
   10.2 Long-Term Average Bit Cell Length
   10.3 Short-Term Average Bit Cell Length
   10.4 Rate of Change
   10.5 Bit Shift
   10.6 Read Signal Amplitude
   10.7 Maximum Recorded Levels
11 TRACK GEOMETRY
   11.1 Track Configuration
        11.1.1 Average Track Pitch
        11.1.2 Variations of the track pitch
        11.1.3 Track Width
        11.1.4 Track Angle
        11.1.5 Track Edge Linearity
        11.1.6 Track Length
        11.1.7 Ideal Tape Centreline
        11.1.8 Azimuth Angles
12 RECORDING OF BLOCKS ON THE TAPE
   12.1 Recorded Main Data Block
   12.2 Recorded Sub Data Block
   12.3 Margin Blocks, Preamble Blocks and Postamble
        Blocks
   12.4 Spacer Blocks
13 FORMAT OF A TRACK
   13.1 Track Capacity
   13.2 Positioning Accuracy
   13.3 Tracking Scheme
14 GROUP FORMATS
   14.1 Group Format 0
   14.2 Group Format 1
   14.3 Extended Gap Frames
        14.3.1 Extended Leading Gap Frames
        14.3.2 Extended Trailing Gap Frames
   14.4 Types of Groups
        14.4.1 Normal Groups
        14.4.2 Spare Groups
        14.4.3 Amble Groups
        14.4.4 Header Groups
15 MAGNETIC TAPE LAYOUT
   15.1 Load/Unload Area
   15.2 Lead-in Area
        15.2.1 Preamble
        15.2.2 Header
        15.2.3 Format Parameter Set
        15.2.4 Master Reference
        15.2.5 Postamble
   15.3 Partition
        15.3.1 Partition Preamble
        15.3.2 Partition Reference
        15.3.3 Partition Postamble
        15.3.4 Partition Data
        15.3.5 End of Partition (EOP)
        15.3.6 Unused Area
   15.4 EOI
   15.5 Repeated Groups
   15.6 Repeated Frames within a Normal Group
   15.7 Relocation of Defective Groups
   15.8 Appending
        15.8.1 Seamless Appending
        15.8.2 Non-Seamless Appending
   15.9 Overwrite
        15.9.1 Overlapped Track Width
        15.9.2 Non-overlapped Track Width
        15.9.3 Rules for Overwrite
SECTION V - APPENDICES
APPENDIX A - MEASUREMENT OF LIGHT TRANSMITTANCE OF THE
             PRISMS
APPENDIX B - RECOGNITION HOLES
APPENDIX C - MEANS TO OPEN THE LID
APPENDIX D - MEASUREMENT OF LIGHT TRANSMITTANCE OF TAPE
             AND LEADERS
APPENDIX E - MEASUREMENT OF SIGNAL-TO-NOISE RATIO
APPENDIX F - METHOD FOR DETERMINING THE NOMINAL AND THE
             MAXIMUM ALLOWABLE RECORDED LEVELS
APPENDIX G - REPRESENTATION OF 8-BIT BYTES BY 10-BIT
             PATTERN
APPENDIX H - MEASUREMENT OF BIT SHIFT
APPENDIX J - RECOMMENDATIONS FOR TRANSPORTATION
APPENDIX K - METHOD OF MEASURING TRACK EDGE LINEARITY
APPENDIX L - READ-AFTER-WRITE
APPENDIX M - DATA ALLOCATION AND C3 PARITY

Describes the physical and magnetic characteristics of a 3,81 mm wide magnetic tape cartridge to enable interchangeability of such cartridges. Also specifies the quality of the recorded signals, and the format and recording method, thereby allowing data interchange by means of such magnetic tape cartridges.