ECMA 248 : 2ED 98

Section 1 - General
1 Scope
2 Conformance
   2.1 Magnetic tape cassette
   2.2 Generating system
   2.3 Receiving system
3 References
4 Definitions
   4.1 Absolute block number
   4.2 a.c. erase
   4.3 algorithm
   4.4 Append file
   4.5 Append volume
   4.6 Average Signal Amplitude (ASA)
   4.7 azimuth
   4.8 back surface
   4.9 bit cell
   4.10 block
   4.11 Block Management Table (BMT)
   4.12 byte
   4.13 cassette
   4.14 compressed data
   4.15 Control Track
   4.16 flux transition position
   4.17 flux transition spacing
   4.18 Logical track set ID
   4.19 Logical volume
   4.20 magnetic tape
   4.21 Master Standard Reference Tape (MSRT)
   4.22 physical recording density
   4.23 Reference Field (RF)
   4.24 Secondary Standard Reference Tape (SSRT)
   4.25 Standard Reference Amplitude (SRA)
   4.26 Standard Reference Current (Ir)
   4.27 Tape Reference Edge
   4.28 Test Recording Current (TRC)
   4.29 track
   4.30 track angle
   4.31 Track Set
   4.32 Typical Field (TF)
   4.33 Unique Identifier (UID)
   4.34 word
5 Conventions and notations
   5.1 Representation of numbers
   5.2 Names
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
Section 2 - Requirements for the case
8 Dimensional and mechanical characteristics of the case
   8.1 General
   8.2 Type S cassette
        8.2.1 Overall dimensions
        8.2.2 Holding areas
        8.2.3 Window
        8.2.4 Label areas (figure 4)
        8.2.5 Datum areas and datum holes
        8.2.6 Support areas
        8.2.7 Guiding grooves
        8.2.8 Recognition holes
        8.2.9 Write-inhibit plug
        8.2.10 Pre-positioning surface
        8.2.11 Cassette lid
        8.2.12 Cassette reel lock
        8.2.13 Reel access holes
        8.2.14 Reels
        8.2.15 Position of the tape in the case
        8.2.16 Tape path zone
        8.2.17 Tape access cavity
    8.3 Type L cassette
        8.3.1 Overall dimensions
        8.3.2 Holding areas
        8.3.3 Window
        8.3.4 Label areas
        8.3.5 Datum areas and datum holes
        8.3.6 Support areas
        8.3.7 Guiding grooves
        8.3.8 Recognition holes
        8.3.9 Write-inhibit plug
        8.3.10 Pre-positioning surface
        8.3.11 Cassette lid
        8.3.12 Cassette reel lock
        8.3.13 Reel access holes
        8.3.14 Reels
        8.3.15 Position of the tape in the case
        8.3.16 Tape path zone
        8.3.17 Tape access cavity
        8.3.18 Cavity for compatibility with Type S
               cassette
Section 3 - Requirements for the unrecorded tape
9 Mechanical, physical and dimensional characteristics
   of the tape
   9.1 Materials
   9.2 Tape length
   9.3 Tape width
   9.4 Width and position of splicing tape
   9.5 Discontinuity
   9.6 Tape thickness
   9.7 Longitudinal curvature
   9.8 Out-of-plane distortions
   9.9 Coating adhesion
   9.10 Layer-to-layer adhesion
   9.11 Tensile strength
        9.11.1 Breaking strength
        9.11.2 Yield strength
        9.11.3 Strength of Splice
   9.12 Residual elongation
   9.13 Electrical resistance of the coated surfaces
   9.14 Tape wind
10 Magnetic recording characteristics
   10.1 Typical Field TF1
   10.2 Average Signal Amplitude (ASA)
   10.3 Resolution
   10.4 Signal-to-noise ratio (S/N)
   10.5 Ease of erasure
   10.6 Tape quality
        10.6.1 Missing pulses
        10.6.2 Missing pulse zone
   10.7 Inhibitor tape
Section 4 - Requirements for an interchanged tape
11 Format for helical tracks
   11.1 General description of the write data path (see
        figure 42)
   11.2 Formation of a Logical Track Set
        11.2.1 Types of information track sets
        11.2.2 Generation of a Logical Track Set
        11.2.3 Subcode data field
        11.2.4 BMT
        11.2.5 Data and information field definitions
   11.3 Track Set information
        11.3.1 Loading the Product Code Arrays
   11.4 Product code array processing
        11.4.1 Error correction method
        11.4.2 Error correction coding for C1 Parity
   11.5 Track assignments
        11.5.1 Sectors
        11.5.2 Sync Blocks
        11.5.3 Track interleave
        11.5.4 Track Sync Blocks
        11.5.5 Byte interleave across Sync Blocks
        11.5.6 Randomization
   11.6 Formation of the contents of a helical track
        11.6.1 Sector details
   11.7 Channel bit coding
        11.7.1 General
        11.7.2 Interleaved-NRZ1
12 Track geometry
   12.1 General
   12.2 Helically recorded tracks
        12.2.1 Location of the tracks
        12.2.2 Track width
        12.2.3 Track angle
        12.2.4 Track pitch
        12.2.5 Location of elements in the helical track
        12.2.6 Location of the Data Area Reference Point
        12.2.7 Straightness of tracks
        12.2.8 Azimuth angles
        12.2.9 Tracking Pilot Signal (TPS)
        12.2.10 Amplitude of servo signals
   12.3 Longitudinal tracks geometry
        12.3.1 Control Track
        12.3.2 Time Code Track signals recording position
13 Method of recording helical tracks
   13.1 Physical recording density
   13.2 Record current optimization
   13.3 Efficiency of erasure
14 Method of recording longitudinal tracks
   14.1 Overview
   14.2 Control Track
        14.2.1 Signal
        14.2.2 Polarity of magnetisation
        14.2.3 Alignment
        14.2.4 Read signal amplitude
        14.2.5 Quality of the Control Track
   14.3 Time Code Track
        14.3.1 Method of recording the Time Code Track
        14.3.2 Physical recording density
        14.3.3 Bit shift
        14.3.4 Read signal amplitude
        14.3.5 Quality of the Time Code Track
   14.4 Format for the Time Code Track
        14.4.1 Count bits
        14.4.2 Phase bit
        14.4.3 Synchronizing pattern
        14.4.4 Supplemental Data
        14.4.5 Extent of Time Code
Section 5 - Requirements for recorded information
15 Recorded information
   15.1 Recording area
   15.2 Magnetic tape layout
        15.2.1 Valid data areas
        15.2.2 Invalid data areas
   15.3 Physical TSID
        15.3.1 Structure surrounding the VSIT area
        15.3.2 Structure of the DIT area
        15.3.3 Structure of the User Data Area
Section 6 - Write operations
16 Write retry sequence
17 Append file operation
   17.1 Append volume
   17.2 Append write
   17.3 Overwrite
   17.4 File extension
Annex A - Measurement of Signal-to-Noise Ratio
Annex B - Representation 8/9 coding patterns
Annex C - Recommendations for Transportation
Annex D - Inhibitor Tape

Gives the magnetic and physical characteristic of magnetic tape cassettes using magnetic tape 12,65 mm wide providing physical interchange of such cassettes between drives. It also covers the quality of the recorded signals the recording method and the recorded format called Digital Tape Format-1 (DTF-1) allowing data interchange between drives by means of such cassettes. The format supports variable length Logical Records high speed search as well as registered algorithm for data compression.