9 track tape
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IBM's System/360, released in 1964, introduced what is now generally known as 9-track tape. The magnetic tape is 1/2 inch (12.7 mm) wide, with 8 data tracks and one parity track for a total of 9 parallel tracks. Data is stored as 8-bit characters, spanning the full width of the tape (including the parity bit). Various recording methods are used to place the data on tape, depending on the tape speed and data density, including PE (phase encoding), GCR (group code recording) and NRZI (non-return-to-zero, inverted, sometimes pronounced "nur-zee").
The standard size of a byte was effectively set at 8 bits with the S/360 and 9 track tape.
Contents |
[edit] IBM generations
| IBM Model | 2400 Series | 3400 Series |
|---|---|---|
| Model numbers | 2401, 2415, 2420, 2440 | 3410, 3420, 3422, 3440 |
| Density (bytes/in) | 800, 1600 | |
| Tape speed (in/s) | 18.75 - 200 | |
| Transfer rate (B/s) | 15,000 - 320,000 | |
| Interblock gap (in) | 0.6 | |
| Rewind speed (in/s, avg.) | ||
| Start time (ms) | ||
| Stop time (ms) | ||
| Length of reel (ft) | 2400 | |
| Base composition | Plastic |
[edit] 2400 Series
The 2400 Series Magnetic Tape Units were introduced with the System/360 and were the first to use 9 track tape. The dimensions of the tape and reels were identical to those used with 7 track units, such as the IBM 729. But older 7 track tapes could only be read and written on special 2400 drives equipped with 7 track read and write heads and the 7 track compatibility option.
[edit] 3400 Series
The 3400 Series Magnetic Tape Units were introduced with the System/370.
[edit] Examples
 Two small 1/2" tapes, front and back. |
 Aluminum foil stickers marked the start and end of tape. |
 The write protection ring prevented the tape from being written on when removed. |
[edit] Standards
- ANSI INCITS 40-1993 (R2003) Unrecorded Magnetic Tape for Information Interchange (9-Track, 800 CPI, NRZI; 1600 CPI, PE; and 6250 CPI, GCR)
- ISO/IEC 1863:1990 9-track, 12.7 mm (½ in) wide magnetic tape for information interchange using NRZ1 at 32 ftpmm (800 ftpi) - 32 cpmm (800 cpi)
- ISO/IEC 3788:1990 9-track, 12.7 mm (½ in) wide magnetic tape for information interchange using phase encoding at 126 ftpmm (3 200 ftpi), 63 cpmm (1600 cpi)
- ANSI INCITS 54-1986 (R2002) Recorded Magnetic Tape for Information Interchange (6250 CPI, Group Coded Recording)
- ANSI INCITS 27-1987 (R2003) Magnetic Tape Labels and File Structure for Information Interchange
[edit] External links
- At bitsavers.org
- Cipher documentation
- DEC TS11 TU80 (1600 PE) TA78 TA79 TU81(1600 PE, 6250 GCR)
- Fujitsu M244x Tape Drive CE Manual
- HP 7970 Maintenance Course Handouts: 800 NRZI & 1600 PE drives
- IBM 2400 Series Tape Drives Manual
- Kennedy tape models
- M4Data documentation
- Univac UNISERVO IIIA, IIIC Magnetic Tape Subsystem Technical Bulletins
- HP 7976A 7978A 7980A (88780AB) (1600 PE, 6250 GCR)] HP 7974A 1600 PE at hpmuseum.net
- A reliable, autoloading, streaming half-inch tape drive (7980A, 88780AB) HP Journal, June 1988
- IBM 9348-012 (1600, 6250)
- Brochures for M4 Data 9906 1600, (-2 → 3200, -5 → 6250), 9914, 9914V (800, 1600, 3200, 6250)
- Qualstar 3400 Series
- Timeline of OEM drive manufacturers
| Magnetic tape data storage formats | ||
|---|---|---|
| Linear | Helical-Scan | |
| Three Quarter Inch (~19 mm) |
||
| Half Inch (12.65 mm) |
UNISERVO (1951) - IBM 7 Track (1952) - 9 Track (1964) - IBM 3480 (1984) - DLT (1984) - IBM 3590 (1995) - T9840 (1998) - T9940 (2000) - LTO Ultrium (2000) - T10000 (2006) |
Redwood SD-3 (1995) - DTF (19xx) - SAIT (2003) |
| Eight Millimeter (8 mm) |
Travan (1995) - IBM 3570 MP (1997) |
|
| Quarter Inch (6.35 mm) |
||
| Eighth Inch (3.81 mm) |
KC Standard, Compact Cassette (1975) - DC100 (1976) - Datassette (1977) - DECtapeII (1979) |
DDS/DAT (1989) |
| Stringy (1.58 - 1.9 mm) |
Exatron Stringy Floppy (1979) - ZX Microdrive (1983) - Rotronics Wafadrive (1984) |
|
