IBM 7 track
Tape Data Recovery - IBM 7 track
IBM 7 track tape was part of IBM’s first magnetic tape data storage devices introduced in 1952. The tape is ½-inch wide and consists of 7 tracks, 6 for data and one for maintaining parity. Data is stored as 6-bit characters.
Important Features
IBM 7 track tape had initial recording density of 100 characters per inch. Later models supported 200, 556 and 800 characters per inch. The system had latency of 1.5ms for the stopped tape to reach its full reading or writing speed. To mark the logical beginning and end, a small aluminum strip was glued a few feet away from the ends of the tape. A removable plastic ring provided in the back of the tape reel enabled write protection feature.
Applications
IBM used 7 track models in various tape storage systems. The first one to use IBM 7 track tape was IBM 726 magnetic tape reader/recorder for the IBM 701. The successive model IBM 727 was introduced for the IBM 701 and IBM 702 in 1953.
The next one to use IBM 7 track tape was the IBM 728 magnetic tape drive used on the SAGE AN/FSQ-7 computer. Though it resembled IBM 727, it had different specifications with 6 data tracks and 1 for synchronization. It used 6 characters (32 data bits, 1 parity bit, 3 end of file bits)/
IBM 729, used in late 700, most 7000 and many 1400 series of computers, was the next to use 7 track tapes. Later models that used 7 track tapes included IBM 7330 and IBM 2400 series. IBM 7330 was a low cost slower tape system used in 1400 series of computers. The 2400 Series Magnetic tapes were used in the System/360. However, most of 2400 Series used IBM 9 Track format drives, but they could also be ordered with 7 track read/write heads, allowing them to read and write 7 track tapes.
