IBM 729
Tape Data Recovery - IBM 729
The IBM 729 Magnetic Tape Unit was part of IBM 7 track family of tape units. They were the popular tape mass storage system used by IBM from the late 1950s through the mid 1960s.
Architecture
IBM 729 used ½-inch magnetic tape up to 2400 feet long, wound on reels with diameter 10 ½ inches. The tape had seven parallel tracks, six for data and one to maintain parity. Character data tapes used even parity while binary data tapes used odd parity. 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.
IBM 729 Models
IBM introduced six models of IBM 729. IBM 729 I was introduced for IBM 709 and IBM 705 III computers. Like the previous model IBM 727, IBM 729 used vacuum tubes. The main difference was the use of a dual gap head that permitted write verify.
IBM 729 II was introduced for the IBM 7000 series computers. This model used a new cabinet style and transistorized circuitry.
The successive models focused on increasing speed and density. IBM 729 III offered speed at the rate of 112.5 inches per second and single density 556. 729 IV had the same speed but offered dual density (200, 556). The fifth model offered high density of 800. The last model improvised on both speed and density, offering high speed of 112.5 in/s and high density of 800.
The 729 series became obsolete with the introduction of 9 track tape drives in IBM System/360.
