|
The IBM 729 Magnetic Tape Unit was IBM's iconic tape mass storage system from the late 1950s through the mid 1960s. It was used on late 700, most 7000 and many 1400 series computers. Like its predecessor, the IBM 727 and many successors, the 729 used 1/2 inch (12.7 mm) tape up to 2400 feet (731 meter) long wound on reels up to 10-1/2 inch (267 mm) diameter. To allow rapid tape acceleration, long vacuum columns were placed between the tape reels and the read/write heads. The tape had seven parallel tracks, six for data and one to maintain odd parity. Aluminum strips were glued several feet from the ends of the tape to serve as logical beginning and end of tape markers. Write protection was provided by a removable plastic ring in the back of the tape reel. A gap between records allowed the mechanism time to stop the tape. Initial tape speed was 75 inch/second and recording density was 200 characters per inch. Later models supported 556 and 800 characters/inch.
Reference:
- IBM 709 Data Processing System, Form A22-6501-0
|
