IBM 726 | 1952
The IBM 726 was IBM's first magnetic tape unit, designed as a dual reader/recorder. Developed for the IBM 701, it was announced on May 21, 1952, and shipped with the 701 from December 20, 1952, until February 28, 1955. Notably, the IBM 726 was capable of reading tape in both forward and reverse directions, a feature not common in later models.
Technical Specifications
- Tracks: 6 Data tracks, 1 Parity track
- Copy Groups per Inch: 100
- Tape Speed: 75 inches/second
- Transfer Rate: 7,500 copy groups/second
- End of Record Gap: 1 inch (equivalent to 100 characters or 16.67 words)
- Start Time: 10 milliseconds
- Stop Time: 10 milliseconds
- Tape Width: 1/2 inch
- Length of Reel: 1,200 feet
- Tape Composition: Cellulose acetate base
Functionality
The IBM 726 utilized odd parity for data recording, which ensured at least one bit transition per copy group and provided error checking capabilities. The system concurrently managed two reels of tape, with two 726 units integrated into each IBM 701 system.
This innovative technology marked a significant advancement in data storage and retrieval, laying the groundwork for future developments in magnetic tape technology.
