Mrs. Coleman doing a washing at Irwinville Farms, Georgia. May 1938. (Photo by By John Vachon).
IBM 701 Tape Drive
The First Magnetic Tape Drive for Computer Data Storage
In 1949, IBM began to plan for a new storage and i/o medium to take the place of punched cards. The new medium would be more compact, faster, cheaper, and reusable. Magnetic tape technology had been used for audio recording and playback since World War II, and it was adapted for computer use — initially in a prototype called the Tape Processing Machine (TPM), 1950-51. Of course computer data storage and retrieval is different from audio recording and playback, requiring accurate positioning (both forwards and backwards) to arbitrary spots and therefore much fancier motors, not to mention stress relief for the tape itself, accomplished with vacuum columns (invented by IBM). New digital recording techniques were developed allowing mapping of computer memory to tape with error detection, coding of records and boundaries, and so forth.
The first magnetic tape drives were successfully demonstrated on the TPM and then adapted to the 701 (also known as the Defense Calculator), IBM's first commercial computer, which could accommodate four tape drives. The 701 tape drive shown above recorded 100 characters per inch and had a throughput of 70 inches (or 7000 characters) per second.
