TRACTOR

TRACTOR was the fastest method yet developed for computer input and output

In April 1960, IBM's Data Processing Division (DPD) announced that IBM had developed a computer tape system that could read and write electronically at the rate of 1.5 million characters -- or the equivalent of four full-length novels -- a second.

TRACTOR was the fastest method yet developed for computer input and output
DPD said the system -- designated TRACTOR -- was the fastest method yet developed for computer input and output. TRACTOR could manipulate as many as 640 sealed cartridges holding 220 miles of magnetic tape, and its full capacity was 60 billion characters of information -- enough to house a library of 150,000 volumes.

One authoritative source* reports that TRACTOR was an automated tape-cartridge library developed for attachment to the U.S. National Security Agency's (NSA) Harvest** supercomputer. Each TRACTOR reel contained an 1800-foot-long tape, capable of holding 120 million characters. The tape reel, together with a take-up reel, was enclosed in a dust-proof cartridge designed to be mounted, dismounted, stored and retrieved by the automated tape library. The cartridges were about 11 inches high, 24 inches long, three inches wide and weighed 15 pounds. TRACTOR could swap one cartridge for another in 18 seconds. NSA's Harvest system reportedly had three automated libraries, representing more online storage than any other system of the time. It remained in operation, with the TRACTOR libraries, for 14 years.

* Emerson W. Pugh, Lyle R. Johnson and John H. Palmer. IBM's 360 And Early 370 Systems. (Cambridge, Mass.: The MIT Press, 1991), p. 235.

** Background information about Harvest is available in James Bamford's Body Of Secrets: Anatomy Of The Ultra-Secret National Security Agency (N.Y.: Anchor Books, 2002).


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