... term for sealed-enclosure magnetic-disk drives in which the read-write head planes over the disk surface on an air cushion. There is a legend that the name arose because the original 1973 engineering prototype for what later became the IBM 3340 featured two 30-megabyte volumes; 30—30 became 'Winchester' when somebody noticed the similarity to the ... — The Jargon File, Version 4.0.0
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