Winchester

Winchester: n.  Informal generic 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 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 common
   term for a famous Winchester rifle (in the latter, the first 30
   referred to caliber and the second to the grain weight of the
   charge).  Others claim, however, that Winchester was simply the
   laboratory in which the technology was developed.