DASD

[deyz-dee]
noun Computers.
  1. an external storage device, as a magnetic disk storage unit, in which the access mechanism and storage medium can be positioned directly at the addresses sought to read or write specific data items.

Origin of DASD

d(irect-)a(ccess) s(torage) d(evice)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018