Direct Access Storage Device
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A Direct Access Storage Device is a Secondary Storage that ...
- AKA: Direct-Access Storage Device.
- See: Tape Drive, Secondary Storage, IBM, Mainframe Computer, Minicomputer, Disk Drive, Drum Memory, IBM 2321 Data Cell, Optical Disc Drive, Access Method, Direct Access (Computing), Sequential Access.
References
2016
- (Wikipedia, 2016) ⇒ https://en.wikipedia.org/wiki/Direct-access_storage_device Retrieved:2016-9-22.
- A direct-access storage device (DASD) pronounced ) is a secondary storage device in which "each physical record has a discrete location and a unique address." IBM developed DASDs for use with mainframe computers and some minicomputers. Disk drives, magnetic drums, data cells and optical disc drives are all classified as DASDs.
Access methods for DASDs include sequential, indexed, and direct. Direct access contrasts with the sequential access method used in tape drives. A record on a DASD can be accessed without having to read through intervening records from the current location, whereas reading anything other than the "next" record on tape requires skipping over intervening records, and requires a proportionally long time to access a distant point in a medium.
The DASD storage class includes both fixed and removable media.
- A direct-access storage device (DASD) pronounced ) is a secondary storage device in which "each physical record has a discrete location and a unique address." IBM developed DASDs for use with mainframe computers and some minicomputers. Disk drives, magnetic drums, data cells and optical disc drives are all classified as DASDs.