Sequential access memory: Difference between revisions

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In computing, '''[[sequential access]] [[computer memory|memory]]''' ('''SAM''') is a class of [[data storage device]]s that read stored data in a sequence. This is in contrast to [[random access memory]] (RAM) where data can be accessed in any order. Sequential access devices are usually a form of [[magnetic storage]].<ref>{{cite|title=difference between sequential and random access operations|url=http://kb.sandisk.com/app/answers/detail/a_id/8150/~/difference-between-sequential-and-random-access-operations}}</ref><ref>{{cite|title=turingTuring machine model of computation sequential acessaccess memory|url=http://www.docfoc.com/1-lecture-13-turing-machine-model-of-computation-sequential-access-memory}}</ref>

While sequential access memory is read in sequence, accessesarbitrary locations can still be made to arbitrary locationsaccessed by "seeking" to the requested ___location. This operation, however, is often relatively inefficient (see [[seek time]], [[rotational latency]]).

Magnetic sequential access memory is typically used for [[secondary storage]] in general-purpose computers due to their higher density at lower cost compared to RAM, as well as resistance to wear and [[non-volatility]]. Examples of SAM devices still in use include [[hard disk]]s, [[CD-ROM]]s and [[magnetic tape]]s. Historically, [[drum memory]] has also been used.