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]] or [[optical storage]].<ref>{{citecitation|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>{{citecitation|title=Turing machine model of computation sequential access 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, arbitrary locations can still be accessed 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]]. [[Magnetic tape]] is the onlya type of sequential access memory still in use; historically, [[drum memory]] has also been used.

== See also ==

{{Portal|Computing}}

* [[Sequential access]]

* [[Basic sequential access method]] (BSAM)

* [[Queued Sequential Access Method|Queued sequential access method]] (QSAM)

* [[Secondary storage]]

** [[Hard disk drive]]

** [[Solid-state drive]]

* [[Magnetic storage]]

* [[Hard disk]]

* [[Magnetic tape]]

* [[Drum memory]]