Parallel RAM: Difference between revisions

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Revision as of 07:58, 10 March 2024

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#Exclusive read exclusive write (EREW)—every memory cell can be read or written to by only one processor at a time

#Concurrent read exclusive write (CREW)—multiple processors can read a memory cell but only one can write at a time

#Exclusive read concurrent write (ERCW)—mostly never considered because it mostly doesn't add more power<ref>{{Cite journal |last=MacKenzie |first=Philip D. |last2=Ramachandran |first2=Vijaya |date=1998-04-06 |title=ERCW PRAMs and optical communication |url=https://www.sciencedirect.com/science/article/pii/S0304397597001990 |journal=Theoretical Computer Science |volume=196 |issue=1 |pages=153–180 |doi=10.1016/S0304-3975(97)00199-0 |issn=0304-3975}}</ref>

#Exclusive read concurrent write (ERCW)—never considered{{cn|date=August 2023}}

#Concurrent read concurrent write (CRCW)—multiple processors can read and write. A CRCW PRAM is sometimes called a '''concurrent random-access machine'''.<ref>Neil Immerman, ''[http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.57.1834&rep=rep1&type=pdf Expressibility and parallel complexity]''. SIAM Journal on Computing, vol. 18, no. 3, pp. 625-638, 1989.</ref>