Dynamic random-access memory: Difference between revisions

Revision as of 13:25, 22 September 2024

Revision as of 15:37, 22 September 2024

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The [[cryptanalysis|cryptanalytic]] machine code-named ''"Aquarius"'' used at [[Bletchley Park]] during [[World War II]] incorporated a hard-wired dynamic memory. Paper tape was read and the characters on it "were remembered in a dynamic store. The store used a large bank of capacitors, which were either charged or not, a charged capacitor representing cross (1) and an uncharged capacitor dot (0). Since the charge gradually leaked away, a periodic pulse was applied to top up those still charged (hence the term 'dynamic')".<ref>{{cite book |first1=B. Jack |last1=Copeland |title=Colossus: The secrets of Bletchley Park's code-breaking computers |url=https://books.google.com/books?id=YiiQDwAAQBAJ&pg=PA301 |date=2010 |publisher=Oxford University Press |isbn=978-0-19-157366-8 |page=301}}</ref>

In November 1965, [[Toshiba]] introduced a bipolar dynamic RAM for its [[electronic calculator]] ''"Toscal" BC-1411''.<ref name="toscal">{{cite web|url=http://www.oldcalculatormuseum.com/s-toshbc1411.html|title=Spec Sheet for Toshiba "TOSCAL" BC-1411|website=www.oldcalculatormuseum.com|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20170703071307/http://www.oldcalculatormuseum.com/s-toshbc1411.html|archive-date=3 July 2017}}</ref><ref>[http://collection.sciencemuseum.org.uk/objects/co8406093/toscal-bc-1411-calculator-with-electronic-calculator Toscal BC-1411 calculator] {{webarchive|url=https://web.archive.org/web/20170729145228/http://collection.sciencemuseum.org.uk/objects/co8406093/toscal-bc-1411-calculator-with-electronic-calculator |date=2017-07-29 }}, [[Science Museum, London]]</ref><ref>[http://www.oldcalculatormuseum.com/toshbc1411.html Toshiba "Toscal" BC-1411 Desktop Calculator] {{webarchive|url=https://web.archive.org/web/20070520202433/http://www.oldcalculatormuseum.com/toshbc1411.html |date=2007-05-20 }}</ref> In 1966, Tomohisa Yoshimaru and Hiroshi Komikawa from Toshiba applied for ana Japanese patent of a memory circuit composed of several transistors and a capacitor, in 1967 they applied for a patent in the US.<ref>{{cite web |title=Memory Circuit |url= https://patents.google.com/patent/US3550092A/en?q=(memory+)&assignee=Toshiba+Corp&before=priority:19670101&after=priority:19640101|website=[[Google Patents]] |access-date=18 June 2023}}</ref>

The earliest forms of DRAM mentioned above used [[bipolar transistors]]. While it offered improved performance over [[magnetic-core memory]], bipolar DRAM could not compete with the lower price of the then-dominant magnetic-core memory.<ref>{{cite web |title=1966: Semiconductor RAMs Serve High-speed Storage Needs |url=https://www.computerhistory.org/siliconengine/semiconductor-rams-serve-high-speed-storage-needs/ |website=Computer History Museum}}</ref> Capacitors had also been used for earlier memory schemes, such as the drum of the [[Atanasoff–Berry Computer]], the [[Williams tube]] and the [[Selectron tube]].