Editing Computer memory (section)

=== MOS memory ===
{{Main|MOS memory}}

The invention of the metal–oxide–semiconductor field-effect transistor ([[MOSFET]]) enabled the practical use of [[metal–oxide–semiconductor]] (MOS) transistors as [[memory cell (computing)|memory cell]] storage elements. MOS memory was developed by John Schmidt at [[Fairchild Semiconductor]] in 1964.<ref>{{Cite book|url=https://books.google.com/books?id=kG4rAQAAIAAJ&q=John+Schmidt|title=Solid State Design - Vol. 6|date=1965|publisher=Horizon House}}</ref> In addition to higher performance, MOS [[semiconductor memory]] was cheaper and consumed less power than magnetic core memory.<ref name="computerhistory1970">{{cite web |title=1970: MOS Dynamic RAM Competes with Magnetic Core Memory on Price |url=https://www.computerhistory.org/siliconengine/mos-dynamic-ram-competes-with-magnetic-core-memory-on-price/ |website=[[Computer History Museum]] |access-date=29 July 2019}}</ref> In 1965, J. Wood and R. Ball of the [[Royal Radar Establishment]] proposed digital storage systems that use [[CMOS]] (complementary MOS) memory cells, in addition to MOSFET [[power devices]] for the [[power supply]], switched cross-coupling, [[switches]] and [[delay-line memory|delay-line storage]].<ref>{{cite conference |last1=Wood |first1=J. |last2=Ball |first2=R. |title=1965 IEEE International Solid-State Circuits Conference. Digest of Technical Papers |chapter=The use of insulated-gate field-effect transistors in digital storage systems |conference=1965 IEEE International Solid-State Circuits Conference. Digest of Technical Papers |date=February 1965 |volume=VIII |pages=82–83 |doi=10.1109/ISSCC.1965.1157606}}</ref> The development of [[silicon-gate]] [[MOS integrated circuit]] (MOS IC) technology by [[Federico Faggin]] at Fairchild in 1968 enabled the production of MOS [[memory chip]]s.<ref>{{cite web |title=1968: Silicon Gate Technology Developed for ICs |url=https://www.computerhistory.org/siliconengine/silicon-gate-technology-developed-for-ics/ |website=[[Computer History Museum]] |access-date=10 August 2019}}</ref> [[NMOS logic|NMOS]] memory was commercialized by [[IBM]] in the early 1970s.<ref>{{cite journal |last1=Critchlow |first1=D. L. |title=Recollections on MOSFET Scaling |journal=IEEE Solid-State Circuits Society Newsletter |date=2007 |volume=12 |issue=1 |pages=19–22 |doi=10.1109/N-SSC.2007.4785536 |doi-access= }}</ref> MOS memory overtook magnetic core memory as the dominant memory technology in the early 1970s.<ref name="computerhistory1970"/>

The two main types of volatile [[random-access memory]] (RAM) are [[static random-access memory]] (SRAM) and [[dynamic random-access memory]] (DRAM). Bipolar SRAM was invented by Robert Norman at Fairchild Semiconductor in 1963,<ref name="computerhistory1966"/> followed by the development of MOS SRAM by John Schmidt at Fairchild in 1964.<ref name="computerhistory1970"/> SRAM became an alternative to magnetic-core memory, but requires six transistors for each [[bit]] of data.<ref name="ibm100">{{cite web |title=DRAM |url=https://www.ibm.com/ibm/history/ibm100/us/en/icons/dram/ |website=IBM100 |publisher=[[IBM]] |access-date=20 September 2019 |date=9 August 2017}}</ref> Commercial use of SRAM began in 1965, when IBM introduced their SP95 SRAM chip for the [[IBM System/360|System/360 Model 95]].<ref name="computerhistory1966"/>

[[Toshiba]] introduced bipolar DRAM [[Memory cell (computing)|memory cells]] for its Toscal BC-1411 [[electronic calculator]] in 1965.<ref name="bc-spec">{{cite web|url=http://www.oldcalculatormuseum.com/s-toshbc1411.html|title=Spec Sheet for Toshiba "TOSCAL" BC-1411|website=Old Calculator Web Museum|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 name="bc">{{cite web |url=http://www.oldcalculatormuseum.com/toshbc1411.html |title=Toshiba "Toscal" BC-1411 Desktop Calculator |archive-url=https://web.archive.org/web/20070520202433/http://www.oldcalculatormuseum.com/toshbc1411.html |archive-date=2007-05-20}}</ref> While it offered improved performance, 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> MOS technology is the basis for modern DRAM. In 1966, [[Robert H. Dennard]] at the [[IBM Thomas J. Watson Research Center]] was working on MOS memory. While examining the characteristics of MOS technology, he found it was possible to build [[capacitors]], and that storing a charge or no charge on the MOS capacitor could represent the 1 and 0 of a bit, while the MOS transistor could control writing the charge to the capacitor. This led to his development of a single-transistor DRAM memory cell.<ref name="ibm100"/> In 1967, Dennard filed a patent for a single-transistor DRAM memory cell based on MOS technology.<ref>{{cite web |title=Robert Dennard |url=https://www.britannica.com/biography/Robert-Dennard |website=[[Encyclopedia Britannica]] |access-date=8 July 2019}}</ref> This led to the first commercial DRAM IC chip, the [[Intel 1103]] in October 1970.<ref name="Intel2003">{{cite web |title=Intel: 35 Years of Innovation (1968–2003) |url=https://www.intel.com/Assets/PDF/General/35yrs.pdf |publisher=Intel |year=2003 |access-date=26 June 2019 |archive-url=https://web.archive.org/web/20211104070452/https://www.intel.com/Assets/PDF/General/35yrs.pdf |archive-date=4 November 2021 |url-status=dead}}</ref><ref name="HC">[http://history-computer.com/ModernComputer/Basis/dram.html ''The DRAM memory of Robert Dennard''] history-computer.com</ref><ref name="Lojek-1103">{{cite book |last1=Lojek |first1=Bo |title=History of Semiconductor Engineering |date=2007 |publisher=[[Springer Science & Business Media]] |isbn=9783540342588 |pages=362–363 |url=https://books.google.com/books?id=2cu1Oh_COv8C&pg=PA362 |quote=The i1103 was manufactured on a 6-mask silicon-gate P-MOS process with 8 μm minimum features. The resulting product had a 2,400 µm, 2 memory cell size, a die size just under 10 mm², and sold for around $21.}}</ref> [[Synchronous dynamic random-access memory]] (SDRAM) later debuted with the [[Samsung Electronics|Samsung]] KM48SL2000 chip in 1992.<ref>{{cite web |title=KM48SL2000-7 Datasheet |url=https://www.datasheetarchive.com/KM48SL2000-7-datasheet.html |publisher=[[Samsung]] |access-date=19 June 2019 |date=August 1992}}</ref><ref name="electronic-design">{{cite journal |title=Electronic Design |journal=[[Electronic Design]] |date=1993 |volume=41 |issue=15–21 |url=https://books.google.com/books?id=QmpJAQAAIAAJ |publisher=Hayden Publishing Company |quote=The first commercial synchronous DRAM, the Samsung 16-Mbit KM48SL2000, employs a single-bank architecture that lets system designers easily transition from asynchronous to synchronous systems.}}</ref>

The term ''memory'' is also often used to refer to [[non-volatile memory]] including [[read-only memory]] (ROM) through modern [[flash memory]]. [[Programmable read-only memory]] (PROM) was invented by [[Wen Tsing Chow]] in 1956, while working for the Arma Division of the American Bosch Arma Corporation.<ref name="Huang2008">{{cite book|author=Han-Way Huang|title=Embedded System Design with C805|url=https://books.google.com/books?id=3zRtCgAAQBAJ&pg=PA22|date=5 December 2008|publisher=Cengage Learning|isbn=978-1-111-81079-5|page=22|url-status=live|archive-url=https://web.archive.org/web/20180427092847/https://books.google.com/books?id=3zRtCgAAQBAJ&pg=PA22|archive-date=27 April 2018}}</ref><ref name="AufaureZimányi2013">{{cite book|author1=Marie-Aude Aufaure|author2=Esteban Zimányi|title=Business Intelligence: Second European Summer School, eBISS 2012, Brussels, Belgium, July 15-21, 2012, Tutorial Lectures|url=https://books.google.com/books?id=7iK5BQAAQBAJ&pg=PA136|date=17 January 2013|publisher=Springer|isbn=978-3-642-36318-4|page=136|url-status=live|archive-url=https://web.archive.org/web/20180427092847/https://books.google.com/books?id=7iK5BQAAQBAJ&pg=PA136|archive-date=27 April 2018}}</ref> In 1967, Dawon Kahng and [[Simon Sze]] of Bell Labs proposed that the [[floating gate]] of a MOS [[semiconductor device]] could be used for the cell of a reprogrammable ROM, which led to [[Dov Frohman]] of [[Intel]] inventing [[EPROM]] (erasable PROM) in 1971.<ref name="computerhistory1971">{{cite web |title=1971: Reusable semiconductor ROM introduced |url=https://www.computerhistory.org/storageengine/reusable-semiconductor-rom-introduced/ |website=[[Computer History Museum]] |access-date=19 June 2019}}</ref> [[EEPROM]] (electrically erasable PROM) was developed by Yasuo Tarui, Yutaka Hayashi and Kiyoko Naga at the [[Electrotechnical Laboratory]] in 1972.<ref>{{cite journal|last1=Tarui|first1=Y.|last2=Hayashi|first2=Y.|last3=Nagai|first3=K.|title=Electrically reprogrammable nonvolatile semiconductor memory|journal=IEEE Journal of Solid-State Circuits|date=1972|volume=7|issue=5|pages=369–375|doi=10.1109/JSSC.1972.1052895|issn=0018-9200|bibcode=1972IJSSC...7..369T}}</ref> Flash memory was invented by [[Fujio Masuoka]] at [[Toshiba]] in the early 1980s.<ref>{{cite web |last=Fulford |first=Benjamin |title=Unsung hero |work=Forbes |date=24 June 2002 |access-date=18 March 2008 |url=https://www.forbes.com/global/2002/0624/030.html |url-status=live |archive-url=https://web.archive.org/web/20080303205125/http://www.forbes.com/global/2002/0624/030.html |archive-date=3 March 2008 |df=dmy-all }}</ref><ref>{{patent|US|4531203|Fujio Masuoka}}</ref> Masuoka and colleagues presented the invention of [[NOR flash]] in 1984,<ref>{{cite web |title=Toshiba: Inventor of Flash Memory |url=http://www.flash25.toshiba.com |website=[[Toshiba]] |access-date=20 June 2019}}</ref> and then [[NAND flash]] in 1987.<ref>{{cite conference |chapter=New ultra high density EPROM and flash EEPROM with NAND structure cell |last1=Masuoka |first1=F. |last2=Momodomi |first2=M. |last3=Iwata |first3=Y. |last4=Shirota |first4=R. |title=1987 International Electron Devices Meeting |year=1987 |pages=552–555 |conference=[[International Electron Devices Meeting|IEDM]] 1987 |book-title=Electron Devices Meeting, 1987 International |publisher=[[IEEE]] |df=dmy |doi=10.1109/IEDM.1987.191485}}</ref> Toshiba commercialized NAND flash memory in 1987.<ref name=":0">{{cite web |title=1987: Toshiba Launches NAND Flash |url=https://www.eweek.com/storage/1987-toshiba-launches-nand-flash |website=[[eWeek]] |date=April 11, 2012 |access-date=20 June 2019}}</ref><ref>{{cite web |title=1971: Reusable semiconductor ROM introduced |url=https://www.computerhistory.org/storageengine/reusable-semiconductor-rom-introduced/ |website=[[Computer History Museum]] |access-date=19 June 2019}}</ref><ref name=":2" />

Developments in technology and economies of scale have made possible so-called '''{{vanchor|very large memory}}''' (VLM) computers.<ref name=":2">{{cite book
 |last        = Stanek
 |first       = William R.
 |title       = Windows Server 2008 Inside Out
 |url         = https://books.google.com/books?id=SbxixF4iAEcC
 |access-date  = 2012-08-20
 |year        = 2009
 |publisher   = O'Reilly Media, Inc.
 |isbn        = 978-0-7356-3806-8
 |pages       = 1520
 |quote       = [...] Windows Server Enterprise supports clustering with up to eight-node clusters and very large memory (VLM) configurations of up to 32&nbsp;GB on 32-bit systems and 2&nbsp;TB on 64-bit systems.
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20130127064935/http://books.google.com/books?id=SbxixF4iAEcC
 |archive-date = 2013-01-27
}}</ref>