Computer memory - Revision history

Popcornfud: WP:SHORTDESC, short descriptions should be under 40 characters

2025-04-18T22:21:16Z

WP:SHORTDESC, short descriptions should be under 40 characters

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	{{~~short~~ description\|~~Computer component~~ that stores information ~~for immediate use~~}}		{{Short description\|Component that stores information}}
	{{Merge from\|Data in use\|discuss=Talk:Computer memory#Proposed merge of Data in use into Computer memory\|date=March 2025}}		{{Merge from\|Data in use\|discuss=Talk:Computer memory#Proposed merge of Data in use into Computer memory\|date=March 2025}}
	{{Use American English\|date=June 2023}}		{{Use American English\|date=June 2023}}

Fgnievinski: Added {{Merge from}} tag

2025-03-17T20:50:39Z

Added {{Merge from}} tag

← Previous revision		Revision as of 20:50, 17 March 2025
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	{{short description\|Computer component that stores information for immediate use}}		{{short description\|Computer component that stores information for immediate use}}
			{{Merge from\|Data in use\|discuss=Talk:Computer memory#Proposed merge of Data in use into Computer memory\|date=March 2025}}
	{{Use American English\|date=June 2023}}		{{Use American English\|date=June 2023}}
	[[File:RAM Module (SDRAM-DDR4).jpg\|thumb\|[[DDR4 SDRAM]] module. {{As of\|2021}}, over 90 percent of computer memory used in PCs and servers was of this type.<ref>{{cite news \|last1=Read \|first1=Jennifer \|title=DDR5 Era To Officially Begin In 2021, With DRAM Market Currently Transitioning Between Generations, Says TrendForce \|url=https://www.emsnow.com/ddr5-era-to-officially-begin-in-2021-with-dram-market-currently-transitioning-between-generations-says-trendforce/ \|access-date=2 November 2022 \|publisher=EMSNow \|date=5 November 2020}}</ref>]]		[[File:RAM Module (SDRAM-DDR4).jpg\|thumb\|[[DDR4 SDRAM]] module. {{As of\|2021}}, over 90 percent of computer memory used in PCs and servers was of this type.<ref>{{cite news \|last1=Read \|first1=Jennifer \|title=DDR5 Era To Officially Begin In 2021, With DRAM Market Currently Transitioning Between Generations, Says TrendForce \|url=https://www.emsnow.com/ddr5-era-to-officially-begin-in-2021-with-dram-market-currently-transitioning-between-generations-says-trendforce/ \|access-date=2 November 2022 \|publisher=EMSNow \|date=5 November 2020}}</ref>]]

Kvng: Reverted good faith edits by 70.26.38.100 (talk): No improvement, WP:NOTBROKEN

2024-10-01T18:37:24Z

Reverted good faith edits by 70.26.38.100 (talk): No improvement, WP:NOTBROKEN

← Previous revision		Revision as of 18:37, 1 October 2024
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	{{Memory types}}		{{Memory types}}

	'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[~~Random-access memory\|~~RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>		'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>

	Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[RAM]] capacity for caching so long as it is not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.		Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[RAM]] capacity for caching so long as it is not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.

70.26.38.100 at 04:35, 26 September 2024

2024-09-26T04:35:26Z

← Previous revision		Revision as of 04:35, 26 September 2024
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	{{Memory types}}		{{Memory types}}

	'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>		'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[Random-access memory\|RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>

	Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[RAM]] capacity for caching so long as it is not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.		Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[RAM]] capacity for caching so long as it is not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.

Tule-hog: /* Volatility categories */ group into section

2024-09-05T18:53:41Z

Volatility categories: group into section

← Previous revision		Revision as of 18:53, 5 September 2024
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	}}</ref>		}}</ref>

			==Volatility categories==
⚫	== Volatile memory ==

		⚫	=== Volatile memory ===
	[[File:Kinds-of-RAM.JPG\|thumb\|Various memory modules containing different types of DRAM (from top to bottom): DDR SDRAM, SDRAM, EDO DRAM, and FPM DRAM]]		[[File:Kinds-of-RAM.JPG\|thumb\|Various memory modules containing different types of DRAM (from top to bottom): DDR SDRAM, SDRAM, EDO DRAM, and FPM DRAM]]
	{{Main\|Volatile memory}}		{{Main\|Volatile memory}}
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	SRAM retains its contents as long as the power is connected and may use a simpler interface, but [[Static random-access memory#Design\|commonly uses six transistors per bit]]. Dynamic RAM is more complicated for interfacing and control, needing regular refresh cycles to prevent losing its contents, but uses only one transistor and one capacitor per bit, allowing it to reach much higher densities and much cheaper per-bit costs.<ref name=":1" /><ref name="HC" /><ref name=":2" />		SRAM retains its contents as long as the power is connected and may use a simpler interface, but [[Static random-access memory#Design\|commonly uses six transistors per bit]]. Dynamic RAM is more complicated for interfacing and control, needing regular refresh cycles to prevent losing its contents, but uses only one transistor and one capacitor per bit, allowing it to reach much higher densities and much cheaper per-bit costs.<ref name=":1" /><ref name="HC" /><ref name=":2" />

	== Non-volatile memory ==		=== Non-volatile memory ===
	{{Main\|Non-volatile memory}}		{{Main\|Non-volatile memory}}

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	Non-volatile memory technologies under development include [[ferroelectric RAM]], [[programmable metallization cell]], [[Spin-transfer torque magnetic RAM]], [[SONOS]], [[resistive random-access memory]], [[racetrack memory]], [[Nano-RAM]], [[3D XPoint]], and [[millipede memory]].		Non-volatile memory technologies under development include [[ferroelectric RAM]], [[programmable metallization cell]], [[Spin-transfer torque magnetic RAM]], [[SONOS]], [[resistive random-access memory]], [[racetrack memory]], [[Nano-RAM]], [[3D XPoint]], and [[millipede memory]].

	== Semi-volatile memory ==		=== Semi-volatile memory ===
	A third category of memory is ''semi-volatile''. The term is used to describe a memory that has some limited non-volatile duration after power is removed, but then data is ultimately lost. A typical goal when using a semi-volatile memory is to provide the high performance and durability associated with volatile memories while providing some benefits of non-volatile memory.		A third category of memory is ''semi-volatile''. The term is used to describe a memory that has some limited non-volatile duration after power is removed, but then data is ultimately lost. A typical goal when using a semi-volatile memory is to provide the high performance and durability associated with volatile memories while providing some benefits of non-volatile memory.

Pancho507: /* See also */ ce

2024-09-03T03:02:09Z

Pancho507: /* See also */ add universal memory

2024-09-03T02:55:38Z

Kvng: unpiped links using script

2024-08-26T23:13:35Z

unpiped links using script

Show changes

Killviconiborki at 10:19, 29 July 2024

2024-07-29T10:19:10Z

← Previous revision		Revision as of 10:19, 29 July 2024
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	'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[random-access memory\|RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>		'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[random-access memory\|RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>

	Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[Random-access memory\|RAM]] capacity for caching so long as not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.		Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[Random-access memory\|RAM]] capacity for caching so long as it is not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.

	Modern computer memory is implemented as [[semiconductor memory]],<ref>{{cite web \|title=The MOS Memory Market \|url=http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-url=https://web.archive.org/web/20030725103322/http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-date=2003-07-25 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1997 \|access-date=16 October 2019}}</ref><ref>{{cite web \|title=MOS Memory Market Trends \|url=http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-url=https://web.archive.org/web/20191016225542/http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-date=2019-10-16 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1998 \|access-date=16 October 2019}}</ref> where data is stored within [[memory cell (computing)\|memory cells]] built from [[MOS transistor]]s and other components on an [[integrated circuit]].<ref name="computerhistory">{{cite journal\|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/\|title=1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated\|journal=The Silicon Engine\|publisher=[[Computer History Museum]]}}</ref> There are two main kinds of semiconductor memory: [[volatile memory\|volatile]] and [[non-volatile memory\|non-volatile]]. Examples of [[non-volatile memory]] are [[flash memory]] and [[Read-only memory\|ROM]], [[Programmable read-only memory\|PROM]], [[EPROM]], and [[EEPROM]] memory. Examples of [[volatile memory]] are [[dynamic random-access memory]] (DRAM) used for primary storage and [[static random-access memory]] (SRAM) used mainly for [[CPU cache]].		Modern computer memory is implemented as [[semiconductor memory]],<ref>{{cite web \|title=The MOS Memory Market \|url=http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-url=https://web.archive.org/web/20030725103322/http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-date=2003-07-25 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1997 \|access-date=16 October 2019}}</ref><ref>{{cite web \|title=MOS Memory Market Trends \|url=http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-url=https://web.archive.org/web/20191016225542/http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-date=2019-10-16 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1998 \|access-date=16 October 2019}}</ref> where data is stored within [[memory cell (computing)\|memory cells]] built from [[MOS transistor]]s and other components on an [[integrated circuit]].<ref name="computerhistory">{{cite journal\|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/\|title=1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated\|journal=The Silicon Engine\|publisher=[[Computer History Museum]]}}</ref> There are two main kinds of semiconductor memory: [[volatile memory\|volatile]] and [[non-volatile memory\|non-volatile]]. Examples of [[non-volatile memory]] are [[flash memory]] and [[Read-only memory\|ROM]], [[Programmable read-only memory\|PROM]], [[EPROM]], and [[EEPROM]] memory. Examples of [[volatile memory]] are [[dynamic random-access memory]] (DRAM) used for primary storage and [[static random-access memory]] (SRAM) used mainly for [[CPU cache]].
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	Two alternatives to the delay line, the [[Williams tube]] and [[Selectron tube]], originated in 1946, both using electron beams in glass tubes as means of storage. Using [[cathode-ray tube]]s, Fred Williams invented the Williams tube, which was the first [[random-access memory\|random-access computer memory]]. The Williams tube was able to store more information than the Selectron tube (the Selectron was limited to 256 bits, while the Williams tube could store thousands) and was less expensive. The Williams tube was nevertheless frustratingly sensitive to environmental disturbances.		Two alternatives to the delay line, the [[Williams tube]] and [[Selectron tube]], originated in 1946, both using electron beams in glass tubes as means of storage. Using [[cathode-ray tube]]s, Fred Williams invented the Williams tube, which was the first [[random-access memory\|random-access computer memory]]. The Williams tube was able to store more information than the Selectron tube (the Selectron was limited to 256 bits, while the Williams tube could store thousands) and was less expensive. The Williams tube was nevertheless frustratingly sensitive to environmental disturbances.

	Efforts began in the late 1940s to find [[non-volatile memory]]. [[Magnetic-core memory]] allowed for recall ~~of memory~~ after power loss. It was developed by Frederick W. Viehe and [[An Wang]] in the late 1940s, and improved by [[Jay Forrester]] and [[Jan A. Rajchman]] in the early 1950s, before being commercialized with the [[Whirlwind I]] computer in 1953.<ref>{{cite web \|title=1953: Whirlwind computer debuts core memory \|url=https://www.computerhistory.org/storageengine/whirlwind-computer-debuts-core-memory/ \|website=[[Computer History Museum]] \|access-date=2 August 2019}}</ref> Magnetic-core memory was the dominant form of memory until the development of [[MOSFET\|MOS]] [[semiconductor memory]] in the 1960s.<ref name="computerhistory1966" />		Efforts began in the late 1940s to find [[non-volatile memory]]. [[Magnetic-core memory]] allowed for memory recall after power loss. It was developed by Frederick W. Viehe and [[An Wang]] in the late 1940s, and improved by [[Jay Forrester]] and [[Jan A. Rajchman]] in the early 1950s, before being commercialized with the [[Whirlwind I]] computer in 1953.<ref>{{cite web \|title=1953: Whirlwind computer debuts core memory \|url=https://www.computerhistory.org/storageengine/whirlwind-computer-debuts-core-memory/ \|website=[[Computer History Museum]] \|access-date=2 August 2019}}</ref> Magnetic-core memory was the dominant form of memory until the development of [[MOSFET\|MOS]] [[semiconductor memory]] in the 1960s.<ref name="computerhistory1966" />

	The first [[semiconductor memory]] was implemented as a [[Flip-flop (electronics)\|flip-flop]] circuit in the early 1960s using [[bipolar transistors]].<ref name="computerhistory1966">{{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]] \|access-date=19 June 2019}}</ref> Semiconductor memory made from [[discrete device]]s was first shipped by [[Texas Instruments]] to the [[United States Air Force]] in 1961. ~~The~~ same year, the concept of [[Solid-state electronics\|solid-state]] memory on an [[integrated circuit]] (IC) chip was proposed by [[applications engineers\|applications engineer]] Bob Norman at [[Fairchild Semiconductor]].<ref>{{Cite web\|url=https://www.computerhistory.org/storageengine/transistors-make-fast-memories/\|title=1953: Transistors make fast memories {{!}} The Storage Engine {{!}} Computer History Museum\|website=www.computerhistory.org\|access-date=2019-11-14}}</ref> The first bipolar semiconductor memory IC chip was the SP95 introduced by [[IBM]] in 1965.<ref name="computerhistory1966"/> While semiconductor memory offered improved performance over magnetic-core memory, it ~~remain~~ larger and more expensive and did not displace magnetic-core memory until the late 1960s.<ref name="computerhistory1966"/><ref>{{cite book \|last1=Orton \|first1=John W. \|title=Semiconductors and the Information Revolution: Magic Crystals that made IT Happen \|date=2009 \|publisher=[[Academic Press]] \|isbn=978-0-08-096390-7 \|page=104 \|url=https://books.google.com/books?id=6YLL9197NfMC&pg=PA104}}</ref>		The first [[semiconductor memory]] was implemented as a [[Flip-flop (electronics)\|flip-flop]] circuit in the early 1960s using [[bipolar transistors]].<ref name="computerhistory1966">{{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]] \|access-date=19 June 2019}}</ref> Semiconductor memory made from [[discrete device]]s was first shipped by [[Texas Instruments]] to the [[United States Air Force]] in 1961. In the same year, the concept of [[Solid-state electronics\|solid-state]] memory on an [[integrated circuit]] (IC) chip was proposed by [[applications engineers\|applications engineer]] Bob Norman at [[Fairchild Semiconductor]].<ref>{{Cite web\|url=https://www.computerhistory.org/storageengine/transistors-make-fast-memories/\|title=1953: Transistors make fast memories {{!}} The Storage Engine {{!}} Computer History Museum\|website=www.computerhistory.org\|access-date=2019-11-14}}</ref> The first bipolar semiconductor memory IC chip was the SP95 introduced by [[IBM]] in 1965.<ref name="computerhistory1966"/> While semiconductor memory offered improved performance over magnetic-core memory, it remained larger and more expensive and did not displace magnetic-core memory until the late 1960s.<ref name="computerhistory1966"/><ref>{{cite book \|last1=Orton \|first1=John W. \|title=Semiconductors and the Information Revolution: Magic Crystals that made IT Happen \|date=2009 \|publisher=[[Academic Press]] \|isbn=978-0-08-096390-7 \|page=104 \|url=https://books.google.com/books?id=6YLL9197NfMC&pg=PA104}}</ref>

	=== MOS memory ===		=== MOS memory ===

Ykhwong at 04:44, 28 July 2024

2024-07-28T04:44:05Z

← Previous revision		Revision as of 04:44, 28 July 2024
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	{{Main\|Volatile memory}}		{{Main\|Volatile memory}}

	Volatile memory is computer memory that requires power to maintain the stored information. Most modern [[semiconductor]] volatile memory is either [[static RAM]] (SRAM) or [[dynamic RAM]] (DRAM).{{efn\|Other volatile memory technologies that have attempted to compete or replace SRAM and DRAM include [[Z-RAM]] and [[A-RAM]].}} DRAM dominates for desktop system memory. SRAM is used for [[CPU cache]]. SRAM is also found in small [[embedded system]]s requiring little memory.		Volatile memory is computer memory that requires power to maintain the stored information. Most modern [[semiconductor]] volatile memory is either [[static RAM]] (SRAM) or [[dynamic RAM]] (DRAM).{{efn\|Other volatile memory technologies that have attempted to compete or replace SRAM and DRAM include [[Z-RAM]] and [[A-RAM]].}} DRAM dominates for desktop system memory. SRAM is used for [[CPU cache]]. SRAM is also found in small [[embedded system]]s requiring little memory.

	SRAM retains its contents as long as the power is connected and may use a simpler interface, but [[Static random-access memory#Design\|commonly uses six transistors per bit]]. Dynamic RAM is more complicated for interfacing and control, needing regular refresh cycles to prevent losing its contents, but uses only one transistor and one capacitor per bit, allowing it to reach much higher densities and much cheaper per-bit costs.<ref name=":1" /><ref name="HC" /><ref name=":2" />		SRAM retains its contents as long as the power is connected and may use a simpler interface, but [[Static random-access memory#Design\|commonly uses six transistors per bit]]. Dynamic RAM is more complicated for interfacing and control, needing regular refresh cycles to prevent losing its contents, but uses only one transistor and one capacitor per bit, allowing it to reach much higher densities and much cheaper per-bit costs.<ref name=":1" /><ref name="HC" /><ref name=":2" />
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	== See also ==		== See also ==
	{{Commons category\|Computer memory}}		{{Commons category\|Computer memory}}


	* [[Memory geometry]]		* [[Memory geometry]]
	* [[Memory hierarchy]]		* [[Memory hierarchy]]

← Previous revision		Revision as of 22:21, 18 April 2025
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	{{~~short~~ description\|~~Computer component~~ that stores information ~~for immediate use~~}}		{{Short description\|Component that stores information}}
	{{Merge from\|Data in use\|discuss=Talk:Computer memory#Proposed merge of Data in use into Computer memory\|date=March 2025}}		{{Merge from\|Data in use\|discuss=Talk:Computer memory#Proposed merge of Data in use into Computer memory\|date=March 2025}}
	{{Use American English\|date=June 2023}}		{{Use American English\|date=June 2023}}

← Previous revision		Revision as of 20:50, 17 March 2025
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	{{short description\|Computer component that stores information for immediate use}}		{{short description\|Computer component that stores information for immediate use}}
			{{Merge from\|Data in use\|discuss=Talk:Computer memory#Proposed merge of Data in use into Computer memory\|date=March 2025}}
	{{Use American English\|date=June 2023}}		{{Use American English\|date=June 2023}}
	[[File:RAM Module (SDRAM-DDR4).jpg\|thumb\|[[DDR4 SDRAM]] module. {{As of\|2021}}, over 90 percent of computer memory used in PCs and servers was of this type.<ref>{{cite news \|last1=Read \|first1=Jennifer \|title=DDR5 Era To Officially Begin In 2021, With DRAM Market Currently Transitioning Between Generations, Says TrendForce \|url=https://www.emsnow.com/ddr5-era-to-officially-begin-in-2021-with-dram-market-currently-transitioning-between-generations-says-trendforce/ \|access-date=2 November 2022 \|publisher=EMSNow \|date=5 November 2020}}</ref>]]		[[File:RAM Module (SDRAM-DDR4).jpg\|thumb\|[[DDR4 SDRAM]] module. {{As of\|2021}}, over 90 percent of computer memory used in PCs and servers was of this type.<ref>{{cite news \|last1=Read \|first1=Jennifer \|title=DDR5 Era To Officially Begin In 2021, With DRAM Market Currently Transitioning Between Generations, Says TrendForce \|url=https://www.emsnow.com/ddr5-era-to-officially-begin-in-2021-with-dram-market-currently-transitioning-between-generations-says-trendforce/ \|access-date=2 November 2022 \|publisher=EMSNow \|date=5 November 2020}}</ref>]]

← Previous revision		Revision as of 03:02, 3 September 2024
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	* [[Memory organization]]		* [[Memory organization]]
	* [[Processor register]]s store data but normally are not considered as memory, since they only store one word and do not include an addressing mechanism.		* [[Processor register]]s store data but normally are not considered as memory, since they only store one word and do not include an addressing mechanism.
	* [[Universal memory]], memory combining both ~~high~~ capacity and high speed		* [[Universal memory]], memory combining both large capacity and high speed

	== Notes ==		== Notes ==

← Previous revision		Revision as of 02:55, 3 September 2024
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	* [[Memory organization]]		* [[Memory organization]]
	* [[Processor register]]s store data but normally are not considered as memory, since they only store one word and do not include an addressing mechanism.		* [[Processor register]]s store data but normally are not considered as memory, since they only store one word and do not include an addressing mechanism.
			* [[Universal memory]], memory combining both high capacity and high speed

	== Notes ==		== Notes ==

← Previous revision		Revision as of 10:19, 29 July 2024
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	'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[random-access memory\|RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>		'''Computer memory''' stores information, such as data and programs, for immediate use in the [[computer]].<ref name=":1">{{cite web \|last1=Hemmendinger \|first1=David \|title=Computer memory \|url=https://www.britannica.com/technology/computer-memory \|website=[[Encyclopedia Britannica]] \|access-date=16 October 2019 \|date=February 15, 2016}}</ref> The term ''memory'' is often synonymous with the terms ''[[random-access memory\|RAM]],'' ''[[main memory]],'' or ''[[primary storage]].'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''.<ref>[[Alan Turing\|A.M. Turing]] and R.A. Brooker (1952). [http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html ''Programmer's Handbook for Manchester Electronic Computer Mark II''] {{webarchive\|url=https://web.archive.org/web/20140102231704/http://www.alanturing.net/turing_archive/archive/m/m01/M01-005.html \|date=2014-01-02 }}. University of Manchester.</ref>

	Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[Random-access memory\|RAM]] capacity for caching so long as not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.		Main memory operates at a high speed compared to [[mass storage]] which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a [[Page cache\|mass storage cache]] and [[write buffer]] to improve both reading and writing performance. Operating systems borrow [[Random-access memory\|RAM]] capacity for caching so long as it is not needed by running software.<ref>{{cite web\| url = https://www.kernel.org/doc/html/latest/admin-guide/sysctl/vm.html\| title = Documentation for /proc/sys/vm/}}</ref> If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''[[virtual memory]]''.

	Modern computer memory is implemented as [[semiconductor memory]],<ref>{{cite web \|title=The MOS Memory Market \|url=http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-url=https://web.archive.org/web/20030725103322/http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-date=2003-07-25 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1997 \|access-date=16 October 2019}}</ref><ref>{{cite web \|title=MOS Memory Market Trends \|url=http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-url=https://web.archive.org/web/20191016225542/http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-date=2019-10-16 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1998 \|access-date=16 October 2019}}</ref> where data is stored within [[memory cell (computing)\|memory cells]] built from [[MOS transistor]]s and other components on an [[integrated circuit]].<ref name="computerhistory">{{cite journal\|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/\|title=1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated\|journal=The Silicon Engine\|publisher=[[Computer History Museum]]}}</ref> There are two main kinds of semiconductor memory: [[volatile memory\|volatile]] and [[non-volatile memory\|non-volatile]]. Examples of [[non-volatile memory]] are [[flash memory]] and [[Read-only memory\|ROM]], [[Programmable read-only memory\|PROM]], [[EPROM]], and [[EEPROM]] memory. Examples of [[volatile memory]] are [[dynamic random-access memory]] (DRAM) used for primary storage and [[static random-access memory]] (SRAM) used mainly for [[CPU cache]].		Modern computer memory is implemented as [[semiconductor memory]],<ref>{{cite web \|title=The MOS Memory Market \|url=http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-url=https://web.archive.org/web/20030725103322/http://smithsonianchips.si.edu/ice/cd/MEMORY97/SEC01.PDF \|archive-date=2003-07-25 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1997 \|access-date=16 October 2019}}</ref><ref>{{cite web \|title=MOS Memory Market Trends \|url=http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-url=https://web.archive.org/web/20191016225542/http://smithsonianchips.si.edu/ice/cd/STATUS98/SEC07.PDF \|archive-date=2019-10-16 \|url-status=live \|website=Integrated Circuit Engineering Corporation \|publisher=[[Smithsonian Institution]] \|year=1998 \|access-date=16 October 2019}}</ref> where data is stored within [[memory cell (computing)\|memory cells]] built from [[MOS transistor]]s and other components on an [[integrated circuit]].<ref name="computerhistory">{{cite journal\|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/\|title=1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated\|journal=The Silicon Engine\|publisher=[[Computer History Museum]]}}</ref> There are two main kinds of semiconductor memory: [[volatile memory\|volatile]] and [[non-volatile memory\|non-volatile]]. Examples of [[non-volatile memory]] are [[flash memory]] and [[Read-only memory\|ROM]], [[Programmable read-only memory\|PROM]], [[EPROM]], and [[EEPROM]] memory. Examples of [[volatile memory]] are [[dynamic random-access memory]] (DRAM) used for primary storage and [[static random-access memory]] (SRAM) used mainly for [[CPU cache]].
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	Two alternatives to the delay line, the [[Williams tube]] and [[Selectron tube]], originated in 1946, both using electron beams in glass tubes as means of storage. Using [[cathode-ray tube]]s, Fred Williams invented the Williams tube, which was the first [[random-access memory\|random-access computer memory]]. The Williams tube was able to store more information than the Selectron tube (the Selectron was limited to 256 bits, while the Williams tube could store thousands) and was less expensive. The Williams tube was nevertheless frustratingly sensitive to environmental disturbances.		Two alternatives to the delay line, the [[Williams tube]] and [[Selectron tube]], originated in 1946, both using electron beams in glass tubes as means of storage. Using [[cathode-ray tube]]s, Fred Williams invented the Williams tube, which was the first [[random-access memory\|random-access computer memory]]. The Williams tube was able to store more information than the Selectron tube (the Selectron was limited to 256 bits, while the Williams tube could store thousands) and was less expensive. The Williams tube was nevertheless frustratingly sensitive to environmental disturbances.

	Efforts began in the late 1940s to find [[non-volatile memory]]. [[Magnetic-core memory]] allowed for recall ~~of memory~~ after power loss. It was developed by Frederick W. Viehe and [[An Wang]] in the late 1940s, and improved by [[Jay Forrester]] and [[Jan A. Rajchman]] in the early 1950s, before being commercialized with the [[Whirlwind I]] computer in 1953.<ref>{{cite web \|title=1953: Whirlwind computer debuts core memory \|url=https://www.computerhistory.org/storageengine/whirlwind-computer-debuts-core-memory/ \|website=[[Computer History Museum]] \|access-date=2 August 2019}}</ref> Magnetic-core memory was the dominant form of memory until the development of [[MOSFET\|MOS]] [[semiconductor memory]] in the 1960s.<ref name="computerhistory1966" />		Efforts began in the late 1940s to find [[non-volatile memory]]. [[Magnetic-core memory]] allowed for memory recall after power loss. It was developed by Frederick W. Viehe and [[An Wang]] in the late 1940s, and improved by [[Jay Forrester]] and [[Jan A. Rajchman]] in the early 1950s, before being commercialized with the [[Whirlwind I]] computer in 1953.<ref>{{cite web \|title=1953: Whirlwind computer debuts core memory \|url=https://www.computerhistory.org/storageengine/whirlwind-computer-debuts-core-memory/ \|website=[[Computer History Museum]] \|access-date=2 August 2019}}</ref> Magnetic-core memory was the dominant form of memory until the development of [[MOSFET\|MOS]] [[semiconductor memory]] in the 1960s.<ref name="computerhistory1966" />

	The first [[semiconductor memory]] was implemented as a [[Flip-flop (electronics)\|flip-flop]] circuit in the early 1960s using [[bipolar transistors]].<ref name="computerhistory1966">{{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]] \|access-date=19 June 2019}}</ref> Semiconductor memory made from [[discrete device]]s was first shipped by [[Texas Instruments]] to the [[United States Air Force]] in 1961. ~~The~~ same year, the concept of [[Solid-state electronics\|solid-state]] memory on an [[integrated circuit]] (IC) chip was proposed by [[applications engineers\|applications engineer]] Bob Norman at [[Fairchild Semiconductor]].<ref>{{Cite web\|url=https://www.computerhistory.org/storageengine/transistors-make-fast-memories/\|title=1953: Transistors make fast memories {{!}} The Storage Engine {{!}} Computer History Museum\|website=www.computerhistory.org\|access-date=2019-11-14}}</ref> The first bipolar semiconductor memory IC chip was the SP95 introduced by [[IBM]] in 1965.<ref name="computerhistory1966"/> While semiconductor memory offered improved performance over magnetic-core memory, it ~~remain~~ larger and more expensive and did not displace magnetic-core memory until the late 1960s.<ref name="computerhistory1966"/><ref>{{cite book \|last1=Orton \|first1=John W. \|title=Semiconductors and the Information Revolution: Magic Crystals that made IT Happen \|date=2009 \|publisher=[[Academic Press]] \|isbn=978-0-08-096390-7 \|page=104 \|url=https://books.google.com/books?id=6YLL9197NfMC&pg=PA104}}</ref>		The first [[semiconductor memory]] was implemented as a [[Flip-flop (electronics)\|flip-flop]] circuit in the early 1960s using [[bipolar transistors]].<ref name="computerhistory1966">{{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]] \|access-date=19 June 2019}}</ref> Semiconductor memory made from [[discrete device]]s was first shipped by [[Texas Instruments]] to the [[United States Air Force]] in 1961. In the same year, the concept of [[Solid-state electronics\|solid-state]] memory on an [[integrated circuit]] (IC) chip was proposed by [[applications engineers\|applications engineer]] Bob Norman at [[Fairchild Semiconductor]].<ref>{{Cite web\|url=https://www.computerhistory.org/storageengine/transistors-make-fast-memories/\|title=1953: Transistors make fast memories {{!}} The Storage Engine {{!}} Computer History Museum\|website=www.computerhistory.org\|access-date=2019-11-14}}</ref> The first bipolar semiconductor memory IC chip was the SP95 introduced by [[IBM]] in 1965.<ref name="computerhistory1966"/> While semiconductor memory offered improved performance over magnetic-core memory, it remained larger and more expensive and did not displace magnetic-core memory until the late 1960s.<ref name="computerhistory1966"/><ref>{{cite book \|last1=Orton \|first1=John W. \|title=Semiconductors and the Information Revolution: Magic Crystals that made IT Happen \|date=2009 \|publisher=[[Academic Press]] \|isbn=978-0-08-096390-7 \|page=104 \|url=https://books.google.com/books?id=6YLL9197NfMC&pg=PA104}}</ref>

	=== MOS memory ===		=== MOS memory ===