Editing History of computing hardware (section)

==Microprocessor computers==
{{Main|History of computing hardware (1960s–present)#Fourth generation}}
The "fourth-generation" of digital electronic computers used [[microprocessor]]s as the basis of their logic. The microprocessor has origins in the [[MOS integrated circuit]] (MOS IC) chip.<ref name="ieee">{{cite journal |last1=Shirriff |first1=Ken |title=The Surprising Story of the First Microprocessors |journal=[[IEEE Spectrum]] |volume=53 |issue=9 |pages=48–54 |date=30 August 2016 |publisher=[[Institute of Electrical and Electronics Engineers]] |url=https://spectrum.ieee.org/the-surprising-story-of-the-first-microprocessors |access-date=13 October 2019 |doi=10.1109/MSPEC.2016.7551353 |s2cid=32003640 |archive-date=2021-07-12 |archive-url=https://web.archive.org/web/20210712091202/https://spectrum.ieee.org/tech-history/silicon-revolution/the-surprising-story-of-the-first-microprocessors |url-status=live}}</ref> Due to rapid [[MOSFET scaling]], MOS IC chips rapidly increased in complexity at a rate predicted by [[Moore's law]], leading to [[large-scale integration]] (LSI) with hundreds of transistors on a single MOS chip by the late 1960s. The application of MOS LSI chips to [[computing]] was the basis for the first microprocessors, as engineers began recognizing that a complete [[computer processor]] could be contained on a single MOS LSI chip.<ref name="ieee"/>

The subject of exactly which device was the first microprocessor is contentious, partly due to lack of agreement on the exact definition of the term "microprocessor". The earliest multi-chip microprocessors were the [[Four-Phase Systems]] AL-1 in 1969 and [[Garrett AiResearch]] [[MP944]] in 1970, developed with multiple MOS LSI chips.<ref name="ieee"/> The first single-chip microprocessor was the [[Intel 4004]],{{sfn|Intel|1971}} developed on a single [[PMOS logic|PMOS]] LSI chip.<ref name="ieee"/> It was designed and realized by [[Marcian Hoff|Ted Hoff]], [[Federico Faggin]], [[Masatoshi Shima]] and [[Stanley Mazor]] at [[Intel]], and released in 1971.{{efn|The Intel 4004 (1971) die was 12&nbsp;mm<sup>2</sup>, composed of 2300 transistors; by comparison, the Pentium Pro was 306&nbsp;mm<sup>2</sup>, composed of 5.5 million transistors.{{sfn|Patterson|Hennessy|1998|pp=27–39}}}} [[Tadashi Sasaki (engineer)|Tadashi Sasaki]] and [[Masatoshi Shima]] at [[Busicom]], a calculator manufacturer, had the initial insight that the CPU could be a single MOS LSI chip, supplied by Intel.<ref name= 4bitSlice>{{cite web |first=William |last=Aspray |date=May 25, 1994 |title=Oral-History: Tadashi Sasaki |url=https://ethw.org/Oral-History:Tadashi_Sasaki |archive-url=https://web.archive.org/web/20200802075939/https://ethw.org/Oral-History:Tadashi_Sasaki |archive-date=2020-08-02 |url-status=live}} [[Tadashi Sasaki (engineer)|Sasaki]] credits the idea for a 4 bit-slice PMOS chip to a woman researcher's idea at Sharp Corporation, which was not accepted by the other members of the Sharp brainstorming group. A 40-million yen infusion from Busicom to Intel was made at Sasaki's behest, to exploit the 4 bit-slice PMOS chip.</ref>{{sfn|Intel|1971}}

[[File:Intel 8742 153056995.jpg|right|thumb|The [[die (integrated circuit)|die]] from an Intel [[Intel MCS-48|8742]], an 8-bit [[microcontroller]] that includes a CPU running at 12&nbsp;MHz, RAM, EPROM, and I/O]]
While the earliest microprocessor ICs literally contained only the processor, i.e. the central processing unit, of a computer, their progressive development naturally led to chips containing most or all of the internal electronic parts of a computer. The integrated circuit in the image on the right, for example, an [[Intel]] 8742, is an [[8-bit computing|8-bit]] [[microcontroller]] that includes a CPU running at 12&nbsp;MHz, 128 bytes of [[random-access memory|RAM]], 2048 bytes of [[EPROM]], and [[input/output|I/O]] in the same chip.

During the 1960s, there was considerable overlap between second and third generation technologies.{{efn|In the defense field, considerable work was done in the computerized implementation of equations such as {{harvnb|Kalman|1960|pp=35–45}}.}} IBM implemented its [[IBM Solid Logic Technology]] modules in [[hybrid circuit]]s for the IBM System/360 in 1964. As late as 1975, Sperry Univac continued the manufacture of second-generation machines such as the UNIVAC 494. The [[Burroughs large systems]] such as the B5000 were [[stack machine]]s, which allowed for simpler programming. These [[pushdown automaton]]s were also implemented in minicomputers and microprocessors later, which influenced programming language design. Minicomputers served as low-cost computer centers for industry, business and universities.{{sfn|Eckhouse|Morris|1979|pp=1–2}} It became possible to simulate analog circuits with the ''simulation program with integrated circuit emphasis'', or [[SPICE]] (1971) on minicomputers, one of the programs for electronic design automation ([[:Category:Electronic design automation software|EDA]]). The microprocessor led to the development of [[microcomputer]]s, small, low-cost computers that could be owned by individuals and small businesses. Microcomputers, the first of which appeared in the 1970s, became ubiquitous in the 1980s and beyond.

[[File:Altair 8800 Computer.jpg|right|thumb|Altair 8800]]
While which specific product is considered the first microcomputer system is a matter of debate, one of the earliest is R2E's [[Micral#Micral N|Micral N]] ([[François Gernelle]], [[André Truong Trong Thi|André Truong]]) launched "early 1973" using the Intel 8008.<ref>{{Cite web |url=https://www.system-cfg.com/detail.php?ident=811 |title=R2E Micral N|website=www.system-cfg.com |access-date=2022-12-02 |archive-date=2022-11-10 |archive-url=https://web.archive.org/web/20221110084947/https://www.system-cfg.com/detail.php?ident=811|url-status=live}}</ref> The first commercially available microcomputer kit was the [[Intel 8080]]-based [[Altair 8800]], which was announced in the January 1975 cover article of ''[[Popular Electronics]]''. However, the Altair 8800 was an extremely limited system in its initial stages, having only 256 bytes of [[DRAM]] in its initial package and no input-output except its toggle switches and LED register display. Despite this, it was initially surprisingly popular, with several hundred sales in the first year, and demand rapidly outstripped supply. Several early third-party vendors such as [[Cromemco]] and [[Processor Technology]] soon began supplying additional [[S-100 bus]] hardware for the Altair 8800.

In April 1975, at the [[Hannover Messe|Hannover Fair]], [[Olivetti]] presented the [[Olivetti P6060|P6060]], the world's first complete, pre-assembled personal computer system. The central processing unit consisted of two cards, code named PUCE1 and PUCE2, and unlike most other personal computers was built with [[Transistor–transistor logic|TTL]] components rather than a microprocessor. It had one or two 8" [[floppy disk]] drives, a 32-character [[plasma display]], 80-column graphical [[thermal printer]], 48 Kbytes of [[random-access memory|RAM]], and [[BASIC]] language. It weighed {{cvt|40|kg|lb}}. As a complete system, this was a significant step from the Altair, though it never achieved the same success. It was in competition with a similar product by IBM that had an external floppy disk drive.

From 1975 to 1977, most microcomputers, such as the [[KIM-1|MOS Technology KIM-1]], the [[Altair 8800]], and some versions of the [[Apple I]], were sold as kits for do-it-yourselfers. Pre-assembled systems did not gain much ground until 1977, with the introduction of the [[Apple II]], the Tandy [[TRS-80]], the first [[SWTPC]] computers, and the [[Commodore PET]]. Computing has evolved with microcomputer architectures, with features added from their larger brethren, now dominant in most market segments.

A NeXT Computer and its [[object-oriented]] development tools and libraries were used by [[Tim Berners-Lee]] and [[Robert Cailliau]] at [[CERN]] to develop the world's first [[web server]] software, [[CERN httpd]], and also used to write the first [[web browser]], [[WorldWideWeb]].

Systems as complicated as computers require very high [[reliability engineering|reliability]]. ENIAC remained on, in continuous operation from 1947 to 1955, for eight years before being shut down. Although a vacuum tube might fail, it would be replaced without bringing down the system. By the simple strategy of never shutting down ENIAC, the failures were dramatically reduced. The vacuum-tube [[Semi-Automatic Ground Environment|SAGE]] air-defense computers became remarkably reliable – installed in pairs, one off-line, tubes likely to fail did so when the computer was intentionally run at reduced power to find them. [[Hot plugging|Hot-pluggable]] hard disks, like the hot-pluggable vacuum tubes of yesteryear, continue the tradition of repair during continuous operation. Semiconductor memories routinely have no errors when they operate, although operating systems like Unix have employed memory tests on start-up to detect failing hardware. Today, the requirement of reliable performance is made even more stringent when [[server farm]]s are the delivery platform.<ref>{{cite web |last=Shankland |first=Stephen |title=Google uncloaks once-secret server |website=CNET |date=1 April 2009 |url=https://news.cnet.com/8301-1001_3-10209580-92.html |access-date=2009-04-01 |url-status=dead |archive-url=https://web.archive.org/web/20140716084210/http://www.cnet.com/news/google-uncloaks-once-secret-server-10209580/ |archive-date=2014-07-16}} "Since 2005, its [Google's] data centers have been composed of standard shipping containers—each with 1,160 servers and a power consumption that can reach 250 kilowatts." —Ben Jai of Google.</ref> Google has managed this by using fault-tolerant software to recover from hardware failures, and is even working on the concept of replacing entire server farms on-the-fly, during a service event.<ref>{{cite web |last=Shankland |first=Stephen |title=Google spotlights data center inner workings |website=CNET |date=30 May 2008 |url=https://news.cnet.com/8301-10784_3-9955184-7.html?tag=nefd.lede |access-date=2008-05-31 |url-status=dead |archive-url=https://web.archive.org/web/20140818092344/http://www.cnet.com/news/google-spotlights-data-center-inner-workings/ |archive-date=2014-08-18}} "If you're running 10,000 machines, something is going to die every day." —Jeff Dean of Google.</ref><ref>{{cite web|title=Google Groups |url=https://groups.google.com/group/google-appengine/browse_thread/thread/a7640a2743922dcf?pli=1 |access-date=11 August 2015 |archive-url=https://web.archive.org/web/20110913014648/https://groups.google.com/group/google-appengine/browse_thread/thread/a7640a2743922dcf?pli=1 |archive-date=2011-09-13|url-status=live}}</ref>

In the 21st century, [[multi-core]] CPUs became commercially available.<ref>{{cite web |last=Shrout |first=Ryan |date=2 December 2009 |website=PC Perspective |url=https://pcper.com/2009/12/intel-shows-48-core-x86-processor-as-single-chip-cloud-computer/ |title=Intel Shows 48-core x86 Processor as Single-chip Cloud Computer|archive-url=https://web.archive.org/web/20100814203128/http://www.pcper.com/article.php?aid=825 |archive-date=2010-08-14 |url-status=live |access-date=2020-12-02}}<br/>{{*}}{{cite web |date=3 December 2009 |title=Intel unveils 48-core cloud computing silicon chip |work=BBC News |url=https://news.bbc.co.uk/2/hi/technology/8392392.stm |access-date=2009-12-03 |archive-date=2012-12-06 |archive-url=https://web.archive.org/web/20121206054225/http://news.bbc.co.uk/2/hi/technology/8392392.stm |url-status=live}}</ref> [[Content-addressable memory]] (CAM){{sfn|Kohonen|1980|p={{page needed|date=August 2023}}}} has become inexpensive enough to be used in networking, and is frequently used for on-chip [[cache memory]] in modern microprocessors, although no computer system has yet implemented hardware CAMs for use in programming languages. Currently, CAMs (or associative arrays) in software are programming-language-specific. Semiconductor memory cell arrays are very regular structures, and manufacturers prove their processes on them; this allows price reductions on memory products. During the 1980s, [[CMOS]] [[logic gates]] developed into devices that could be made as fast as other circuit types; computer power consumption could therefore be decreased dramatically. Unlike the continuous current draw of a gate based on other logic types, a CMOS gate only draws significant current, except for leakage, during the 'transition' between logic states.{{sfn|Mead|Conway|1980|pp=11-36}}

CMOS circuits have allowed computing to become a commercial [[Product (business)|product]] which is now ubiquitous, embedded in [[embedded system|many forms]], from greeting cards and [[Mobile phone|telephone]]s to [[Satellite communications#History|satellites]]. The [[thermal design power]] which is dissipated during operation has become as essential as computing speed of operation. In 2006 servers consumed 1.5% of the total U.S. electricity consumption.<ref>{{cite report |date=2007 |title=Energystar report |page=4 |url=https://www.energystar.gov/ia/partners/prod_development/downloads/EPA_Report_Exec_Summary_Final.pdf?f272-71fc |access-date=2013-08-18 |archive-date=2013-10-22 |archive-url=https://web.archive.org/web/20131022230644/http://www.energystar.gov/ia/partners/prod_development/downloads/EPA_Report_Exec_Summary_Final.pdf?f272-71fc |url-status=live }}</ref> The energy consumption of computer data centers was expected to double to 3% of world consumption by 2011. The [[System on a chip|SoC]] (system on a chip) has compressed even more of the [[integrated circuit]]ry into a single chip; SoCs are enabling phones and PCs to converge into single hand-held wireless [[mobile computing|mobile device]]s.<ref>{{cite web |first=Walt |last=Mossberg |date=9 July 2014 |url=https://recode.net/2014/07/09/how-the-pc-is-merging-with-the-smartphone/ |title=How the PC is merging with the smartphone |access-date=2014-07-09 |url-status=live |archive-date=2014-07-09 |archive-url=https://web.archive.org/web/20140709183504/http://recode.net/2014/07/09/how-the-pc-is-merging-with-the-smartphone/}}</ref>

{{anchor|quantum computing}}[[Quantum computing]] is an emerging technology in the field of computing. ''MIT Technology Review'' reported 10 November 2017 that IBM has created a 50-[[qubit]] computer; currently its quantum state lasts 50 microseconds.<ref>{{cite web |url=https://www.technologyreview.com/s/609451/ibm-raises-the-bar-with-a-50-qubit-quantum-computer/ |first=Will |last=Knight |work=MIT Technology Review |date=10 November 2017 |title=IBM Raises the Bar with a 50-Qubit Quantum Computer |access-date=2017-11-10 |url-status=live |archive-date=2017-11-12 |archive-url=https://web.archive.org/web/20171112050728/https://www.technologyreview.com/s/609451/ibm-raises-the-bar-with-a-50-qubit-quantum-computer/}}</ref> Google researchers have been able to extend the 50 microsecond time limit, as reported 14 July 2021 in ''Nature'';<ref name=quantumErrorCorrection/> stability has been extended 100-fold by spreading a single logical qubit over chains of data qubits for [[quantum error correction]].<ref name=quantumErrorCorrection>{{cite journal |doi=10.1038/s41586-021-03588-y |doi-access=free |collaboration=Google Quantum AI |author=Julian Kelly |display-authors=etal |date=15 July 2021 |title=Exponential suppression of bit or phase errors with cyclic error correction |journal=Nature |volume=595 |issue=7867 |pages=383–387 |pmid=34262210 |pmc=8279951 |url=https://www.nature.com/articles/s41586-021-03588-y.pdf?pdf=button%20sticky}} Cited in {{cite web |author=Adrian Cho |date=14 July 2021 |title=Physicists move closer to defeating errors in quantum computation |magazine=Science |url=https://www.science.org/content/article/physicists-move-closer-defeating-errors-quantum-computation}}</ref> ''Physical Review X'' reported a technique for 'single-gate sensing as a viable readout method for spin qubits' (a singlet-triplet spin state in silicon) on 26 November 2018.<ref>{{Cite journal |title=Single-Shot Single-Gate rf Spin Readout in Silicon |first1=P. |last1=Pakkiam |first2=A. V. |last2=Timofeev |first3=M. G. |last3=House |first4=M. R. |last4=Hogg |first5=T. |last5=Kobayashi |first6=M. |last6=Koch |first7=S. |last7=Rogge |first8=M. Y. |last8=Simmons |date=26 November 2018 |journal=Physical Review X |volume=8 |issue=4 |at=041032 |via=APS |doi=10.1103/PhysRevX.8.041032 |arxiv=1809.01802 |bibcode=2018PhRvX...8d1032P |s2cid=119363882}}</ref> A Google team has succeeded in operating their RF pulse modulator chip at 3&nbsp;[[kelvin]]s, simplifying the cryogenics of their 72-qubit computer, which is set up to operate at 0.3&nbsp;[[kelvin|K]]; but the readout circuitry and another driver remain to be brought into the cryogenics.<ref name=72qubits>{{cite web |first=Samuel K. |last=Moore |work=IEEE Spectrum |date=13 March 2019 |title=Google Builds Circuit to Solve One of Quantum Computing's Biggest Problems |url=https://spectrum.ieee.org/google-team-builds-circuit-to-solve-one-of-quantum-computings-biggest-problems |access-date=2019-03-14 |archive-date=2019-03-14 |archive-url=https://web.archive.org/web/20190314213116/https://spectrum.ieee.org/tech-talk/semiconductors/design/google-team-builds-circuit-to-solve-one-of-quantum-computings-biggest-problems |url-status=live}}</ref>{{efn|name=ibmEagle |IBM's 127-qubit computer cannot be simulated on traditional computers.<ref name=127qubits>{{cite web |author=Ina Fried |date=14 Nov 2021 |url=https://www.axios.com/ibm-quantum-computing-axios-hbo-bd9d50b7-3c11-4586-bdb1-8bbc9928ad1b.html |title=Exclusive: IBM achieves quantum computing breakthrough |website=Axios |archive-url=https://web.archive.org/web/20211115133314/https://www.axios.com/ibm-quantum-computing-axios-hbo-bd9d50b7-3c11-4586-bdb1-8bbc9928ad1b.html |archive-date=2021-11-15 |url-status=live}}</ref>}} ''See: [[Quantum supremacy]]''<ref>{{cite web |first=Russ |last=Juskalian |date=22 February 2017 |title=Practical Quantum Computers |url=https://mittr-frontend-prod.herokuapp.com/s/603495/10-breakthrough-technologies-2017-practical-quantum-computers/amp/ |work=MIT Technology Review|access-date=2020-12-02|archive-url=https://web.archive.org/web/20210623193833/https://mittr-frontend-prod.herokuapp.com/s/603495/10-breakthrough-technologies-2017-practical-quantum-computers/amp/ |archive-date=2021-06-23 |url-status=live}}</ref><ref>{{cite web |first=John D. |last=MacKinnon |date=19 December 2018 |url=https://www.wsj.com/articles/congress-expected-to-pass-bill-spurring-quantum-computing-11545250595 |work=The Wall Street Journal |title=House Passes Bill to Create National Quantum Computing Program |access-date=2018-12-20 |archive-url=https://web.archive.org/web/20181220084728/https://www.wsj.com/articles/congress-expected-to-pass-bill-spurring-quantum-computing-11545250595 |archive-date=2018-12-20 |url-status=live}}</ref> Silicon qubit systems have demonstrated [[quantum entanglement|entanglement]] at [[action at a distance|non-local]] distances.<ref>{{cite web |url=https://scitechdaily.com/quantum-computing-breakthrough-silicon-qubits-interact-at-long-distance/ |author=Princeton University |date=25 December 2019 |title=Quantum Computing Breakthrough: Silicon Qubits Interact at Long-Distance |work=SciTechDaily |access-date=2019-12-26 |archive-date=2019-12-26 |archive-url=https://web.archive.org/web/20191226165255/https://scitechdaily.com/quantum-computing-breakthrough-silicon-qubits-interact-at-long-distance/ |url-status=live}}</ref>

Computing hardware and its software have even become a metaphor for the operation of the universe.<ref>{{harvnb|Smolin|2001|pp=53–57}}. Pages 220–226 are annotated references and guide for further reading.</ref>