Editing Microcomputer (section)

== History ==
[[Image:Early Personal Computers.jpg|thumb|320px|right|A collection of early microcomputers, including a [[Processor Technology]] SOL-20 (top shelf, right), an MITS [[Altair 8800]] (second shelf, left), a [[TV Typewriter]] (third shelf, center), and an [[Apple I]] in the case at far right]]

=== TTL precursors ===
Although they did not contain any microprocessors, but were built around [[transistor-transistor logic]] (TTL), [[Hewlett-Packard]] calculators as far back as 1968 had various levels of programmability comparable to microcomputers. The HP 9100B (1968) had rudimentary conditional (if) statements, statement line numbers, jump statements ([[go to]]), registers that could be used as variables, and primitive subroutines. The programming language resembled [[assembly language]] in many ways. Later models incrementally added more features, including the [[BASIC]] programming language (HP 9830A in 1971). Some models had tape storage and small printers. However, displays were limited to one line at a time.<ref>{{cite web|url=http://www.hpmuseum.org|title=The Museum of HP Calculators}}</ref> The [[Hewlett Packard 9100A|HP 9100A]] was referred to as a [[personal computer]] in an advertisement in a 1968 [[Science (journal)|Science]] magazine,<ref>{{cite web|url=http://www.hp.com/hpinfo/abouthp/histnfacts/museum/personalsystems/0021/other/0021ad.pdf |archive-url=https://web.archive.org/web/20060312220318/http://www.hp.com/hpinfo/abouthp/histnfacts/museum/personalsystems/0021/other/0021ad.pdf |archive-date=2006-03-12 |url-status=live |title=Powerful Computing Genie|publisher = Hewlett Packard |access-date=2012-08-30}}</ref> but that advertisement was quickly dropped.<ref>{{cite web|url=http://www.sciencemag.org/cgi/issue_pdf/frontmatter_pdf/162/3852.pdf |archive-url=https://web.archive.org/web/20070621133200/http://www.sciencemag.org/cgi/issue_pdf/frontmatter_pdf/162/3852.pdf |archive-date=2007-06-21 |url-status=live |title=Restoring the Balance Between Analysis and Computation |access-date=2012-08-30}}</ref>  HP was reluctant to sell them as "computers" because the perception at that time was that a computer had to be big in size to be powerful, and thus decided to market them as calculators.  Additionally, at that time, people were more likely to buy calculators than computers, and, purchasing agents also preferred the term "calculator" because purchasing a "computer" required additional layers of purchasing authority approvals.<ref>{{cite web|url=http://www.hp.com/hpinfo/abouthp/histnfacts/museum/personalsystems/0021/0021history.html|title=History of the 9100A desktop calculator, 1968|website=HP virtual museum|access-date=2019-07-19}}</ref>

The [[Datapoint 2200]], made by [[Datapoint|CTC]] in 1970, was also comparable to microcomputers.  While it contains no microprocessor, the [[instruction set]] of its custom TTL processor was the basis of the instruction set for the [[Intel 8008]], and for practical purposes the system behaves approximately as if it contains an 8008.  This is because Intel was the contractor in charge of developing the Datapoint's CPU, but ultimately CTC rejected the 8008 design because it needed 20 support chips.<ref>{{cite web |url=http://www.computermuseum.li/Testpage/MicroprocessorHistory.htm |title=MicroprocessorHistory |publisher=Computermuseum.li |date=1971-11-15 |access-date=2012-08-30 |url-status=dead |archive-url=https://web.archive.org/web/20150923205820/http://www.computermuseum.li/Testpage/MicroprocessorHistory.htm |archive-date=2015-09-23 }}</ref>

Another early system, the [[Kenbak-1]], was released in 1971. Like the Datapoint 2200, it used [[Integrated circuit#SSI|small-scale integrated]] [[transistor–transistor logic]] instead of a microprocessor. It was marketed as an educational and hobbyist tool, but it was not a commercial success; production ceased shortly after introduction.<ref>{{cite web|url=http://www.vintage-computer.com/kenbak-1.shtml|title=Kenbak-1|website=The Vintage Computer|access-date=2006-08-14|archive-date=2011-01-22|archive-url=https://web.archive.org/web/20110122235215/http://www.vintage-computer.com/kenbak-1.shtml|url-status=dead}}</ref>

=== Early microcomputers ===
In late 1972, a French team headed by [[François Gernelle]] within a small company, Réalisations & Etudes Electroniques (R2E), developed and patented a computer based on a microprocessor – the Intel 8008 8-bit microprocessor. This [[Micral|Micral-N]] was marketed in early 1973 as a "Micro-ordinateur" or ''microcomputer'', mainly for scientific and process-control applications. About a hundred [[Micral|Micral-N]] were installed in the next two years, followed by a new version based on the Intel 8080. Meanwhile, another French team developed the Alvan, a small computer for office automation which found clients in banks and other sectors. The first version was based on LSI chips with an Intel 8008 as peripheral controller (keyboard, monitor and printer), before adopting the [[Zilog Z80]] as main processor.

In late 1972, a [[California State University, Sacramento|Sacramento State University]] team led by Bill Pentz built the Sac State 8008 computer, able to handle thousands of patients' medical records.  The Sac State 8008 was designed with the Intel 8008. It had a full set of hardware and [[Computer program#Sac State 8008|software components]]: a disk operating system included in a series of programmable read-only memory chips (PROMs); 8 Kilobytes of RAM; IBM's Basic Assembly Language (BAL); a hard drive; a color display; a printer output; a 150 bit/s serial interface for connecting to a mainframe; and even the world's first microcomputer front panel.<ref>{{cite web|url=http://www.digibarn.com/stories/bill-pentz-story/index.html |title=Digibarn Stories: Bill Pentz and (Earliest) History of the Microcomputer (August 2008) |website=DigiBarn Computer Museum |date=August–November 2008 |access-date=2012-08-30}}</ref><ref>{{cite web|last=Terdiman |first=Daniel |url=https://www.cnet.com/news/inside-the-worlds-long-lost-first-microcomputer/ |title=Inside the world's long-lost first microcomputer |website=[[CNET]] |date=2010-01-08 |access-date=2012-08-30}}</ref>

In early 1973, [[Sord Computer Corporation]] (now [[Toshiba|Toshiba Personal Computer System Corporation]]) completed the SMP80/08, which used the [[Intel 8008]] microprocessor. The SMP80/08, however, did not have a commercial release. After the first general-purpose microprocessor, the [[Intel 8080]], was announced in April 1974, Sord announced the SMP80/x, the first microcomputer to use the 8080, in May 1974.<ref name="ipsj">{{Cite web | url=http://museum.ipsj.or.jp/en/computer/personal/0086.html |title = SMP80/X series-Computer Museum}}</ref>

Virtually all early microcomputers were essentially boxes with lights and switches; one had to read and understand binary numbers and machine language to program and use them (the Datapoint 2200 was a striking exception, bearing a modern design based on a monitor, keyboard, and tape and disk drives).  Of the early "box of switches"-type microcomputers, the MITS [[Altair 8800]] (1975) was arguably the most famous.  Most of these simple, early microcomputers were sold as [[electronic kits]]—bags full of loose components which the buyer had to solder together before the system could be used.

[[Image:PDP-11-M7270.jpg|thumb|Microcomputer module LSI-11/2]]

The period from about 1971 to 1976 is sometimes called the [[:Category:Early microcomputers|first generation]] of microcomputers. Many companies such as [[Digital Equipment Corporation|DEC]],<ref>{{cite web
 |title = 16-bit timeline
 |url = http://gordonbell.azurewebsites.net/digital/timeline/16-bit.htm
 |date = 19 November 1997
}}</ref> [[National Semiconductor]],<ref>{{cite magazine
 |title = Paper Tape Readers Work With IMP Micros
 |magazine = Computerworld
 |date = 23 Oct 1974
 |page = 28
 |url = https://books.google.com/books?id=GpEtWjI3whwC&pg=PA28
}}</ref> [[Texas Instruments]]<ref>{{cite magazine
 |title = Upward Compatible Software and Downward Compatible Price
 |magazine = Computerworld
 |date = 10 Dec 1975
 |page = 49
 |url = https://books.google.com/books?id=shitkFDw7DkC&pg=PA49
}}</ref> offered their microcomputers for use in terminal control, peripheral device interface control and industrial machine control. There were also machines for engineering development and hobbyist personal use.<ref>{{cite magazine|url=https://books.google.com/books?id=kawCnk4051wC&pg=PA154|title=Computer Adventures|last=Hawkins|first = William J.|date = December 1983|magazine = Popular Science}}</ref> In 1975, the [[Processor Technology]] [[SOL-20]] was designed, which consisted of one board which included all the parts of the computer system. The [[SOL-20]] had built-in EPROM software which eliminated the need for rows of switches and lights. The [[Altair 8800|MITS Altair]] just mentioned played an instrumental role in sparking significant hobbyist interest, which itself eventually led to the founding and success of many well-known [[personal computer]] hardware and software companies, such as [[Microsoft]] and [[Apple Computer]]. Although the Altair itself was only a mild commercial success, it helped spark a huge industry.

=== Home computers ===
By 1977, the introduction of the second microcomputer generation as [[consumer goods]], known as [[home computer]]s, made them considerably easier to use than their predecessors because their predecessors' operation often demanded thorough familiarity with practical electronics. The ability to connect to a monitor (screen) or TV set allowed visual manipulation of text and numbers. The [[BASIC]] language, which was easier to learn and use than raw machine language, became a standard feature. These features were already common in [[minicomputer]]s, with which many hobbyists and early produces were familiar.

In 1979, the launch of the [[VisiCalc]] [[spreadsheet]] (initially for the [[Apple II]]) first turned the microcomputer from a hobby for computer enthusiasts into a business tool. After the 1981 release by IBM of its [[IBM PC]], the term [[personal computer]] became generally used for microcomputers compatible with the IBM PC architecture ([[IBM PC–compatible]]).