Editing Acorn Computers (section)

====The microcomputer systems====
{{More citations needed|section called "The microcomputer systems"|date=March 2010}}
CPU had financed the development of a SC/MP based microcomputer system using the income from its design-and-build consultancy.

This system was launched in January 1979 as the first product of '''Acorn Computer Ltd.''', a trading name used by CPU to keep the risks of the two different lines of business separate. Acorn was chosen because the microcomputer system was to be expandable and growth-oriented. It also had the attraction of appearing before "[[Apple Inc.|Apple Computer]]" in a telephone directory.<ref>{{cite web|url=http://www.businessweekly.co.uk/news/cambridge-torchbearers/arm-and-man-hauser%E2%80%99s-list-legacy-stands-test-time%7Cdate=July|title=News - Business Weekly - Technology News - Business news - Cambridge and the East of England|website=businessweekly.co.uk|url-status=dead|archive-url=https://web.archive.org/web/20160305021446/http://www.businessweekly.co.uk/news/cambridge-torchbearers/arm-and-man-hauser%E2%80%99s-list-legacy-stands-test-time%7Cdate=July|archive-date=5 March 2016|access-date=12 May 2018}}</ref>

[[File:Acorn Computers price list 1979 march.png|thumb|upright|left|March 1979 price list]]
Around this time, CPU and [[Andy Hopper]] set up ''Orbis Ltd.'' to commercialise the [[Cambridge Ring (computer network)|Cambridge Ring]] networking system Hopper had worked on for his [[Doctor of Philosophy|PhD]], but it was soon decided to bring him into CPU as a director because he could promote CPU's interests at the [[University of Cambridge Computer Laboratory]].

CPU purchased Orbis, and Hopper's Orbis shares were exchanged for shares in CPU Ltd. CPU's role gradually changed as its Acorn brand grew, and soon CPU was simply the holding company and Acorn was responsible for development work.

At some point, Curry had a disagreement with Sinclair and formally left Science of Cambridge, but did not join the other Acorn employees at Market Hill until a little while later.

[[File:AcornSystem1.jpg|thumb|The [[Acorn System 1]], upper board; this one was shipped on 9 April 1979.]]
The Acorn Microcomputer, later renamed the [[Acorn System 1]], was designed by [[Sophie Wilson]] (then Roger Wilson). It was a semi-professional system aimed at engineering and laboratory users, but its price was low enough, at around £80 ({{Inflation|UK-GDP|80|1979|r=-1|fmt=eq|cursign=£}}),<ref>{{cite web|url=http://www.speleotrove.com/acorn/acornPriceList.gif|title=Acorn System 1 price list|website=speleotrove.com|url-status=dead|archive-url=https://web.archive.org/web/20120309184119/http://www.speleotrove.com/acorn/acornPriceList.gif|archive-date=9 March 2012|access-date=22 July 2010}}</ref> to appeal to the more serious enthusiast as well. It was a very small machine built on two cards, one with an [[light-emitting diode|LED]] display, keypad, and [[Compact audio cassette|cassette interface]] (the circuitry to the left of the keypad), and the other with the rest of the computer (including the [[central processing unit|CPU]]). Almost all CPU signals were accessible via a [[Eurocard (printed circuit board)|Eurocard]] connector.

The [[Acorn System 2|System 2]] made it easier to expand the system by putting the CPU card from the System 1 in a {{convert|19|in|mm|adj=on}}<!--mm are not primary here!--> Eurocard rack that allowed a number of optional additions.<ref>{{cite web|url=https://chrisacorns.computinghistory.org.uk/Computers/System2.html|last=Whytehead|first=Chris|title=Acorn System 2|website=Chris's Acorns|publisher=The Centre for Computing History|url-status=live|archive-url=https://web.archive.org/web/20210613044709/https://chrisacorns.computinghistory.org.uk/Computers/System2.html|archive-date=13 June 2021|access-date=2 September 2021}}</ref> The System 2 typically shipped with keyboard controller, external keyboard, a text display interface, and a cassette operating system with built-in [[BASIC]] [[interpreter (computer software)|interpreter]].

The [[Acorn System 3|System 3]] moved on by adding [[floppy disk]] support,<ref>{{cite web|url=https://chrisacorns.computinghistory.org.uk/Computers/System3.html|last=Whytehead|first=Chris|title=Acorn System 3|website=Chris's Acorns|publisher=The Centre for Computing History|url-status=live|archive-url=https://web.archive.org/web/20210613044714/https://chrisacorns.computinghistory.org.uk/Computers/System3.html|archive-date=13 June 2021|access-date=2 September 2021}}</ref> and the [[Acorn System 4|System 4]] by including a larger case with a second drive.<ref>{{cite web|url=https://chrisacorns.computinghistory.org.uk/Computers/System4.html|last=Whytehead|first=Chris|title=Acorn System 4|website=Chris's Acorns|publisher=The Centre for Computing History|url-status=live|archive-url=https://web.archive.org/web/20210613044704/https://chrisacorns.computinghistory.org.uk/Computers/System4.html|archive-date=13 June 2021|access-date=2 September 2021}}</ref> The [[Acorn System 5|System 5]] was largely similar to the System 4, but included a newer 2&nbsp;[[megahertz|MHz]] version of the [[MOS Technology 6502|6502]].<ref>{{cite web|url=http://acorn.chriswhy.co.uk/Computers/System5.html|last=Whytehead|first=Chris|title=Acorn System 5<!-- From the title element. Page title is "Acorn System Computers" but the page is specifically about the System 5 -->|website=Chris's Acorns|publisher=The Centre for Computing History|url-status=live|archive-url=https://web.archive.org/web/20210613044706/https://chrisacorns.computinghistory.org.uk/Computers/System5.html|archive-date=13 June 2021|access-date=2 September 2021}}</ref>

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