Editing PERQ (section)

==Software==

The PERQ's original [[P-code machine#UCSD p-Machine|p-Code]]-like instruction set (called ''Q-Code'') was optimized for [[Pascal (programming language)|Pascal]] (specifically, an extended PERQ Pascal). Q-Code instructions could be executed at a rate of up to 1 [[million instructions per second]].<ref>[http://www.chilton-computing.org.uk/acd/sus/perq_pr/p007.htm PERQ Publicity: ICL's PERQ Brochure], Chilton Computing, UK.</ref> This gave rise to the alternative definition of the PERQ name: ''Pascal Evaluation Real Quick''. In fact it was generally more efficient to use Pascal than to attempt to create "[[assembly language]]" programs directly with Q-Code.{{Citation needed|date=June 2009}}

===Operating systems===
A variety of [[operating system]]s were developed for the PERQ. These included:<ref name="faq"/>

;POS (PERQ Operating System): The initial single-task operating system for PERQ workstations, developed by 3RCC. POS and its utilities were written in PERQ Pascal.

;MPOS (Multitasking POS): A [[Computer multitasking|multitasking]] version of POS, not officially released by 3RCC.

;[[Accent kernel|Accent]]: A multitasking research operating system developed at CMU, with a [[window manager]] called Sapphire. Accent was a predecessor of the [[Mach kernel]] which many later operating systems would use. A [[UNIX System V]]-compatible environment running under Accent in a Sapphire window, called ''QNIX'', was developed by [[Spider Systems]].

;PNX ({{IPAc-en|'|p|i:|n|ɪ|k|s}}  {{respell|PEE|nix}}): A port of [[Unix]] for the PERQ, based on [[Seventh Edition Unix]] and [[UNIX System III]]. This was developed by ICL at [[Bracknell]], [[Dalkeith Palace]] and later [[Kidsgrove|Kidsgrove (Staffordshire)]] for the UK research community.<ref name="faq"/> PNX used its own microcode, more appropriate for the [[C (programming language)|C programming language]], called ''C-Code''.

;[[Flex machine|FLEX]]:  Developed by the [[Royal Signals and Radar Establishment]], FLEX was implemented in microcode and similar to other early workstation systems such as [[Lisp machine]]s, [[UCSD Pascal]] or [[Modula-2]], except that the language of choice was [[ALGOL 68]].

=== Compilers ===

ICL and 3RCC contracted with the [[Edinburgh Regional Computing Center]] (ERCC) over 1981-1982 to supply an optimised [[Fortran#FORTRAN_77|Fortran77]] compiler.  This also resulted in an [[Edinburgh_IMP|Imp]] compiler being created, as the F77 compiler from the ERCC was written in Imp.  The ERCC compilers generated [[Q-Code]].  By 1987, maintenance of the PERQ compiler suite had been taken over by a commercial spin-off group of ex-ERCC employees, [[Edinburgh Portable Compilers|Edinburgh Portable Compilers Ltd]] (EPCL).

===Applications===
[[File:Spy text editor running on a PERQ workstation.jpg|thumb|150px|right|''Spy'' third party [[text editor]] from 1983 running on a PERQ workstation at Bletchley Park in 2013.]]
The PERQ was a popular early graphical workstation; therefore, it helped spawn many early third-party applications that took advantage of the [[graphical user interface]] and [[raster graphics|bitmapped graphics]]. [[Intran]] (around 1982) produced a pioneering graphical program suite called MetaForm, which consisted of the separate Graphics Builder, Font Builder, Form Builder, and File Manager programs. The PERQ also served as a dedicated platform for several pioneering [[hypertext]] programs, such as [[ZOG (hypertext)|ZOG]], [[KMS (hypertext)|KMS]], and [[Guide (hypertext)|Guide]]. DP ("Drawing Program"), a [[Computer-aided design|CAD]] system used for creating [[circuit diagram]]s on the PERQ, was written by Dario Giuse at CMU.<ref>{{Cite web |url=http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA126401 |title=Entry for ''DP - Command Set'' at the  Defense Technical Information Center |access-date=2008-12-03 |archive-url=https://web.archive.org/web/20090531004614/http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA126401 |archive-date=2009-05-31 |url-status=dead }}</ref>