Editing QED (text editor)

{{Short description|Line-oriented text editor for the SDS 940}}
{{for|the Latin proverb commonly put at the end of mathematical explanations|Quod erat demonstrandum}}

{{Infobox software
| name                   = QED
| title                  = 
| logo                   = 
| screenshot             = 
| caption                = 
| developer              = [[Butler Lampson]], [[L. Peter Deutsch]], [[Dana Angluin]]
| released               = {{Start date and age|1967}}<ref>{{cite web| url = http://doc.cat-v.org/unix/unix-before-berkeley/| title = A History of UNIX before Berkeley}}</ref><!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} -->
| discontinued           = 
| latest release version = 
| latest release date    = 
| repo                   = 
| programming language   = 
| operating system       = [[Berkeley Timesharing System]]
| platform               = [[SDS 940]]
| size                   = 
| language               = English
| language count         = <!-- DO NOT include this parameter unless you know what it does -->
| language footnote      = 
| genre                  = [[Text editor]]
| license                = 
| website                = 
}}

'''QED''' is a line-oriented computer [[text editor]] that was developed by [[Butler Lampson]] and [[L. Peter Deutsch]] for the [[Berkeley Timesharing System]] running on the [[SDS 940]]. It was implemented by L. Peter Deutsch and [[Dana Angluin]] between 1965 and 1966.<ref>{{citation|last=Lampson|first=Butler|title=Systems| date = January 12, 2007 | website=[[Microsoft Research]] | url = http://research.microsoft.com/lampson/Systems.html#qed | access-date = 2008-04-05 | archive-url = https://web.archive.org/web/20080413182609/http://research.microsoft.com/lampson/Systems.html |archive-date=2008-04-13}}.</ref><ref>''cf''. {{citation|last1=Angluin|first1=Dana C.|last2=Deutsch|first2=L. Peter|title=Reference Manual: Q. E. D. Time-Sharing Editor|date=March 26, 1968|location=Washington|publisher=Office of Secretary of Defence|url=http://bitsavers.trailing-edge.com/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-15_QED.pdf|archive-url=https://web.archive.org/web/20171201043600/http://bitsavers.trailing-edge.com/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-15_QED.pdf|archive-date=2017-12-01|url-status=live}}.</ref>

QED (for "quick editor")<ref>{{citation|doi=10.1145/356589.356591|last1=van Dam|first1=Andries|last2=Rice|first2=David E.|title=On-line Text Editing: A Survey|journal=ACM Computing Surveys|volume=3|issue=3|year=1971|pages=93–114|s2cid=3142185 |url=http://portal.acm.org/citation.cfm?doid=356589.356591|url-access=subscription}}.</ref> addressed [[teleprinter]] usage, but systems "for [[CRT display]]s [were] not considered, since many of their design considerations [were] quite different."<ref>{{citation|doi=10.1145/363848.363863|last1=Deutsch|first1=L. Peter|last2=Lampson|first2=Butler W.|title=An online editor|journal=Communications of the ACM |volume=10|issue=12|year=1967|pages=793–799, 803|url=http://research.microsoft.com/en-us/um/people/blampson/04-OnlineEditor/04-OnlineEditor.htm<!-- http://portal.acm.org/citation.cfm?id=363848.363863&coll=ACM&dl=ACM&CFID=15669714&CFTOKEN=68334085 -->|doi-access=free}}, p. 793.</ref>

==Later implementations==
[[Ken Thompson]] later wrote a version for [[Compatible Time-Sharing System|CTSS]]; this version was notable for introducing [[regular expression]]s. Thompson rewrote QED in [[BCPL]] for [[Multics]].  The Multics version was ported to the [[GE-600 series|GE-600]] system used at [[Bell Labs]] in the late 1960s under [[General Comprehensive Operating System|GECOS]] and later GCOS after [[Honeywell]] took over [[General Electric|GE]]'s computer business.  The GECOS-GCOS port used I/O routines written by A. W. Winklehoff.  [[Dennis Ritchie]], [[Ken Thompson]] and [[Brian Kernighan]] wrote the QED manuals used at Bell Labs.<ref>D. M. Ritchie and K. L. Thompson, "QED Text Editor", [https://www.nokia.com/bell-labs/about/dennis-m-ritchie/qedman.pdf MM-70-1373-3] (June 1970), reprinted as "QED Text Editor Reference Manual", MHCC-004, Murray Hill Computing, Bell Laboratories (October 1972).</ref><ref>B. W. Kernighan, "A Tutorial Introduction to the QED Text Editor under GE-TSS", MM-70-1373-6 (June 1970), reprinted as "Tutorial Introduction to QED Text Editor", MHCC-002, Murray Hill Computing, Bell Laboratories (October, 1972).</ref><ref>B. W. Kernighan, "A Guide to the Advanced Use of QED Text Editor", MM-70-1373-7 (July 1970), reprinted as "A Guide to Advanced Use of QED Text Editor", MHCC-003, Murray Hill Computing, Bell Laboratories (October, 1972).</ref>
Given that the authors were the primary developers of the [[Unix]] operating system, it is natural that QED had a strong influence on the classic [[Unix|UNIX]] text editors [[ed (text editor)|ed]], [[sed]] and their descendants such as [[Ex (text editor)|ex]] and [[sam (text editor)|sam]],<ref>
{{citation|last=Ritchie|first=Dennis|title=An incomplete history of the QED Text Editor|location=Murray Hill|publisher=Bell Labs|date=February 12, 2004|url=https://www.bell-labs.com/usr/dmr/www/qed.html}}.</ref> and more distantly [[AWK]] and [[Perl]].

A version of QED named FRED (Friendly Editor) was written at the
[[University of Waterloo]] for Honeywell systems<ref>{{cite web|last1=Fraser|first1=Peter|title=The FRED Text Editor|url=http://www.thinkage.ca/english/gcos/product-uwtools.shtml|website=Thinkage Ltd.|access-date=1 June 2015}}</ref> by Peter Fraser.  A University of Toronto team consisting of [[Tom Duff]], [[Rob Pike]], Hugh Redelmeier, and David Tilbrook implemented a version of QED that runs on [[Unix|UNIX]]; David Tilbrook later included QED as part of his QEF tool set.

QED was also used as a character-oriented editor on the Norwegian-made [[Norsk Data]] systems, first Nord TSS, then [[Sintran III]]. It was implemented for the [[Nord-1]] computer in 1971 by Bo Lewendal who after working with Deutsch and Lampson at [[Project Genie]] and at the [[Berkeley Computer Corporation]], had taken a job with Norsk Data (and who developed the Nord TSS later in 1971).{{Citation needed|date=February 2017}}

==See also==
*[[QEdit]], a similarly named, but unrelated DOS text editor by SemWare

==References==
{{reflist|30em}}

==Further reading==
{{refbegin}}
*[http://www.thinkage.ca/english/gcos/expl/fred/expl.html FRED - the friendly editor.]
*[https://web.archive.org/web/20211228102320/http://www.qef.com/html/toolsdesc.html#qed QED as part of QEF tools]
*[https://github.com/arnoldrobbins/qed-archive QED Archive] - an archive of source code of several versions of QED
*[https://github.com/chneukirchen/qed-caltech Caltech QED] with changes to compile on Linux 
{{refend}}

[[Category:Line editor]]