AT&T Blit - Revision history

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[[File:Teletype DMD 5620.jpg|thumb|A Teletype DMD 5620 connected to the [[wikipedia:SDF Public Access Unix System|SDF Public Access Unix System]]]]

'''Blit''' is a programmable [[wikipedia:raster graphics|raster graphic]] [[wikipedia:computer terminal|computer terminal]] designed by [[wikipedia:Rob Pike|Rob Pike]] and Bart Locanthi Jr. of [[wikipedia:Bell Labs|Bell Labs]] and released in 1982.

==History==
The Blit programmable [[wikipedia:bitmap|bitmap]] [[wikipedia:computer graphics|graphics]] [[wikipedia:computer terminal|terminal]] was designed by [[wikipedia:Rob Pike|Rob Pike]] and Bart Locanthi Jr. of [[wikipedia:Bell Labs|Bell Labs]] in 1982. The Blit technology was commercialized by [[wikipedia:AT&T Corporation|AT&T]] and [[wikipedia:Teletype_Corporation|Teletype]]. In 1984, the [[AT&T 5620|'''DMD''' (dot-mapped display) '''5620''']] was released,<ref>[http://www.brouhaha.com/~eric/retrocomputing/att/5620/ AT&T/Teletype 5620 Dot Mapped Display Terminal]</ref> followed by models [[AT&T 630_MTG|'''630 MTG''']] (multi-tasking graphics) in 1987 and [[AT&T_730 MTG|'''730 MTG''']] in 1989. The 5620 used a [[wikipedia:Western Electric|Western Electric]] 32100 processor (aka [[wikipedia:Bellmac 32|Bellmac 32]]) and had a 15-inch green phosphor display with 800×1024×1 resolution (66×88 characters in the initial text mode) interlaced at 30 Hz. The 630 and 730 had [[wikipedia:Motorola 68000|Motorola 68000]] processors and a 1024×1024×1 monochrome display at 60 Hz (most had amber displays, but some had white or green displays).

The [[wikipedia:folk etymology|folk etymology]] for the ''Blit'' name is that it stands for ''Bell Labs Intelligent Terminal'', and its creators have also joked that it actually stood for ''Bacon, Lettuce, and Interactive Tomato''. However, Rob Pike's paper on the Blit explains that it was named after the second syllable of ''[[wikipedia:bit blit|bit blit]]'', a common name for the bit-block transfer operation that is fundamental to the terminal's graphics.<ref>{{cite journal
| first = Rob
| last = Pike
| author-link = wikipedia:Rob Pike|Rob Pike
| title = The Blit: A Multiplexed Graphics Terminal
| url = http://doc.cat-v.org/bell_labs/blit/
| work = AT&T Bell Laboratories Technical Journal
| volume = 63
| issue = 8
| year = 1984
| pages = 1607–1631
| doi = 10.1002/j.1538-7305.1984.tb00056.x
| s2cid = 34062559
| url-access = subscription
}}</ref> Its original nickname was ''Jerq'', inspired by a joke used during a demo of a Three Rivers' [[wikipedia:PERQ|PERQ]] graphic workstation and used with permission.<ref>{{cite web |url=https://inbox.vuxu.org/tuhs/CAKzdPgz37wwYfmHJ_7kZx_T=-zwNJ50PhS7r0kCpuf_F1mDkww@mail.gmail.com/ |title=Re: [TUHS] Blit source |last=Pike |first=Rob |date=19 December 2019 |publisher=TUHS |access-date=29 October 2020 |quote=The name, originally coined for a fun demo of the Three Rivers Perq by folks at Lucasfilm, was borrowed with permission by us}}</ref>

==Functionality==
When initially switched on, the Blit looked like an ordinary textual [[wikipedia:dumb terminal|"dumb" terminal]], although taller than usual. However, after logging into a [[wikipedia:Unix|Unix]] host (connected to the terminal through a [[wikipedia:serial port|serial port]]), the host could (via special escape sequences) load software to be executed by the processor of the terminal. This software could make use of the terminal's full graphics capabilities and attached peripherals such as a [[wikipedia:computer mouse|computer mouse]]. Normally, users would load the window systems ''mpx'' (or its successor ''mux''), which replaced the terminal's [[wikipedia:user interface|user interface]] by a mouse-driven windowing interface, with multiple terminal windows all multiplexed over the single available serial-line connection to the host.

Each window initially ran a simple [[wikipedia:terminal emulator|terminal emulator]], which could be replaced by a downloaded interactive graphical application, for example a more advanced terminal emulator, an editor, or a clock application. The resulting properties were similar to those of a modern Unix windowing system; however, to avoid having user interaction slowed by the serial connection, the interactive interface and the host application ran on separate systems—an early implementation of [[wikipedia:distributed computing|distributed computing]].

==Window systems==
Pike wrote two window systems for the Blit, ''mpx'' for [[wikipedia:Research Unix#Versions|8th Edition Unix]] and ''mux'' for 9th Edition, both sporting a minimalistic design. The design of these influenced the later [[wikipedia:Plan 9 from Bell Labs|Plan 9]] window systems [[wikipedia:8½ (Plan 9)|8½]] and [[wikipedia:Rio (windowing_system)|rio]]. When the Blit was commercialized as the DMD 5620, a variant of mpx called "layers" was added to [[wikipedia:UNIX System V#SVR3|SVR3]].<ref>{{cite web |title=AT&T 5620 (and Related Terminals) Frequently Asked Questions |author=Eric Smith |date=25 August 2005 |url=http://www.brouhaha.com/~eric/retrocomputing/att/5620/5620_faq.html}}</ref>

9front (a Plan 9 fork) contains a Blit emulator that runs its original firmware,<ref>{{cite web|title=Blit emulator source code|url=http://git.9front.org/plan9front/plan9front/HEAD/sys/src/games/blit/f.html}}</ref> which can be used with mux (available in recently released [[wikipedia:Research Unix|Research Unix]] v8<ref>{{cite web|title=[TUHS] 8th Edition Research Unix on SIMH|url=http://minnie.tuhs.org/pipermail/tuhs/2017-March/009440.html|access-date=2017-12-20|archive-url=https://web.archive.org/web/20170730032618/http://minnie.tuhs.org/pipermail/tuhs/2017-March/009440.html|archive-date=2017-07-30|url-status=dead}}</ref>).

==See also==
* [[wikipedia:3B series computers|3B series computers]], some of which also used the WECO 32000 processor, were often used with DMD 5620s
* [[wikipedia:Rio (windowing system)|rio]]
* [[wikipedia:Thin client|Thin client]]
* [[wikipedia:X terminal|X terminal]]

==References==
{{Reflist}}
;Notes
*{{citation |url=http://www.osnews.com/story/26315/Blit_a_multitasking_windowed_UNIX_GUI_from_1982 |title=Blit: a multitasking, windowed UNIX GUI from 1982 |first=Thom |last=Holwerda |work=[[wikipedia:OSNews|OSNews]] |date=August 29, 2012 |accessdate=September 15, 2012 }}

==External links==
* Bart Locanthi, Rob Pike: [https://web.archive.org/web/20070928060025/http://herpolhode.com/rob/movies/blit.mpg <cite>Blit</cite> (MPEG)] [https://www.youtube.com/watch?v=Pr1XXvSaVUQ (YouTube)], the classic animated short about the windowing terminal project (it was necessary to explain how mice worked back then; this was 1982, two years before the [[wikipedia:Macintosh|Mac]]) ([[wikipedia:MPEG|MPEG]])
* Source code (contains proprietary code) [http://www.brouhaha.com/~eric/retrocomputing/att/5620/software/ <cite>5620</cite>]

[[Category:AT&T|Blit]]
{{category raster}}
[[Category:Graphics]]
[[Category:Local Processing]]
[[Category:1982]]

@@ Line 14: / Line 14: @@
    | volume = 63
    | issue = 8
-   | year = 1984
+   | date = 1984
    | pages = 1607–1631
    | doi = 10.1002/j.1538-7305.1984.tb00056.x
@@ Line 48: / Line 48: @@
    | url = http://git.9front.org/plan9front/plan9front/HEAD/sys/src/games/blit/f.html
    | website = 9front Git Repository
-   | access-date 17 February 2026
+   | access-date = 17 February 2026
 }}</ref> which can be used with mux (available in recently released [[wikipedia:Research Unix|Research Unix]] v8<ref>{{cite web
    | title = &#91;TUHS&#93; 8th Edition Research Unix on SIMH
@@ Line 72: / Line 72: @@
    | first = Thom
    | last = Holwerda
-   | work = OSNews
+   | website = OSNews
    | date=August 29, 2012
    | access-date = September 15, 2012

@@ Line 7: / Line 7: @@
 The [[wikipedia:folk etymology|folk etymology]] for the ''Blit'' name is that it stands for ''Bell Labs Intelligent Terminal'', and its creators have also joked that it actually stood for ''Bacon, Lettuce, and Interactive Tomato''. However, Rob Pike's paper on the Blit explains that it was named after the second syllable of ''[[wikipedia:bit blit|bit blit]]'', a common name for the bit-block transfer operation that is fundamental to the terminal's graphics.<ref>{{cite journal
-  | first = Rob
+| first = Rob
-  | last = Pike
+| last = Pike
-  | title = The Blit: A Multiplexed Graphics Terminal
+| title = The Blit: A Multiplexed Graphics Terminal
-  | url = http://doc.cat-v.org/bell_labs/blit/
+| url = http://doc.cat-v.org/bell_labs/blit/
-  | journal = AT&T Bell Laboratories Technical Journal
+| journal = AT&T Bell Laboratories Technical Journal
-  | volume = 63
+| volume = 63
-  | issue = 8
+| number = 8
-  | date = 1984
+| date = 1984
-  | pages = 1607–1631
+| pages = 1607–1631
-  | doi = 10.1002/j.1538-7305.1984.tb00056.x
+| doi = 10.1002/j.1538-7305.1984.tb00056.x
-  | s2cid = 34062559
+| s2cid = 34062559
-  | url-access = subscription
+| url-access = subscription
-  }}</ref>  Its original nickname was ''Jerq'', inspired by a joke used during a demo of a Three Rivers' [[wikipedia:PERQ|PERQ]] graphic workstation and used with permission.<ref>{{cite web
+}}</ref>  Its original nickname was ''Jerq'', inspired by a joke used during a demo of a Three Rivers' [[wikipedia:PERQ|PERQ]] graphic workstation and used with permission.<ref>{{cite web
-  | url = https://inbox.vuxu.org/tuhs/CAKzdPgz37wwYfmHJ_7kZx_T=-zwNJ50PhS7r0kCpuf_F1mDkww@mail.gmail.com/
+| url = https://inbox.vuxu.org/tuhs/CAKzdPgz37wwYfmHJ_7kZx_T=-zwNJ50PhS7r0kCpuf_F1mDkww@mail.gmail.com/
-  | title = Re: &#91;TUHS&#93; Blit source
+| title = Re: &#91;TUHS&#93; Blit source
-  | last = Pike
+| last = Pike
-  | first = Rob
+| first = Rob
-  | date = 19 December 2019
+| date = December 19, 2019
-  | website = TUHS
+| website = TUHS
-  | access-date = 29 October 2020
+| accessdate = October 29, 2020
-  | quote = The name, originally coined for a fun demo of the Three Rivers Perq by folks at Lucasfilm, was borrowed with permission by us
+| quote = The name, originally coined for a fun demo of the Three Rivers Perq by folks at Lucasfilm, was borrowed with permission by us
 }}</ref>
@@ Line 37: / Line 37: @@
 ==Window systems==
 Pike wrote two window systems for the Blit, ''mpx'' for [[wikipedia:Research Unix#Versions|8th Edition Unix]] and ''mux'' for 9th Edition, both sporting a minimalistic design. The design of these influenced the later [[wikipedia:Plan 9 from Bell Labs|Plan 9]] window systems [[wikipedia:8½ (Plan 9)|8½]] and [[wikipedia:Rio (windowing_system)|rio]]. When the Blit was commercialized as the DMD 5620, a variant of mpx called "layers" was added to [[wikipedia:UNIX System V#SVR3|SVR3]].<ref>{{cite web
-  | title = AT&T 5620 (and Related Terminals) Frequently Asked Questions
+| title = AT&T 5620 (and Related Terminals) Frequently Asked Questions
-  | first = Eric
+| first = Eric
-  | last = Smith
+| last = Smith
-  | access-date = 25 August 2005
+| accessdate = August 25, 2005
-  | url = http://www.brouhaha.com/~eric/retrocomputing/att/5620/5620_faq.html
+| url = http://www.brouhaha.com/~eric/retrocomputing/att/5620/5620_faq.html
 }}</ref>
 front (a Plan 9 fork) contains a Blit emulator that runs its original firmware,<ref>{{cite web
-  | title = Blit emulator source code
+| title = Blit emulator source code
-  | url = http://git.9front.org/plan9front/plan9front/HEAD/sys/src/games/blit/f.html
+| url = http://git.9front.org/plan9front/plan9front/HEAD/sys/src/games/blit/f.html
-  | website = 9front Git Repository
+| website = 9front Git Repository
-  | access-date = 17 February 2026
+| accessdate = February 17, 2026
 }}</ref> which can be used with mux (available in recently released [[wikipedia:Research Unix|Research Unix]] v8<ref>{{cite web
-  | title = &#91;TUHS&#93; 8th Edition Research Unix on SIMH
+| title = &#91;TUHS&#93; 8th Edition Research Unix on SIMH
-  | url = http://minnie.tuhs.org/pipermail/tuhs/2017-March/009440.html
+| url = http://minnie.tuhs.org/pipermail/tuhs/2017-March/009440.html
-  | access-date = 2017-12-20
+| accessdate = December 20, 2017
-  | archive-url = https://web.archive.org/web/20170730032618/http://minnie.tuhs.org/pipermail/tuhs/2017-March/009440.html
+| archiveurl = https://web.archive.org/web/20170730032618/http://minnie.tuhs.org/pipermail/tuhs/2017-March/009440.html
-  | archive-date = 2017-07-30
+| archivedate = July 30, 2017
-  | url-status = dead
+| url-status = dead
 }}</ref>).
@@ Line 68: / Line 68: @@
 ;Notes
 *{{citation
-  | url = http://www.osnews.com/story/26315/Blit_a_multitasking_windowed_UNIX_GUI_from_1982
+| url = http://www.osnews.com/story/26315/Blit_a_multitasking_windowed_UNIX_GUI_from_1982
-  | title = Blit: a multitasking, windowed UNIX GUI from 1982
+| title = Blit: a multitasking, windowed UNIX GUI from 1982
-  | first = Thom
+| first = Thom
-  | last = Holwerda
+| last = Holwerda
-  | website = OSNews
+| website = OSNews
-  | date=August 29, 2012
+| date = August 29, 2012
-  | access-date = September 15, 2012
+| accessdate = September 15, 2012
 }}