TheADM-3Awas an influential earlyvideo display terminal,introduced in 1976.[1]It was manufactured byLear Sieglerand had a 12-inch screen displaying 12 or 24 lines of 80 characters. It set a new industry low single unit price of $995.[a]Its "dumb terminal"nickname came from some of the original trade publication advertisements.[2]It quickly became commercially successful because of the rapid increase of computer communications speeds, and because of newminicomputerandmicrocomputersystems released to the market which required inexpensive operator consoles.
 Terminal with keypad | |
| Manufacturer | Lear Siegler |
|---|---|
| Type | Computer terminal |
| Release date | 1976 |
| Introductory price | US$995(equivalent to $5,300 in 2023) |
History
editThis sectionneeds additional citations forverification.(July 2016) |
Lear Siegler, Inc. (LSI) manufactured its firstvideo display terminalin 1972 – the 7700A.
In 1973, LSI hired a new head of engineering, Jim Placak. He and his team created the ADM-1 later that year. It set a new pricing low in the industry at $1,500.[b]Its lower cost was primarily due to a unique single printed circuit board design. In early 1973 the LSI division in Anaheim, California that manufactured these and other products hired a management team for this product line – a VP, national sales manager, and one regional sales manager – for the western region. The ADM-1 was followed by the ADM-2 in early '74. It had expanded functionality and a detached keyboard.
The initials "ADM" were referred to as meaning "American Dream Machine" in some advertising.[3]
ADM-3
editThe ADM-3 followed and the first manufactured units were introduced at1975 National Computer Conferencein Anaheim, Calif., May 19–22, 1975, in booth 2348 at a price of $995.[4][2]Its innovativewave solderedsingle board design, which included the keyboard and all connectors, was packaged in an original clam shell enclosure.
Within weeks of the launch of the ADM-3, Cagan[clarification needed]started to book very large orders. Its 'Dumb Terminal' nickname came from some of the original trade publication ads, and quickly caught on industry wide.[2]Due to two emerging trends, the device immediately became the best selling in the industry. Computer communications speeds were rapidly increasing, and a wave of general purpose and dedicated single applicationminicomputersystems were hitting the market from dozens of manufacturers. These required inexpensive operator consoles that could match the speeds. With no fast low cost printers available, the ADM-3 (painted in a variety of custom colors for theOEMs) became the de facto standard. By December 20, 1976, the widely usedTeletype Model 33 KSRelectromechanical printing terminal, which could only print ten characters per second, sold for $895 or $32/month, while the ADM-3, which could display up to 1,920 characters per second, went for $995 or $36/month.[5]
ADM-3 options
editThe original ADM-3 terminal displayed only capital letters.[6]In 1976, an option was added to allow it to display both lower and upper case.[6][7]The standard version of the terminal displayed only twelve (rather than twenty-four) rows of eighty characters.[2][6]In those days RAM was expensive, and halving the display size halved the RAM requirement[8](and likewise all uppercase required only six bits per character to be stored rather than seven). Further optional add-ons included agraphics cardenabling it to emulate aTektronix 4010[9]and an extension port which would allow daisy chaining several ADM-3As on a singleRS-232line.[2]
ADM-3A
editIn 1976, the ADM-3A was introduced.[1]The ADM-3A added support for control codes to move the cursor around on the screen, and directly position the cursor at any point in the display. It did not, however, support “clear to end of line” or “clear to end of screen”, or other more advanced codes that appeared in later terminals, such as theVT52andVT100.
The ADM-3A's overall setup was controlled by 20[6][10]DIP switchesunder the nameplate at the front of the machine, beside the keyboard, including setting speed from 75 to 19,200 baud. The advanced configuration options allowed split speed connection, sending at one rate, and receiving at another.
Hardware
edit
The 5×7 dot matrix characters were displayed in amber, green, or whitephosphoron black (the cursor was 7×9). The keyboard had 59 keys. The 12-inchmonochromeCRT[11]was mounted in the top half of the case, which was hinged in the back and opened like a clamshell. The CRT was typically made byBall Brothers.[12][better source needed]
Unlike later terminals, such as theVT100,the ADM-3A did not use a microprocessor in its implementation, but instead usedTTL.[10]It did, however, use RAM chips, rather than theCirculating Memoryused by earlier terminals, such as theDatapoint 3300.
Legacy
editThe use of theHJKL keysfor moving the cursor in thevieditor and its descendants originated from the ADM-3A,University of California, Berkeley'sTeletype Model 33replacement, just prior to thevieditor's creation;[13][14][15][16][17]the cursor-movement arrows were printed on those four keys.[18][discuss]TheHome keyandtildelabel printed on the^key may have additionally led to the establishment of thetildecharacter ( "~" ) as the representation of thehome directoryin many Unix shells.[discuss]Thecaretcharacter is also commonly used to represent the beginning of line or "home" position inregular expressiondialects.
The←,↓,↑,→andHomelabels printed on theH,J,K,L,and~ ^keys were a visual reference to the control charactersCtrl+H,Ctrl+J,Ctrl+K,Ctrl+L,andCtrl+~ ^that were required to move the cursor left, down, up, right, and to the top/left corner (or "Home" position) of the terminal, respectively.[19]TheCtrl+HandCtrl+Jfunctions were the standardASCIIbackspaceandline feedrespectively, but the interpretations ofCtrl+K,Ctrl+L,andCtrl+~ ^were new to the ADM-3A. Also common with other terminals,Ctrl+Gproduced an audible beep unless disabled via DIP switch andCtrl+Itabbed the cursor to the next tabstop, with tabstops fixed at each 8th character position.Ctrl+Zwas used to clear the screen.
Finally, theControl keywas located above, not below, theShift key—in the same place where most modern PC keyboards put theCaps Lock key.[c]Many standard Unixkey combinationswere designed with the QWERTY layout and the ADM-3A's original Ctrl key placement in mind.[citation needed]Many of those key combinations are still in use today, even on non-Unix operating systems. Seasoned computer users familiar with the original layout often claim that the different position of the Ctrl key on modern PC keyboard layouts makes the use of Ctrl key combinations more cumbersome.[20][21][22][better source needed]Solutions exist for many operating systems to switch around the Caps Lock and Ctrl keys in software,[21][23]thus making the PC keyboard layout more closely resemble the ADM-3A's keyboard layout.
The legacy of the ADM-3A's keyboard also lives on in Japan, where thelocal layoutfollows it almost exactly. Local Mac keyboard layouts even retain the ADM-3A's position of the Control key, transposing it with the Caps Lock key.
See also
editNotes
edit- ^About $5,000 today
- ^About $10,000 today
- ^Very earlyPC keyboardsalso had the Ctrl key located above the Shift key, just like the ADM-3A's keyboard.
References
edit- ^ab"Lear Siegler Updates ADM-1, Gives ADM-3 Full Cursor Ability".Computerworld.Vol. 10, no. 27. July 5, 1976. p. 17.ISSN0010-4841.RetrievedSeptember 10,2019.
- ^abcde"Introducing The $995 Dumb Terminal".Computerworld.Vol. 9, no. 31. July 30, 1975. p. S/3.ISSN0010-4841.
- ^"Lear Siegler advertisement".Computerworld.May 21, 1984.RetrievedJune 4,2022.
- ^"Compact ADM-3 Parading".Computerworld.Vol. 9, no. 20. May 14, 1975. p. 57.ISSN0010-4841.
- ^"ComData advertisement".Computerworld.Vol. 10, no. 51. December 20, 1976. p. 15.ISSN0010-4841.
- ^abcd"ADM-3 Maintenance Manual"(PDF).Archived(PDF)from the original on 2018-03-03.Retrieved2017-06-23.
- ^"Lower Case Feature Available for ADM-3".Computerworld.Vol. 10, no. 13. March 29, 1976. p. 27.ISSN0010-4841.
- ^"ADM-3A Lower Case Option" Clone "".Archived fromthe originalon October 19, 2016.
- ^"User's Manual RG-512 Retro-Graphics Card for the ADM-3A Computer Terminal"(PDF).Digital Engineering, Inc. 1980.Archived(PDF)from the original on 2022-04-20.Retrieved2022-03-23.
- ^ab"ADM-3A Maintenance Manual"(PDF).Archived(PDF)from the original on 2019-01-26.Retrieved2017-06-24.
- ^"ADM-3A CRT Replacement".Archived fromthe originalon October 20, 2016.
- ^"Old tech: ADM-3A serial terminal, FreeBSD, and some fun. – Quelab".quelab.net.Archivedfrom the original on 2019-01-08.Retrieved2019-01-08.
- ^McKusick, Marshall Kirk (January 1999). "Twenty Years of Berkeley Unix: From AT&T-Owned to Freely Redistributable". In DiBona, Chris; Ockman, Sam (eds.).Open Sources: Voices from the Open Source Revolution.Sebastopol (CA): O'Reilly and Associates, Inc.ISBN1-56592-582-3.Archivedfrom the original on 28 September 2021.Retrieved23 September2020.
Working from an editor named em that they had obtained from Professor George Coulouris at Queen Mary's College in London, they worked to produce the line-at-a-time editor ex....With the arrival of some ADM-3a terminals offering screen-addressable cursors, Joy was finally able to write vi, bringing screen-based editing to Berkeley.
- ^McKusick, Marshall Kirk (January 1985)."A Berkeley Odyssey"(PDF).Unix Review.Archived(PDF)from the original on 2021-07-04.Retrieved2020-09-23.
- ^"Procedural Dungeons of Doom: The Making of Rogue – Chapter 1".3 June 2016.Archivedfrom the original on 29 October 2020.Retrieved23 September2020.
- ^"Berkeley UNIX and the Birth of Open-Source Software".Lab Notes: Research from the Berkeley College of Engineering.UC Regents. 11 November 2001. Archived fromthe originalon 2001-11-11.Retrieved23 September2020.
In 1969, UC Berkeley electrical engineering graduate Kenneth Thompson and his Bell Laboratories colleague Dennis Ritchie wanted to play a computer game called "Space Travel" on a dusty old mainframe computer. To do it, the two were forced to write a new operating system for the machines.
- ^Craddock, David L. (3 June 2016)."The Making of Rogue – Chapter 1".Procedural Dungeons of Doom.Archivedfrom the original on 29 October 2020.Retrieved23 September2020.
By the time Toy and Wichman started at UC Santa Cruz, BSD UNIX had entered widespread usage across UC campuses and was branching out to other schools. Each new version of BSD, released on cassette tape, included handy programs written by Joy and other hackers. One program was curses, written by Ken Arnold. Arnold had written curses according to the UNIX creed: a simple tool fashioned for a specific purpose. Wielding curses like a paintbrush, users could place text such as letters, numbers, and symbols at any location on the screen.
- ^"ADM-3A Operators Manual"(PDF).pp.3–6.Archived(PDF)from the original on 20 December 2022.
- ^"Tenth Anniversary ADM 3A Dumb Terminal Video Display Terminal User's Reference Manual"(PDF).Lear Siegler, Inc. April 1986. pp.1–5.Archived(PDF)from the original on 2019-01-26.Retrieved2017-06-24.
- ^"History of the War against Caps Lock".CAPSoff.Archived fromthe originalon July 30, 2016.
- ^ab"Remap Caps Lock".Archivedfrom the original on 2019-08-22.Retrieved2019-09-10.
- ^"MovingTheCtrlKey".Emacs Wiki.Archivedfrom the original on 2019-09-17.Retrieved2019-09-10.
- ^"Swapping Capslock and Control Keys".Archived fromthe originalon 2011-02-25.
External links
edit
- Lear Siegler ADM-3Aon theterminals wiki
- Lear Siegler ADM 3A
- Lear Siegler, Inc. (LSI) Terminal ADM3A
- "Digital Engineering, Inc. Retrographics RG-512".Archived fromthe originalon 2019-12-25.
- Gangwere, Morgan."Old tech: ADM-3A serial terminal, FreeBSD, and some fun".Quelab.