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Inverse-T Arrow Key Layout Adoption History
===========================================
By Michael Walden
Created: 2023-10-04 (First public release)
Updated: 2023-10-04
Introduction
------------
The following is a chronological list (which is as accurate as possible with
the information available on the net) of computing devices that adopted the DEC
inverse-T arrow key layout into them. The inverse-T arrow key layout was
developed by Jim Burrows [1] while at DEC's Roxbury, Massachusetts facility
[2]. It was a great improvement over the many arrow key layouts in use up to
that point [4]. Many computing devices even had keyboards that lacked
dedicated arrow keys. [3]
This list only has devices that were produced up to the end of the 1980s. This
list does not include any no-name or small-name IBM clone computers and no-name
or small-name IBM compatible keyboards.
Contributions
-------------
If you have any corrections or additions, please let me know in an email and I
will include them on this page.
If you have any comments about this web page that you would like to email me,
please feel free to do so (be sure to mention "Inverse-T" in your message).
Tell me if you would like your comment to be featured here, and I will try to
add it to the comment section at the bottom of the page if I am not overwhelmed
with user comments! I will do this as time permits.
My email address can be found by going to my [Contact Michael Walden] page.
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Update 2023-04-30
In a surprise discovery by David Murray (The 8-Bit Guy) [4], he found a
terminal from April 1970 that incorporated the inverse-T layout that was
developed before and independently from the DEC team's work done in the early
eighties.
• ADDS Consul 880 (Consul 880A) (April, 1970)
https://Terminals-Wiki.org/wiki/index.php/ADDS_Consul_880
(Note that the pictures on this page are of the ADDS Consul 880A which was
introduced in September, 1973.)
Apparently, this instance of the inverse-T arrow key layout went unnoticed or
was forgotten by the industry and not copied in any other computing devices.
Update 2023-08-03
In a second surprise discovery by me, I found a Japanese computer from May 1981
that incorporated the inverse-T layout. It is unclear if they copied this from
the ADDS Consul 880 terminal, or came up with it independently.
• Fujitsu FM-8 (Fujitsu Micro 8) (May 1981)
https://en.Wikipedia.org/wiki/FM-8
https://www.Old-Computers.com/museum/computer.asp?c=377
The following three computers apparently derive their inverse-T layout from the
Fujitsu FM-8.
• Fujitsu FM-7 ("Fujitsu Micro 7") (November 1982)
https://en.Wikipedia.org/wiki/FM-7
• Secoinsa FM-7 (1984) (Spain)
https://YouTu.be/4LTMYocpE9M
(See: Keyboard @ 1:35, Keyboard @ 18:32, Release in Spain 1984 @ 19:07)
• Fujitsu FM 77 AV (1985)
https://www.Old-Computers.com/museum/computer.asp?c=373
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The List
--------
Note: Not all of the different computing devices have an image of the keyboard
in the links provided. Take my word for it that the keyboards have the
inverse-T layout.
• DEC LK201 Keyboard (1982)
https://en.Wikipedia.org/wiki/LK201
https://Deskthority.net/wiki/DEC_LK201
• DEC Rainbow 100 (1982)
https://en.Wikipedia.org/wiki/Rainbow_100
• DECmate II (aka PC278) (1982)
https://en.Wikipedia.org/wiki/DECmate#DECmate_II
https://BitSavers.org/pdf/dec/pdp11/catalogs/PDP-11_Systems_and_Options_Catalog_198310.pdf
(see document page 5-07 / pdf page 146) (PC2K1-AA USA or LK201-BA USA-Canada)
https://www.RIComputerMuseum.org/collections-gallery/small-systems-at-ricm/decmate-ii
• DEC Professional 350 (PRO-350), DEC Professional 325 (PRO-325) (1982)
https://en.Wikipedia.org/wiki/DEC_Professional_%28computer%29
https://www.Vintage-Computer.com/machines.php?decpro350
• Spectravideo SVI-328 (June 1983 - Summer CES, Chicago) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< The first known non-DEC product to include the inverse-T arrow key layout.
https://Old-Computers.com/museum/computer.asp?st=1&c=228 (not including the recently discovered ADDS Consul 880 and Fujitsu FM-8 / FM-7 PCs)
https://en.Wikipedia.org/wiki/SV-328
(The Inverse-T is located at the right side on top of the numeric keypad)
• Convergent Technologies NGEN (Late 1983)
https://en.Wikipedia.org/wiki/Convergent_Technologies#NGEN
http://www.BitSavers.org/pdf/convergent/ngen/pictures/KB-001_1.jpg
http://www.BitSavers.org/pdf/convergent/ngen/pictures/KB-001_2.jpg
(a "6-key cursor control pad" is located on the right side of the keyboard above the numeric keypad)
• ACT Apricot PC (September 1983)
https://Old-Computers.com/museum/computer.asp?c=499
http://ActApricot.org/machines/apricot_this_is_my_pc.html
https://en.Wikipedia.org/wiki/Apricot_PC
• Tandy 2000 (September 1983)
https://en.Wikipedia.org/wiki/Tandy_2000
https://www.TRS-80.com/wordpress/models/
(11/1983 Radio Shack releases the Model 2000)
https://Old-Computers.com/museum/computer.asp?st=1&c=1219
(December 1981 - INCORRECT DATE in main body. Correct date in technical information at bottom)
https://www.DigiBarn.com/collections/systems/trs80-model2000/index.html
https://www.DigiBarn.com/collections/systems/trs80-model2000/IMG_0397.jpg
• TRS-80 - Model 4P (October 1983)
https://en.Wikipedia.org/wiki/TRS-80#Model_4
"A "luggable" version known as the Model 4P (1983)"
https://www.TRS-80.com/wordpress/models/
10/1983 Radio Shack announces the Model 4P (Portable), at a price of about $1,799
https://Old-Computers.com/museum/computer.asp?st=1&c=1083
Keyboard 1 (no Inverse-T)
https://Old-Computers.com/museum/photos/tandy_model4P_keyboard_1.jpg
Keyboard 2 (Inverse-T located to the right of the caps key)
https://Old-Computers.com/museum/photos/tandy_model4P_front_ebay_2.jpg
https://web.archive.org/web/20080828124839/http://www.429bauhaus.no-ip.com/Tandy/TRS80Model4P.html
https://web.archive.org/web/20070707061850/http://www.429bauhaus.no-ip.com/Tandy/TRS80Model4PImages/TRS80Model4PKeyboard.jpg
(When was this keyboard released to market? After October 1983?)
• DEC VT220 (Monochromomme text terminal) (Nov 1983)
https://en.Wikipedia.org/wiki/VT220
https://Terminals-Wiki.org/wiki/index.php/DEC_VT220
• HP-150 (November 1983)
https://en.Wikipedia.org/wiki/HP-150
http://www.Columbia.edu/cu/computinghistory/hp150.html
http://www.Columbia.edu/cu/computinghistory/hp150.jpg
https://www.HPMuseum.net/display_item.php?hw=43
The HP 150: Touch Screen MS-DOS PC from 1983
https://YouTu.be/ExKowj2g8N8
(3:47 - Inverse T zoomed in)
(4:29 - Full keyboard with Inverse T)
(5:52 - ROM characters zoomed in (Not Inverse T related))
(6:48 - ROM fonts (Not Inverse T related))
• Beehive ATL-008 (December 1983)
https://BitSavers.org/pdf/beehive/TM0283T1-1_ATL-008_UM_Feb84.pdf
(p71, p202 - 212)
(Inverse-T on the left side of the keyboard)
• DEC VT240 (Monochromomme text and graphics) (Jan 1984)
DEC VT241 (Color text and graphics)
https://Terminals-Wiki.org/wiki/index.php/DEC_VT240
• DECmate III (1984)
https://en.Wikipedia.org/wiki/DECmate#DECmate_III
• Mindset Model No. M-1001 (2 May 1984)
https://en.Wikipedia.org/wiki/Mindset_(computer)
https://www.Old-Computers.com/museum/computer.asp?st=1&c=986
The Mindset: The Atari ST or PC That Might Have Been
https://YouTu.be/MRpFqz5dOPA
(31:36 Inverse-T keys)
• EPSON PX-8 / Geneva (1984)
https://Old-Computers.com/museum/computer.asp?st=1&c=198
https://en.Wikipedia.org/wiki/Epson_PX-8_Geneva
https://Vintage-Computer.com/machines.php?epsonpx8
https://AtariMagazines.com/creative/v10n10/10_Epson_PX8_Geneva.php
(The orange cursor control keys at the right are arranged in the inverse T layout)
• Tandy 1000 (1984)
https://Old-Computers.com/museum/computer.asp?c=1210
Keyboard
https://Old-Computers.com/museum/photos/tandy_1000_3.jpg
https://en.Wikipedia.org/wiki/List_of_TRS-80_and_Tandy-branded_computers#PC-compatible_computers
"The later Tandy 1000 systems and follow-ons were also marketed by DEC,
as Tandy and DEC had a joint manufacturing agreement.[16]"
https://en.Wikipedia.org/wiki/Tandy_1000#Tandy_1000
• IBM Model M keyboard (1985)
https://en.Wikipedia.org/wiki/Model_M_keyboard
IBM Model M keyboard, Part no. 1391401
https://Commons.Wikimedia.org/wiki/File:ModelM.jpg (OLD URL)
https://Commons.Wikimedia.org/wiki/File:IBM_Model_M_keyboard_(US_layout_with_101_keys).jpg
• DECmate III+ (1985)
https://en.Wikipedia.org/wiki/DECmate#DECmate_III+
• Epson PX-4 (1985)
https://en.Wikipedia.org/wiki/Epson_PX-4
https://Electrickery.nl/comp/px4/index.html
(see the three orange keys on right side of keyboard)
• Atari 520ST (April 1985)
https://en.Wikipedia.org/wiki/Atari_ST
https://Flickr.com/photos/rankovukcevic/139788969/lightbox
• AT&T UNIX PC Model 7300 (1985)
https://en.Wikipedia.org/wiki/AT%26T_Unix_PC
• IBM 3161/3163 (1985)
https://en.Wikipedia.org/wiki/IBM_3101#IBM_3161.2F3163
https://Commons.Wikimedia.org/wiki/File:Ibm3161-setup.jpg
• Atari 1040ST (1986)
https://en.Wikipedia.org/wiki/Atari_ST
• IBM Personal Computer XT - Enhanced Keyboard (April 1986)
https://en.Wikipedia.org/wiki/IBM_Personal_Computer_XT
Submodels 268, 278 and 089 came with 101-key keyboards (essentially the IBM Model M,
but in a modified variant that used the XT's keyboard protocol and lacked LEDs).
https://en.Wikipedia.org/wiki/List_of_IBM_Personal_Computer_models
IBM P/N 5160-268, 278 and 089 Announced in April 1986 - Withdrawn June 1987 -
Shipped with Enhanced Keyboard
also see:
IBM PC keyboard - Enhanced keyboard
https://en.Wikipedia.org/wiki/IBM_PC_keyboard#Keyboard_layouts
Model M (Enhanced) - 101 Keys
• IBM PC Convertible (April 3, 1986)
https://en.Wikipedia.org/wiki/IBM_PC_Convertible
• IBM RT (6150) (Late 1986)
https://Old-Computers.com/museum/computer.asp?st=1.&c=867
https://Old-Computers.com/museum/forum.asp?c=867&st=1.
"The engineering that went into this system was amazing, and it certainly
shaped the computer market into what it is today by introducing both the
RISC architecture and the original Model M keyboard layout."
• Amiga 2000 (1986)
https://en.Wikipedia.org/wiki/Amiga_2000
• Amiga 500 (January 1987)
https://en.Wikipedia.org/wiki/Amiga_500
• Apple Macintosh II (March 2, 1987)
https://en.Wikipedia.org/wiki/Macintosh_II
• Apple Extended Keyboard (March 2, 1987)
https://en.Wikipedia.org/wiki/Apple_Extended_Keyboard
• IBM Personal System/2 (April, 1987) (all included a Model M keyboard)
https://en.Wikipedia.org/wiki/IBM_Personal_System/2
• Acorn Archimedes (June 1987)
https://en.Wikipedia.org/wiki/Acorn_Archimedes
https://en.Wikipedia.org/wiki/Acorn_Archimedes#/media/File:Acorn_Archimedes_A3000_Computer_Main_Unit.jpg
• Focus FK-555 Keyboard (1987-07-02)
https://YouTu.be/bUYuTBWfxr0
(FCC ID.io FSQ4VYFK-555 - 1987-07-02)
• DEC VT320 (August 1987)
https://en.Wikipedia.org/wiki/VT320
• Focus FK-2001 Keyboard (1988-08-29)
https://YouTu.be/yEwataeE5P8
(FCC ID: FSQ4VYFK-2001 - 1988-08-29)
• NeXT Computer (October 12, 1988)
https://en.Wikipedia.org/wiki/NeXT#First_generation
https://en.Wikipedia.org/wiki/NeXT_Computer
• Focus FK-1001 Keyboard (1988-12-12)
https://YouTu.be/i3PZHF7gbmI
(FCC ID: FSQ4VYFK-1001 - 1988-12-12)
• CASIO AI-1000 Personal Computer (1989)
https://YouTu.be/H-yuZ2pejGU
(A Lisp pocket calculator/computer)
https:/CASIO.Ledudu.com/pockets.asp?type=84&lg=eng
http://Calculators.Torensma.net/index.php?page.id=16&calculator.id=27&action=detail
https://JamelTayeb.com/2018/02/03/misunderstandings-part-2/
http://www.PiSi.com.pl/piotr433/pb2000ee.htm
https://PockEmul.com (No CASIO AI-1000, but nice calculator emulator)
• Key Tronic KB101 Plus (1989-01-30)
https://www.RecycledGoods.com/key-tronic-corp-vintage-tastatur-keyboard-kb101-plus/
(FCC ID: CIG8AVE03417 - 1989-01-30)
Key Tronic Corporation manufactured keyboards from the beginning of the PC
era, and somewhere along the way made a keyboard with the inverse-T layout in
it. If you know of a Key Tronic keyboard model (which includes the inverse-T
layout (preferably the first one)) and date of release, please let me know and
I will add it here. The KB101 Plus may be the first one, but I suspect the non
Plus version may have been the first.
• Acorn Archimedes A3000 / Acorn BBC A3000 (May 1989)
https://www.Old-Computers.com/museum/computer.asp?st=1&c=697
https://www.Retro-Kit.co.uk/page.cfm/content/Acorn-BBC-A3000
• OmniKey 102 by Northgate Computer Systems, Inc. (1989-12-04)
https://en.Wikipedia.org/wiki/Northgate_Computer_Systems
https://www.eBay.com/itm/145317998848
(FCC ID: GT6OMNIKEY02 - 1989-12-04)
(42 total devices currently in the list (Plus 5 devices in the Updates))
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Related Links
-------------
[1] The Nerd Corner: Inverse-T History, by Jim Burrows (aka Brons) (LK201 keyboard (1982))
http://Home.Comcast.net/~brons/NerdCorner/InverseT-History.html (OLD URL)
https://www.Eldacur.com/~brons/NerdCorner/InverseT-History.html
Note that around September 21, 2009 I had submitted some questions to the
author of this page and he updated the page and mentioned me (Michael
Walden) on the page near the bottom. Also note that it was around this
time that I started creating this Inverse-T Arrow Key Layout Adoption
History list.
[2] Quote: "The LK201 keyboard ... was developed at DEC's Roxbury, Massachusetts facility."
https://en.Wikipedia.org/wiki/VT220
[3] Arrow keys - Wikipedia
https://en.Wikipedia.org/wiki/Arrow_keys
[4] David Murray / The 8-Bit Guy - The History of Cursor Keys (April 30, 2023)
https://YouTu.be/BytowtVycc0
See at 1:02 for discussion on ADDS Consul 880 terminal. This video covers most
of the other dedicated cursor key layouts in use in the 70s & 80s.
Note: David lists the following computer with inverse-T layout:
Commodore 65 (un-released / prototype)
https://YouTu.be/BytowtVycc0?t=839 (13:59)
I don't include it in the list since it was never sold in stores.
David also mentions the following computers with inverse-T layout:
Sun SPARCstation
https://YouTu.be/BytowtVycc0?t=862 (14:22)
Silicon Graphics
https://YouTu.be/BytowtVycc0?t=864 (14:24)
I do not include them since model numbers and release dates are not
clearly available on the Internet. If you have these details, let
me know and I will add them to the list (if they are from before
1990).
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Comments
--------
None yet. Send me an email comment.
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© 2023 Michael Walden
(This document was originally published here: https://MW.Rat.bz/inverse-t )
Counter: 2458 (Since 2023-10-04)
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