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Tandy Radio Shack

The Tandy TRS 80 model 1 was the first member of one of the most famous computer family. It was one of the first home computer and was launched at the same time as famous computers like the Apple II or the Commodore PET. Beside, Tandy competitors nicknamed was "Trash-80".

The TRS-80 was developed was developed within the Radio Shack engeneering group, based upon several processor chips, SC/MP, PACE, 8008, 8080 and finally the Z80.

It used a black & white TV set, made by RCA, without tuner as monitor. The earlier models use a poor basic called Basic Level 1 (the Basic and the OS fit in the 4 KB ROM!). It was replaced later with the Basic Level 2 which needed a 12 KB ROM.

To offset its poor characteristics, Tandy developed a device called Expansion Interface which brings a lot of new features : additional 16 or 32kb RAM, two tape unit connectors, a printer port, a floppy disk controller, a serial port and a real time clock.

Tandy did as well 5, 10 and 15 MB hard drives. The case for them is about the size of a small PC tower. It's possible to fit 2 drives into each case. They were compatible with all TRS-80 versions.

When it was connected to a floppy disk unit, the TRS-80 uses the TRS DOS operating system, it was pretty bugged and most of the TRS-80 users prefered NEW DOS, it was an operating system done by a third-party company called Apparat. This OS was the real TRS-80 operating system.

LS-DOS was also an excellent DOS, superior to NEW DOS for most users. Interestingly, Microsoft's MS-DOS became more and more like LS-DOS each time it was updated, although never as good. LS-DOS was finally adopted by Tandy as the official DOS for the Model 4.

Documentation for all the TRS machines was superb. Even Microsoft provided documentation for its BASIC interpreter listing all the machine calls. You could use these calls when programming with either machine code or BASIC.

The Model I was followed by the TRS 80 model II (a business computer) and model III which had almost the same characteristics as the model I.


Contributors : Donald French, Paul D Moore

Please consider donating your old computer / videogame system to or one of our partners from anywhere in the world (Europe, America, Asia, etc.).

Special thanks to Marc Neiger who donated us this computer !


I recognized it as a pimped-up prop in a tedious office scene in the first episode of the series Andor ("Kassa," 2022). Reminded me of another office prop appearance, in the mid-1980s Remington Steele, which showed it playing full-color video. Photos:

Friday 11th August 2023
Josh Karpf (United States)

I found an old 5 1/4" disk with 12 years of work on it that I would like to convert to my new computer or just print. Does anyone know how to do that?

Tuesday 3rd August 2021
Lawrence M Kapenstein (United States)

Need to have data printed from my 8" disks. Anyone help?

Monday 5th March 2018
John C Sullivan (United States)


MANUFACTURER  Tandy Radio Shack
TYPE  Home Computer
YEAR  1977
BUILT IN LANGUAGE  Basic Level 1 (4k ROM models)
Basic Level II (12k ROM models)
KEYBOARD  Full-stroke keyboard, 53 Keys, optional numeric keypad
CPU  Zilog Z80
SPEED  1.77 MHz
RAM  4 kb / 16 kb depending on models (up to 48 kb)
VRAM  1 kb
ROM  4 kb (Basic Level 1) or 12kb (Basic Level 2)
TEXT MODES  32 x 16, 64 x 16
COLORS  monochrome
I/O PORTS  Monitor, cassette interface, expansion port
PRICE  #26-1003 : Model I, Level I, 16K = 700 (France,81)
#26-1004 : Model I, Level II, 4K = 640 r (France,81)
#26-1006 : Model I, Level II, 16K = $1099

Software for this system!

1980 Big Five Software
1980 Big Five Software
1980 Big Five Software

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Ready prompt
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Pixel Deer
BASIC code
Shooting gallery
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