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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

Special thanks to Marc Neiger who donated us this computer !



I remember Christmas morning that we found the TRS 80 under the tree. I did my first computer graphics on it doing point graphing a few years later and even wrote my own game after a while.

I will have to ask my Dad what happened to it, its probably just in the attic somewhere next to an atari (what we really wanted that Christmas).

Friday 12th May 2017
Alan  (USA)
Cloud Ninjas

Hi there,

I''ve added a category in my iPad app to challenge your knowledge of vintage computers:$pt$ls$1$mt$8

Regards, Emerson

PS: thanks for this amazing website...lot of fond memories :)...and useful information $)

Saturday 24th August 2013
The Legend of Zhizz

In October 1977, my first semester in high school, my father bought a TRS-80 (model 1). The Radio Shack store in Bryan, TX was unpacking it, their first one, to put on display and my father bought it before they even turned it on. It was the optional 16K memory model. We kept it a few years and added accessories, including hard drives, a thermal printer, and later a dot-matrix printer and TRS-80 desk. It was sold to a local businessman for his bookkeeping, after we got an Apple II. I remember the dot matrix printer was made of steel, cost $1000 and was very slow and loud, sounding like tiny men with jackhammers inside.

Wednesday 30th January 2013
Henry (Texas)


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

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