A Quick History...

RadioShack was formed in 1921 when they opened their first store in Boston supplying equipment to ship-radio operators and radio ham enthusiasts.

The boom in CB radio in the 70's saw the company grow significantly.

When the CB radio market collapsed, its parent company, the Tandy Corporation, who by then dealt solely with electronics, searched for the next trend.

Steve Leininger was signed up from National Semiconductor and given the brief to develop a computer.

Tandy TRS-80 Model 1
In early 1977 the prototype was ready and Charles Tandy agreed to manufacture 3,500 units - one for each RadioShack store.

The original TRS-80 was part of the famous trio of consumer computers launched in 1977, along with the Commodore PET and the Apple II.

It was a Z80 based computer with only monochrome text-mode graphics which limited its potential, but it still proved to be a success.
Over the next six years, RadioShack were to release over a dozen different models in the TRS-80 line...

Tandy TRS-80 Color Computer
To remain competitive, the company had to have a colour computer and set up a joint venture with Motorola Semiconductor to develop the TRS-80 Color Computer (which quickly .became known as the "Co-Co").

The original version was housed in a large silver-grey case with a calculator style keyboard in a black surround. It had 4K, 16K or 32K of RAM. Versions with at least 16K shipped with Microsoft Color BASIC, or if you had the money, Extended Color BASIC. Only TV out was available as a display device.

The processor used was the Motorola MC6809E and the full chipset were Motorola IC's.

Over the next few years, there were changes to the cosmetic design - the black keyboard surround was dropped, the badging changed locations and the case was changed to white with ventilation slots which ran the length of the case.

Tandy TRS-80 Color Computer 2
In 1983 the TRS-80 Color Computer 2 was released.

The motherboard was redesigned to get rid of the "dead", unused space created by re-engineering of the support chips into custom IC's which meant that the case could be 25% smaller and the size of the PSU reduced - all cutting production costs. After the first production run, the old style keyboard was replaced with a full-travel, proper typewriter-style keyboard. The machine was 100% compatible with the Color Computer 1, not not with all peripherals..

CoCo 2 was offered in 16K or 64K models and later models had a redesign to allow the use of lower case characters and the ability to change the colour of the text screen border (although bizarrely, this was not enabled in BASIC).

The final run of machine saw the name badge change from "RadioShack TRS-80 Color Computer 2" to "Tandy Color Computer 2".

Tandy TRS-80 Color Computer 3
In 1986 Tandy announced the Color Computer 3.

It came with 128K of RAM (upgradable to 512K), but remained compatible with most CoCo 2 software and peripherals.

The graphics and memory controller hardware was replaced with a new application-specific integrated circuit called "GIME", which stood for "Graphics Interrupt Memory Enhancement" chip.

Additional new features included output to composite video (as well as TV), a paged memory management unit, text display with real lower case, text character attributes (8 foreground and background colours, underline and blink), new graphics resolutions and 16 possible colours from a palette of 64.

Microware wrote further extensions to the Microsoft Extended Color BASIC in ROM.

The downfall of the CoCo 3 was really the paradox of the powerful CPU. Although the most advanced 8-Bit processor ever made, the video hardware was derived from a chip designed for character based terminals. It was certainly no match for advanced graphics capabilities of the Atari 400 and 800 which were part of the CoCo's main competition at the time.

The sound was also very limited in comparison to the Commodore 64 which sported the famous SID chip.

Games drove software and system sales and with the programming difficulties of the 6809E CPU, the small amount of dedicated software produced for the machine just couldn't compete with the mass of cross platform ports of many ,very popular games.

In October 1990, Tandy announced that the CoCo 3 was to be dropped, with no apparent replacement planned...


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