TRS-80

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The Tandy TRS-80 model 1 was tandy's entry into the home computer market. It looked like a very thick keyboard (like the later Commodore VIC and used a Zilog Z80 procesor. It had 4K RAM and a 4K ROM with Microsoft tiny BASIC. Software could be saved on cassette tape. It was accompanied by a green on black display. The video hardware was very primitive and could only display text at a 64 characters by 16 lines resolution in upper case. Primitive graphics could be displayed because 64 characters of the character set displayed as a grid of 2x3 blocks. Writing to the screen caused "snow" on the screen because no bus arbitration logic was used to arbitrate between CPU writes to the screen RAM and display logic reads from the same RAM. Not withstanding this primitive display hardware many very adictive arcade type games were available for the tandy TRS-80. Later a model 2 system came available that had an 8K BASIC rom, and 16K of RAM. To upgrade to a floppy disk based system you had to buy the "expansion interface" that added a "single density" floppy disk interface (which was based on a 1771 single density floppy disk controller chip, but it lacked a separate external "data seperator", and was thus very unreliable)32K more RAM, a serial interface (option) and a centronics printer interface. The resulting system was concidered usable as a SOHO solution. many clones of the TRS-80 model 1 came on the market, including the LOBO, the LNW-80 (which was only available in kit form), the "bart smith" system from new zealand and the Dutch ASTER CT-80.

Tandy later came with the TRS-80 model 16, which was a totaly different UNIX based (it used Microsofts Xenix)16 bit system (68000 plus Z80), and the Model 3, a more integrated and much improved model 1.

Tandy also produced the TRS-80 Color Computer (Coco) using a Motorola 6809 processor. This machine was clearly aimed at the home market, where the Model 2 and above were sold as business machines. It competed directly with the Commodore 64

The Coco 1 came with 4K of RAM. It used a regular TV for a display, had an expansion slot for program cartidges or a floppy disk controller. Later models (Coco2 and Coco3) increased the RAM to 16K and 128K. The Coco came with a version of Microsoft Basic in ROM. It had an expansion slot that could be used to insert program cartridges, or even an external floppy drive. A version of OS-9 - a UNIX like operating system - could be run from the floppy, including a C compiler.

A British clone of the Coco was called the Dragon 32 .