I remember using the TRS-80s Models 1, 2 (Xenix), 3 and 4. The graphics on the TRS were Black and White (Really Green and Black) but that wasn't what the TRS-80s were best for. TRS-80s were probably one of the best pre-IBM/PC platform for serious programming and word Processing. The TRS-80 Models 3 and 4 were able to run CP/M so getting software for it was not as much of a problem as for other platforms. The TRS-80 runs on the Zilog Z-80 (enhanced Intel 8080 like) processor.
The Tandy TRS Coco is a radical departure from the TRS-80. It runs on the Motorola 6809E (enahanced) processor with the fantantic (for the time) Motorola MC6847 Video Graphic Generator, something the TRS-80 sorely needed.
Unfortunately, the software it could run was more limited than for TRS-80 Model 3 and 4 since those computers could run CP/M software.
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