Tandy 2000
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The Tandy 2000 was a computer which used the 8 MHz Intel 80186 microprocessor. By comparison, the IBM PC-XT used the older 4.7 MHz 8088 processor, and the IBM PC-AT used the newer 6 MHz Intel 80286. Due to the more efficient design of the 80186, the Tandy 2000 ran significantly faster than other PC compatibles, and slightly faster than the PC-AT. While touted as being compatible with the IBM XT, the Tandy 2000 was different enough for most software beyond purely text oriented to not work properly. It differed by having a Tandy-specific video mode (640x400, but not related to or forward-compatible with VGA) and keyboard scan codes, and possible other differences. The computer was poorly supported by Radio Shack in the following years; eventually the remaining unsold computers were converted into the first Radio Shack Terminals (which, oddly enough, had been one of the original backup plans for the original Trs-80 Model 1). The Tandy 2000 computer was the only computer sold by Radio Shack that had both logos on the case "Tandy" and "TRS-80". The Tandy 2000 computer was the first to have the "Tandy" logo on it.
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[edit] Specifications
8 MHz Intel 80186, 128kB RAM (expandable to 768kB, 896kB with motherboard and ROM modifications), 1 or 2 720kb 5-1/4" floppy drives, 10MB MFM full-height hard drive (upgradable to two 32MB half-height drives, 2 80MB drives with ROM mods and 3rd-party low-level formatting software), proprietary parallel printer port (requires adapter cable to connect to a Centronics-port printer), proprietary serial port.
[edit] Compatibility Issues
The Tandy 2000 was nominally BIOS-compatible with the IBM XT, which allowed extremely well-behaved DOS software to run on both platforms. However, most DOS software of the time bypassed the BIOS to achieve higher performance, rendering the software incompatible with the Tandy 2000.
[edit] Graphics
The graphics hardware was proprietary to the T2K...CGA compatibility was hit and miss. The text-mode address space was in a different location, but third party memory-resident software hacks remedied this by copying the PC-compatible text-mode memory to the T2K's text-space 5-10 times per second. This caused a bit of choppiness in the display, but worked fairly well.
[edit] Serial Port
The serial port hardware was completely different from the PC-XT's. PC-compatible terminal emulation software had to either maintain strict BIOS usage of the serial hardware, or else use a FOSSIL driver, which was a software wrapper that virtualized the serial hardware (see also DEC Rainbow), allowing the terminal software to work on a wider variety of hardware.
[edit] Media
The floppy drives were a proprietary 720kb 5-1/4" floppy format. No other computer used this disk format, which was single-sided high-density, using standard 1.2Mb double-sided high-density disks. The drives could read and write 360kb floppies, but caution had to be used when doing so, if the disks were to be subsequently used in an IBM-compatible. There were hardware hacks to use 720kb 3.5" floppy drives, but it was unclear whether disks formatted in this way were compatible with standard PC-compatibles.
[edit] Operating System
The Tandy 2000 required a proprietary version of MS-DOS that would only run on this machine. Standard MS- or PC-DOS would not run on a Tandy 2000. The highest version of DOS that Tandy released for the T2K was 2.11.03, with a few minor 3rd-party patches after the fact.
[edit] Software
In spite of all this, there were many very good software packages released for the Tandy 2000, including WordPerfect 4.2 (WP5.1 could work with software patches), Lotus 123, AutoCAD, and many fine shareware office programs. Microsoft even tweaked out a version of Xenix for the Tandy 2000 (used with Tandy's Token-Ring network card).
[edit] End of Life
After Tandy essentially ceased support of the Tandy 2000, a group of users formed the Tandy 2000 Orphans, with software reviews, software and hardware hacks, and a shareware/freeware repository. There was also a BBS based in Texas that had an extensive library of compatible software to download (its descendant exists on the web at http://www.juge.com).
