Tandy 2000

Infobox computer
Name = Tandy 2000
Photo =
Type = Personal Computer
Released = 1983
Discontinued = ?
Processor = Intel 80186 @ 8 MHz
Memory = 128 KB - 768 KB (896KB w/mods)
Storage = 10 MB hard drive, 1 or 2 720 KB 5.25" floppies
OS = MS-DOS; XenixThe Tandy 2000 was a personal computer introduced by Radio Shack in late 1983 which used the 8 MHz Intel 80186 microprocessor. By comparison, the IBM PC XT (introduced in March 1983) used the older 4.7 MHz 8088 processor, and the IBM PC AT (introduced in 1984) would later use 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 on the market, and slightly faster than the PC AT.

While touted as being compatible with the IBM XT, the Tandy 2000 was different enough that most software that was not purely text-oriented did not work properly. It differed by having a Tandy-specific video mode (640x400, but not related to or forward-compatible with the 1987 VGA standard), keyboard scan codes, and possible other differences.Clarifyme|date=March 2008 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 coincidentally had been one of the backup plans for the original TRS-80 Model I).

The Tandy 2000 was the only computer sold by Radio Shack that had both the "Tandy" and "TRS-80" logos on its case, marking the beginning of the phaseout of the "TRS-80" brand.

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

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.

Graphics

The Tandy 2000's proprietary graphics hardware allowed a display of up to 640x400 (non-interlaced) pixels with 16 colors onscreen, which was a particularly high-resolution and colorful display for its day. CGA compatibility was hit or 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 Tandy 2000's text space at a rate of 5-10 times per second. This caused a bit of choppiness in the display, but worked fairly well.

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.

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 on standard 1.2Mb double-sided high-density disks. The drives could read and write 360kb floppies, the standard of the time on IBM compatible systems, but caution had to be used when doing so, if the disks were to be subsequently used in another type of system, as the tracks written were narrower than those generated on a 360kb drive. There were hardware hacks to use 720kb 3.5" floppy drives, but it was unclear whether disks formatted in this way worked with other PC compatibles.

Operating system

The Tandy 2000 required a specific 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 Radio Shack released for the Tandy 2000 was 2.11.03, with a few minor 3rd-party patches after the fact. A modified version of Windows 1.0 was able to run on the Tandy 2000.

Software

Software packages that were released for the Tandy 2000, included WordPerfect 4.2 (WP5.1 could work with software patches), Lotus 1-2-3, AutoCAD, and shareware office programs. Microsoft released a version of Xenix for the Tandy 2000 (used with Tandy's Token-Ring network card).Clarifyme|date=March 2008

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 available for download; neither the BBS nor its web-based descendant is active today.

See also

* Tandy 1000