Tandy 2000 Emulator
All of a sudden I got this desire to begin another emulation project. I remember using the Tandy 2000 when I worked at Radio Shack in the late 1980's when it was used to run the back office "Store Operating System" program. I remember being impressed by the vector-like color graphics.
So, I began amassing what I need for an emulation project. Well, I forgot how rare this machine actually was and how tough it is to locate information on it. Some of the reason is illuminated in the following, taken (in edited form) from the Tandy 2000 FAQ by Jeff Hellige.
The TRS-80 Model 2000 was Tandy's first try at marketing a MS-DOS based machine. -- technically superior to the IBM PC-XT and cheaper. It was manufactured between November 1983 and June 1984, though there was enough inventory on-hand to continue selling them well into 1986. Interestingly, the inside of the front face plate on both of my machines have the date "8/13/84" written in black Sharpie marker.
Anyway, at one point there were so many Model 2000's stacked in Tandy warehouses and factories that Tandy "sold" 7,500 of them to Radio Shack stores and Computer Centers to be used as the SOS machine I alluded to above. Finally in 1989 Tandy sold the remaining machines off for next to nothing in one big sale. The 2000HD was the Model 2000 shipped with a Tandon 10meg MFM hard disk installed. The machines used in Radio Shack stores as Point-of-sale systems tended to be fitted with the external hard disk unit. The Model 2000 was housed in a stylish white case with black drive bezels with power and reset switches recessed in the front panel near the TRS-80 emblem.
What made the Model 2000 so much more advanced than the IBM PC-XT? Several reasons:
- CPU: 8mhz Intel 80186 when the PC-XT was running an 8088 at 4.77mhz.
The 80186 is a 16bit CPU.
- Floppy: Mitsubishi 720k DSQD (80 track, Quad Density) floppies versus
the 360k DSDD floppies used by the PC-XT.
- Graphics: 8 colors at 640x400 when CGA was 4 colors at 320x200 and
640x200 in black/white.
- Price: $2999 vice $3658 for a similarly equipped IBM PC-XT, as of 9/1/83.
Model 2000: 128k RAM, 80186 at 8mhz, dual 720k floppy drives, monochrome
graphics with VM-1 monitor, RS-232 (built-in) & parallel
printer ports (built-in), MS-DOS 2.0
IBM PC-XT: 128k RAM, 8088 at 4.77mhz, dual 320k floppy drives, mono
display (text only), RS-232 and parallel printer ports,
All of the above combined to make the Model 2000 an excellent business machine at the time, especially for CAD work. Tandy at one time used the machine in most of the Radio Shack Computer Center's for in-house databases and accounting. The Model 2000 was also faster than the early PC-AT, which used a 6mhz 80286 CPU, and which was announced in August 1984. The PC-AT listed for $4000 without a hard drive, video card, or monitor, while that rose to $6700 with the addition of a 20meg hard disk, color card and monitor.
If the machine was so advanced, why wasn't it successful? Great question. The Model 2000 had one thing against it, and it proved to be a big problem. Even though it ran MS-DOS the Model 2000 couldn't run most software made for the PC-XT because of it's hardware differences. This was at a time when IBM compatibility was becoming a major selling point. Any software written to access the hardware of the PC-XT directly would fail on the Model 2000. Only software which was either written specifically for the machine or which accessed the hardware using only MS-DOS calls would run properly. Programs which deal with graphics are especially problematic.
Ok, so right off the bat, emulating a PC is pretty complex, and emulating an oddball PC at that should be a real challenge. Good news is that there are a few good PC/XT emulators out there that I think I can mold into a T2k Emulator. The hard work is going to be the nice vector-like graphics.
So, I began amassing some of what I'm going to need for this project:
- Tandy 2000 Technical Reference Guide (26-5404)
- Tandy 2000 Programmer's Reference (26-2403)
- Tandy 2000 MS-DOS/BASIC Reference Guides
Next, I set out to find a T2K system to work with. I was able to locate a nice 2000HD system for the cost of shipping from a kind gentleman in Iowa. It's a pretty complete system but only has the monochrome video. I was able to locate a Color Graphics card from Digital Dinos. It's the Model 2000 Hi-Res Monochrome Graphics Board (26-5140) plus the Model 2000 Hi-Res Color Graphics Chip Kit (26-5141). This gives me color capability, but I still need a color monitor.
The problem with the monitor is that the screen resolution of the hi-res graphics board (640x400) exceeded the capabilities of the then currently available CGA monitors (640x200), so Tandy designed its own color monitor, the CM-1 (26-5112). Rumor has it that early "multi-sync" monitors have the capability to work with the lower horizontal scanning frequency (26.4kHz) and resolution used by the T2K. I think that the Atari ST1224 will work but will need a custom cable. I was ultimately able to find a CM-1 monitor and I build my own cable for it.
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Last updated 2020-06-19 19:59 -0400