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Antique emulators

The end of 1979 brought another defining moment in my path towards engineering (and ultimately EDN gadgeteer). That year under the Christmas tree there was an actual computer — A Tandy TRS-80 Model III. It came with 16K of RAM and an attached cassette tape player for loading programs and data. Initially all I could do was “cload galaxy“, which was plenty of fun. Then a couple weeks later some family friends came over and Mike (who was several years older) showed me how I could press the Break key, type list, and see the BASIC code for whatever game I was playing. “You mean that’s how the game works? Cool!”

First BASIC, then z80 assembly language and computer architecture.  Along the way the RAM was expanded to 48K and two diskette drives were added. The computer, unfortunately, is long gone, left behind during a college move. It was obsolete and had already been cannibalized to provide parts for a strobe light and other college EE gadgets. Some items still remain, however. The photo to the right is actually my original copy of the TRSDOS owner’s manual, and somewhere I have a few copies of 80 Micro magazine as well.

Why the trip down memory lane? I ran across a TRS-80 emulator that runs on your PC. This emulator is written in x86 assembly language and is incredibly complete. The sound works, the diskette and hard drives are emulated, the cassette drive is emulated via wave files or, believe it or not, an actual cassette drive connected to your PC sound card. You can read and write old TRS-80 tapes. It can even read those old TRSDOS single sided 360K diskettes (if you have any) in your PC’s 5.25″ 1.2M floppy drive (if you have one). It even emulates the VS-100 voice synthesizer.

Author David Keil has preserved a wealth of TRS-80 software on his WWW page.  In addition to TRSDOS you can find NEWDOS and LDOS, Scripsit (word processing), Microsoft Basic, and many of the games you loved to play:  Eliza, 13 Ghosts, the various Scott Adams and Infocom  adventures, and of course Zork.  Notably missing is one of my favorites, Asylum.

I’ve had a good time playing with it, if there’s a TRS-80 in your past then check it out.

Steve Ravet

EDN Gadgeteer

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