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Ohio Scientific Microcomputer Emulator

July 2017

Just a quick update before I redo this page to focus more on the C1P, and emulation. The URL will remain the same, so it's safe to bookmark! So, I've been working on an emulator for simple 6502 based machines like the OSI and Compukit microcomputers. The emulator is written in C, and I'll release it under the GNU GPL version 3 once it's a little more complete. It already runs pretty well and is able to load OSI Superboard II / C1P (and UK101) software, including the O.S.I. Invaders game that prompted me to start this page (see below). At the end of this page you'll find links to other OSI/Compukit emulation projects and related information.

Screenshot of the C1P's initial BASIC prompt Screenshot of O.S.I. Invaders Screenshot of Le Passe-Temps

September 2016

Clearing out the garage, I found a cassette tape from 1978 containing O.S.I. Invaders for the Ohio Scientific Inc. Challenger 1P. I spent hours playing this when I was a kid. Best Space Invaders clone ever! (Okay, not a clone exactly, considering the C1P's character-based graphics, but the play is amazingly good, and fun.)

Photograph of the audio original cassette from which the recording was made

I dug out a dusty tape deck, plugged it into my PC, et voilĂ ! Now all I need is a C1P. (Actually, Google turns up some emulators (links below), but a non-proprietary one would be best... No, wait, an actual C1P would be best, much to Conan's lament.)


Here are the notes my grandfather wrote on the paper liner:

Start recorder
Press L
  (Takes 12 minutes)
  Puts in machine language and then lines of BASIC
Self starting

  ?FRE(U) = 224

  LOADER       000 - 011
  MACHINE CODE 011 - 140
  BASIC        140 - 175

42910 by Tim, level 15, 15/12/81
28250 by Tim, level 5, 2/3/81
18830 by Tim, level 4, 30/11/81

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