Ops-Normal.org

For the inner nerd...

https://www.trs-80.com/wordpress/cpm/#: ... dification.

There seems to be plenty of interest in these nowadays, I sold mine recently and got a good price for it.

I bought a base model (Level 1 and 4K) not long after they came out on a trip to USA, smuggled it into UK, and modded the video frequency and upgraded it to level 2 software and a magnificent 16K of RAM.

I remember the hours I sat watching that flashing asterisk as it attempted loading from tape, praying for it to get through to the end without a glitch. Especially with the quite large (and relatively expensive in those days) 747 sim program that I treated myself to in a moment of madness.

But it did enable me to get to grips with programming microprocessors which was of great benefit in a later life when I had to do it for a living. Happy days.

My school had the foresight to buy 4 of the first models, plus a Commodore PET and an early Apple, for an activity in 1977/8. The staff didn't know how they worked, but they had the brains to let us loose on them and work it out for ourselves. One of my classmates went on to design one of the early computer games. The Maths department had always been cutting edge - in the corner of the room was an analogue computer wired together from components 20 years before, builders including one S. Hawking.
If you wanted to play a game on it, you had to write the program yourself. 'Pong' was the one we usually chose to do.

When available I added the Expansion, all that memory ! and had a pair of 5.25 floppy discs, from a radio rally somewhere.
I recall trying, and failing, to interface with two rotators to track OSCAR. The program I had written worked but I couldn't get the mechanics to work.