PDP-11/04 running CAPS-11

Mattis Lind mattislind at gmail.com
Sun Apr 5 15:39:54 CDT 2015

During approximately one and a half year I have been restoring a little
PDP-11/04 computer with a TU60 DECassette drive and a LA30P Decwriter. I
have followed the trail of Lou and got it to run CAPS-11 as well as

It has been an interesting journey to repair it and actually trying to use
it give a glimpse of what it was like to develop software 40 years ago on a
minimalistic system like this. Since it only has 8kW of memory the BASIC
system uses overlays. It takes at least half a minute to load the runtime
environment when you hit the RUN command - and then half a minute to get
back to the editor again after running. Indeed patience demanding.

I put together a webpage:

and a short video when it runs: https://www.youtube.com/watch?v=EQsP444N5zQ


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