The Story So Far

A project log for EDSAC In Your Pocket

A pocket sized recreation of a room filling computer from 1949

david-boucherDavid Boucher 10/23/2018 at 18:580 Comments

I've started documenting this project at a point where it's almost complete, so this log is mainly a catch up for those who are interested.


The core EDSAC simulator software is operational and can run various EDSAC programs. The code needs a bit of a tidy up but that is all really. There are a few more things that I want to add to the software as a whole though:

A demo mode - this will load a specified program, run it to its conclusion, pause to display the output, then reboot and repeat until interrupted.

The ability to control the simulator using commands sent over USB serial - Currently, the simulator sends it output to the USB serial interface as well as to the screen. I plan to expand this so that it can accept commands this way too. The upshot of this would be that it would to possible to try out the simulator using just a Teensy connected to a USB serial terminal with no other components connected. It would also allow me to implement my next feature...

The ability to load an EDSAC program over USB serial and run it, then save it to EEPROM - At the moment, the only EDSAC programs that can be run are the ones compiled into the simulator software. I plan to change this.

Once I've done these things and I'm happy with the state of the software I will release it under a free licence. There will be two versions: the EDSAC In Your Pocket version to be loaded into a Teensy 3.1/2 and a version that can be run from a Linux command line, which I might call EDSAC On Your Command Line.


The hardware is complete and I've added a parts list to the project page. I will add the design files for the 3D printed parts when I do the software release. There are only four parts: the main case (front and sides) the back and two internal supports. The case looks a little plain at the moment, so I might do something to jazz it up.