Small Computer Workshop

The Small Computer Workshop is an integrated development system for 8-bit retro computers.

It runs on Windows and includes a text editor, assembler and simulator.


WARNING: This software is completely free. It comes with absolutely no warranty. Currently this program is far from complete and polished. It contains many bugs and quirks.

It has been released ‘early’ primarily to allow users to modify the Small Computer Monitor program, which was created with this system.

Sorry, I don’t normally release software with so many issues and without documentation. The decision to release this program now is motivated by user requests rather than being planned. That’s my excuse anyway!

I have only run this program on Windows 10, but it should run on much older versions of Windows.

Latest Version

SCWorkshop v0.3.6 includes SCM v1.3.0 source code:

Older Versions


The most annoying bugs relate to the text editor, which does quite a few odd things. But after a while, you get used to it!

Update 2018-03-25: If you get Error 13 at startup it is probably due to your international settings having a decimal character other than a period (“.”). The workaround is to change the Clock value in Definition.txt to an integer. There is a Definition.txt file for each ‘Computer’ type in the Resources folder.


The Z80 simulator is not complete. For example, it does not generate a parity flag. However, the commonly used features are supported.


The program does not need to be installed, just run SCWorkshop.exe.

Source files, which are part of the Small Computer Monitor, should be saved in the SCMonitor folder. Source files for other projects should not be saved there as trying to assemble any file in this folder results in assembly of the Monitor program.

The output of the assembler is stored in the folder “Output”. Files from the previous assembly will be overwritten.

Some of the simulation views only update if there is time. A well-specified computer should manage rapid updates when in “Jog” mode. In “Run” mode there is no attempt to update most views, regardless of the computer’s performance.

Homebrew 8-bit retro computing