Source Solutions, Inc.

A replacement firmware for 128K Spectrums, based on v1.4 of the Derby development ROM.
The Better Uncommented Spectrum ROM Assembly (featuring the X80 FPU instruction set).
A Z80/AY music player library for 8-bit computers.
50 ULAplus™ Games
Action
An external command for UnoDOS (or esxDOS) that replicates the PLAY command from 128 BASIC.
An open source replacement firmware for the ZX Spectrum and clones.
An open source operating system for the ZX-Uno and divMMC.