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Reverse engineering the SSE SoftBox, a CP/M system for Commodore PET/CBM computers

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This repository holds files related to the SoftBox, a Z80-based single board computer for CP/M that attaches to Commodore PET/CBM computers as an IEEE-488 peripheral.


  • apps/: disassemblies of SoftBox applications that run under CP/M

  • bios/: SoftBox EPROMs (CP/M BIOS)

  • cpm22/: SoftBox system image with BDOS and configuration data (CPM.PRG)

  • hardbox/: HardBox EPROMs

  • ls287/: address decoding PROMs and equivalent equations

  • terminals/: SoftBox terminal programs that run on the Commodore side (K.PRG)

  • tools/: tools to convert between CBM DOS disk images and CP/M disk images