I built this S-100 bus kit (like a Heathkit, bags of parts) in late 1977. It started with a 1.8Mhz 8080, 4KB of static RAM, and a 16x64 memory mapped video display. I initially used a reel-to-reel tape drive for storage. The first software I wrote (8080 assembler) on it was an 8080 disassembler, so I could study the firmware (now called a BIOS). 4KB of RAM wasn't enough to do much of anything, so my first upgrade was a 16KB Processor Technology DRAM board, which I eventually upgraded to 64KB with new chips and a little rewiring of the timing circuit. After tiring of the hassles of using tape storate, my next upgrade was a California Computer Systems S-100 floppy disk card, implemented as an interrupt-driven device. The CCS board came with a copy of CP/M and a skeletal BIOS, and I used that to bootstrap CP/M onto the system. I later added a Quantum Q540 40MB hard drive, also interrupt driven. By the end of its life (circa 1982), this computer was in a bigger S-100 chassis, had a Godbout 5Mhz 8085 S-100 CPU, 256KB of DRAM, and a custom (wire-wrapped) circuit board to provide the Polymorphic-specific system logic (serial port, interrupt controller, scratchpad RAM, real-time clock, etc.) that the Polymorphic system board had previously provided. It was also running MP/M.