Prime 300

The Prime 300 had a main store of 32KB to 512 KB and from 6MB of Pertec disc storage. It ran DOSVM operating system, also referred to as PRIMOS 3, but still used earlier DOS for booting. One of the first minicomputers with microcode-supported virtual memory capability. The virtual memory was simpler than used in later systems. Addresses were 16 bits, with each of up to 32 time-sharing (time slice) users, receiving a virtual 64K address space. It had S-mode and R-mode instructions.