• 1976

Hardware Description

The Prime 400 ran at 0.5 MIPS, had a main store of up to 8mb and 160MB of disc storage. The name PRIMOS was now used for the operating system and the P400 ran PRIMOS 4. It ran a V-mode instruction set, along with the S-mode and R-mode instructions. It had a segmented virtual memory architecture, somewhat similar to Multics.