Commodore CBM 600 and 720

Summary

Commodore intended the CBM-II series to succeed the PET in 1982. The business models display 80 characters per line on a monochrome screen. Their MOS 6509 processor extends the 6502 to address up to 1 MB, though in practice the machines have 256 KB. They also include SID sound, RS-232 and the PET’s IEEE-488 interface for drives and printers. An Intel 8088 expansion board allows CP/M-86 and MS-DOS to run, but the computers are not IBM-compatible.

The 600-series models, sold as B128 in the USA, use keyboard cases; 700-series models such as the CBM 720 have built-in screens. The computers were expensive to manufacture, software was scarce, and production ended around 1984. The Commodore B500 belongs to the same family.