Commercial Operating System

Commercial Operating System is a discontinued family of operating systems from Digital Equipment Corporation.
They supported the use of DIBOL, a programming language combining features of BASIC, FORTRAN and COBOL. COS also supported IBM RPG.

Implementations

The Commercial Operating System was implemented to run on hardware from the PDP-8 and PDP-11 families.

COS-310

COS-310 was developed for the PDP-8 to provide an operating environment for DIBOL. A COS-310 system was purchased as a package which included a desk, VT52 VDT, and a pair of eight inch floppy drives. It could optionally be purchased with one or more 2.5 MB removable media hard drives. COS-310 was one of the operating systems available on the DECmate II.

COS-350

COS-350 was developed to support the PDP-11 port of DIBOL, and was the focus for some vendors of turnkey software packages.
Pre-COS-350, a PDP 11/05 single-user batch-oriented implementation was released; the multi-user PDP 11/10-based COS came about 4 years later. The much more powerful PDP-11/34 "added significant configuration flexibility and expansion capability."