Columbus UNIX, or CB UNIX, was a variant of the UNIXoperating system used internally at Bell Labs for administrative databases and transaction processing. It was developed at the Columbus, Ohio branch and was little-known outside the company.
Volume 1 and Volume 2 of the UNIX Programmers Manual CB Version
The interprocess communication features developed for CB UNIX were message queues, semaphores and shared memory support. These eventually appeared in mainstream Unix systems starting with System V in 1983, and are now collectively known as System V IPC.