[ITS] According to a conspiracy theory long popular among ITS and TOPS-20 fans, Unix's growth is the result of a plot, hatched during the 1970s at Bell Labs, whose intent was to hobble AT&T's competitors by making them dependent upon a system whose future evolution was to be under AT&T's control. This would be accomplished by disseminating an operating system that is apparently inexpensive and easily portable, but also relatively unreliable and insecure (so as to require continuing upgrades from AT&T). This theory was lent a substantial impetus in 1984 by the paper referenced in the back door entry. In this view, Unix was designed to be one of the first computer viruses (see virus) - but a virus spread to computers indirectly by people and market forces, rather than directly through disks and networks. Adherents of this "Unix virus" theory like to cite the fact that the well-known quotation "Unix is snake oil" was uttered by DEC president Kenneth Olsen shortly before DEC began actively promoting its own family of Unix workstations. (Olsen now claims to have been misquoted.)

Columbus UNIX, or CB UNIX, is a discontinued variant of the UNIX operating system used internally at Bell Labs for administrative databases and transaction processing. It was developed at the Columbus, Ohio branch, based on V6, V7 and PWB Unix.

The term "Research Unix" refers to early versions of the Unix operating system for DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC).