RSX-11

RSX-11 is a discontinued family of multi-user real-time operating systems for PDP-11 computers created by Digital Equipment Corporation. In widespread use through the late 1970s and early 1980s, RSX-11 was influential in the development of later operating systems such as VMS and Windows NT. As the original Real-Time System Executive name suggests, RSX was designed (and commonly used) for real time use, with process control a major use. It was also popular for program development and general computing. RSX-11 began as a port to the PDP-11 architecture of the earlier RSX-15 operating system for the PDP-15 minicomputer, first released in 1971. The main architect for RSX-15 (later renamed XVM/RSX) was Dennis “Dan” Brevik. Commenting on the RSX acronym, Brevik says: "At first I called the new system DEX-15. It was an acronym for 'Digital's Executive - for the PDP-15.' The homonymic relation between DEC, DEX and deques (used as the primary linkage mechanism in the kernel) appealed to my sense of whimsy. People readily adopted the acronym without question. But in a short time I was asked to submit the choice to the corporate legal department for a trademark search and registration.