for privately operated computer bulletin board systems (BBSs). The program was released as "freeware" as an add-on module (or "Door") for the popular RBBS-PC. It enabled users connected on one node of a bulletin board system to "chat" with users dialed in on other nodes. Initially, CBSIM supported a maximum of 32 concurrent nodes (connected users), and allowed dynamic creation and cataloging of "channels" by the users of the BBS on which it was installed. The source code was released to the public from the inception of the CBSIM project, and this source code quickly became the foundation for multi-node chat systems embedded in other popular BBS software products. In the middle '80s, a version of CB was written for the DEC RSTS/E operating system. It was accomplished by using a rare shared R/W Runtime system, to keep track of users in the CB simulator. This was one of the first and only usage of a shared memory area, mapped to Basic-Plus virtual arrays, to keep track of a program usage. Using CB, you could communicate to other users across DECNET to other nodes of the system. Built in was also a pseudo-tty module, which allowed you to execute programs, while 'chatting' in CB on the same terminal. The software was made available though DECUS SIG RSTS users group. References An Introduction to CompuServe's Citizens' Band Simulator. Columbus, Ohio: CompuServe Incorporated. 1986. "CB-ing Turns Ten". CompuServe Magazine (October 1990): 34. October 1990. "1980 Technology Happenings". Computerworld Goff, Leslie Jay. August 9, 1999. "RSTS/E CB Simulator". Written by the author of the program 2016. External links The Strange Case of the Electronic Lover Online chat CompuServe