CompuServe CB

Sandy Trevor

Searching for help, I stumbled into an odd corner of the electronic village, a “forum” on the CompuServe Information Service devoted entirely to a permanent floating conversation about the ins and outs of Word…

– James Gleick; Chasing Bugs in the Electronic Village; 1992.

CompuServe CB was the first public, commercial multi-user chat program. It first went live on February 21, 1980, built to over a million subscribers by 1988, and was CompuServe’s most popular service through their acquisition by AOL in 1997.

In the middle of the start of the beginning of a series of technological revolutions — from 1985 through 1995 — CompuServe provided the common virtual space for technical support for high-tech companies from Adobe to IBM to Lotus to Microsoft. Each company had one or more CompuServe “Forums” which included a number of virtual “conference rooms” for visitors to chat, all supported by the CB technology.

Because of its ubiquitous use in the technical community, CompuServe CB was widely influential on chatting culture, and many of the common abbreviations used on the Internet, such as IMHO, MORF, and textual emoticons like 😉 first came into common online use on CB.

Architecturally, the original CB application was based on a Macro-10 program using features of CompuServe’s proprietary PDP-10 operating system, in particular shared read/write memory segments. The original author was Sandy Trevor, a V.P. at the time, who eventually “wrote it in assembly language over a weekend on my kitchen table.” The very simple architecture enabled the system to support the kinds of high-demand interactivity that chat requires; for example, CB was able to support over 300 simultaneous users on a 1 mips DEC KI-10, six times more users than typical at that time.

For universality of access, only the simplest of ASCII terminals was needed to use CB, but of course by late 1989 innovation had reared its creative head and more sophisticated CB clients were developed that included separate windows for sending and receiving, similar to today’s instant messaging clients.

Early implementations of CB included encrypted communications and enhancements to support multi-user games. The first recorded online wedding was performed on CB in 1983. By 1995, CompuServe CB supported multimedia, which “got rolling” with Mick Jagger’s historic online conference from London on December 7, 1995.

Resources. The following references provide more information:

  • Bowen, Charles; How to Get the Most Out of CompuServe; 1982
  • Want, Wallace; Wang, Wally; CompuServe for Dummies; 1996.