BBS legend Ward Christensen logs off for last time at 78

Co-creator of the Computerized Bulletin Board System heads for big forum in the sky

Obit Ward Christensen, co-founder of the Computerized Bulletin Board System (CBBS) and developer of the XMODEM file transfer protocol, has died aged 78.

Christensen and Randy Suess developed the software behind CBBS, the first Bulletin Board System (BBS), during a Chicago blizzard in 1978 to allow Chicago Area Computer Hobbyists' Exchange (CACHE) members to exchange data. The concept was simple, at least in retrospect. The computer running the BBS software allowed users to connect, using dial-up at the time, and download and upload software and data. This data might be software or messages – some private, some public – but it predated the modern World Wide Web by decades.

Similar systems such as Community Memory predated Christensen and Suess's creation by a few years, but theirs was the first public dial-up BBS. The theory behind the system was that it would be a virtual cork board, where users could pin requests and information for others to see. CBBS officially went online on February 16, 1978, and began a wave of BBSes that would continue until the arrival of the World Wide Web and the rapid decline of the technology.

Christensen was also responsible for the MODEM file transfer protocol in 1977, which was later renamed to XMODEM after Keith Petersen tweaked it to turn on "quiet mode" so the code could run unattended. The protocol allows users to transmit files between computers, provided both are running the software.

XMODEM is a very simple file transfer protocol. While it might be considered inefficient compared to modern variants, it follows the tried-and-trusted method of breaking data into packets to be sent to the recipient. If the packet wasn't correctly received, a retry request was sent, and so on.

The ease with which XMODEM could be implemented made it very popular in the BBS market, although it spawned many variants as developers sought to overcome its limitations. In Howard Rheingold's book, The Virtual Community: Homesteading on the Electronic Frontier, Christensen was quoted as saying it was "the single most modified program in computing history."

It is difficult for modern web users to understand the impact of BBSes during the 1980s and into the 1990s. Many were run by enthusiasts, often from their own homes with only one phone line, meaning only one user at a time could dial in. Larger systems could make use of multiple phone lines. The advent of internet dial-up signified the end of the BBS as it was initially conceived.

BBSes predated much of the connected world as it is understood today. As well as virtual community pinboards, they hosted forums and message boards, precursors to blogs and social network sites. Their development, which began with a Chicago snowstorm, holds immense importance in the story of how the World Wide Web came to be.

Christensen worked at IBM until his retirement in 2012. ®