Ward Christensen
Ward Leon Christensen was an American computer scientist who was the inventor of the XMODEM file transfer protocol and a co-founder of the CBBS bulletin board, the first bulletin board system ever brought online.
Early life
Christensen was born on October 23, 1945, in West Bend, Wisconsin, to Florence and Roy Christensen. His father was a safety director at West Bend Company and his mother sold World Book encyclopedias. Christensen also had a brother, Donald Christensen.Christensen attended West Bend High School. In his senior year of high school in 1963, he created a computer that won first place in a science fair. After graduating high school, Christensen attended the University of Wisconsin–Madison before transferring to Milton College. He graduated from Milton College with a Bachelor of Arts degree in physics and chemistry in 1968.
Career
Christensen, along with collaborator Randy Suess, members of the Chicago Area Computer Hobbyists' Exchange, started development of the first BBS during a blizzard in Chicago, Illinois, and officially established CBBS four weeks later, on February 16, 1978. CACHE members frequently shared programs and had long been discussing some form of file transfer, and the two used the downtime during the blizzard to implement it.In 1968, Christensen was hired by IBM as a systems engineer in the sales office. Christensen would work for IBM until his retirement in 2012. His last position with IBM was a field technical sales specialist.
Christensen was noted for building software tools for his needs. He wrote a cassette-based operating system before floppy disks and hard disks were common. When he lost track of the source code for some programs, he wrote ReSource, an iterative disassembler for the Intel 8080, to help him regenerate the source code. In 1977, he wrote XMODEM, a protocol to send computer files over phone lines. Jerry Pournelle wrote in 1983 of a collection of CP/M public-domain software that "probably 50 percent of the really good programs were written by Ward Christensen, a public benefactor." In May 2005, Christensen and Suess were both featured in BBS: The Documentary. Christensen taught soldering techniques, until his death, through Build-a-Blinkie, a non-profit organization that hosts "learn-to-solder" events in the Great Lakes area.