Ward Leon Christensen (October 23, 1945 – October 11, 2024) was an American computer scientist who was the inventor of the
XMODEM
XMODEM is a simple file transfer protocol developed as a quick hack by Ward Christensen for use in his 1977 MODEM.ASM terminal program. It allowed users to transmit files between their computers when both sides used MODEM. Keith Petersen made a ...
file transfer protocol and a co-founder of the
CBBS
CBBS ("Computerized Bulletin Board System") was a computer program created by Ward Christensen and Randy Suess to allow them and other computer hobbyists to exchange information between each other. Jason Scott: , 2005, Episode 1
In Ja ...
bulletin board, the first
bulletin board system
A bulletin board system (BBS), also called a computer bulletin board service (CBBS), is a computer server running list of BBS software, software that allows users to connect to the system using a terminal program. Once logged in, the user perfor ...
(BBS) ever brought online.
Early life
Christensen was born on October 23, 1945, in
West Bend, Wisconsin
West Bend is a city in Washington County, Wisconsin, United States, and its county seat. As of the 2020 census, the population was 31,752. It is part of the Milwaukee metropolitan area.
History
Early history and settlement
Northeastern Washi ...
, to Florence (née Hohmann) 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
The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. It was founded in 1848 when Wisconsin achieved st ...
before transferring to
Milton College.
He graduated from Milton College with a
Bachelor of Arts
A Bachelor of Arts (abbreviated B.A., BA, A.B. or AB; from the Latin ', ', or ') is the holder of a bachelor's degree awarded for an undergraduate program in the liberal arts, or, in some cases, other disciplines. A Bachelor of Arts deg ...
degree in physics and chemistry in 1968.
[''re: R/1ST BBS QUESTIONS'' (Msg 46394)](_blank)
from Ward Christensen to Steve Culver, July 31, 1993.
Career
Christensen, along with collaborator
Randy Suess
Randy John Suess (January 27, 1945 – December 10, 2019) was the co-founder of the CBBS bulletin board, the first bulletin board system (BBS) ever brought online. Suess, along with collaborator Ward Christensen, whom he met when they were both me ...
, members of the Chicago Area Computer Hobbyists' Exchange (CACHE), started development of the first
BBS during a blizzard in
Chicago
Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...
,
Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...
, and officially established
CBBS
CBBS ("Computerized Bulletin Board System") was a computer program created by Ward Christensen and Randy Suess to allow them and other computer hobbyists to exchange information between each other. Jason Scott: , 2005, Episode 1
In Ja ...
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
International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...
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
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs.
Time-sharing operating systems scheduler (computing), schedule tasks for ...
before
floppy disk
A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...
s and
hard disks
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
were common. When he lost track of the
source code
In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer.
Since a computer, at base, only ...
for some
programs, he wrote ReSource, an iterative
disassembler
A disassembler is a computer program that translates machine language into assembly language—the inverse operation to that of an assembler. The output of disassembly is typically formatted for human-readability rather than for input to an asse ...
for the
Intel 8080
The Intel 8080 is Intel's second 8-bit computing, 8-bit microprocessor. Introduced in April 1974, the 8080 was an enhanced successor to the earlier Intel 8008 microprocessor, although without binary compatibility.'' Electronic News'' was a week ...
, to help him regenerate the source code. In 1977, he wrote
XMODEM
XMODEM is a simple file transfer protocol developed as a quick hack by Ward Christensen for use in his 1977 MODEM.ASM terminal program. It allowed users to transmit files between their computers when both sides used MODEM. Keith Petersen made a ...
, a protocol to send computer files over phone lines.
Jerry Pournelle
Jerry Eugene Pournelle (; August 7, 1933 – September 8, 2017) was an American scientist in the area of operations research and ergonomics, human factors research, a science fiction writer, essayist, journalist, and one of the first bloggers. ...
wrote in 1983 of a collection of
CP/M
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/Intel 8085, 85-based microcomputers by Gary Kildall of Digital Research, Dig ...
public-domain software
Public-domain software is software that has been placed in the public domain, in other words, software for which there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, ...
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
Soldering (; ) is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creatin ...
techniques, until his death, through Build-a-Blinkie, a non-profit organization that hosts "learn-to-solder" events in the Great Lakes area.
Personal life
Christensen lived in
Dolton, Illinois, when he invented
XMODEM
XMODEM is a simple file transfer protocol developed as a quick hack by Ward Christensen for use in his 1977 MODEM.ASM terminal program. It allowed users to transmit files between their computers when both sides used MODEM. Keith Petersen made a ...
in 1977 and co-invented
CBBS
CBBS ("Computerized Bulletin Board System") was a computer program created by Ward Christensen and Randy Suess to allow them and other computer hobbyists to exchange information between each other. Jason Scott: , 2005, Episode 1
In Ja ...
in 1978.
Christensen died from a
heart attack
A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...
at his home in Rolling Meadows, Illinois, on October 11, 2024, at the age of 78. At the time of his death, he was in a relationship with Debra Adamson. He also left behind his brother, Donald, and his nieces, Carin and Dana Christensen.
Awards
Christensen received two 1992
Dvorak Awards for Excellence in Telecommunications, one with Randy Suess for developing the first BBS, and a lifetime achievement award "for outstanding contributions to PC telecommunications." In 1993, he received the
Pioneer Award from the
Electronic Frontier Foundation
The Electronic Frontier Foundation (EFF) is an American international non-profit digital rights group based in San Francisco, California. It was founded in 1990 to promote Internet civil liberties.
It provides funds for legal defense in court, ...
.
References
External links
*
{{DEFAULTSORT:Christensen, Ward
1945 births
2024 deaths
American computer programmers
IBM employees
Milton College alumni
People from Dolton, Illinois
People from Rolling Meadows, Illinois
People from West Bend, Wisconsin