Danny Cohen
Danny Cohen's Photo
Danny Cohen in 2009
Born(1937-12-09)December 9, 1937
DiedAugust 12, 2019(2019-08-12) (aged 81)
Other namesJames A. Finnegan.
Alma materTechnion, Harvard
Known forEndianness, Being an Internet pioneer, first to run a visual flight simulator across the ARPANet
AwardsNational Academy of Engineering member, IEEE Fellow, USAF Meritorious Civilian Service Award
Scientific career
FieldsMathematics, Computer Science, Computer Graphics
InstitutionsHarvard University, California Institute of Technology, University of Southern California, Myricom, Sun Microsystems
Doctoral advisorIvan E. Sutherland

Danny Cohen (December 9, 1937 – August 12, 2019) was an Israeli American computer scientist specializing in computer networking. He was involved in the ARPAnet project and helped develop various fundamental applications for the Internet. He was one of the key figures behind the separation of TCP and IP (early versions of TCP did not have a separate IP layer); this allowed the later creation of UDP.[1][2]

Cohen is probably now best known for his 1980 paper "On Holy Wars and a Plea for Peace"[3] which adopted the terminology of endianness for computing (a term borrowed from Jonathan Swift's Gulliver's Travels). Cohen served on the computer science faculty at several universities and worked in the private industry.


Cohen earned a bachelor's degree in mathematics at the Technion – Israel Institute of Technology in 1963. He was a graduate student in the math department at the Massachusetts Institute of Technology (MIT) from 1965 to 1967.[citation needed]

In 1967, Cohen developed the first real-time visual flight simulator on a general purpose computer and the first real-time radar simulator. Cohen's flight simulation work led to the development of the Cohen-Sutherland computer graphics line clipping algorithms, created with Ivan Sutherland at Harvard University.[4] He received a Ph.D. from Harvard in 1969 as a student of Sutherland. His thesis was titled: "Incremental Methods for Computer Graphics".[5]

After serving on the computer science faculty at Harvard through 1973, and at California Institute of Technology in 1976, Cohen joined the Information Sciences Institute at the University of Southern California to work on a packet-voice project designed to allow interactive, real-time speech over the ARPANet (and the Internet during its early development).[6][7] The Network Voice Protocol project was a forerunner of Voice over Internet Protocol (VoIP). In 1981, he adapted the visual simulator to run over the ARPANet which was an early application of packet switching networks to real-time applications. He started the MOSIS project in 1980.[citation needed]

In 1993, he worked on Distributed Interactive Simulation through several projects funded by the United States Department of Defense (DoD). He prototyped a local area network technology called ATOMIC, which was the forerunner of Myrinet.[8] In 1994, Cohen co-founded Myricom (with Chuck Seitz, and others) which commercialized Myrinet. Cohen also started the FastXchange project for electronic commerce and a digital library.

Cohen served on several panels and boards for the US DoD, National Institutes of Health, and United States National Research Council, including 5 years on the USAF Scientific Advisory Board. He served as both a factual and expert witness in patent infringement legal cases about VoIP. Cohen was a commercial pilot with SEL/MEL/SES and Instrument ratings.[citation needed]

In 1993 Cohen received the Meritorious Civilian Service Award from the United States Air Force. He was a member of the National Academy of Engineering (2006)[9] and an IEEE Fellow (2010).[10]

Since 2001, Cohen was a distinguished engineer for Sun Microsystems working on very fast communication over short distances, using optical and electrical signaling, in Sun's chief technical officer organization.[11]

Cohen continued as an adjunct professor of computer science at USC.[12]

In 2012, Cohen was inducted into the Internet Hall of Fame by the Internet Society.[13] In 2013 Vint Cerf hosted an event at Google honoring Cohen.[14]

Danny Cohen died in Palo Alto, California on August 12, 2019, at the age of 81.[15]

Selected publications



  1. ^ Where Wizards Stay Up Late: The Origins of the Internet, by Katie Hafner and Matthew Lyon, 1996, Simon & Schuster, ISBN 0-684-81201-0, pg. 236
  2. ^ "Separation of TCP and IP". internet-history mailing list archive. Internet Society. 26 June 2022. Retrieved 11 July 2022.
  3. ^ Cohen, Danny (April 1, 1980). On Holy Wars and a Plea for Peace. IETF. IEN 137. ...which bit should travel first, the bit from the little end of the word, or the bit from the big end of the word? The followers of the former approach are called the Little-Endians, and the followers of the latter are called the Big-Endians. Also published at IEEE Computer, October 1981 issue.
  4. ^ Principles of Interactive Computer Graphics p.124 and p.252, by Bob Sproull and William M. Newman, 1973, McGraw-Hill Education, International edition, ISBN 0-07-085535-8
  5. ^ a b Cohen, D. (April 1969). Incremental Methods for Computer Graphics (PDF) (Thesis). ARPA. Archived from the original (PDF) on February 12, 2017.
  6. ^ Danny Cohen; Stephen Casner; James W. Forgie (April 1, 1981). "A Network Voice Protocol NVP-II" (PDF). USC/ISI and Lincoln Laboratory. Retrieved September 22, 2013.[permanent dead link]
  7. ^ Danny Cohen (November 22, 2007). "Specifications for the Network Voice Protocol". RFC 741. doi:10.17487/RFC0741. Retrieved September 22, 2013.
  8. ^ Danny Cohen; Gregory Finn (1993). "ATOMIC: A Low-Cost, Very-High-Speed, Local Communication Architecture". 1993 International Conference on Parallel Processing - ICPP'93 Vol1. ACM. pp. 39–46. doi:10.1109/ICPP.1993.43. ISBN 978-0-8493-8983-2. S2CID 16388035.
  9. ^ "Dr. Danny Cohen". National Academy of Engineering. Retrieved March 20, 2018.
  10. ^ "Introducing the Class of 2010". The Institute. IEEE. March 8, 2010. Retrieved March 20, 2018.
  11. ^ "Danny Cohen". Company bio page. Sun Microsystems. Archived from the original on March 21, 2009. Retrieved September 21, 2013.
  12. ^ "Faculty Detail, Computer Science Department - USC Viterbi School Of Engineering". Archived from the original on November 26, 2012. Retrieved September 21, 2013.
  13. ^ 2012 Inductees Archived 2012-12-13 at the Wayback Machine, Internet Hall of Fame website. Last accessed April 24, 2012
  14. ^ Danny Cohen's Google Festschrift: produced by MediaOne on YouTube
  15. ^ Hafner, Katie (August 16, 2019). "Danny Cohen, Who Helped Set the Stage for a Digital Era, Dies at 81". The New York Times. Retrieved August 16, 2019.