brock@brock.cs.unc.edu (J. Dean Brock) (05/14/89)
There's a brief article (3 pages) by Olof Soderblom in the Winter 88 issue of Connect, "A 3Com Publication". (Someone gave me a copy -- got no idea how one is usually obtained.) I infer that he believes that any network based on "the technique of arranging terminals in series around a closed transmission ring and arbitrating access to the ring by circulating a message indicating when it is free" (Sonderblom's words) relates to his patent. He states that the token ring was conceived in 1967 and the first token ring was the Svenska Handelsbanken (a Swedish bank) network connecting 2,500 terminals at 500 branch office. That ring came operational in the early 1970's. IBM was the prime network contractor for the Svenska Handelsbanken network.
farber@pcpond.UUCP (David J. Farber) (05/15/89)
Yes, Sonderblom claims that his patents cover most varients of the " token loop" technology. His basic application was as a terminal control loop. It was only in a much latter USA patent ( if my memory serves me late 1970s) that he added claims to cover a loop with completely decentralized control. The initial patents did not cover that. To my knowledge the DCS (Distributed Computer System) underlieing token ring was the first operational ring to have fully decentralized control (and the operating system was one of the first fully distributed fault tolerent message based systems) dated in the 1970 - 1974 time frame. Dave
farber@pcpond.UUCP (David J. Farber) (05/15/89)
BTW my signature line is: --------------- David J. Farber; Prof. of CS and EE, Director - Distributed Systems Labs. University of Pennsylvania/200 South 33rd Street/Philadelphia, PA 19104-6389 Comm: 215-898-9508 (office), 215-274-8192 (fax); 302-740-1198 (cellular) "Mathematics and science are the study of what IS; Computer science is the study of what can be DONE." "The fundamental principle of science, the definition almost, is this: the sole test of the validity of any idea is experiment." -- Richard P. Feynman
boomer@athena.mit.edu (Don Alvarez) (05/15/89)
In article <8124@thorin.cs.unc.edu> brock@brock.cs.unc.edu (J. Dean Brock) writes: >[article by Olof Soderblom] states that the token ring was conceived in 1967 >and the first token ring [...] came operational in the early 1970's. Sounds to me like the 17 year life-time for patents is about to make this a non-problem. If "early 1970's" = 1972, then 1972+17 = 1989. -Don Alvarez -- + -------------------------------------------------------------------------- + | Don Alvarez M.I.T. Center For Space Research (617) 253-7457 | | boomer@SPACE.MIT.EDU coming soon: Princeton University Dept. of Physics | + -------------------------------------------------------------------------- +
Mills@UDEL.EDU (05/16/89)
Dave, You missed "Engineering is the art of DOING IT." What are you suggesting we DO? Dave