[ih] Dave Farber's DCS

Dave Crocker dhc at dcrocker.net
Wed Jul 22 18:44:41 PDT 2020

On 7/22/2020 4:48 PM, Karl Auerbach via Internet-history wrote:
> (IBM had to concede to DCS that IBM did not invent the token ring 
> network concept.)

IBM's token product came during my time at Univ. of Delaware, almost 10 
years after the DCS work, and Farber had an IBM contract.  They sent a 
senior tech out to present their token ring design to him and his 
students, all of whom were EEs (other than me).  This was clearly an 
intent to get the august professor to bless their work.

In spite of not being all that well versed in the fine-grained technical 
aspects of local area networking design choices, I could tell that their 
design had a basic problem:  The Irvine ring had a cost of one bit-time 
per node the packet went through.  The IBM insertion ring design imposed 
an entire packet-time per node.  So much for scaling.

After the presentation, it was interesting watching the discomfort among 
Dave and the other students, non-verbally negotiating who was going to 
deliver the assessment to the IBM person.


Dave Crocker
Brandenburg InternetWorking

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