[ih] Dave Farber's DCS

Brian E Carpenter brian.e.carpenter at gmail.com
Thu Jul 23 22:30:36 PDT 2020

What was the date, approx?

The Cambridge Ring (1974 onwards) avoided that particular defect by having
a packet size of 4 bytes (2 byte address, 2 byte payload) so really it was
more of a memory bus than a network. (Not that I ever worked on it.)

Of course IBM didn't care about you people, they only cared about the Söderblom

On 23-Jul-20 13:44, Dave Crocker via Internet-history wrote:
> 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.
> d/

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