[ih] Early History of the Internet

[Scott Bradner]

and the DEC unibus Ethernet card could not receive more than 2 packets back to back
woe to anyone (including me) who set their NFS block size to 4K

Scott

> On Jan 10, 2024, at 3:39 PM, Karl Auerbach via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> You are right about complexity of hardware.  Ethernet was genius - a marvel of simplicity in the way it extrapolated from the way we humans talk in a noisy room to the world of electronic communications with minimal inter-device coordination.  Was the Aloha net the first to do this kind of thing?
> 
> But lest we think Ethernet went smoothly at first, let us pause and remember the original 3COM 3C501 Ethernet card - it took too long to recover from a transmit operation to be ready to receive a response packet from a fast peer.  I think I banged my head against several walls trying to get a 3C501 work on a slow PC/AT using Romkey/Bridgham PC/IP when the other end was an early Sun workstation.
> 
> DCS did indeed depend on the properties of their network - it was essentially a broadcast medium with an additional interesting function: When the packet went around the ring and came back to the sender there was a flag that indicated whether any device had accepted the message (and copied it from the ring.)  This served as a kind of "someone is interested" acknowledgement with effectively zero cost.
> 
> (I vaguely remember another similar flag that was set as the packet went around the ring, but my memory has faded about that.)
> 
> If I remember correctly the actual transmission signal format was based on telco T-1.
> 
> I get the impression that Dave Farber is rather pleased that his project undermined the IBM patent on token rings.
> 
>         --karl--
> 
> 
> On 1/10/24 12:20 PM, Dave Crocker via Internet-history wrote:
>> On 1/10/2024 12:03 PM, Karl Auerbach via Internet-history wrote:
>>> I first became aware of that work in the rather early 1970s when I was at SDC.  Frank Heinrich (one of Farber's students) had worked on a distributed file system for DCS.
>> 
>> When Dave showed me one of the network cards for DCS, the token-vs-contention battles were underway.  He explained some aspects of the card, including the part that did token resolution at startup.
>> 
>> It took a quarter of the real-estate and used a contention-based scheme.  Given this, it seemed clear to me that, absent extremely strong needs for highly predictable access times, this meant that Ethernet would win handily.
>> 
>> d/
>> 
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