[e2e] Applications with UDP checksum disabled

Craig Partridge craig at aland.bbn.com
Mon Mar 11 09:39:45 PST 2002


In message <200203092308.g29N8OTr025496 at calcite.rhyolite.com>, Vernon Schryver 
writes:

>I do not think that fairly represents the history of NFS, although it
>is repeated by many people who I doubt were there.  I think the people
>responsible knew perfectly well about bus errors and other hazards
>and did not "discover" anything of the sort.

I was at the original NFS announcement in Boston by Rusty (last name forgotten)
of SUN -- the assertion was that Ethernet and hardware were so reliable
that it was worth turning off the checksum.

I can attest that the BBN subsidiary selling multiprocessor computers (name
now forgotten) did indeed discover around 1989 that they needed the UDP
checksum to protect their NFS filesystems from corruption due to bus
voltage problems in their early computers.

I also remember that, around 1988 or so, it became common knowledge amongst
maintainers of large software systems that compiles done over NFS without
checksums often caused bad binaries.  (I personally hit the problem, compiling,
as I recall, the MH email system).

Craig



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