[e2e] Applications with UDP checksum disabled

[Vernon Schryver]

> From: Craig Partridge <craig at aland.bbn.com>

> >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)

Perhaps that was Rusty Sandberg.

> 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).

Even in the 1980's, the stretch between 1984 or 1985 and 1988 or 1989 was
a very long time.
Years before 1989 Sun was shipping CPUs that were a lot faster, and
other vendors (e.g. my employer) were shipping with UDP checksums on
by default.  Those early Sun CPUs were slooooow.