10 Mar
2023
10 Mar
'23
7:24 a.m.
I have one datapoint. In late 1994 or early 1995 at Internet 1.0 startup Open Market we
were working on web servers and IIRC had no trouble with 1000 (or 1024?) simultaneous
clients using TCP. This was Alpha OSF/1 and probably had 256 MB or some such ungodly
amount of RAM. The big change from the NCSA server was a single process model rather than
one process per connection. I think there was a select(2) limit that was smaller, so
perhaps there were a few processes rather than just one. I have the sources somewhere.
Andy Payne was the lead engineer and I remember him slapping my fingers when I changed the
way logging worked.
Regarding TCP performance one story about the turning point was Van Jacobson tuning the
most-likely path down to a very few vax instructions for packet receiption. That was
what, Reno maybe? One of the later BSDs.
-Larry
On Mar 9, 2023, at 7:59 PM, Tom Lyon
<pugs78(a)gmail.com> wrote:
Sun chose UDP for NFS at a point when few if any people believed TCP could go fast.
I remember (early 80s) being told that one couldn't use TCP/IP in LANs because they
were WAN protocols. In the late 80s, WAN people were saying you couldn't use TCP/IP
because they were LAN protocols.
But UDP for NFS was more attractive because it was not byte stream oriented, and
didn't require copying to save for retransmissions. And there was hope we'd be
able to do zero copy transmissions from the servers - also the reason for inventing Jumbo
packets to match the 8K page size of Sun3 systems.
I did get zero copy serving working with ND (network disk block protocol) - but it was
terribly specific to particular hardware components.
On Thu, Mar 9, 2023 at 4:24 PM ron minnich <rminnich(a)gmail.com
<mailto:rminnich@gmail.com>> wrote:
> Ca. 1981, if memory serves, having even small numbers of TCP connections was not
common.
>
> I was told at some point that Sun used UDP for NFS for that reason. It was a
reasonably big deal when we started to move to TCP for NFS ca 1990 (my memory of the date
-- I know I did it on my own for SunOS as an experiment when I worked at the SRC -- it
seemed to come into general use about that time).
>
> What kind of numbers for TCP connections would be reasonable in 1980, 90, 2000, 2010?
>
> I sort of think I know, but I sort of think I'm probably wrong.