[COFF] Re: [TUHS] Re: the wheel of reincarnation goes sideways

[Bakul Shah <bakul@iitbombay.org>]

On Mar 9, 2023, at 11:55 AM, Dan Cross <crossd@gmail.com> wrote:
> 
> Suppose that 1000 users telnet'ed into the x86 machine, but remained
> essentially idle; what resources would that consume? We'd have 1000
> open TCP connections, a thousand shell processes, a thousand
> telnetd's, etc. All of that would consume some amount of RAM (though
> there'd be a lot of sharing of text and read-only data and so on),
> some VM space requiring RAM for paging structures and so on, some
> accounting data in the kernel, 1000 pseudo-ttys allocated, entries in
> the process table, etc. But, most of those shells would spend most of
> their time blocked waiting on input, so wouldn't consume CPU
> continuously, and similarly with the TCP connections mostly idle, the
> kernel is not generally wasting a lot of processor time on the login
> sessions. There'd be some bookkeeping data on disk, but that would be
> small. System overhead would amount to maybe a few megabytes, I'd
> imagine.

Not the same but in 1995 at Real Networks our server s/w running on
a 50Mhz or 100Mhz Pentium could handle 1000 TCP control connections
(mostly idle) and 1000 UDP "streams", each sending 10 packets/second,
which was the limiting factor. IIRC we had reduced per socket tcp
send/recv buffer size to a small number. I don't recall now whether
these machines had more than 16GB but we didn't want to tie up lots
of memory in idle buffers.

We got a real boost in traffic in Oct'95 when people all over the
world wanted to know the verdict in O.J.Simpson's murder trial in
real time! After that I added code for feeding live streams to any
downstream servers so that theoretically a 3 level distribution
tree can deliver live data to a billion people.