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<p>You had a 20 that would handle <font size="5"><tt>600</tt></font>
students in 1977<i>???</i> Yikes!! What kind of monster was that
and how did you do this without melting?<br>
</p>
<p>As I recall, the maximum number of lines that an RSX-20F front
end would handle with a full complement of DH11's is 128. I have
heard of a site (Case Western Reserve) having more than one front
end handling lines, which I would imagine could get you up to
256. There was also another site that moved the terminal handling
code out of section 0, which was probably a great idea.</p>
<p>I also recall that the maximum job number that you could get on
CFS was 512 for a maximum of 128 jobs per node.<br>
</p>
<p>But I don't think I'm aware of any 20 doing more than about 70
active users without some serious load issues. That would be a
mix of text editing, email and maybe some iterative program
development. At Columbia, our standard 20 configuration was two
DF20's (?) for (I think) 3.5 MW. We experimented with 'maxing' a
20 out with two DH20's and an MA20 for 3.75 MW, but it did not
perform substantially better.</p>
<p>I'm not sure what the limiting factor was, whether it was paging
or CPU. If it was paging, then assuming you weren't doing too
many multi-section programs, a 32MW Toad would clearly handle a
higher number of users (and perhaps far higher), but you are then
talking about contending for other things, RH20's, disks and at
some point, you are just out of CPU.<br>
</p>
<div class="moz-cite-prefix">There was a multi-processor version of
TENEX, but nothing like that exists in any Tops-20 source that
I've seen.<br>
</div>
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<pre class="moz-quote-pre" wrap="">On 11/11/21 2:43 PM, Paul Koning wrote:
:-) They sure where logged out when the message "plato off" appeared on every terminal...
paul
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<pre class="moz-quote-pre" wrap="">On Nov 11, 2021, at 2:29 PM, Steve Davidson <a class="moz-txt-link-rfc2396E" href="mailto:steve@davidson.net"><steve@davidson.net></a> wrote:
Paul,
Don’t you mean 600 logged OUT students?
-Steve
SF:IP2
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<pre class="moz-quote-pre" wrap="">On Nov 11, 2021, at 13:45, Paul Koning <a class="moz-txt-link-rfc2396E" href="mailto:paulkoning@comcast.net"><paulkoning@comcast.net></a> wrote:
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<pre class="moz-quote-pre" wrap="">Indeed. I still remember the blistering I got (in 1977) when I added a new feature and the result was a system crash (buffer overflow due to falling behind) in the middle of the day, at max load. Max load was 600 logged-in students. Ouch.
paul
<blockquote type="cite"><hr width="100%" size="2"><pre class="moz-quote-pre" wrap="">On Nov 11, 2021, at 1:25 PM, Thomas DeBellis <a class="moz-txt-link-rfc2396E" href="mailto:tommytimesharing@gmail.com"><tommytimesharing@gmail.com></a> wrote:
...
100 students? That's all? Heh... I can't even remember how many we had online with six 20's, but it didn't matter. If one of them went out, you got your choice of machine room phone color: bright red hot or white hot. Been there, done that. Glad I'm not doing it any more.
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