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<p>Indeed; but there was a time when the PDP-11's 16 bit (64K)
address space and eight register file seemed positively generous.
That's when you compare it to the PDP-8's <i>single</i>
accumulator and 12 bit (4K) address space.</p>
<p>I continue to be astounded what they managed to do with that. In
addition to a nice package of languages, with a memory management
unit (essentially a bank switcher), they got the thing to
timeshare. That's right; TSS-8. There's one still running at the
Computer History Museum on an 8/I.<br>
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<p>So they got DECnet running on the PDP-8? Wow. I wonder how
they did that; whether they re-targeted a BLISS compiler to emit
PAL. I remember looking at the source to PDP-8 VT (video)
TECO. Many awe most inspiring kludges. What a tour de force.
Very humbling.</p>
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<p>The Algol compiler on the 20 has more than 2 bugs... Sigh...<br>
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<pre class="moz-quote-pre" wrap="">On 12/20/19 9:08 PM, Paul Koning wrote
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<pre class="moz-quote-pre" wrap="">If you go far enough back, the space efficiency gets pretty amazing. There's RSTS-11, which ran 16 timesharing users on a 28kW PDP-11/20. (Not well, but it ran.) Or RT-11, quite comfortable in 8 kW and a 256 kbyte system disk. Or DOS-11, which would even run, I think, in 4 kW.
Somewhat earlier still, in 1961 two people implemented the first ever ALGOL compiler in 6 months, and it ran on a 4 kW machine (27 bit). (It's known to have two bugs.)
paul
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<pre class="moz-quote-pre" wrap="">On Dec 20, 2019, at 8:51 PM, Thomas DeBellis <a class="moz-txt-link-rfc2396E" href="mailto:tommytimesharing@gmail.com"><tommytimesharing@gmail.com></a> wrote:
...
But the mini-computer operating systems are just plain cool. It is amazing what they squeezed into the PDP-8's 12 bit address space and PDP-11's run some of the most interesting collection of OS's that I've ever seen.
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