21 Dec
2019
21 Dec
'19
5:21 a.m.
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 /single/ accumulator and 12 bit (4K)
address space.
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.
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.
The Algol compiler on the 20 has more than 2 bugs...? Sigh...
------------------------------------------------------------------------
On 12/20/19 9:08 PM, Paul Koning wrote
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
> ------------------------------------------------------------------------
> On Dec 20, 2019, at 8:51 PM, Thomas DeBellis <tommytimesharing at gmail.com>
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.