21 Dec
2019
21 Dec
'19
3:08 a.m.
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.
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