21 Jun
2019
21 Jun
'19
4:30 p.m.
According to this page that Dennis Ritchie wrote, the original PDP-11
they used was indeed an 11/20 but it was before there were PDP-11 model
numbers:
https://www.bell-labs.com/usr/dmr/www/picture.html
And, of course, the PDP-7 Unix development came before the PDP-11 version :)
Cheers, Warren
21 Jun
21 Jun
5:21 p.m.
Warren said
According to this page that Dennis Ritchie wrote, the
original PDP-11
they used was indeed an 11/20 but it was before there were PDP-11 model
numbers:
https://www.bell-labs.com/usr/dmr/www/picture.html
And, of course, the PDP-7 Unix development came before the PDP-11 version :)
Cheers, Warren
It states that their 11/20 had a KS-11 memory management unit, was that mandatory for
running v1 Unix on an 11/20?
The 1971 Unix Programmer's Manual mentions their 11/20 had 24 KB (surely KW?) memory
rather than 28KW.
https://www.bell-labs.com/usr/dmr/www/1stEdman.html
Having recently acquired a 3rd-party 8KW unibus memory module (stack + drivers + control,
all integrated into a
DD-11-sized form) that is the same model and brand as the 16KW unit in my ex-BHP
steelworks FOX 2 (11/15), perhaps
there is the very, very slim hope that if the whole thing works it might be enough to run
v1 someday. That day
however is a long way away, but I think I now have most of the hardware needed.
Steve.
6:10 p.m.
On Jun 21, 2019, at 8:21 PM, Steve Malikoff via cctalk
<cctalk at classiccmp.org> wrote:
Warren said
Curious. Recently on this list we learned that CSS built an MMU for the 11/20, rather
different in structure from the later ones (not quite a Unibus peripheral but more in that
direction). But that wasn't called KS-11.
According to this page that Dennis Ritchie wrote,
the original PDP-11
they used was indeed an 11/20 but it was before there were PDP-11 model
numbers:
https://www.bell-labs.com/usr/dmr/www/picture.html
And, of course, the PDP-7 Unix development came before the PDP-11 version :)
Cheers, Warren
It states that their 11/20 had a KS-11 memory management unit, was that mandatory for
running v1 Unix on an 11/20? The 1971 Unix Programmer's Manual mentions their
11/20 had 24 KB (surely KW?) memory rather than 28KW.
https://www.bell-labs.com/usr/dmr/www/1stEdman.html
I would assume kW. In the PDP11 world we didn't normally speak of bytes or kbytes,
certainly not for memory and often not elsewhere either. So we'd say the disks have
256 word blocks (except 32 in the RC11 and 1 in the RF11).
paul
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