4 Jul
2016
4 Jul
'16
4:54 p.m.
Greg Lehey:
And why? Yes, the 8088 was a reasonably fast processor, so fast that
they could slow it down a little so that they could use the same
crystal to create the clock both for the CPU and the USART. But the
base system had only 16 kB memory, only a little more than half the
size of the 6th Edition kernel. Even without the issue of disks
(which could potentially have been worked around) it really wasn't big
enough for a multiprogramming OS.
=====
Those who remember the earliest UNIX (even if few of us have
used it) might disagree with that. Neither the PDP-7 nor the
PDP-11/20 on which UNIX was born had memory management: a
context switch was a swap. That would have been pretty slow
on floppies, so perhaps it wouldn't have been saleable, but
it was certainly possible.
In fact Heinz Lycklama revived the idea in the V6 era to
create LSX, a UNIX for the early LSI-11 which had no
memory management and a single ca. 300kiB floppy drive.
It had more memory than the 8088 system, though: 20kiW,
i.e. 40kiB. Even so, Lycklama did quite a bit of work to
squeeze the kernel down, reduce the number of processes
and context switches, and so on.
Here's a link to one of his papers on the system:
https://www.computer.org/csdl/proceedings/afips/1977/5085/00/50850237.pdf
I suspect it would have been possible to make a XENIX
that would have worked on that hardware. Whether it
would have worked well enough to sell is another question.
Norman Wilson
Toronto ON
4 Jul
4 Jul
6:13 p.m.
QNX, which wasn't Unix compat at the time but sorta close, in the mid
1980's was very very small and ran just fine on a 80286. If my memory
serves me correctly I had 4-10 people logged into that box on terminals.
QNX, at least until they put real posix conformance in it, was a really
tiny micro kernel with the rest of the os in processes. It fit in a
4K instruction cache with room to spare.
QNX, in my opinion, is the only really interesting and commercially
proven microkernel.
On Mon, Jul 04, 2016 at 12:54:15PM -0400, Norman Wilson wrote:
Greg Lehey:
And why? Yes, the 8088 was a reasonably fast processor, so fast that
they could slow it down a little so that they could use the same
crystal to create the clock both for the CPU and the USART. But the
base system had only 16 kB memory, only a little more than half the
size of the 6th Edition kernel. Even without the issue of disks
(which could potentially have been worked around) it really wasn't big
enough for a multiprogramming OS.
=====
Those who remember the earliest UNIX (even if few of us have
used it) might disagree with that. Neither the PDP-7 nor the
PDP-11/20 on which UNIX was born had memory management: a
context switch was a swap. That would have been pretty slow
on floppies, so perhaps it wouldn't have been saleable, but
it was certainly possible.
In fact Heinz Lycklama revived the idea in the V6 era to
create LSX, a UNIX for the early LSI-11 which had no
memory management and a single ca. 300kiB floppy drive.
It had more memory than the 8088 system, though: 20kiW,
i.e. 40kiB. Even so, Lycklama did quite a bit of work to
squeeze the kernel down, reduce the number of processes
and context switches, and so on.
Here's a link to one of his papers on the system:
https://www.computer.org/csdl/proceedings/afips/1977/5085/00/50850237.pdf
I suspect it would have been possible to make a XENIX
that would have worked on that hardware. Whether it
would have worked well enough to sell is another question.
Norman Wilson
Toronto ON
--
---
Larry McVoy lm at mcvoy.com http://www.mcvoy.com/lm
9:12 p.m.
Thoth Thucks ....
Actually to give Mike Malcom created Thoth ney QNX was very slick. I agree with Larry. It
was very impressive at the time. So between Thoth (which was Unix-similar) and Minix
(which was V7 Unix API clone) I think it is safe to say there are reasonable existance
proofs for saying V7 was quite possible on the 8086/8088 family.
Sent from my iPad
On Jul 4, 2016, at 2:13 PM, Larry McVoy
<lm(a)mcvoy.com> wrote:
QNX, which wasn't Unix compat at the time but sorta close, in the mid
1980's was very very small and ran just fine on a 80286. If my memory
serves me correctly I had 4-10 people logged into that box on terminals.
QNX, at least until they put real posix conformance in it, was a really
tiny micro kernel with the rest of the os in processes. It fit in a
4K instruction cache with room to spare.
QNX, in my opinion, is the only really interesting and commercially
proven microkernel.
On Mon, Jul 04, 2016 at 12:54:15PM -0400, Norman
Wilson wrote:
Greg Lehey:
And why? Yes, the 8088 was a reasonably fast processor, so fast that
they could slow it down a little so that they could use the same
crystal to create the clock both for the CPU and the USART. But the
base system had only 16 kB memory, only a little more than half the
size of the 6th Edition kernel. Even without the issue of disks
(which could potentially have been worked around) it really wasn't big
enough for a multiprogramming OS.
=====
Those who remember the earliest UNIX (even if few of us have
used it) might disagree with that. Neither the PDP-7 nor the
PDP-11/20 on which UNIX was born had memory management: a
context switch was a swap. That would have been pretty slow
on floppies, so perhaps it wouldn't have been saleable, but
it was certainly possible.
In fact Heinz Lycklama revived the idea in the V6 era to
create LSX, a UNIX for the early LSI-11 which had no
memory management and a single ca. 300kiB floppy drive.
It had more memory than the 8088 system, though: 20kiW,
i.e. 40kiB. Even so, Lycklama did quite a bit of work to
squeeze the kernel down, reduce the number of processes
and context switches, and so on.
Here's a link to one of his papers on the system:
https://www.computer.org/csdl/proceedings/afips/1977/5085/00/50850237.pdf
I suspect it would have been possible to make a XENIX
that would have worked on that hardware. Whether it
would have worked well enough to sell is another question.
Norman Wilson
Toronto ON
--
---
Larry McVoy lm at mcvoy.com http://www.mcvoy.com/lm
7 Jul
7 Jul
2:20 a.m.
New subject: Microkernels (was: OS for IBM PC (was: Algol68 vs. C at Bell Labs))
On Monday, 4 July 2016 at 11:13:30 -0700, Larry McVoy wrote:
QNX, in my opinion, is the only really interesting and commercially
proven microkernel.
Tandem's Guardian was a microkernel, and a very successful one at
that. At one point (mid-1980s) Guardian systems were running the
majority of the world's ATMs.
Greg
--
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10:51 a.m.
New subject: Microkernels (was: OS for IBM PC (was: Algol68 vs. C at Bell Labs))
Greg 'groggy' Lehey scripsit:
Tandem's Guardian was a microkernel, and a very
successful one at
that.
I doubt if anyone knew or knows that who didn't work there. I did a
lot of TAL programming on those machines, and I had no clue about the
structure of the kernel.
--
John Cowan http://www.ccil.org/~cowan cowan(a)ccil.org
The work of Henry James has always seemed divisible by a simple dynastic
arrangement into three reigns: James I, James II, and the Old Pretender.
--Philip Guedalla
11:36 p.m.
New subject: Microkernels (was: OS for IBM PC (was: Algol68 vs. C at Bell Labs))
On Thursday, 7 July 2016 at 6:51:08 -0400, John Cowan wrote:
Greg 'groggy' Lehey scripsit:
I think so, though it wasn't high on the list of features. Nor should
it be. But the message system in particular (for communicating
between kernel processes) makes for a very interesting design. Adding
networking was as simple as extending the message system beyond the
local cluster, and Tandem was running an internal world-wide network
by the early 1980s. It makes an interesting (if not particularly
good) comparison with the Internet.
Greg
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Tandem's Guardian was a microkernel, and a
very successful one at
that.
I doubt if anyone knew or knows that who didn't work there.
2851
days inactive
2854
days old
5 comments
5 participants
participants (5)
-
Clement T. Cole -
Greg 'groggy' Lehey -
John Cowan -
Larry McVoy -
Norman Wilson