[TUHS] OS for IBM PC (was: Algol68 vs. C at Bell Labs)

[TUHS] OS for IBM PC (was: Algol68 vs. C at Bell Labs)

[Norman Wilson]

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

[TUHS] OS for IBM PC (was: Algol68 vs. C at Bell Labs)

[Larry McVoy]

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 

[TUHS] OS for IBM PC (was: Algol68 vs. C at Bell Labs)

[Clement T. Cole]

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 at 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 

[TUHS] Microkernels (was: OS for IBM PC (was: Algol68 vs. C at Bell Labs))

[Greg 'groggy' Lehey]

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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[TUHS] Microkernels (was: OS for IBM PC (was: Algol68 vs. C at Bell Labs))

[John Cowan]

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 at 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

[TUHS] Microkernels (was: OS for IBM PC (was: Algol68 vs. C at Bell Labs))

[Greg 'groggy' Lehey]

On Thursday,  7 July 2016 at  6:51:08 -0400, John Cowan wrote:
> 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 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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[TUHS] OS for IBM PC (was: Algol68 vs. C at Bell Labs)

[Greg 'groggy' Lehey]

On Thursday, 30 June 2016 at  8:49:26 -0700, Larry McVoy wrote:
> On Thu, Jun 30, 2016 at 11:32:08AM -0400, Dan Cross wrote:
>> Something I never understood about the IBM PC: even the 8088 machine was
>> fairly beefy compared to e.g. a PDP-11/20. The 6th Edition Unix kernel was
>> objectively pretty small and understandable; mini-Unix showed that that
>> sort of software could be used on a machine without an MMU. I've never
>> understood why IBM didn't just write a real OS in a high-level language
>> instead of saddling the world with MS-DOS. Perhaps it's naive of me, but
>> even if they didn't use Unix directly, it was an existence proof that such
>> a thing was possible. I suppose, again, it was less a technical issue and
>> more a business issue, or perhaps I'm underestimating the amount of work or
>> missing some of the technical complexities.
>
> I wonder if they just didn't know.  Unix was Bell Labs and
> Universities for the most part.  Was the timing such that they may
> not have been aware of Unix?  Or maybe they knew about Unix but
> thought it was for the vax?

Not directly related, but I don't know which other message in this
subthread is more relevant:

Don't forget the constraints on the PC design.  The IBM model number
was 5150: it was a last-ditch attempt to salvage the not very
successful 5100 series.  To do so they outsourced things that IBM
would normally have developed in-house.  And that meant taking
existing products, not creating new ones.  The success of the PC
caught IBM by surprise, like the 704 30 years earlier.

At the time IBM talked to Microsoft, Microsoft's OS plans were clear:
XENIX.  See the August 1980 (I think) issue of Byte, where there's a
long story about why XENIX is the correct choice of operating system.
You can be sure that Microsoft tried to sell that first.  But instead
they had to go out and buy QDOS from Seattle Computer Products.

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.