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| Re: PDP 11/40 system manual [message #371942 is a reply to message #371935] |
Thu, 09 August 2018 17:47   |
Andreas Kohlbach
Messages: 1456
Registered: December 2011
Karma: 0
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Senior Member |
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On Thu, 9 Aug 2018 15:31:31 -0500, Charles Richmond wrote:
>
> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>> Elliott Roper <nospam@yrl.co.uk> writes:
>>
>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>>> PDP-11?
>>
>> Yes, many.
>
> *Not* that I disagree... but which other computers do you find elegant???
Personally I would say the Zenith Z-100 from 1982
<https://en.wikipedia.org/wiki/Zenith_Z-100>. Because it had two CPUs
(8085 8Bit and 8088 16Bit) so the user could run either CP/M or the so
called Z-DOS. Although this was not compatible with MS-DOS there was a
nice software library available.
--
Andreas
My random toughts and comments
https://news-commentaries.blogspot.com/
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| Re: PDP 11/40 system manual [message #371943 is a reply to message #371942] |
Thu, 09 August 2018 17:52 |
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Originally posted by: Bob Eager
On Thu, 09 Aug 2018 17:47:11 -0400, Andreas Kohlbach wrote:
> On Thu, 9 Aug 2018 15:31:31 -0500, Charles Richmond wrote:
>>
>> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>>> Elliott Roper <nospam@yrl.co.uk> writes:
>>>
>>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer
>>>> than a PDP-11?
>>>
>>> Yes, many.
>>
>> *Not* that I disagree... but which other computers do you find
>> elegant???
>
> Personally I would say the Zenith Z-100 from 1982
> <https://en.wikipedia.org/wiki/Zenith_Z-100>. Because it had two CPUs
> (8085 8Bit and 8088 16Bit) so the user could run either CP/M or the so
> called Z-DOS. Although this was not compatible with MS-DOS there was a
> nice software library available.
More of a kludge than elegant. That could be done with an NEC V20 or V30,
on one chip. Although a bit later on!
But the DEC Rainbow did the same.
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371944 is a reply to message #371936] |
Thu, 09 August 2018 17:54 |
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Originally posted by: Bob Eager
On Thu, 09 Aug 2018 17:36:24 -0400, Peter Flass wrote:
> Charles Richmond <numerist@aquaporin4.com> wrote:
>> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>>> Elliott Roper <nospam@yrl.co.uk> writes:
>>>
>>>> On 8 Aug 2018, hancock4@bbs.cpcn.com wrote (in
>>>> article<21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com>):
>>>
>>>> > Bitsavers uploaded the system manual for the PDP 11/40.
>>>
>>>> > http://www.bitsavers.org/pdf/dec/pdp11/1140/DEC-11-H40SA-A-
D_PDP-11_40_System_
>>>> > manual.pdf
>>>
>>>> > 358 pages, undated.
>>>
>>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer
>>>> than a PDP-11?
>>>
>>> Yes, many.
>>>
>>>
>> *Not* that I disagree... but which other computers do you find
>> elegant???
>>
>>
> System/360.
All that base register stuff...
For me, the ICL 2900 (largely designed by Manchester University).
One variable size accumulator.
One B register.
One descriptor register.
One stack frame register and one stack front register.
Two off-stack bases for other data.
Segmentation and paging.
Performance good at front of stack due to caching. Better than trying to
optimise register use.
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371947 is a reply to message #371942] |
Thu, 09 August 2018 18:24 |
tutu
Messages: 111
Registered: April 2013
Karma: 0
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Senior Member |
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On Thu, 09 Aug 2018 17:47:11 -0400, Andreas Kohlbach wrote:
> On Thu, 9 Aug 2018 15:31:31 -0500, Charles Richmond wrote:
>>
>> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>>> Elliott Roper <nospam@yrl.co.uk> writes:
>>>
>>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer
>>>> than a PDP-11?
>>>
>>> Yes, many.
>>
>> *Not* that I disagree... but which other computers do you find
>> elegant???
>
> Personally I would say the Zenith Z-100 from 1982
> <https://en.wikipedia.org/wiki/Zenith_Z-100>. Because it had two CPUs
> (8085 8Bit and 8088 16Bit) so the user could run either CP/M or the so
> called Z-DOS. Although this was not compatible with MS-DOS there was a
> nice software library available.
I had a Xerox 16/8 - z80 and 8088 with their own RAM, HD, a very nice cp/
m machine. It had a mouse port on the back of the keyboard - which
worked, one of the standard Logitech units plugged right in.
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| Re: PDP 11/40 system manual [message #371948 is a reply to message #371874] |
Thu, 09 August 2018 18:42 |
Elliott Roper
Messages: 129
Registered: October 2012
Karma: 0
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Senior Member |
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On 9 Aug 2018, Huge wrote
(in article <ft2elhF238vU3@mid.individual.net>):
> On 2018-08-08, Elliott Roper<nospam@yrl.co.uk> wrote:
>> On 8 Aug 2018, hancock4@bbs.cpcn.com wrote
>> (in article<21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com>):
>>
>>> Bitsavers uploaded the system manual for the PDP 11/40.
>>>
>>> http://www.bitsavers.org/pdf/dec/pdp11/1140/DEC-11-H40SA-A-D _PDP-11_40_Syst
>>> em_
>>> manual.pdf
>>>
>>> 358 pages, undated.
>>
>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>> PDP-11?
>
> Apart from the swapped bytes, no.
......but they were not swapped! Byte addresses increased byte by byte as did
words increase word by word
Everything else I ever saw except of course the VAX did it wrongly (That
excludes byte only addressing schemes like the Motorola 6809 IIRC)
OK 11's and VAXes made core dumps of text look ugly.
Elegant as the VAX was, it was but a bloated 11 with a usable address space.
The 6809 looked like an 11 that ran out of money.
I guess everybody's idea of elegance is skewed by the first machine you
really really loved.
--
To de-mung my e-mail address:- fsnospam$elliott$$ PGP Fingerprint: 1A96 3CF7
637F 896B C810 E199 7E5C A9E4 8E59 E248
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| Re: PDP 11/40 system manual [message #371951 is a reply to message #371948] |
Thu, 09 August 2018 19:44 |
Michael Black
Messages: 2799
Registered: February 2012
Karma: 0
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Senior Member |
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On Thu, 9 Aug 2018, Elliott Roper wrote:
> I guess everybody's idea of elegance is skewed by the first machine you
> really really loved.
>
I think that's true. I started with the 6502 and when I started looking
at 8080 code, it looked "odd". Just different from what I was used to. I
moved to the 6809, lots of similarity to the 6502, and then the 68000, but
didn't stick with it since that clearance Atari 520st had a fault that I
never fully tracked down. I think one reason I didn't use Linux until
2001 was because I kept hoping to come across a used Mac that was good
enough to run Linux, me wanting to stick with the 68000. That didn't
happen, though after I bought a used 200MHz Pentium to run Linux in 2001,
I soon found a very cheap Mac 6100 which had the RISC CPU in it and could
run Linux, but I never got to that.
Of course, by then it was really just habit, it's not like I've ever
programmed anything in assembly language after the 6809.
Michael
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| Re: PDP 11/40 system manual [message #371953 is a reply to message #371951] |
Thu, 09 August 2018 22:31 |
Joe Pfeiffer
Messages: 764
Registered: January 2012
Karma: 0
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Senior Member |
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Michael Black <mblack@pubnix.net> writes:
> On Thu, 9 Aug 2018, Elliott Roper wrote:
>
>
>
>> I guess everybody's idea of elegance is skewed by the first machine you
>> really really loved.
>>
> I think that's true. I started with the 6502 and when I started
> looking at 8080 code, it looked "odd". Just different from what I was
> used to. I moved to the 6809, lots of similarity to the 6502, and
> then the 68000, but didn't stick with it since that clearance Atari
> 520st had a fault that I never fully tracked down. I think one
> reason I didn't use Linux until 2001 was because I kept hoping to come
> across a used Mac that was good enough to run Linux, me wanting to
> stick with the 68000. That didn't happen, though after I bought a used
> 200MHz Pentium to run Linux in 2001, I soon found a very cheap Mac
> 6100 which had the RISC CPU in it and could run Linux, but I never got
> to that.
>
> Of course, by then it was really just habit, it's not like I've ever
> programmed anything in assembly language after the 6809.
And for *any* of those, the discovery of how clean the -11 was should
have been a revelation. The only machine I've ever worked on that
remotely approximated the clean-ness of that was the Motorola 6811.
The funny thing being I do a lot of hobby assembly programming now on
PIC processors, which are just plain *weird* from any standpoint you
care to name (and I say this from the perspective of someone who has
done assembly programming on a CDC 6400), but is just perfect for little
embedded applications.
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| Re: PDP 11/40 system manual [message #371954 is a reply to message #371944] |
Thu, 09 August 2018 22:41 |
Quadibloc
Messages: 4399
Registered: June 2012
Karma: 0
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Senior Member |
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On Thursday, August 9, 2018 at 3:54:51 PM UTC-6, Bob Eager wrote:
> On Thu, 09 Aug 2018 17:36:24 -0400, Peter Flass wrote:
>> System/360.
> All that base register stuff...
But surely that's unavoidable, if you want to have more than 64 K of memory?
John Savard
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| Re: PDP 11/40 system manual [message #371964 is a reply to message #371951] |
Fri, 10 August 2018 07:36 |
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Originally posted by: David Wade
On 10/08/2018 00:44, Michael Black wrote:
> On Thu, 9 Aug 2018, Elliott Roper wrote:
>
>
>
>> I guess everybody's idea of elegance is skewed by the first machine you
>> really really loved.
>>
> I think that's true. I started with the 6502 and when I started looking
> at 8080 code, it looked "odd". Just different from what I was used to.
> I moved to the 6809, lots of similarity to the 6502, and then the 68000,
> but didn't stick with it since that clearance Atari 520st had a fault
> that I never fully tracked down. I think one reason I didn't use Linux
> until 2001 was because I kept hoping to come across a used Mac that was
> good enough to run Linux, me wanting to stick with the 68000. That
> didn't happen, though after I bought a used 200MHz Pentium to run Linux
> in 2001, I soon found a very cheap Mac 6100 which had the RISC CPU in it
> and could run Linux, but I never got to that.
>
> Of course, by then it was really just habit, it's not like I've ever
> programmed anything in assembly language after the 6809.
>
> Â Michael
>
If one is looking for elegance in early machines, then the Ferranti
Pegasus is an interesting starting point. According to Simon Lavington's
book
https://www.amazon.co.uk/Pegasus-Story-History-Vintage-Compu ter/dp/1900747405
it was one of the first computers to be designed to be easy to program,
rather than easy to build.
It has a remarkably orthogonal instructions, with uniform address
modifications on each instruction. A nice page about it here:-
https://cswww.essex.ac.uk/staff/lavington/Pegasus/index.htm
Dave Wade
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| Re: PDP 11/40 system manual [message #371967 is a reply to message #371954] |
Fri, 10 August 2018 09:57 |
Peter Flass
Messages: 8375
Registered: December 2011
Karma: 0
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Senior Member |
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Quadibloc <jsavard@ecn.ab.ca> wrote:
> On Thursday, August 9, 2018 at 3:54:51 PM UTC-6, Bob Eager wrote:
>> On Thu, 09 Aug 2018 17:36:24 -0400, Peter Flass wrote:
>
>>> System/360.
>
>> All that base register stuff...
>
> But surely that's unavoidable, if you want to have more than 64 K of memory?
>
> John Savard
>
That's what makes it elegant -it's a compromise between addressable memory
and instruction size.
--
Pete
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| Re: PDP 11/40 system manual [message #371974 is a reply to message #371946] |
Fri, 10 August 2018 12:01 |
Bill Findlay
Messages: 286
Registered: January 2012
Karma: 0
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Senior Member |
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> Charles Richmond<numerist@aquaporin4.com> writes:
>> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>>> Elliott Roper <nospam@yrl.co.uk> writes:
>>>
>>>> On 8 Aug 2018, hancock4@bbs.cpcn.com wrote
>>>> (in article<21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com>):
>>>
>>>> > Bitsavers uploaded the system manual for the PDP 11/40.
>>>
>>>> > http://www.bitsavers.org/pdf/dec/pdp11/1140/DEC-11-H40SA-A-D _PDP-11_40_Sy
>>>> > stem_
>>>> > manual.pdf
>>>
>>>> > 358 pages, undated.
>>>
>>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>>>> PDP-11?
>>>
>>> Yes, many.
>>
>> *Not* that I disagree... but which other computers do you find elegant???
I quite liked the PDP-11 (we ran Unix on a /40 and a /45), and thought the
VAX-11
(Unix on a /780 and a /750) was generally better; neither would rate as
favourites.
I agree with the nominations of the Ferranti Pegasus, and of the MU5/ICL
2900;
and propose the very different English Electric KDF9:
<http://www.findlayw.plus.com/KDF9/>
People tend to focus on the arithmetic stack of the KDF9.
In my view the hardware multiprogramming support and the
internal parallelism are more significant advances.
BTW None of these was the first computer I used.
That was an ICT/ICL 1903. I like that too. 8-)
--
Bill Findlay
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| Re: PDP 11/40 system manual [message #371979 is a reply to message #371974] |
Fri, 10 August 2018 13:04 |
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Originally posted by: Bob Eager
On Fri, 10 Aug 2018 17:01:56 +0100, Bill Findlay wrote:
> BTW None of these was the first computer I used.
> That was an ICT/ICL 1903. I like that too. 8-)
The first one I used was an Elliott 4130. It had some quite advanced
features such as the ability to share programs between virtual machines,
and good multiprogramming support.
I know this because I hacked it a lot.
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371980 is a reply to message #371874] |
Fri, 10 August 2018 13:06 |
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Originally posted by: Bob Eager
On Fri, 10 Aug 2018 16:45:34 +0000, Huge wrote:
> On 2018-08-10, Bob Eager <news0073@eager.cx> wrote:
>> On Fri, 10 Aug 2018 14:46:30 +0000, Huge wrote:
>>
>>> On 2018-08-10, David Wade <g4ugm@dave.invalid> wrote:
>>>
>>> [24 lines snipped]
>>>
>>>> If one is looking for elegance in early machines, then the Ferranti
>>>> Pegasus is an interesting starting point. According to Simon
>>>> Lavington's book
>>>>
>>>> https://www.amazon.co.uk/Pegasus-Story-History-Vintage-Compu ter/
>> dp/1900747405
>>>>
>>>>
>>> Fascinating. Thank you!
>>
>> Must get that. Simon is great fun, and we have spent time in the pub
>> together on more than one occasion.
>>
>> (Computer Conservation Society, monthly meetings near Covent Garden)
>
> When and where? I might be persuaded to schlep in from Norfolk for that!
Southampton Street (BCS London offices).
http://computerconservationsociety.org/lectures/current/lect ure.htm
I quite often go. Whatever the talk is, it's interesting. And so are the
people. Sometimes end up in the pub afterwards.
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371982 is a reply to message #371967] |
Fri, 10 August 2018 13:50 |
hancock4
Messages: 6746
Registered: December 2011
Karma: 0
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Senior Member |
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On Friday, August 10, 2018 at 9:57:39 AM UTC-4, Peter Flass wrote:
> Quadibloc <jsavard@ecn.ab.ca> wrote:
>> On Thursday, August 9, 2018 at 3:54:51 PM UTC-6, Bob Eager wrote:
>>> On Thu, 09 Aug 2018 17:36:24 -0400, Peter Flass wrote:
>>
>>>> System/360.
>>
>>> All that base register stuff...
>>
>> But surely that's unavoidable, if you want to have more than 64 K of memory?
>>
>> John Savard
>>
>
> That's what makes it elegant -it's a compromise between addressable memory
> and instruction size.
IMHO, System/360 represented an elegant design because it
was able to use a single architecture to serve four different
categories of data processing (large/small/business/sci-eng).
Previously, most computers were designed to serve only one
of those categories. Many companies required multiple
computers if they had multiple needs.
While S/360 didn't totally eliminate multiple computers for
a single company (such as a S/360 in the business office
with some DECs in the labs), many were able to share their
business office needs and engineering needs on the same machine.
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| Re: PDP 11/40 system manual [message #371985 is a reply to message #371935] |
Fri, 10 August 2018 15:01 |
Rich Alderson
Messages: 489
Registered: August 2012
Karma: 0
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Senior Member |
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Charles Richmond <numerist@aquaporin4.com> writes:
> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>> Elliott Roper <nospam@yrl.co.uk> writes:
>>> On 8 Aug 2018, hancock4@bbs.cpcn.com wrote
>>> (in article<21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com>):
>>>> Bitsavers uploaded the system manual for the PDP 11/40.
>>>> http://www.bitsavers.org/pdf/dec/pdp11/1140/DEC-11-H40SA-A-D _PDP-11_40_System_manual.pdf
>>>> 358 pages, undated.
>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>>> PDP-11?
>> Yes, many.
> *Not* that I disagree... but which other computers do you find elegant???
My first computer was the IBM 1401. *Not* an elegant architecture, but not
without points of interest.
The first I fell in love with was the IBM System/360, thanks to a high school
graduation gift from a sweetheart, Germain's _Programming the IBM 360_. One of
these days I'm going to put his simulator on Hercules and go through the
exercises just for giggles.
When introduced to the PDP-10, 8 years later, I found it annoying: No base
register, only a single index register per instruction, so some of my favorite
tricks simply did not work. No condition codes; what's with all these SKIPx
and JUMPx and Txxx (test) instructions? And then a miracle happened.
I still think in EBCDIC, nearly 50 years later, rather than ASCII, which I sort
of learned less than 40 years ago, and I still have a fondness for the 360
instruction architecture, but the orthogonality of the PDP-10 instruction set,
the uniform use of bits 7-8 to indicate no-modification/immediate/memory/self
on all the data movement instructions, the elegance of single instructions to
conditionalize the execution path rather than a sequence in which you have to
be careful of changes to the condition codes you're checking, even the word
addressing rather than byte addressing, have forever spoiled me for lesser
systems.
"But that's just my opinion, I could be wrong." --Dennis Miller
--
Rich Alderson news@alderson.users.panix.com
Audendum est, et veritas investiganda; quam etiamsi non assequamur,
omnino tamen proprius, quam nunc sumus, ad eam perveniemus.
--Galen
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| Re: PDP 11/40 system manual [message #371986 is a reply to message #371951] |
Fri, 10 August 2018 16:17 |
Andreas Kohlbach
Messages: 1456
Registered: December 2011
Karma: 0
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Senior Member |
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On Thu, 9 Aug 2018 19:44:06 -0400, Michael Black wrote:
>
> On Thu, 9 Aug 2018, Elliott Roper wrote:
>
>> I guess everybody's idea of elegance is skewed by the first machine you
>> really really loved.
>>
> I think that's true. I started with the 6502 and when I started
> looking at 8080 code, it looked "odd". Just different from what I was
> used to.
Same here. Starting on the 6502 (6510 in a Commodore 64) and only
recently had a look into the "Z80 Bible". It's all reversed what you had
at the ",". Then you had no STA on the Z80, all was done via LD. You just
reversed what was before or after the ",". Also interesting it had
"primitives" like it was called later on the Intel 8086. Like LDIR: you
put your search string in one register, the number of loops into another
and let the magic happen. Of course to pair two 8bit registers into one
16bit register was convenient.
--
Andreas
My random toughts and comments
https://news-commentaries.blogspot.com/
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| Re: PDP 11/40 system manual [message #371989 is a reply to message #371985] |
Fri, 10 August 2018 18:05 |
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Originally posted by: Bob Eager
On Fri, 10 Aug 2018 15:01:06 -0400, Rich Alderson wrote:
> I still think in EBCDIC, nearly 50 years later, rather than ASCII, which
> I sort of learned less than 40 years ago, and I still have a fondness
> for the 360 instruction architecture, but the orthogonality of the
> PDP-10 instruction set, the uniform use of bits 7-8 to indicate
> no-modification/immediate/memory/self on all the data movement
> instructions, the elegance of single instructions to conditionalize the
> execution path rather than a sequence in which you have to be careful of
> changes to the condition codes you're checking, even the word addressing
> rather than byte addressing, have forever spoiled me for lesser systems.
I was going to mention the PDP-10, but forgot. I did quite a lot of
assembly language programming on one.
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371990 is a reply to message #371936] |
Fri, 10 August 2018 18:10 |
John Levine
Messages: 1405
Registered: December 2011
Karma: 0
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Senior Member |
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In article <1028478389.555543171.735142.peter_flass-yahoo.com@news.eternal-september.org>,
Peter Flass <peter_flass@yahoo.com> wrote:
>>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>>>> PDP-11?
>>>
>>> Yes, many.
>>
>> *Not* that I disagree... but which other computers do you find elegant???
>
> System/360.
The S/360 was a tour de force but it had plenty of uglies that people
have been dealing with ever since, the worst of which was 24 bit
addressing.
The PDP-8, on the other hand, was close to perfectly elegant.
--
Regards,
John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly
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| Re: PDP 11/40 system manual [message #371991 is a reply to message #371990] |
Fri, 10 August 2018 18:26 |
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Originally posted by: Bob Eager
On Fri, 10 Aug 2018 22:10:46 +0000, John Levine wrote:
> In article
> <1028478389.555543171.735142.peter_flass-yahoo.com@news.eternal-
september.org>,
> Peter Flass <peter_flass@yahoo.com> wrote:
>>>> > Thanks. Unbounded nostalgia. Was there ever a more elegant computer
>>>> > than a PDP-11?
>>>>
>>>> Yes, many.
>>>
>>> *Not* that I disagree... but which other computers do you find
>>> elegant???
>>
>> System/360.
>
> The S/360 was a tour de force but it had plenty of uglies that people
> have been dealing with ever since, the worst of which was 24 bit
> addressing.
>
> The PDP-8, on the other hand, was close to perfectly elegant.
I agree there, too. Simple enough for an introductory course on assembly
language.
There's a reason I have two replica PDP-8s, and am building a third!
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371992 is a reply to message #371874] |
Fri, 10 August 2018 18:49 |
Bill Findlay
Messages: 286
Registered: January 2012
Karma: 0
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Senior Member |
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On 10 Aug 2018, Huge wrote
(in article <ft6eqeFug6vU1@mid.individual.net>):
> On 2018-08-10, Bob Eager<news0073@eager.cx> wrote:
>> On Fri, 10 Aug 2018 16:45:34 +0000, Huge wrote:
>>
>>> On 2018-08-10, Bob Eager<news0073@eager.cx> wrote:
>>>> On Fri, 10 Aug 2018 14:46:30 +0000, Huge wrote:
>>>>
>>>> > On 2018-08-10, David Wade<g4ugm@dave.invalid> wrote:
>>>> >
>>>> > [24 lines snipped]
>>>> >
>>>> > > If one is looking for elegance in early machines, then the Ferranti
>>>> > > Pegasus is an interesting starting point. According to Simon
>>>> > > Lavington's book
>>>> > >
>>>> > > https://www.amazon.co.uk/Pegasus-Story-History-Vintage-Compu ter/
>>>> dp/1900747405
>>>> > Fascinating. Thank you!
>>>>
>>>> Must get that. Simon is great fun, and we have spent time in the pub
>>>> together on more than one occasion.
>>>>
>>>> (Computer Conservation Society, monthly meetings near Covent Garden)
>>>
>>> When and where? I might be persuaded to schlep in from Norfolk for that!
>>
>> Southampton Street (BCS London offices).
>>
>> http://computerconservationsociety.org/lectures/current/lect ure.htm
>>
>> I quite often go. Whatever the talk is, it's interesting. And so are the
>> people. Sometimes end up in the pub afterwards.
>
> Ta!
There will be a talk on ICL 1900 Series resurrection next month:
Title: ICL 1900 Software Recovery
Speaker: Bill Gallagher, Delwyn Holroyd & Brian Spoor
Date: Thursday 20th September 2018
Time: 14:30
Location: BCS, 5 Southampton St, London WC2E 7HA
I will be in the audience, having contributed to the restoration of 1900
Pascal:
<http://www.findlayw.plus.com/ICL1900/index.html>
--
Bill Findlay
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| Re: PDP 11/40 system manual [message #371993 is a reply to message #371992] |
Fri, 10 August 2018 19:07 |
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Originally posted by: Bob Eager
On Fri, 10 Aug 2018 23:49:58 +0100, Bill Findlay wrote:
> On 10 Aug 2018, Huge wrote (in article
> <ft6eqeFug6vU1@mid.individual.net>):
>
>> On 2018-08-10, Bob Eager<news0073@eager.cx> wrote:
>>> On Fri, 10 Aug 2018 16:45:34 +0000, Huge wrote:
>>>
>>>> On 2018-08-10, Bob Eager<news0073@eager.cx> wrote:
>>>> > On Fri, 10 Aug 2018 14:46:30 +0000, Huge wrote:
>>>> >
>>>> > > On 2018-08-10, David Wade<g4ugm@dave.invalid> wrote:
>>>> > >
>>>> > > [24 lines snipped]
>>>> > >
>>>> > > > If one is looking for elegance in early machines, then the
>>>> > > > Ferranti Pegasus is an interesting starting point. According
>>>> > > > to Simon Lavington's book
>>>> > > >
>>>> > > > https://www.amazon.co.uk/Pegasus-Story-History-Vintage-
Computer/
>>>> > dp/1900747405
>>>> > > Fascinating. Thank you!
>>>> >
>>>> > Must get that. Simon is great fun, and we have spent time in the
>>>> > pub together on more than one occasion.
>>>> >
>>>> > (Computer Conservation Society, monthly meetings near Covent
>>>> > Garden)
>>>>
>>>> When and where? I might be persuaded to schlep in from Norfolk for
>>>> that!
>>>
>>> Southampton Street (BCS London offices).
>>>
>>> http://computerconservationsociety.org/lectures/current/lect ure.htm
>>>
>>> I quite often go. Whatever the talk is, it's interesting. And so are
>>> the people. Sometimes end up in the pub afterwards.
>>
>> Ta!
>
> There will be a talk on ICL 1900 Series resurrection next month:
>
> Title: ICL 1900 Software Recovery Speaker: Bill Gallagher, Delwyn
> Holroyd & Brian Spoor Date: Thursday 20th September 2018 Time: 14:30
> Location: BCS, 5 Southampton St, London WC2E 7HA
>
> I will be in the audience, having contributed to the restoration of 1900
> Pascal:
>
> <http://www.findlayw.plus.com/ICL1900/index.html>
More details on my link above!
I'll be there too. I'm the tall one with very untidy white hair and a
check shirt!
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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| Re: PDP 11/40 system manual [message #371994 is a reply to message #371985] |
Fri, 10 August 2018 19:10 |
Alfred Falk
Messages: 195
Registered: June 2012
Karma: 0
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Senior Member |
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Rich Alderson <news@alderson.users.panix.com> wrote in
news:mddh8k2vyfh.fsf@panix5.panix.com:
> When introduced to the PDP-10, 8 years later, I found it annoying: No
> base register, only a single index register per instruction, so some of
> my favorite tricks simply did not work. No condition codes; what's
> with all these SKIPx and JUMPx and Txxx (test) instructions? And then
> a miracle happened.
>
> I still think in EBCDIC, nearly 50 years later, rather than ASCII,
> which I sort of learned less than 40 years ago, and I still have a
> fondness for the 360 instruction architecture, but the orthogonality of
> the PDP-10 instruction set, the uniform use of bits 7-8 to indicate
> no-modification/immediate/memory/self on all the data movement
> instructions, the elegance of single instructions to conditionalize the
> execution path rather than a sequence in which you have to be careful
> of changes to the condition codes you're checking, even the word
> addressing rather than byte addressing, have forever spoiled me for
> lesser systems.
I loved the -10 for its orthogonal instruction set. It could be displayed
on a single page of the programming card. It didn't take long to learn.
I had started out on the IBM 1620, and then wrote extensively in assembler
for the PDP-9 and when I came to the PDP-10 the family resemblance made it
familiar but oh! so much better.
I never did much with the 360, but when I did, I was always having to look
up instruction descriptions to understand what they actually did. I never
developed any affection for it.
The Data General Nova instruction set was (sort of) admirable for its cut-
down simplicity. The DG Eclipse had to be admired for the way they added a
lot of useful instructions, while still being 100% compatible with the Nova,
but pretty it was not. Even more so with the 32-bit MV series.
I did a little coding for the CDC 6xxx. There were some clever things in
that design, but I never thought it was elegant.
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| Re: PDP 11/40 system manual [message #371995 is a reply to message #371994] |
Fri, 10 August 2018 19:57 |
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Originally posted by: terry-groups
On Friday, August 10, 2018 at 7:10:03 PM UTC-4, Alfred Falk wrote:
> The Data General Nova instruction set was (sort of) admirable for its cut-
> down simplicity. The DG Eclipse had to be admired for the way they added a
> lot of useful instructions, while still being 100% compatible with the Nova,
> but pretty it was not. Even more so with the 32-bit MV series.
The Nova was an interesting beast and elegant in its own way - quite a step up from the sparseness of the PDP-8, but not all of the bells and whistles (and "special" memory locations) of the PDP-11.
I was a developer on one non-DG operating system for the Nova, and a maintainer for another. Some time later, Data General sent me a stack of my STRs (bug reports) for RDOS and Extended BASIC back, along with a large pile of other people's STRs and source tapes for both, with a note that essentially said "Congratulations! You're now the maintainer." To be fair, I did give them an XBASIC STR that was fundamentally unsolveable (ask if you want the details).
The Eclipse ("Real" Eclipse, not "Big Bird") was pretty clean, too. The Nova 3 and Eclipse S/200 were essentially the same product ('181 ALUs) but the Eclipse had more microcode. Likewise for the Nova 4 and Eclipse S/140 (29K-series ALUs). This all pre-dated studies on instruction set complexity vs. speed (like when DEC found out that a good percentage of the VAX instruction set could be replaced by emulator traps and emulated by the remaining instructions without penalty). As part of maintaining RDOS, I built all of the zillion xRDOS flavors and they all ran about the same speed on my test S/230. So, whenever I was working in a piece of code that had conditionals for different processors, I would optimize out a lot of those special cases.
Don't get me started on Big Bird. It kept the DG from hitting the skids earlier than it did, but it was too little, too late, too expensive (as in "not enough cheaper than a VAX-11/780 to justify going with those oddballs from DG").
Very little is made of the M/600 which was its own kettle of fish, a mini trying to steal market share from the lower end of the IBM 370 product line (mostly Models 115 and 125).
And then there was the mN601. I'd call that an interesting first effort, but the low price of the chip was offset by the rather complicated support circuitry, and if you actually wanted to run regular DG peripherals and software, the price savings over a discrete CPU were small and the performance loss was big.
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| Re: S/360 addressing, was PDP 11/40 system manual [message #371996 is a reply to message #371954] |
Fri, 10 August 2018 20:49 |
John Levine
Messages: 1405
Registered: December 2011
Karma: 0
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Senior Member |
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In article <c1165d5b-1d41-4f6b-935a-dc1a586ff9db@googlegroups.com>,
Quadibloc <jsavard@ecn.ab.ca> wrote:
> On Thursday, August 9, 2018 at 3:54:51 PM UTC-6, Bob Eager wrote:
>> On Thu, 09 Aug 2018 17:36:24 -0400, Peter Flass wrote:
>
>>> System/360.
>
>> All that base register stuff...
>
> But surely that's unavoidable, if you want to have more than 64 K of memory?
The issue was that they wanted to have a single architecture that was
usable on a 16K 360/30 and a 4MB 360/70. So it needed large addresses
in the architecture (should have been 32 bits but they wimped out and
limited it to 24 which was clearly a mistake), but they needed small
addresses in the instructions to make the instruction density high
enough.
Base+displacement addressing was a reasonable approach, but they made
two mistakes. One is that code addressing should have been PC
relative rather than base relative so the RX and RS branch
instructions should have had 16 bit branch offsets. This would have
allowed branches 64K in either direction (instructions are halfword
aligned so don't store the low zero bit) which is a lot of code. They
fixed this much later by adding relative addressing to s/390.
The other was that they thought that base addressing gave them
position independent code, from what they said in the architecture
articles in the IBM SJ. Branch addressing with BALR to set the base
register is position independent, but pointers stored in memory are
not. This could have been addressed by disciplined programming (as it
was in TSS/360) but instructions like "load pointer and add base
register" would have given people a hint of how things were supposed
to work.
--
Regards,
John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly
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| Re: PDP 11/40 system manual [message #372007 is a reply to message #371989] |
Sat, 11 August 2018 07:34 |
Peter Flass
Messages: 8375
Registered: December 2011
Karma: 0
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Senior Member |
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Bob Eager <news0073@eager.cx> wrote:
> On Fri, 10 Aug 2018 15:01:06 -0400, Rich Alderson wrote:
>
>> I still think in EBCDIC, nearly 50 years later, rather than ASCII, which
>> I sort of learned less than 40 years ago, and I still have a fondness
>> for the 360 instruction architecture, but the orthogonality of the
>> PDP-10 instruction set, the uniform use of bits 7-8 to indicate
>> no-modification/immediate/memory/self on all the data movement
>> instructions, the elegance of single instructions to conditionalize the
>> execution path rather than a sequence in which you have to be careful of
>> changes to the condition codes you're checking, even the word addressing
>> rather than byte addressing, have forever spoiled me for lesser systems.
>
> I was going to mention the PDP-10, but forgot. I did quite a lot of
> assembly language programming on one.
>
Yes, I loved the -10 too, although I didn't program it extensively. I was
sorry when it was canceled, although I suspect it would have been difficult
to expand the architecture to larger memory sizes.
--
Pete
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| Re: PDP 11/40 system manual [message #372008 is a reply to message #371990] |
Sat, 11 August 2018 07:34 |
Peter Flass
Messages: 8375
Registered: December 2011
Karma: 0
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Senior Member |
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John Levine <johnl@taugh.com> wrote:
> In article <1028478389.555543171.735142.peter_flass-yahoo.com@news.eternal-september.org>,
> Peter Flass <peter_flass@yahoo.com> wrote:
>>>> > Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>>>> > PDP-11?
>>>>
>>>> Yes, many.
>>>
>>> *Not* that I disagree... but which other computers do you find elegant???
>>
>> System/360.
>
> The S/360 was a tour de force but it had plenty of uglies that people
> have been dealing with ever since, the worst of which was 24 bit
> addressing.
The /67 had full 32-bit addressing, which (IMHO) is the way they should
have gone with later models.
>
> The PDP-8, on the other hand, was close to perfectly elegant.
>
--
Pete
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| Re: PDP 11/40 system manual [message #372010 is a reply to message #371973] |
Sat, 11 August 2018 08:03 |
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Originally posted by: Kerr-Mudd,John
On Fri, 10 Aug 2018 15:40:31 GMT, Bob Eager <news0073@eager.cx> wrote:
> On Fri, 10 Aug 2018 14:46:30 +0000, Huge wrote:
>
>> On 2018-08-10, David Wade <g4ugm@dave.invalid> wrote:
>>
>> [24 lines snipped]
>>
>>> If one is looking for elegance in early machines, then the Ferranti
>>> Pegasus is an interesting starting point. According to Simon
>>> Lavington's book
>>>
>>> https://www.amazon.co.uk/Pegasus-Story-History-Vintage-Compu ter/
> dp/1900747405
>>>
>>>
>> Fascinating. Thank you!
>
> Must get that. Simon is great fun, and we have spent time in the pub
> together on more than one occasion.
>
> (Computer Conservation Society, monthly meetings near Covent Garden)
>
>
>
Emulator here [& others]. I've not tried it yet.
http://sw.ccs.bcs.org/CCs/simulate.htm
--
Bah, and indeed, Humbug.
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| Re: PDP 11/40 system manual [message #372015 is a reply to message #371985] |
Sat, 11 August 2018 10:25 |
Dan Espen
Messages: 3867
Registered: January 2012
Karma: 0
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Senior Member |
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Rich Alderson <news@alderson.users.panix.com> writes:
> Charles Richmond <numerist@aquaporin4.com> writes:
>
>> On 8/9/2018 1:45 PM, Rich Alderson wrote:
>>> Elliott Roper <nospam@yrl.co.uk> writes:
>
>>>> On 8 Aug 2018, hancock4@bbs.cpcn.com wrote
>>>> (in article<21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com>):
>
>>>> > Bitsavers uploaded the system manual for the PDP 11/40.
>
>>>> > http://www.bitsavers.org/pdf/dec/pdp11/1140/DEC-11-H40SA-A-D _PDP-11_40_System_manual.pdf
>
>>>> > 358 pages, undated.
>
>>>> Thanks. Unbounded nostalgia. Was there ever a more elegant computer than a
>>>> PDP-11?
>
>>> Yes, many.
>
>> *Not* that I disagree... but which other computers do you find elegant???
>
> My first computer was the IBM 1401. *Not* an elegant architecture, but not
> without points of interest.
1401 was my first also. One could do quite a bit in a small amount of
storage. The A and B registers would tell you about the data the
previous instruction processed. (Usually where the word mark was.)
Word marks were like the trailing null with C strings without the bother.
A shame none of that carried over to the S/360.
We could have had a 7 bit character with one bit reserved for the word mark.
> The first I fell in love with was the IBM System/360, thanks to a high school
> graduation gift from a sweetheart, Germain's _Programming the IBM 360_. One of
> these days I'm going to put his simulator on Hercules and go through the
> exercises just for giggles.
Likewise, my next system was S/360 and I accumulated extensive
experience with the machine. My first impression was that the machine
was over-complicated, on purpose. The lack of sector addressing on
the disks is my best example. After using disks for years on a 1440,
disks became more complicated than I thought they should be.
3270s are another example. A simple thing like screen addressing
couldn't be done with row/column numbers in bytes?
The 24 bit addressing was more a failure in the programming department
than in hardware design. Why any programmer would attempt to use
the high order byte for data instead of just assuming it would be
part of the address some day is a mystery. IBM stepped in it big
putting a 3 byte address right in the DCB. A DCB without a version
number or other reliable marker. Still a problem to this day,
I've done huge amounts of assembly programming and the instructions
get the job done. Issues with the base registers are easy to deal with
once you figure out that each subroutine should have it's own base
register, don't attempt to make all code addressible at once.
--
Dan Espen
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| Re: PDP-10 addressing, PDP 11/40 system manual [message #372016 is a reply to message #372007] |
Sat, 11 August 2018 11:23 |
John Levine
Messages: 1405
Registered: December 2011
Karma: 0
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Senior Member |
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In article <1173318279.555679658.757757.peter_flass-yahoo.com@news.eternal-september.org>,
Peter Flass <peter_flass@yahoo.com> wrote:
> Yes, I loved the -10 too, although I didn't program it extensively. I was
> sorry when it was canceled, although I suspect it would have been difficult
> to expand the architecture to larger memory sizes.
We don't have to guess. They did expand the addressing for the DEC-20
and it was pretty ugly. The extra address bits were called the
section number, with some addressing being within the current section
and some being global. TOPS-20 supported it but I don't recall many
programs using it.
--
Regards,
John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly
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| Re: PDP 11/40 system manual [message #372023 is a reply to message #371990] |
Sat, 11 August 2018 13:25 |
Quadibloc
Messages: 4399
Registered: June 2012
Karma: 0
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Senior Member |
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On Friday, August 10, 2018 at 4:10:47 PM UTC-6, John Levine wrote:
> The PDP-8, on the other hand, was close to perfectly elegant.
The Honeywell H-112, which, unfortunately, was only implemented once, and that
in a serial machine like the PDP-8/S, had it beat in one way.
It didn't reserve an entire 3-bit opcode for input-output instructions, but put
them in with the operate microinstructions.
Because of that, instead of DAC and TAD, in addition to an addition instruction,
it could also have a load instruction and a store instruction.
John Savard
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| Re: PDP-10 addressing, PDP 11/40 system manual [message #372024 is a reply to message #372016] |
Sat, 11 August 2018 13:32 |
Quadibloc
Messages: 4399
Registered: June 2012
Karma: 0
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Senior Member |
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On Saturday, August 11, 2018 at 9:23:08 AM UTC-6, John Levine wrote:
> In article <1173318279.555679658.757757.peter_flass-yahoo.com@news.eternal-september.org>,
> Peter Flass <peter_flass@yahoo.com> wrote:
>> I was
>> sorry when it was canceled, although I suspect it would have been difficult
>> to expand the architecture to larger memory sizes.
> We don't have to guess. They did expand the addressing for the DEC-20
> and it was pretty ugly. The extra address bits were called the
> section number, with some addressing being within the current section
> and some being global. TOPS-20 supported it but I don't recall many
> programs using it.
The Sigma 9 from Xerox/SDS also took an existing architecture with a full-length
address in the instruction, and modified it to use more memory than that address
could support.
I think it was ugly too; but I suppose that it could still be said that if the
memory expansion method actually used was a kludge, that doesn't prove th at
something better might not be possible.
John Savard
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| Re: PDP 11/40 system manual [message #372033 is a reply to message #371874] |
Sat, 11 August 2018 16:19 |
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Originally posted by: Bob Eager
On Sat, 11 Aug 2018 09:51:18 +0000, Huge wrote:
> On 2018-08-10, Bill Findlay <findlaybill@blueyonder.co.uk> wrote:
>> On 10 Aug 2018, Huge wrote (in article
>> <ft6eqeFug6vU1@mid.individual.net>):
>>
>>> On 2018-08-10, Bob Eager<news0073@eager.cx> wrote:
>>>> On Fri, 10 Aug 2018 16:45:34 +0000, Huge wrote:
>>>>
>>>> > On 2018-08-10, Bob Eager<news0073@eager.cx> wrote:
>>>> > > On Fri, 10 Aug 2018 14:46:30 +0000, Huge wrote:
>>>> > >
>>>> > > > On 2018-08-10, David Wade<g4ugm@dave.invalid> wrote:
>>>> > > >
>>>> > > > [24 lines snipped]
>>>> > > >
>>>> > > > > If one is looking for elegance in early machines, then the
>>>> > > > > Ferranti Pegasus is an interesting starting point. According
>>>> > > > > to Simon Lavington's book
>>>> > > > >
>>>> > > > > https://www.amazon.co.uk/Pegasus-Story-History-Vintage-
Computer/
>>>> > > dp/1900747405
>>>> > > > Fascinating. Thank you!
>>>> > >
>>>> > > Must get that. Simon is great fun, and we have spent time in the
>>>> > > pub together on more than one occasion.
>>>> > >
>>>> > > (Computer Conservation Society, monthly meetings near Covent
>>>> > > Garden)
>>>> >
>>>> > When and where? I might be persuaded to schlep in from Norfolk for
>>>> > that!
>>>>
>>>> Southampton Street (BCS London offices).
>>>>
>>>> http://computerconservationsociety.org/lectures/current/lect ure.htm
>>>>
>>>> I quite often go. Whatever the talk is, it's interesting. And so are
>>>> the people. Sometimes end up in the pub afterwards.
>>>
>>> Ta!
>>
>> There will be a talk on ICL 1900 Series resurrection next month:
>>
>> Title: ICL 1900 Software Recovery Speaker: Bill Gallagher, Delwyn
>> Holroyd & Brian Spoor Date: Thursday 20th September 2018 Time: 14:30
>> Location: BCS, 5 Southampton St, London WC2E 7HA
>>
>> I will be in the audience, having contributed to the restoration of
>> 1900 Pascal:
>>
>> <http://www.findlayw.plus.com/ICL1900/index.html>
>
> [Makes note.]
>
> Since I've actually used a 1900, that one looks interesting, thank you.
I should have said...so have I. I spent two summers working at the
University of Sussex, including some PLAN programming. And then, nearly a
decade later, doing consultancy work for BT (more PLAN).
To be fair, the latter was on a 2900 running DME.
--
Using UNIX since v6 (1975)...
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
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