On 28/05/2023 12:55, gareth evans wrote:

On 28/05/2023 12:34, The Natural Philosopher wrote:

On 28/05/2023 12:24, Tauno Voipio wrote:

The basic PDP-11 architecture limited addressing to 64 kilobytes,
with 8 last kilobytes reserved for I/O, leaving 56 kilobytes for
program use.

Well the one I used had ran Unix, had 64k of program memory *and* 64k of
data memory an IIRC a 20Mbyte hard drive, and we accessed it via serial
consoles.

UNIX in a total of 128K? The kids of today with their VDUs needing
several MB of video storage (3 bytes for each colour of each pixel)
just won't believe you!

Prior to X windows, that was not far off what SCO Unix ran on. I
remember 'Venix' on a 286.

Cant remember how much RAM, but less than a MB I am sure

Likewise SUN SPARC stations.


--
Truth welcomes investigation because truth knows investigation will lead
to converts. It is deception that uses all the other techniques.

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On Sun, 28 May 2023 16:34:55 -0000 (UTC)
Jim Jackson <jj@franjam.org.uk> wrote:

On 2023-05-28, Ahem A Rivet's Shot <steveo@eircom.net> wrote:

On Sun, 28 May 2023 08:10:56 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:

Having used a PDP11 back in the day, with I think 128k of RAM, the C
complier (and the C CROSS compiler we had on it, to generate 6809
code) were both far more primitive than today's offerings.

Its almost impossible to compare like for like.

This is certainly true - you could however almost certainly
port an OS of the era (say Tripos or an early Unix) to run on the Pi
Pico and result in an experience fairly similar to a PDP-11 era mini.

Did the pdp11 have an MMU? or was it an option? I believe there is a
non-mmu version of Linux. So with loads stripped out it might be a goer.

Unix was created on a PDP-11.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

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On 28/05/2023 18:51, Ahem A Rivet's Shot wrote:

On Sun, 28 May 2023 16:34:55 -0000 (UTC)
Jim Jackson <jj@franjam.org.uk> wrote:

On 2023-05-28, Ahem A Rivet's Shot <steveo@eircom.net> wrote:

On Sun, 28 May 2023 08:10:56 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:

Having used a PDP11 back in the day, with I think 128k of RAM, the C
complier (and the C CROSS compiler we had on it, to generate 6809
code) were both far more primitive than today's offerings.

Its almost impossible to compare like for like.

This is certainly true - you could however almost certainly
port an OS of the era (say Tripos or an early Unix) to run on the Pi
Pico and result in an experience fairly similar to a PDP-11 era mini.

Did the pdp11 have an MMU? or was it an option? I believe there is a
non-mmu version of Linux. So with loads stripped out it might be a goer.

Unix was created on a PDP-11.

Yes. It was

"Some models, beginning with the PDP-11/45, can be set to use 32K words
(64 KB) as the "instruction space" for program code and a separate 32K
words of "data space". Some operating systems—notably Unix since edition
V7, and RSX11-M+—rely on this feature."

Wiki

There seem to have been three possible memory models, the original 64k
map, the twin 64k maps as described above, and full MMU allowing up to I
think 256K bytes.

Which suggests that *early* linux could probably run well on a Z80 :-)



--
Those who want slavery should have the grace to name it by its proper
name. They must face the full meaning of that which they are advocating
or condoning; the full, exact, specific meaning of collectivism, of its
logical implications, of the principles upon which it is based, and of
the ultimate consequences to which these principles will lead. They must
face it, then decide whether this is what they want or not.

Ayn Rand.

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On Sun, 28 May 2023 18:28:26 -0000 (UTC)
Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

On Sun, 28 May 2023 18:51:28 +0100, Ahem A Rivet's Shot wrote:

Unix was created on a PDP-11.

According to Dennis Ritchie[1], Unix was, in 1969, cross-assembled on a
GE 465 running GECOS, targetted for execution on a spare DEC PDP 7. It
wasn't until 1970 that they gained access to a new PDP 11, and began the labour of porting Unix to it. They later, in 1971 or so, rewrote the Unix kernel from assembly to (the then new) C language.

Yes true - I should have said /portable/ unix was created on the
PDP-11 but then I tend to think that unix didn't really become unix until
then.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

--- SoupGate-Win32 v1.05
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On 28/05/2023 22:09, Ahem A Rivet's Shot wrote:

On Sun, 28 May 2023 18:28:26 -0000 (UTC)
Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

On Sun, 28 May 2023 18:51:28 +0100, Ahem A Rivet's Shot wrote:

Unix was created on a PDP-11.

According to Dennis Ritchie[1], Unix was, in 1969, cross-assembled on a
GE 465 running GECOS, targetted for execution on a spare DEC PDP 7. It
wasn't until 1970 that they gained access to a new PDP 11, and began the
labour of porting Unix to it. They later, in 1971 or so, rewrote the Unix
kernel from assembly to (the then new) C language.

Yes true - I should have said /portable/ unix was created on the
PDP-11 but then I tend to think that unix didn't really become unix until then.

It is always difficult to fit gradual analogue evolution into the frame
of Boolean thinking so beloved of hoi polloi.

The stupid man asks 'is it dangerous?'
The intelligent man asks 'how dangerous is it?'

--
"First, find out who are the people you can not criticise. They are your oppressors."
- George Orwell

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On 29/05/2023 10:35, The Natural Philosopher wrote:

On 28/05/2023 22:09, Ahem A Rivet's Shot wrote:

On Sun, 28 May 2023 18:28:26 -0000 (UTC)
Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

On Sun, 28 May 2023 18:51:28 +0100, Ahem A Rivet's Shot wrote:

Unix was created on a PDP-11.

According to Dennis Ritchie[1], Unix was, in 1969, cross-assembled on a
GE 465 running GECOS, targetted for execution on a spare DEC PDP 7. It
wasn't until 1970 that they gained access to a new PDP 11, and began the >>> labour of porting Unix to it. They later, in 1971 or so, rewrote the
Unix
kernel from assembly to (the then new) C language.

Yes true - I should have said /portable/ unix was created on the
PDP-11 but then I tend to think that unix didn't really become unix until
then.

It is always difficult to fit gradual analogue evolution into the frame
of Boolean thinking so beloved of hoi polloi.
The stupid man asks 'is it dangerous?'
The intelligent man asks 'how dangerous is it?'

When I started this train of thought, musing upon my experiences
amongst the undergraduate apprenti (colloquial plural used in
Westinghouse, Chippenham) I was talking about 52 years ago in 1971.

I find it to be salutary to think about all that had been achieved in
the previous 52 years taking us back to 1919 when even valves (tubes
to the Yanks) were largely unheard of.

Looking at the technical advances in the 52 years on from 1919 it is no surprise that great strides were made in the next 52 years from 1971
taking us from the single processor integer-only 16 bit PDP11/20
to the multi-processor RPi 4B with shedloads of on-chip memory
and not only floating point capability but also vectored forms
of floating point with 64 32 and 16bit processing all contained in a
single silicon chip.

When I've finally got around to refubishing all the old clocks that
are waiting my attention I might at last tackle the RPi400 that I
bought 2 years ago for some 64 bit assembly language :-)

And on the (OT) subject of horology how the prices of long case
(grandfather) clocks have fallen when you can get a good one for
£200 when 30 years ago you had to spend £2K!

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Ahem A Rivet's Shot <steveo@eircom.net> wrote:

This is certainly true - you could however almost certainly port an OS of the era (say Tripos or an early Unix) to run on the Pi Pico and
result in an experience fairly similar to a PDP-11 era mini.

https://www.cnx-software.com/2021/02/23/fuzix-unix-like-operating-system-ported-to-raspberry-pi-pico-and-esp8266/

There's also a port of 2.11BSD to the STM32 and PIC32 microcontrollers, so a Pico port might be feasible: https://www.osnews.com/story/135795/discobsd-a-2-11bsd-based-unix-like-operating-system-for-stm32-and-pic32-microcontrollers/

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The Natural Philosopher <tnp@invalid.invalid> writes:

Prior to X windows, that was not far off what SCO Unix ran on. I
remember 'Venix' on a 286. Cant remember how much RAM, but less than a
MB I am sure

Surely 640k is enough for anyone.

--
+-----------------------------------------------------------+
| Jason F. McBrayer jmcbray@carcosa.net |
| A flower falls, even though we love it; and a weed grows, |
| even though we do not love it. -- Dogen |

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