LISP on PDP-11

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Paulo Rebordão

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Jun 9, 2025, 12:31:38 PM6/9/25
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I recently did some reading on LISP and got interested. What are the options for the PiDP-11?


Paulo Rebordão

Steve Platt

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Jun 9, 2025, 12:43:09 PM6/9/25
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There is a version, LISPF, from Uppsala University (Sweeden).  It was written in Fortran.

I got it running under RSX-11M back in the late 70s.  At one point, I modified it to virtualize the cell derefencing, using paging tables, LRU page replacement, etc.  A lot more cells, but slower.  Alas, that is lost to time.

I recently (a year or so ago?) found a copy of the source.  Not sure where I got it from.  It looks like the most recent version (2015?) also has a translation into C.  And the original single-text-file release you'll have to manually break up.  And all sorts of other things.

If you can't find it (and want it), let me know and I'll send it along.

Steve

On 6/9/2025 12:31 PM, Paulo Rebordão wrote:
I recently did some reading on LISP and got interested. What are the options for the PiDP-11?


Paulo Rebordão

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Johnny Billquist

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Jun 9, 2025, 2:57:57 PM6/9/25
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If you install RSX, there is XLisp, which is not far from Common Lisp,
and with extensions for object oriented programming.

Johnny
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|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol

Steve Platt

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Jun 9, 2025, 4:02:07 PM6/9/25
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Cool.  At this point, I'd go with XLisp.  I used it for quite a number of years -- a good system.

Johnny Billquist

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Jun 9, 2025, 4:10:21 PM6/9/25
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With that said, I've only made V1.7 of XLisp run under RSX. I wanted to
stick with a version that was still pretty small. It grew some in V2.

Johnny

On 2025-06-09 22:02, 'Steve Platt' via [PiDP-11] wrote:
> Cool.  At this point, I'd go with XLisp.  I used it for quitea number
> b22b594b-0e14-41b0-88cc-7daed2a55258%40comcast.net <https://
> groups.google.com/d/msgid/pidp-11/
> b22b594b-0e14-41b0-88cc-7daed2a55258%40comcast.net?

John Hudak

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Jun 9, 2025, 4:54:37 PM6/9/25
to Paulo Rebordão, [PiDP-11]
I know you are asking about running LISP on a PDP11.  There are some fairly good emulators for later gen symbolics machines and the TI Explorer (which I was chained to for a number of years back in the day.)


On Mon, Jun 9, 2025 at 12:31 PM Paulo Rebordão <pjreb...@gmail.com> wrote:
I recently did some reading on LISP and got interested. What are the options for the PiDP-11?


Paulo Rebordão

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Henry Bent

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Jun 9, 2025, 5:02:50 PM6/9/25
to John Hudak, Paulo Rebordão, [PiDP-11]
That's a very good point.  The PDP-11 was not, as far as I am aware, widely used as a LISP machine.  You're much better off looking at some other simulation options.  You could even go all the way back to the start and get a LISP package for a PDP-1 from https://simh.trailing-edge.com/software.html if you can set up that environment.  It all depends on what your goals are, as there are many dialects of LISP that ran on a variety of hardware at many points.

-Henry

Johnny Billquist

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Jun 9, 2025, 5:14:41 PM6/9/25
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The PDP-11 wasn't big in AI and research, where a lot of Lisp work was
done. That was a lot of big machines like some IBM stuff, or PDP-10.

But it's not because the PDP-11 can't do it just fine, it's just that
doing large software on the PDP-11 falls afoul of the small address space.

But really - a PDP-1? That is way more limited than a PDP-11, and with
way older, more primitive environment and software. I wouldn't go there
if I had some interest in Lisp unless I had some very specific thing I
wanted to explore.

You can run Lisp on a PDP-8 as well, if you want to. Works just fine,
but it's old dialects, and limited amount of memory.

The PDP-11 was much more popular in places where you wanted to interact
with physical things in a lab, and wanted a computer around to control
and play with. Small and simple to use (relatively speaking).
But it was also used in a lot of interactive systems, and in a lot of
software development.

Johnny

On 2025-06-09 23:02, Henry Bent wrote:
> That's a very good point.  The PDP-11 was not, as far as I am aware,
> widely used as a LISP machine.  You're much better off looking at some
> other simulation options.  You could even go all the way back to the
> start and get a LISP package for a PDP-1 from https://simh.trailing-
> edge.com/software.html <https://simh.trailing-edge.com/software.html> if
> you can set up that environment.  It all depends on what your goals are,
> as there are many dialects of LISP that ran on a variety of hardware at
> many points.
>
> -Henry
>
> On Mon, 9 Jun 2025 at 16:54, John Hudak <jjh...@gmail.com
> <mailto:jjh...@gmail.com>> wrote:
>
> I know you are asking about running LISP on a PDP11.  There are some
> fairly good emulators for later gen symbolics machines and the TI
> Explorer (which I was chained to for a number of years back in the day.)
>
> https://lisp-machine.org/ <https://lisp-machine.org/>
>
> On Mon, Jun 9, 2025 at 12:31 PM Paulo Rebordão <pjreb...@gmail.com
> <mailto:pjreb...@gmail.com>> wrote:
>
> I recently did some reading on LISP and got interested. What are
> the options for the PiDP-11?
>
>
> Paulo Rebordão
>
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Paulo Rebordão

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Jun 9, 2025, 5:33:54 PM6/9/25
to Henry Bent, John Hudak, [PiDP-11]
I know there are a lot of Lisp options available, but I need to find something to do with my PiDP-11 :)

Paulo Rebordão


Paulo Rebordão

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Jun 9, 2025, 5:34:53 PM6/9/25
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Johnny, where can I get XLisp for RSX ?

Paulo Rebordão

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Jun 9, 2025, 5:39:07 PM6/9/25
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Just noticed that on my PiDP DU1 drive there's a file XLISP.DSK
Is it a disk image ?

A segunda-feira, 9 de junho de 2025 à(s) 19:57:57 UTC+1, b...@softjar.se escreveu:

Johnny Billquist

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Jun 9, 2025, 7:25:59 PM6/9/25
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Start by installing my PiDP-11 RSX image. In there you then have RPM -
use that to just install XLISP, and you'll be good to go.
(Actually, XLISP is also included in my TCP/IP package, but I suspect
you want to update things anyway, and there are additional reasons why
you should switch to the image I created.)

Johnny

On 2025-06-09 23:34, Paulo Rebordão wrote:
> Johnny, where can I get XLisp for RSX ?
>
> A segunda-feira, 9 de junho de 2025 à(s) 19:57:57 UTC+1, b...@softjar.se
> escreveu:
>
> If you install RSX, there is XLisp, which is not far from Common Lisp,
> and with extensions for object oriented programming.
>
> Johnny
>
> On 2025-06-09 18:31, Paulo Rebordão wrote:
> > I recently did some reading on LISP and got interested. What arethe
> > options for the PiDP-11?
> >
> >
> > Paulo Rebordão
> >
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>
> --
> Johnny Billquist || "I'm on a bus
> || on a psychedelic trip
> email: b...@softjar.se || Reading murder books
> pdp is alive! || tryin' to stay hip" - B. Idol
>
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Johnny Billquist

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Jun 9, 2025, 7:28:30 PM6/9/25
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I don't know, but I don't think so. It's not something I've done anyway.

Johnny

On 2025-06-09 23:39, Paulo Rebordão wrote:
> Just noticed that on my PiDP DU1 drive there's a file XLISP.DSK
> Is it a disk image ?
>
> A segunda-feira, 9 de junho de 2025 à(s) 19:57:57 UTC+1, b...@softjar.se
> escreveu:
>
> If you install RSX, there is XLisp, which is not far from Common Lisp,
> and with extensions for object oriented programming.
>
> Johnny
>
> On 2025-06-09 18:31, Paulo Rebordão wrote:
> > I recently did some reading on LISP and got interested. What arethe
> > options for the PiDP-11?
> >
> >
> > Paulo Rebordão
> >
> > --
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> >
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>
> --
> Johnny Billquist || "I'm on a bus
> || on a psychedelic trip
> email: b...@softjar.se || Reading murder books
> pdp is alive! || tryin' to stay hip" - B. Idol
>
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Jerry Weiss

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Jun 9, 2025, 8:24:56 PM6/9/25
to Johnny Billquist, pid...@googlegroups.com
Back in my post grad days (circa early 1980), UIC ran LISP under UNIX (v7 IIRC) on a PDP-11 that I used for several courses.  I don't recall much about that version.  I found a link here - https://github.com/PDP-10/its/blob/master/src/rms/lisp11.265 that appears to support rt11,SITS, or standalone, but not UNIX. I am not well versed in the LISP domain, perhaps Lars knows more about this.

Lars Brinkhoff

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Jun 10, 2025, 1:13:36 AM6/10/25
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Paulo Rebordão wrote:
I recently did some reading on LISP and got interested. What are the options for the PiDP-11?

Richard Stallman wrote a LISP for the PDP-11 while at Harvard:

This may be a later version that was in use at the MIT AI lab.

isy...@gmail.com

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Jun 12, 2025, 10:35:31 AM6/12/25
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Out of idle curiosity, anyone still got a LISP machine????

Lars Brinkhoff

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Jun 12, 2025, 11:49:25 AM6/12/25
to isy...@gmail.com, [PiDP-11]
Out of idle curiosity, anyone still got a LISP machine????

Yes, there are several people who have Lisp machines.  There are also emulators for various models.

If we're talking ITS adjacent, it would be the CADR LIspm.  I think maybe only a handful (two?) have "survived" (in the most generous sense) and they are not in working condition.  There is an emulator though. 
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