ITS programming languages

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Andrew Barron

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Jul 9, 2025, 8:52:46 PMJul 9
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Hi, how do I get BASIC to run on ITS?  I cannot find it anywhere on the disk and :BASIC does not work.

Also, for FORTRAN, COBOL, and ALGOL, do I write a program in EMACS then compile it from there? How does that work?

 I was able to get FORTRAN, COBOL, ALGOL, and BASIC to work on TOPS-10. I successfully wrote programs on each.

Thanks!!
Andrew

Lars Brinkhoff

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Jul 10, 2025, 1:07:44 AMJul 10
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Andrew wrote:
Hi, how do I get BASIC to run on ITS?  I cannot find it anywhere on the disk and :BASIC does not work.

I believe ITS did have BASIC, but it has not been installed.  I seem to recall it was used for some minor game. 

Also, for FORTRAN, COBOL, and ALGOL, do I write a program in EMACS then compile it from there? How does that work?

ITS' strength isn't the usual crop of programming languages, but the more exotic Maclisp, Logo, Muddle, and CLU.  Macsyma also has a built-in programming language, but it's another syntax on top of Maclisp.  There are also programming tools targeting PDP-11, IMLAC, Minsky's 2500, and microcomputers. 

There is a FORTRAN hello world ready to go in the HELLO directory.  It's a old F40 FORTRAN-IV compiler.  Later FORTRAN-10 was also in use on ITS.

ITS doesn't have COBOL or ALGOL.  Presumably the TOPS-10 versions could be made to run under DECUUO.  Generally, ITS only imported other languages if there was a specific application needed.

Noah Friedman

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Jul 13, 2025, 8:10:47 PMJul 13
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On Wednesday, July 9, 2025 at 10:07:44 PM UTC-7 Lars Brinkhoff wrote:
ITS doesn't have COBOL or ALGOL.

Demonstrating COBOL on ITS could be hilarious, though.

Andrew Barron

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Jul 14, 2025, 6:29:47 PMJul 14
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The TOPS-10 and TOPS-20 simulations have COBOL. I have written a couple of test programs.

The TOPS-20 sim has Interlisp-10, MACLISP (maybe?), ALGOL, BLISS-10, BLISS-36, COBOL-68, COBOL-74, SNOBOL, C (the KCC version, not ANSI-C), MDL (Muddle), FORTH, PASCAL, SAIL, SIMULA, FORTRAN, and BASIC. So far, I have successfully written and executed programs in COBOL, PASCAL, BASIC, and FORTRAN. BLISS-36 is proving a challenge, as there are very few examples on the web. Plenty of manuals, but not many easy examples. 

I also tried out, ALGOL, COBOL, FORTRAN, and BASIC on the TOPS-10 sim.

Lots of fun, but VERY time consuming. 


cheers AndrewB



Larry Masinter

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Jul 14, 2025, 8:30:13 PMJul 14
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> The TOPS-20 sim has Interlisp-10, 

As part of the Medley Interlisp project, we have set up the Interlisp Online service, which runs Interlisp-D in a docker container on the net with remote login.   This lets people try things out ffrom a browser without installing anything.

For some of the demos and exploration, and demonstration of 1970's era AI experiments, it would be good to see if Interlisp-10 could be used in the same setup.    Has anyone considered a packaged simulation of a tenex/tops-20 machine and file system?



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Jeff Spears

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Aug 11, 2025, 11:20:53 AMAug 11
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Hello Andrew;
About COBOL? Check out this link:


It may explain why ITS did not run COBOL.
:-)
ok...jef

Nigel Williams

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Aug 12, 2025, 3:28:03 AMAug 12
to Andrew Barron, PiDP-10
On Tue, Jul 15, 2025 at 8:29 AM Andrew Barron <zl...@outlook.co.nz> wrote:
> The TOPS-20 sim has Interlisp-10, MACLISP (maybe?), ALGOL, BLISS-10, BLISS-36, COBOL-68, COBOL-74, SNOBOL, C (the KCC version, not ANSI-C), MDL (Muddle), FORTH, PASCAL, SAIL, SIMULA, FORTRAN, and BASIC.

There is PROLOG20 to try out as well:

https://www.saildart.org/[*,LOG]/

Stanford made their own version:
https://saildart.org/[PRO,SYS]/

Lars Brinkhoff

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Aug 12, 2025, 3:37:44 AMAug 12
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There's Essex BCPL for TOPS-10.  Quentin explains how to build it on his blog.

There's also BBN's BCPL for TENEX and TOPS-20.  We only have source code, and it's written mostly in BCPL.  So there's a bootstrapping problem.  Please help!

Andrew Barron

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Aug 12, 2025, 7:11:33 AMAug 12
to Nigel Williams, PiDP-10
Thanks for the info Nigel. I’ll check it out 

Cheers 
Andrew 

From: Nigel Williams <n...@retrocomputingtasmania.com>
Sent: Tuesday, August 12, 2025 7:27:49 PM
To: Andrew Barron <zl...@outlook.co.nz>
Cc: PiDP-10 <pid...@googlegroups.com>
Subject: Re: [pidp-10] Re: ITS programming languages
 
On Tue, Jul 15, 2025 at 8:29 AM Andrew Barron <zl...@outlook.co.nz> wrote:
> The TOPS-20 sim has Interlisp-10, MACLISP (maybe?), ALGOL, BLISS-10, BLISS-36, COBOL-68, COBOL-74, SNOBOL, C (the KCC version, not ANSI-C), MDL (Muddle), FORTH, PASCAL, SAIL, SIMULA, FORTRAN, and BASIC.

There is PROLOG20 to try out as well:



Stanford made their own version:
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