FORTH [was: Re: DIBOL and RPG for RSTS]

Guy N. decguy at
Sat Mar 28 08:34:45 CDT 2020

On Fri, 2020-03-27 at 20:42 -0400, Bill Gunshannon via cctalk wrote:
> On 3/27/20 8:25 PM, Paul Koning wrote:
> > 
> > If you want to try something entirely different, dig up the FORTH
> runtime system that's part of the V10.1 "unsupported" kit.  It's a
> neat language.  Still in use, in fact.
> > 
> I used that FIG FORTH package ages ago on real PDP-11's.
> Was never impressed with Forth so much.  Only time I was
> impressed was when I worked with OpenPROM which was all
> written in Forth.  Wanted to do one for the PDP-11 but
> lost interest when Sun gave it to IEEE and they wanted
> several thousand dollars just to look at it.

FORTH! Now that's classic.  I had reached at least journeyman level with
it in the 80s.  It was great for hardware bringup, relatively easy to
get it running and it gave you lots of power over the new hardware.
FORTH plus an oscilloscope usually beat a logic analyzer - writing a
'scope loop in a few lines of FORTH was much faster than getting the
logic analyzer set up.

The real power of the language is not so much in writing programs,
rather it's a way to create domain-specific languages.  I did my FORTH
apprenticeship under someone who had implemented a compiler for "relay
equations" (a notation for describing connections of actual relays to
build control systems).  The old-timers (in the 80s) could still write
their relay equations, but they were then compiled and the computer did
programmatically what the relays would have done in hard-wired logic.

Somewhere around here I still have a Rockwell R65F11, with the
development ROM and documentation....

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