Re: [CAD_CAM_EDM_DRO] EMC? Jon ?

HI Alex,

As you've said, Forth is very tight, using words stacked on words, and can get
very hard to understand if not well commented.

I think I remember it being described as "self documenting", although I think
just the opposite is probably true.

I ran it to it in about '84, at the "Home-brew robotics" club in the bay area
(CA). One of the members was using it to run stepper motors. It appeared to be
quite powerful and compact.

A new job later had me writing code for a microwave sweeper, which had been
initially written in Forth, and subsequently in assembly (6801). So I had to
use the Forth code as reference material to the algorithms in the asm code.

Hadn't heard much of it sense. I got a business trip to Anaheim to learn 'C' in
a week; wife and two very young boys got a trip to Disneyland.

My concentration stayed on 'C' pretty much from then on (and asm). The 'C' has
served me well.

It would be curious to study the language, now that I have been programming for
a few years.

Alan KM6VV


Alex Holden wrote:

> On 23 Jul 2005, at 23:14, Roy J. Tellason wrote:
>
>>(Never saw a Jupiter ACE, though. :-)
>
>
> They're pretty rare now; probably worth a few bob.
>
>
>>So I looked into it, and while there's a fair amount of programming
>>capability in there, it was real difficult for me to see how this
>>could be
>>used in any sort of a control application. Maybe that was particular
>>extensions that were written for it or something? In any case,
>>I'd like to
>>implement some stuff using it, but need to find more info, if any
>>of you
>>guys know of any.
>
>
> Forth's popularity is waning now (the UK Forth Interest Group
> recently announced they will no longer be publishing a journal), but
> there are still plenty of die-hards around who claim that Forth lets
> them be several times as productive as C programmers. Forth has some
> unusual features which make it well suited for low level control type
> applications. The language, the development environment, and the OS
> (typically with multitasking ability) are all part and parcel of a
> traditional embedded Forth system. Despite this, the systems are
> usually very small (much smaller than a comparable C based OS and
> toolchain). Forth systems are traditionally interactive- you connect
> a terminal up to them, write snippets of code, and immediately try
> them out. The language is very extensible- in effect you write a
> Forth program by inventing your own words (describing them using
> sentences of simpler built-in words or words that you have already
> invented yourself) and then eventually making a top-level sentence
> out of your invented words. This interactivity and extensibility
> encourages bottom-up development, which is great when the main
> purpose of the program is to interface to hardware, as in most
> embedded control systems. Forth is also usually pretty fast - not as
> fast as C, but much faster than a BASIC interpreter, and the code it
> produces is generally very compact indeed - much more compact than
> compiled C code (part of this is due to the development philosophy
> which encourages the use of lots of very short reusable words).
>
> The way I see it, Forth is a useful tool for low level stuff (eg.
> interactively debugging a new piece of hardware), but it can be
> difficult to understand other people's Forth code (especially if they
> haven't bothered with comments), and high level stuff can get ugly,
> especially all the manual data stack manipulation.
>
> There are also a couple of companies which sell expensive
> professional Forth development systems for embedded systems which
> include a flashy GUI and optimising compilers that produce code about
> as fast as compiled C code. They're intended to compete directly with
> the high-end C development systems.
> http://www.forth.com/
> http://www.mpeltd.demon.co.uk/
>
>
>>I think an outboard box with 8-bit parts running Forth might make
>>one heck of
>>a nifty addition to a CAM setup... :-D
>
>
> There's lots of ready-built Forth hardware around, including more
> powerful stuff like tiny LPC2106 (60Mhz 32 bit ARM with 64K of RAM
> and 128K of Flash) based boards:
> http://www.mpeltd.demon.co.uk/tiniarm.htm
>