Ask Chuck Moore About 25X, Forth And So On

Chuck Moore is, among other things, a chip designer. His latest design, the 25x, is based on a 5x5 array of X18 microprocessor cores, and could provide 60,000 MIPS with a production cost of about one dollar. And Moore has the chops to back that up: he's been designing tiny, efficient processors for many years. He's also the inventor of the programming language Forth, which has evolved from a miniscule but radically fast language "difficult for a human to read" (according to The Secret Guide) to the even more radical colorForth. How radical? Try "includes own operating system; has own 27-key Dvorak keyboard layout; meaningful color syntax." How's that for starters? Ask below your questions for Chuck about processors and programming (ask all you'd like, but one per post, please) We'll pass the best ones on to him, answers soon to follow.

Comments

Forth as intermediate language

[Ed Avis]

Many high-level languages compile into C code, which is then compiled with gcc or whatever. Do any use Forth instead? I understand Forth is a stack-based language: doesn't that present problems when compiling for CPUs that mostly work using registers?

revolutionary

[rnd()]

Put on your Thomas Kuhn hat for a moment and tell us:

What is the most revlutionary (i.e., it is scoffed at by those in control/power) idea in the software industry today? Explain how this idea will eventually win out and revolutionize software as we know it.

What's the next Big Computational Hurdle?

[DG]

Now that sub-$1k computers are running in the GHz range, it seems that all the computational tasks on a common desktop system are not processor-bound.

3D, rendered-on-the-fly games get well over 30 frames per second at insanely high resolutions and levels of detail. The most bloated and poorly-written office software scrolls though huge documents and recalculates massive spreadsheets in a snap. Compiling the Linux kernel can be done in less than 5 minutes. And so on.

It seems that the limiting speed of modern computers is off the processor, in IO.

What then, do you forsee coming down the pike that requires more processor power than we have today? What's the underlying goal you intend to solve with your work?

Where is forth going?

[JanneM]

I learned forth early on in my programming career; it was very memory and CPU efficient, something that was important on early microcomputers. It was also a great deal of fun (though far less fun to try and understand what you wrote a week earlier...). Today, even small, cheap microcontrollers are able to run fairly sophisticated programs, and it is far easier to cross-compile stuff on a 'big' machine and just drop the compiled code onto the development board.

Forth has (in my eyes) always been about small and efficient. Today, though, embedded apps are more likely to be written in C than in forth, and the "OS as part to the language" thing isn't as compelling today as it was in the eighties. Where is forth being used today, and where do you see it going in the future?

/Janne

What about memory protection?

[jcr]

From the web pages, I don't see any mention of access control.

Can this processor be used in a multi-user, general-purpose mode?

-jcr

Programming languages...

[Midnight Ryder]

This one would probably require a bit more time to answer than you probably have available, but a quick rundown would be cool: Where do you see programming languages headed -vs- where do you think they SHOULD be headed? Java, C#, and some of the other 'newer' languages seem to be a far cry from Fourth, but are languages headed (in your opinion) in the proper direction?

Quick question

[jd]

I have often conjectured that multi-threaded processors (ie: processors that can store multiple sets of internal states, and switch between them) could be useful, as the bottleneck moves from the processor core to communications and dragging stuff out of memory.

(If you could microcode the "instruction set", all the better. A parallel processor array can become an entire Object Oriented program, with each instance stored as a "thread" on a given processor. You could then run a program without ever touching main memory at all.)

I'm sure there are neater solutions, though, to the problems of how to make a parallel array useful, have it communicate efficiently, and yet not die from boredom with a hundred wait-states until RAM catches up.

What approach did you take, to solve these problems, and how do you see that approach changing as your parallel system & Forth language evolve?

The direction of 25x Microcomputer...

[Midnight Ryder]

The 25x concept looks like it could really a damned interesting idea. But one of the questions in my mind is where you want to head with it? Is this something that is to be used for very specialized research and scientiffic applications, or is this something that you envision for a general 'desktop' computer for normal people eventually?

Secondly, if you are considering the 25x for a desktop machine that would be accessable by people that aren't full-time geeks, what about software? Forth is a lost development art for many people (It's probably been 10 years since I even looked at any Fourh code) and porting current C and C++ application would be impossible - or would it? Is there a potential way to minimize the 'pain' of completely re-writing a C++ app to colorForth for the 25x machines, which could help to speed adoption of a platform?

Massively Parrallel Computing

[PureFiction]

The 25X system reminded me of IBM's Blue Gene computer, where a large number of inexpensive CPU cores are placed on a single chip.

The biggest problem in dealing with a large number of small cores lies in the programming. I.e. how do you design and code a program that can utilize a thousand cores efficiently for some kind of operation? This goes beyond multi-threading into an entirely different kind of program organization and execution.

Do you see Forth (or future extensions to Forth) as a solution to this kind of problem? Does 25X dream of scaling to the magnitude that IBM envisions for Blue Gene? Do you think massively parrallel computing with inexpensive, expendable cores clustered on cheap die's will hit the desktop or power-user market, or forver be constrained to research...