6502.org

See here (and the earlier 8-board system)

It's networked up (and network booted) using NadaNet, and can be used for multi-voice sound synthesis.

(By Michael J. Mahon – July 26, 2008, Revised – May 7, 2010)



(seen here)

I wonder how hot it gets

He'll be fine - there's no power supply!

But seriously, the earlier system was better arranged for convective cooling. I'm a big fan of fanless computing. (No pun intended.)

got a bunch of 2+ and 2E motherboards if anyone wants to duplicate...

scratch, I should consider for my own music studio, already got ESQ-1s, a theremin and an 1891 pump organ....

Wowser.

Didn't know there were so many Apple IIe boards lying around. Thought they'd all been ebayed..

Only 17? The last paragraph of this article briefly mentions a "supercomputer" with 256 6502s. (I don't know if Bob and his colleagues actually built it, though.)

http://bob-bishop.awardspace.com/Mandelbrot/index.html

That is an awesome find! Talk about a stress test. That's it. May take hours in machine code @2MHz... and there's code too!

The CC65 package has a Mandelbrot Generator in the sample code. I adopted that for the SBC-3. The code took 7 minutes and 46.4 seconds to run (65816 clocked at 7.1MHz generating a 320x200 color display).

Here a picture of the results:


The article was very impressive. I would like to use some of that code in the future, when I can get the time.

Daryl

backscratch, boards still offered for anyone who wants them, just pay shipping. will inventory. Mostly 2+, some 2Es in there. doing variation based on my Thinking Dolphin based on Darryl's SBC-1 on paper...

I recall seeing some of those in a hotel room in Saudi Arabia.

The code in the article can be sped up in a number of ways, such as using a smaller timeout value than 256 (e.g. 32 as in CC65). 7.1 MHz compared to 1 Mhz Apple II (or 2.5 MHz Apple IIgs) helps too, of course, as would using 16-bit native mode on the 65C816. (I thought about replacing the multiply routine with a faster table-driven technique, like 4AB = (A+B)^2 - (A-B)^2, but I never got around to doing much about that.) The BASIC loop in lines 300-550 would be much faster in assembly, since the all the necessary values already pre-computed; the FP math would be replaced with fixed point math (and the FP to one's complement fixed point conversion wouldn't happen inside the loop any more, nor would saving/restoring the ZP each time), and so on.

One modification I made was to separate the calculation from rendering. I just stored the data in RAM, then I could apply coarse value coloring or fine value coloring to the same data without having to recalculate the data (which was the slow part). (The built-in BASIC graphics routines were ROM-space-optimzed, and thus slow; redisplaying the image was fairly quick using speed-optimized routines.)

The next month's article (Bob doesn't have a scan of it on his website for whatever reason) has a modified BASIC program that uses (if memory serves) the neighboring value technique described in the article. I still have both issues somewhere in the bat cave. It was an interesting, but slow, program. I'd let it run overnight, and I can remember my father making me get out of bed at some ungodly hour of the morning one day because "the computer is beeping". Of course, back then I considered anything before 11:45 A.M. to be some ungodly hour of the morning.

I came across this post at the FPGA4FUN forums.
It's someone's mandlebrot project on a Spartan 3E based Nexys 2 Digilent board, started in April 2011. Check out his Wiki, it's pretty cool, although VHDL coding... I think it's the owner of the forum.

It sure looks cool....I like it.