Slashdot Mirror
Hand-made Web Server, Built From 200 TTL Chips
ps writes "Bill Buzbee has constructed a hand-made CPU, complete with
hardware address translation, memory mapped I/O, and DMA, out of 200
74-series TTL chips wired together with thousands of individually wrapped
wires. By using a port of Adam Dunkels' uIP TCP/IP stack to the Magic-1, it
currently serves up live web pages
at an amazing speed of 3 MHz. See the website for photos and
schematics."
I have a theory that everyone who sends a post warning that a machine will catch fire when slashdotted is the product of either a "Faith-based" education initiative, or Christian home-shcooling.
Maybe people aren't interested because it's not that great an idea.
http://www.mirrordot.org/
Jeez, I have a headache already just thinking about this. "...thousands of wirewrap connections..". To learn microprocessors, I wirewrapped demo prototype boards in mid 1980's and eventually made one for each of the major CPU chips available at the time (Z80, 6803, 6809, 8051). Each one had 40 wirewraps on the CPU, 28 on the EPROM, 28 on the RAM, 30+ on the I/O, 24+ on the UART, 16-20 on each of the ADC and DAC chips, on and on.
Then getting the thing to work! Using crash-and-burn EPROM erasing and testing. Before being able to afford a U-V EPROM eraser, I'd have a 10-20 chips sitting on the garage roof. Slowly losing their minds in the sunshine.
Things are SO much better now. Highly integrated Atmel AVRs and PICs that program over and over directly from the parallel port of the PC and don't have to be removed from the circuit. Simulators that work. JTAG structures that allow the functionality of in-circuit-emulators that are built right into every processor chip. SPICE.Microcontrollers like the AVR Tiny13 that have 10-bit ADC built in, operate at 20 MIPS, reprogram 10000 times, run on 1 milliamp, a cost less than a dollar.
I still wirewrap when there's no other way to get a prototype built and there needs to be TTL logic or bus-interfaced I/O or sensors on the board.
But I get halfway through the building of the prototype and this horrid feeling just creeps over me. It's like being in a solidifying muck of concrete that is getting harder by the minute and you can't pull yourself out. "Why am I doing this?".
So someone makes a web-server out of TTL chips and 'thousands of wirewrap connections'. Show it to someone like your boss and they'll say, "Cool, now make ten more". Then realize that by using modern tools, you can do the same thing in a FPGA that costs a few dollars. And make modifications that take a half-hour to write. And don't require connecting 50 logic-analyser little connectors, or studying miles of logic charts until you go mad, or trying to find the one broken wire in the six-deep layer of wires on the back of the wirewrapped board. Or finding that the one broken wire is the bottom wrap on a pin that has three other wraps on top of it...
It's called progress, gentlemen. Take advantage of it.
INFORMATIVE?
Mods, what are you SMOKING?
He posted the text of the SLASHDOT posting, not the actual site. He's "mirroring" the Slashdot article on Slashdot. The same text is available by scrolling up to the top of the page. How is this informative?