5 ms·

No, the processor appears to be constructed from 74LSxxx TTL logic chips. The memory is 2x32KB off-the-shelf SRAM units, but there comes a point where building

No, the processor appears to be constructed from 74LSxxx TTL logic chips. The memory is 2x32KB off-the-shelf SRAM units, but there comes a point where building things out of quad J-K flip-flops just becomes an exercise in patience and unnecessary spending. The registers are FFs, why make all of the memory that way? Just to say you did it? It doesn't add to the learning experience, just the drudgery.

deleted 15y ago
[deleted]
stephen_g 15y ago
Yep... In the long run, I think you would get at least equal educational value by prototyping some parts of the computer in TTL logic, and then writing it in VHDL for an FPGA. Then, you could go into far more advanced things like pipelining, instruction caching and even multi-core design... And it would be a lot faster (both in terms of building the thing, and in terms of how fast the processor would clock) and cheaper.
accepted 15y ago
I think the GP comments wants to say that just soldering the TTL chips w.r.t somebody else's design is not that impressive. I too think so, I have not checked but if I found that the has designed the whole processor (custom op-codes and a whole new implementation of ALU) I would be much more impressed.
- sehugg 15y ago
  According to the website he "built and designed" the computer which I assume includes the instruction set, assembler, etc. I can't find any evidence to the contrary. It's definitely cool -- not groundbreaking, because after all, people used to do this by hand :) It's a bit like rebuilding classic cars. Its fun to touch the hardware and imagine what Woz may have been thinking when he designed the Apple I 30+ years ago.
  - Arjuna 15y ago
    This is Jack Eisenmann's website for the Duo Adept, which includes further project details: http://web.mac.com/teisenmann/iWeb/adeptpage/menu.html http://web.mac.com/teisenmann/iWeb/adeptpage/menu.html
  - jarin 15y ago
    It's not quite like rebuilding a classic car. It's more like a high schooler using the school workshop to fabricate car parts and building a car from his own blueprints. Sure, he may have purchased the speedometer and tires, but that doesn't really diminish the accomplishment. Hopefully he will go on to work on a replacement for computer—car analogies.

deleted 15y ago

[deleted]

stephen_g 15y ago

Yep... In the long run, I think you would get at least equal educational value by prototyping some parts of the computer in TTL logic, and then writing it in VHDL for an FPGA. Then, you could go into far more advanced things like pipelining, instruction caching and even multi-core design... And it would be a lot faster (both in terms of building the thing, and in terms of how fast the processor would clock) and cheaper.

accepted 15y ago

I think the GP comments wants to say that just soldering the TTL chips w.r.t somebody else's design is not that impressive. I too think so, I have not checked but if I found that the has designed the whole processor (custom op-codes and a whole new implementation of ALU) I would be much more impressed.

sehugg 15y ago
According to the website he "built and designed" the computer which I assume includes the instruction set, assembler, etc. I can't find any evidence to the contrary. It's definitely cool -- not groundbreaking, because after all, people used to do this by hand :) It's a bit like rebuilding classic cars. Its fun to touch the hardware and imagine what Woz may have been thinking when he designed the Apple I 30+ years ago.
- Arjuna 15y ago
  This is Jack Eisenmann's website for the Duo Adept, which includes further project details: http://web.mac.com/teisenmann/iWeb/adeptpage/menu.html http://web.mac.com/teisenmann/iWeb/adeptpage/menu.html
- jarin 15y ago
  It's not quite like rebuilding a classic car. It's more like a high schooler using the school workshop to fabricate car parts and building a car from his own blueprints. Sure, he may have purchased the speedometer and tires, but that doesn't really diminish the accomplishment. Hopefully he will go on to work on a replacement for computer—car analogies.