Complete computer designed and built from logic gates

http://www.homebrewcpu.com/overview.htm

by jgrahamc • 17 years ago

98 29 17 years ago

Undeniably impressive, but saddening nevertheless. The man insisted on replicating the mistakes of the past: Von Neumann bottleneck, C, Unix. This creation is a "model airplane" - a world-class one, to be sure, but a model airplane still.

JeremyChase• 17 years ago

Building the hardware is an amazing project. You are suggesting that he should have designed a new architecture, core language, and operating system as well?

Maybe he should just cure cancer too.

jacquesm6• 17 years ago

I'm sure that just doing this is a major project, and that if I read it right he did this in his spare time. Between having a wife, kids, a day job and a house to keep up he's done pretty good. And it's very well designed from the aesthetics point of view as well.

jacquesm6• 17 years ago

a repost of:

http://news.ycombinator.com/item?id=741639

By popular request...

What I find extremely impressive is that he not only designed a computer from the ground up using nothing but TTL, he also designed the cpu and instruction set.

Most people would be tempted to re-create an existing design, this guy basically did on his own what would have taken a whole corporation consisting of lots of people 30 years ago.

It's not like a re-enactment, it is a completely original design.

cabalamat• 17 years ago

Surely it's more fun to do your own design? It would be for me, anyway.

jacquesm6• 17 years ago

Definitely, but designing an instructionset is not that easy. Small changes in how you lay out your instructions can have a big impact on the design.

The nicest I think are 68K and mips, everything else is pretty messy.

A good standard by which to measure how good an instruction set is is how many lines of code it takes to simulate it.

rlm4• 17 years ago

I wish I knew how to get started on something like that...

jgrahamc• 17 years ago

You could start by building a ALU and work up from there.

rlm4• 17 years ago

I've built an ALU for a simulator ;)

But I wouldn't know where to go from there and I wouldn't know how to make a physical one.

Are there any OCW-courses (or similar) on the subject? Preferably with a hands-on approach :)

kapuzineralex• 17 years ago

Incredible! Both thumbs and both big toes up!

smithjchris• 17 years ago

Lovely project. Wish I had the patience for that (and a nice logic analyser). By the time I'd started at university, it was all FPGAs, HDL and simulation. A shame really.

The nearest I ever got was a pure TTL digital clock.

jacquesm6• 17 years ago

There is something very good about learning the hard way how to debug a logic circuit instead of having an FPGA in some factory made board. You get to see how finicky hardware really is.

joshu• 17 years ago

This is awesome.

Surely there's some ROM in there. I can't imagine the microcode is in an FSM.

When I was at CMU, my capstone engineering class was to build a machine that was capable of a small set of tasks (One that I remember was multiply two 16-bit numbers.) We were to optimize for some specific thing -- ours was "most sleep" (that is, least work) and "least wire wrapping." So it was as simple as possible; entire control path fit in a PLA for example.

Anyway, one of the other groups apparently optimized for AWESOME. We were there with our single board and a multicolor cloud of wire-wrap; they showed up with a multiple board computer. The boards had a pair of 68-pin IDC connectors and two huge wide cables as a bus.

The machine basically was fully asynchronous and had no clock. One board was an ALU, one was the control unit, etc. For their demo they both ran with one or two ALU boards and got different performance.

This was 1995 or so, so quite progressive for the time.

wallflower• 17 years ago

Computers constructed from solely logic gates have an impeccable pedigree: Apollo's onboard flight computer

"The Apollo flight computer was the first to use integrated circuits (ICs). The Block I version used 4,100 ICs, each containing a single 3-input nor logic gate. The later Block II version used dual 3-input nor gates in a flat-pack, approximately 5,600 gates in all. "

http://en.wikipedia.org/wiki/Apollo_Guidance_Computer

lupin_sansei• 17 years ago

Didn't the Apollo flight computer crash/have to be restarted during the landing phase?

dan_the_welder• 17 years ago

Yes.

Luc2• 17 years ago

Nice. I've got a 4-bit one built from relais by a German guy: http://www.relaiscomputer.de/kurz6.htm

bmunro• 17 years ago

>Shortly after I declared Magic-1 "hardware complete", I casually mentioned to my wife that I was starting to think about Magic-2. Her response was swift, and final:

> "No, there will be no Magic-2!"

...omitted...

> She's the love of my life, the woman I plan on growing old with, mother of my children, my partner and best friend. I have to respect her wishes on this.

> So, there will be no Magic-2.

> Instead, we'll call the follow-on project "Magic-16".

Complete computer designed and built from logic gates

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