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Clockless Computing: The State Of The Art

Posted by timothy on from the that's-unpossible dept.

Michael Stutz writes: "This article in Technology Review is a good overview of the state of clockless computing, and profiles the people today who are making it happen." The article explains in simple terms some of the things that clockless chips are supposed to offer (advantages in raw performance, power consumption and security) and what characteristics make these advantages possible.

2 of 140 comments (clear)

  1. Asynchronous vs. synchronous computing by isj · · Score: 3, Interesting

    The article is very interesting. I though that research in asynchronous computing died in the sixties. What the article misses is that async. operations has an overhead too - the synchronization "here is the data". Synchronous computing does not have that.

    I have previously read (forgotten where) that in theory async. computers will always be slower that sync. computers. It seems that that is not true anymore. I guess that the latests-and-greatest CPUs have a non-trivial percentage of idle time for instructions which takes slightly longer than an integral number of clock ticks. If an instruction takes 2.1ns and the clock runs at 1ns, everything have to assume that the instruction takes 3ns.

    Also imagine a fully async. computer. No need for a new motherboard or even changing settings in the BIOS when new and faster RAM chips are available - the system will automatically adapt.

    I think that we will see more and more async. parts in the year to come. But I don't know if everything is going to be asynchronous.

  2. Reliability by numo · · Score: 3, Interesting

    Well, I think that the reason the async chips are not being used is quite simple - a clocked system is much easier to design and verify. You know how long before and after a clock edge your signal needs to be there to be recognised. You know that if these constraints match across your system, it will work. Yes, this makes the system as fast as its slowest link - some circuits operate near their limits, some are actually wasting the time. But it works. An asynchronous design would be a pure hell to debug - that's probably why the industry doesn't (yet) mess with it.

    BTW, does anybody here remember analog computing? A bunch of cleverly connected operating amplifiers? These things were asynchronous, just as mother nature is. If you can get the physics work for you, bingo - compare the time the nature needs for raytracing a complex scene compared to a digital model :-) The only drawback is that the most of us prefer slow digital model of thermonuclear reaction and similar problems...