X-Message-Number: 25987 Date: Fri, 8 Apr 2005 10:36:50 -0400 From: Thomas Donaldson <> Subject: To Pat Clancy, re parallel computers To Pat Clancey, re computers: Believe it or not, when I was in the computer industry my specialty was programming parallel computers. (I left the industry not deliberately but because I came down with a brain tumor -- an astrocytoma, which made keeping an ordinary job hard if not impossible, for practical reasons). However you wish to define an "algorithm", I will point out one major feature of parallel computers of the kind that consist of separate single computers communicating with one another: it's quite possible for every single computer on the net to be doing something different from any other one, and ALL simultaneously. And TIME makes a big difference in real life. If one processor fails to get needed information from others at the time it needs it, the system can collapse. Yes, when we humans program such computers we try hard to avoid such a situation. In fact, one line of engineering such parallel computers works hard to make them look to the user as if they are a single computer. However no one yet goes about programming brains, which are NOT put together that way. Among other things done with parallel computers is to design them and their message passing so that they can stop and wait for messsages which have not yet arrived. Yes, this can slow things down a bit. Think, though, of what you do when you're walking on a road and it looks like a car will hit you. A lot of your neurons work together to get you to move out of the way, and they all work simultaneously while doing different things. Your neurons have learned the "algorithm" of getting out of the way so that they can work all at once, simultaneously, to MOVE YOU. So far as I know, no one has really attempted to do such a fine programming of any computer --- instead they use the methods I describe (very briefly) in the previous paragraph. And that's the difference, and why I said there was a difference. Best wishes and long long life to all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=25987