[rc5] A possibly stupid idea
yp at bc.sympatico.ca
Thu May 29 15:14:39 EDT 1997
At 08:48 PM 5/29/97 +0100, you wrote:
>I was just wondering about the possibility of someone writing an
>operating system specifically to search through these keys. This would
>(?) increase the efficiency of the searches and allow them to run better
>on 286s and other low level computers.
Talked about it with a few gurus, and turned it down. Even optimising Linux
wouldn't give you a very huge advantage, plus you'd loose the ability to
"multitask" -- that is, you wouldn't be stealing spare cycles from machines.
I couldn't very well do anything like that on the 40 or so machines in my
office, but running the client in idle mode is great. The idle mode bit
appeals to the masses.
>I guess at the least it would only need to be able to go through an
>assigned keyspace and then output results. You don't even need a packet
>driver; floppy disks could be used to transport the data to another
>computer that could then transmit up to the server. Then the newly
>assigned keyspace could be put back on the disk and put back to the pc.
Sneakernet would be painful with any amount of clients, unless you could
assign a weeks worth of keys to them at a time.
>I own two computers here: a 90 mhz Pentium and a 16 mhz i386. The 386 is
>basically sitting around collecting dust because I really have no use
>for it now. I was thinking about the possibility of letting it help
>break the code (every cycle helps, right?). Since that would be the only
>thing it would be doing, it makes since (to me) that it be specialised
>for just that.
You could always throw a client onto the 386 and run it anyway. I've got
one that takes about 10 hours to process a key. Pentium 133 next to it
takes 1/2 hour.
The big problem with older machines (286/386 and equivalents in the mac/sun
worlds) is that the hardware doesnt' have the math stuff to do it. Some
processors don't have shift or rotate commands, which take something like
12345 and turn it into 51234. (yeah, i know that's not binary, and that
machines do binary. Go away and don't be so technically picky). To fudge
that rotate command on a processor without it can take a hundred or so times
as long. And most encryption type stuff uses a lot of rotation.
Now if someone out there has access to a wafer fab plant, and could whip up
a custom processor...
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