[HARDWARE] my $0.02 re: dedicated crack boxes

Paul Everett repton at repton.org
Sat Sep 18 22:51:38 EDT 1999

In my oppinion, I think that its still a better idea to just use some
basic PC based machines for rc5 cracking.

I'm all for building some kind of "rack of motherboards" as suggested
somewhere here before.

each unit would be:

2x celeron 400	106.00
abit BP6 mobo	 80.00
32mb dimm	 41.00
nic		 12.00
floppy		  8.00

(prices in pounds, excluding VAT, current from www.dabs.co.uk)

this works out to about 185 US dollars.
this would crack at about 2.2MKeys/second.

You would need one PSU between 2 or 3 boards, adding about $10/board to
the cost. So you have about $200/unit, including PSU and any oddments. You
could also probably overclock the celerons a bit. If you managed to run
then at (say) 500mhz, that would be about 2.75Mkeys/second, which works
out to $73 per MKey/sec. Even without overclocking you have $91/MKey/sec.
You could save a bit by getting rid of the floppy drive and using boot
ROMs in the network cards. If you can overclock more than 500mhz (may be
possible, i'm not an expert on this) then its even better value.

This setup has several advantages over a FPGA/whatever solution:

1. The one off cost is low, there is no minimum order
2. the development costs are zero, as the hardware and software is
   readily available.
3. as the machines are standard PC's, they could be used for other things
   as well as rc5 - as rc5 runs with a low priority you could, say, use
   them for rendering or compiling, but rc5 would use all the cpu when
   you weren't doing anything else.
4. as the machines are standard PC's, you can sell them easily if you need
   the cash or get bored of the project.

And, as the prices of celeron processors drops (which it is doing) this
becomes more and more preferable over other solutions.

Whats more, I've actually done this. Well, not quite. About a year ago a
built a rack pretty much as specified, but using 386 motherboards instead
of dual celerons. I could easily just chuck some different motherboards in
there though.

Take a look at http://www.repton.org/racks/ if you want. Its got info on
my rack, including some detail about exactly -how- i did it. There are
photos too, and also details of a rack of Pentium 2 machines belonging to
another d.net member.
(p.s. if anyone else has done something similar, please send me info so i
can add it)
(p.p.s. if anyone from distributed.net is watching, and i know you are, i
wouldn't say no to a link from the main site)


Paul Everett                                 Microsoft is not the answer.
repton at repton dot org                       Microsoft is the question.
http://www.repton.org                                 "No" is the answer.
   "God, root, what is the difference?" - Pitr, www.userfriendly.org

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