[RC5] Golomb Rulers (was "sexy" projects)
j-zbiciak1 at ti.com
Tue Mar 3 20:49:47 EST 1998
'Thomas Womack' said previously:
| I've read about those; I haven't had the chance to do VLSI design myself,
| but I checked the pricing fairly carefully before posting. Yes, it's
| possible to do the design for free - but what gets you, and what I can see
| no way to avoid, are fabrication costs.
MOSIS is pretty expensive for large quantities. I'm sure you could
cut a pretty good deal, though, if you wanted an even number of wafer's
worth of a chip. (Typically, MOSIS wafers have many different chips on
them, so most of the $ probably goes into mask generation/verification
for each of the different chips. With only one type of chip on the
whole wafer, I imagine that portion of the cost goes down.)
Imagine fabricating a Pentium (~120 sq mm device) at MOSIS. They charge
$920 / sq mm for the first 25 parts, and $690 / sq mm for each additional
batch of 25. This translates to $3900 - $5200 a chip! And that's for an
MMX Pentium in 0.35 micro technology. Obviously, the cost of the fab for
short runs is *much* higher than it would be for more sizable runs.
When you consider that an MMX Pentium probably sells for 1/30th of this
price, and is probably fabbed for less still, it becomes apparent that
the cost target originally proposed only makes sense for large runs of
such a DES super-cracking device.
| Doing it three orders of magnitude
| faster for a factor of fifty less cost is impressive - but you need another
| two orders of magnitude cost reduction to make hardware approaches at all
I will say that you're right, $10,000 for a full-custom device which
cracks a DES encoded message in "a few minutes" is probably far
fetched. In quantity, though, I would say not. Perhaps add a factor
of 2 or so.
+----------- Joseph Zbiciak ----------+ Eliminate idle cycles!
| - - - - j-zbiciak1 at ti.com - - - - | http://www.distributed.net/
|- http://www.primenet.com/~im14u2c/ -|
| - - -Texas Instruments, Dallas- - - | "Give them a light, and they'll
+-----#include "std_disclaimer.h"-----+ follow it anywhere." -- Firesign
To unsubscribe, send 'unsubscribe rc5' to majordomo at lists.distributed.net
rc5-digest subscribers replace rc5 with rc5-digest
More information about the rc5