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Tue Nov 9 01:00:01 PST 2010


certainly be an exercise in extreme pain, culminating in bashing the
damn things with a sledgehammer and throwing them into a ditch somewhere
(or giving them to a children's hospital, which is a much better thing
to do).  However, it is entirely possible that Saddam is desperate
enough (given the embargo that likely makes it moderately difficult for
him to get even cheap Duron boxes) to be willing to throw his available
computer hackers at the task.  Perhaps he just wants them to train his
pilots using flight simulators, since he's a bit short on planes...;-)

The possibility of his building an "unmanned aerial vehicle" on top of
the PS2 is not quite as crazy (and indeed is almost certainly feasible),
but again I fail to see the motivation for using a PS2 instead of, say,
an ordinary laptop computer (of which hundreds would fit into a single
truck, once again).  Hitler managed to build his "buzz bombs" with
1940's technology, so UAV's are clearly not particularly difficult to
make.  I'll bet that I could engineer one from scratch inside a month or
two (right after I learned to fly, of course:-) that would have a 90%
chance or better of working.  These days, with satellites kindly
providing us with electronically readable absolute locations (to within
10 meters or so) I find it excruciatingly difficult to believe that an
ordinary laptop with a handful of servos couldn't be glued into a piper
cub to build a UAV capable of taking off, flying to some predefined
location along some predefined trajectory remaining (say) 15 meters
above the ground (to clear ground trash but remain below most radar) and
then crash itself into any given 100 meter circle within its fuel range.

After all, the timescale of the steering and piloting corrections
required to fly any non-jet plane is long, long, long compared to the
speed of a laptop, and we're talking solving some simple negative
feedback coarse grained differential equations here.  As in "drifting to
the left, move the stick to the right" while integrating the trajectory
with realtime corrections from the GPS. Over seconds.  Pretty much the
same code used to write flight SIMULATORS, which have been around since
the original IBM PC (which was ALSO almost certainly capable of flying a
small plane).  Maybe flying a jet through rugged mountains would be a
bit trickier, but still -- a rack of playstation 2's?  Why not dedicated
moslem kamakazi's?  They are (to be cynical) preprogrammed and probably
more readily available, judging from the number of suicide attacks that
occur in the middle east.  Better at evasive maneuvers and dealing with
accidents of the road, too.

> could be true... screweyer stuff has happened..

This is certainly correct.  And I'm certain that (given enough effort)
PS2's COULD be used to build UAV's or even to do nuclear weapons
research (we'll see if they are featured in the next major bid to Los
Alamos;-).  It would be a most peculiar statement of the distorting
effects of the embargo if indeed it has driven Saddam to spend much
money importing PS2's and expecting his computer folks to deal with all
the manifold headaches of using them as general purpose computers (or as
de facto programmable device controllers).  OTOH, they >>do<< have a lot
of onboard "smarts" for doing e.g. "enemy AI" and simple physics
calculations, as any game system must (after all, what are they running
but moderately sophisticated classical physics simulations?).

I wonder if he's running the market on PDA's? or any of the myriad
programmable device controllers available to the world today?  Or if
he's set up an ASIC shop in (say) Taiwan?  In a world where devices as
evil as singing christmas cards with "infinite" battery capacity exist
(hammer time again:-) custom silicon is obviously WAY too cheap for our
own good...;-)

> > Actually, if you beleive NBC news, we should all be using Play Station
> > 2's.  They actually had someone on saying that the PS2's are "1000 times
> > more powerfull than any desk top computer".  I may have the quote a
> > little wrong, but that was pretty much what he said.

The /. article suggests that it is a 300 MHz, 128 bit CPU, "every bit as
powerful as the processors found in most desktop and laptop computers"
(no pun intended, I'm sure -- a bit >>more<< powerful would have me
doubt my own understanding of binary logic:-).  I'd suggest that this is
a much fairer statement, although I'm also sure that the CPU is (as
advertised) very good at doing graphics transformations.  The system is
still constrained by the current VLSI scale and silicon available to all
systems designers, and still must talk to memory and peripherals over a
bottlenecked bus.  When a number like 1000x more powerful appears, I
think back to the old days, when various "special purpose" CPU's touting
incredibly fast (for their day) floating point speeds were knocking
around the PC market.  In many cases the claim was technically true from
(as Obi Wan would say) a certain point of view -- if one loaded the
CPU's registers in a particular way and was doing just the right mix of
instructions and didn't have to go even to an L2 cache, one could get 10
or 100x the nominal throughput of a general purpose CPU plodding along
on operations out of main memory.

DSP's, for a while, were often touted for this sort of purpose, as was
the (IIRC) i860, and when it comes right down to it, the PS2 is YADSP
being offered up as a general purpose computer.  The incredible pain of
programming a DSP for a general purpose calculation without anything
like an operating system or real programming language was conveniently
ignored.  The i860 faired somewhat better, but never had supercomputer
vendors exactly quaking in their boots.  The PS2 is in better shape than
most of the DSP-based efforts -- it at least has been engineered from
the beginning for >>something<< like general purpose use and does have a
general purpose CPU integrated in the engine, but still...

This long ramble, at the end, has a bit of a beowulf-relevant point.
The beowulf concept (that differentiates it from the manifold virtual
parallel machine efforts that preceded it) has from the beginning been
one of COTS technology and mainstream, proper OS and programming
support.  It is quite difficult enough to engineer a beowulf with a high
quality, open source operating system, over the counter devices
(especially network devices) living on a standardized bus, excellent
compilers, and venerable (and "mostly" debugged:-) communications
libraries.  Building "one-of-a-kind" cluster supercomputers out of
components being used far from their intended purpose and missing most
of the above is the sort of thing undertaken by companies like Thinking
Machines -- it takes years and top-level expertise and a major
investment in engineering and when you're finally done, you find that
Moore's Law ate all of your efforts alive and you're lucky if you can
recover development costs on sales before even the dimmest customer
begins to realize that maintenance alone is costing more then the
hardware that would replace the whole shebang.  Or (in the case of the
CM5) possibly even the costs of electricity and cooling. [Which also
happens even with beowulfs -- ten 200 MHz pentium class nodes cost
approximately $600/year to feed and are likely slower, for most
purposes, than a single Duron node that costs $600.]

I wonder if Iraq executes its computer scientists who fail?  I wonder if
all those PS2's are really Christmas gifts for Saddam's many relatives?
I wonder when we'll see the first UAV terrorist attack?  I wonder when
people will finally wake up and realize that killing each other to
achieve a better way of life is as oxymoronic as it gets?

   rgb

-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu







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