[Beowulf] Supercomputers - iPad versus Cray

Ellis H. Wilson III ellis at cse.psu.edu
Thu Mar 8 12:24:52 PST 2012

On 03/08/2012 02:01 PM, Lux, Jim (337C) wrote:
> -----Original Message-----
> From: beowulf-bounces at beowulf.org [mailto:beowulf-bounces at beowulf.org] On Behalf Of Mark Hahn
> Sent: Thursday, March 08, 2012 10:31 AM
> To: Beowulf Mailing List
> Subject: Re: [Beowulf] Supercomputers - iPad versus Cray
> using iPad is just stupid, since it's an embarassingly expensive piece of eyecandy, not a computer.  (yeah, yeah, you might love yours, but you still wrote a cheque for 65% of what you paid that landed directly on Apple's big pile of cash.)
> Ahh.. but precisely because it is eyecandy means that $/FLOP means you're comparing the wrong metric. iPads are not computers.  They're media storage and display devices.  So the value (not the cost) needs to be compared to alternatives.  It's "is my iPad cheaper than buying and carrying hardback books, watching pay-per-view videos,etc on an airplane or hotel room or airport concourse."

I fully agree that iPads and similar tablet devices fill a much-needed 
gap between tiny-screened and underpowered phones and full-blown 
computers.  However, I certainly didn't intend to, nor did I get from 
other peoples posts, to argue about the iPads worth for the purpose it 
was created.  I argued this is a foolish, sensationalist use of it for a 
cluster.  Whether or not an iPad is a good tablet I take no position on, 
having never owned one myself nor shopped around for them.

Regarding power/computation, I think it's a silly metric to consider for 
this usage (probably just plugged into the wall).  If we're concerned 
about the cost to power a cluster when all nodes are on, that's a fair 
concern, but it has to scale first.  These machines won't allow for 
scaling with their included hardware, so that's not a reasonable 
consideration.  If instead we want to have a cluster that is low power 
because we'll be running off battery for some duration, then it's 
foolish to use these since they rely on wifi or 3g to communicate, not 
to mention having a touchscreen, accelerometer and all kinds of other 
gadgets that eat battery-life.

In short, I think the power/computation argument is totally contrived to 
give a scientific spin to an otherwise sensationalist "research" 
directive.  In fact, I'd faster support a cluster of furbies because 
it's overtly absurd and frankly, funnier, than a cluster of iPads.  This 
has the dangerous potential to being taken seriously (i.e. calling it 
"research" and aligning it with the directives of a big university such 
as Tennessee).  If he just came out and said, "this is ridiculous, but 
we're bored and have some funding to burn" then I'd be on-board ;D.  I'm 
sure Engadget or someone similar would love an article like that, not to 
mention Apple.

Last, regarding educational purposes for mesh network routing, there are 
plenty of systems that are cheap as dirt that would be better for this 
kind of stuff, such as the ones we've been discussing on the list 
recently, that are far cheaper.



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