Mark Hahn <[EMAIL PROTECTED]> wrote > http://www.computerworld.com.au/index.php?id=312084283 > > very amusing and effective stunt for SiCortex!
Stunt being the operative word. It was an interesting demo of how little power it took to run that cluster, since people are notoriously "underpowered". However as green policy it is perfectly silly. The energy that went into growing and delivering the food which "powered" the cyclists could have been more efficiently delivered directly to the computer. And unless these guys pedaled for a very long time the amount of energy consumed during this stunt would have been nothing compared to what went into building the computer, the bikes, their clothes, moving all of it to wherever this stunt was performed, etc. etc. The article talks about Guinness records - no good can come of that. The numbers that matter in terms of "green" policy are the power consumption at peak computing load, sustained computing load, and when idle; where those three load levels would ideally have some standardized measure so that different machines could be compared for their running efficiency, and end users could choose products accordingly. Also of interest for "green" policy is the amount of energy that goes into building the machines. I don't know how to estimate that directly, but the energy _cost_ can be estimated. Sadly the limits are both obvious and rather far apart, so they don't tell us much: the cost of the energy required is more than zero and less than or equal to the price of the machine (unless that price was subsidized or the manufacturer is trying to go out of business). For instance, for a $1000 node at $0.10 per kilowatt-hour the energy used lies somewhere between 0 and 10,000 kilowatt-hours. As I said, a pretty wide estimate! If the node has a lifetime of 3 years and uses 300W on average, that's (300 * 24 * 365 * 3)/1000 = 7884 kilowatt-hours. (I know, no AC or room lighting included.) Which says that the energy required to manufacture and deliver that node is typically less than half of the total power consumed over the machine's lifetime. My gut feeling is that it's a lot less than half, which makes the power consumption at load numbers the place to look for green computing policy. It would be fun to see "energy content" stickers on computers, so that green policy could include that variable, but I just don't see it happening. Regards, David Mathog [EMAIL PROTECTED] Manager, Sequence Analysis Facility, Biology Division, Caltech _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
