[Beowulf] RE: Capitalization Rates - How often should you replace a cluster? (resent - 1st sending wasn't posted ).

Lux, James P james.p.lux at jpl.nasa.gov
Fri Jan 16 20:15:56 PST 2009

On 1/16/09 12:03 PM, "Robert G. Brown" <rgb at phy.duke.edu> wrote:

> On Fri, 16 Jan 2009, Greg Lindahl wrote:
>> On Thu, Jan 15, 2009 at 04:26:00PM -0500, Lechner, David A. wrote:
>>> Sometimes the newer technology uses less power and is cheaper to
>>> operate....(anyone ever create a KW/MFLOP vs. Time curve?  has that
>>> really gone down? )
> I've had discussions on and off line with people who argue that to
> minimize "TCO" replacement every twelve months is in order.  In general
> I don't agree with that -- maybe in a horribly inefficient corporate
> environment with a high payoff to staying bleeding edge current and
> equally high expenses for management and maintenance, but noplace sane
> -- and would "recommend" a general replacement cycle of the period you
> keep your systems under HW maintenance.  Usually three or four years, in
> other words.

I wonder how much of that is driven by tax regulations and the "depreciation
life" of various and sundry things. Odd numbers are popular in regulations
(e.g. 3,5, or 7 years)

Of course, the 3 year accelerated depreciation also affects the
manufacturer's development and pricing policies (i.e. If businesses find it
useful to depreciate over 3 years, then mfrs will make boxes that fit into
that model)


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