There is a difference between the 'Intro to Chargeback' reports that lowly
sysprogs might give to management as their first look at computer accounting
and the high-powered What-If modeling done by capacity planning scientists
trying to show the outcome of buying a zIIP this month and a zAAP next month
and switching to that new z05 with accelerator J in six months.
What is that sysprog going to be able to give his bosses and what requires a
Capacity Planning Department stuffed with CompSci PhDs? Remember that guy
was going to CODE it up himself.
/Tom Kern
On Thu, 5 Jun 2008 14:17:35 +0900, Timothy Sipples
<[EMAIL PROTECTED]> wrote:
>I've said this before, but just be very, very careful. What you're
>describing is a measure of the (medium-term) *average* (hardware?) cost per
>CPU-second. The average cost is very substantially different from the
>marginal cost of processing an additional CPU-second, which is much more
>nearly zero. Said another way, in capital investment economics marginal
>costs are almost always lower than average costs -- in mainframe economics
>much lower -- except perhaps at specific, individual price discontinuities
>("stair steps"). For a price discontinuity example, if you're running a
>System z9 BC Model Z04, i.e. a machine with all CP capacity enabled, then
>the marginal cost of the next MIPS requires moving to an EC model and the
>associated upgrade expense. Nowadays mainframe computing arguably has fewer
>price discontinuities than distributed computing.
>
>Folks, it's super-critical managers understand this phenomenon. Otherwise
>you get all sorts of really weird and perverse behaviors.?)
>
>Honestly I don't think the average cost is particularly meaningful.
>Marginal costs are much more interesting and valuable.
>
>As a general rule, mainframe economics are characterized by decent (but
>steadily declining each year) initial fixed costs, low (and steadily
>declining each year) marginal costs, and progressively lower marginal costs
>as workload grows ("the curve"). There are some nuances for each major
>component of those costs (staff/services, hardware, software, and
>facilities/network), but that's the general rule by the time you add it all
>up. Your mileage may vary, but if that's not what you're experiencing it's
>worth investigating.
>
>- - - - -
>Timothy Sipples
>IBM Consulting Enterprise Software Architect
>Specializing in Software Architectures Related to System z
>Based in Tokyo, Serving IBM Japan and IBM Asia-Pacific
>E-Mail: [EMAIL PROTECTED]
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