Reliability v. Fire Risk (original v9n21) [power-off]

[BHamilton.osbuSouth at xerox.com]

Here at Xerox we did some studies a few years ago on powering down Xerox
(not Sun) workstations.  The hard facts are: powering down a Xerox 8010 or
6085 workstation each night saves on the order of $1/night in electricity
and air conditioning costs.  Multiply by approx. 25K workstations and it
adds up to MEGABUCKS per year.

Reliability: there was a SLIGHT increase in "infant mortality" of some
components, such that a large site BEGINNING a power-down program might
want to stock some additional spares.

We plan to start a similar study soon with Sun 4/110's and SPARCstations.
Anecdote: a fellow across the hall from me has been powering down his
4/110 every day for about a year with no problems.  "exit SunView",
"Halt", and the boot-up cycle only take a couple of minutes.

Most PC users are accustomed to powering down after use.  A SPARCstation
should be able to be treated like a PC.  Public files belong on a server
(which stays up), not on a slow workstation disk.

Even if equipment is left powered up, it is every electronics engineer's
responsibility to design equipment to tolerate power cycling.  In my
experience over the past ten years in greater Los Angeles, you can expect
an average of three or four power failures per year.  Also, most systems
have failure modes where the only way to perform a complete system reset
is to cycle power.

--Bruce
BHamilton.osbuSouth at Xerox.COM
213/333-8075