Andrew wrote:
(Zymurgy) wrote in message . com...
Andy Hall wrote
PoP wrote:
Jason Arthurs wrote:
My server currently runs in the loft
I am curious!
I would have thought that running any sort of equipment in the loft is
asking for trouble. Reason being that the temperature up there can go
outside the specs of the equipment. It gets damned cold up there in
winter and sweating hot in the summer.
If you don't take any steps to control the temperature then it could be.
Methinks you worry too much.
Any decent kit (i.e something that's not been cobbled up in a 3rd
party case) has a wide operating temperature, and it is the rate of
change of the ambient temperature that causes an issue,
not the actual maximum or minimum temperatures.
That's rubbish. Electronic equipment can and does fail when operated
outside of its specified temperature range. The spec for any piece of
equipment is a worst case figure and you may well be able to operate a
particular example well outside that spec but there will be a limit at
both high and low temperature.
I have to agree. Ther are failure modes associated with temperature
cycling, most;y mechanical stress leading to failures of joiints and
frit seals on chips, but by far and away the usual cause of
semiconductor PERMANENT as well as TEMPORARY degratation is overtemperature.
My firewall (Compaq Pentium 2) is in the loft with no special
insulation around it, and the projected low for tonight is -4.
The low temperatures we get in this country (even left outside) would
not generally be a problem for most electronic equipment if left
powered up to keep it warm.
Most commercial equipment can reasonably be expected to work between 0C
and 40C. The chips themselves are generally in spec between -5 and 70C,
but that is not the whole story....MIL spec stuff is rated between -25C
and 125C
I have had computer room air conditioning failures causing a very
steep step change in temperature (up to ~32 degrees C in 1 case) I had
3 disk failures out of an installed base of ~600 and 1 machine auto
shut down due to overtemperature out of 200 (and this was found to be
too close to adjacent kit).
So? The air con failed and the ambient temperature became too high. It
has nothing to do with rate of change. Even if you had raised the
temperature over the space of a week you would have seen the same
failures.
Precisely. Internal air temps over 50C are almost certainly indicative o
very high junction temperatures - go ovcer 175 junction on MOS and its
'good night, vienna'.
Similarly I have seen machines operate at either end of their
envelopes [1] without incident.
That's what they're designed to do. Take them outside their envelope
and they *will* fail eventually.
Mostly thety stop working before they fail. Chips are made to lie
withing specs, but no manufacturer in the world designs his kit to
accept components that are all at the worst possible end of the
specification spectrum.
Insdtead a monte carlo analyisis is done at best. In practice what
actually happens is that the designers do their best, a few prototypes
are temperature tested, and the production goes ahead. If lots of users
report a similar problem then the design may be examined, but mostly
they just get replacement boards. Its cheaper.
Even MIL spec kit os not necessarily designed to any different
standards, but it may well be sample tested in an envoironmental chamber
to ensure it works over the specifed range.
Andrew