On Thu, 08 Dec 2011 19:59:05 +0000
Nix <n...@esperi.org.uk> wrote:
> On 7 Dec 2011, Attila Kinali told this:
> > I have two stability issues: The CPU runs at 60°C when the system
> > is idle.
>
> SIO Temp: +53.0°C (low = -55.0°C, high = +127.0°C)
> (crit = +127.0°C)
>
> (room temperature: 15C.)
>
> > Configuration is a bare net5501-700 in the standard case, with
> > a low power 2.5" sata harddisk mounted on top of it.
>
> That extra heat would be the HDD, then. They really can spit out heat,
> low power or not (it seems to be correlated mostly with age, I suspect
> due to bearing wear).
The harddisk is new and low power (iirc <1W standby and <3W running).
Toghether with the CPU that's about 10W of power at full throttle.
As the system is sold with a 25W power supply, hence i'd expect it to
be able to disipate at least 20W, but even 10W is too much... and if
you have a look at the case, you see why.
> > When using the
> > CPU to its limit (like by using cpuburn), the temperature will rise
> > to 80°C.
>
> I see no increase in temperature *at all* under heavy CPU load. I find
> this very surprising: 120 wakeups per second (from the timer interrupt
> and the entropy key daemon) shouldn't be stopping the thing from going
> to sleep and cooling down, should it? (Not that 53C really worries me.)
120 IRQs/s is nothing. Dont forget that a standard Linux system is
configured to 250Hz timer interrupts these days. Systems that need to
be responsive are even configured to 1kHz timer interrrupts. And as
the interrupt service routine is very small, it's still plenty of time
to sleep.
In short: Even with 120 IRQ/s your system is still basically idle.
> Running an HDD without a fan in the mix to give some airflow seems risky
> to me, no matter the case.
Why? It's a low power notebook HD. These are made to be run in
enviroments where there is no airflow at all. Just a little bit of
conduction trough the housing.
> > This has been tested and reproduced with Linux kernels 2.6.38.x, 2.6.39.1
> > and 3.0.1 (vanilla, no patches).
>
> FWIW, I've been using a Soekris net5501 for two and a half years now (no
> HDD or wifi). Linux kernels from 2.6.30 up to 3.2rc. No crashes not
> attributable to user error, not one. It's sufficiently reliable that I
> just bought a second one in case lightning strikes the first one and
> cuts me off from the Internet :)
That's exactly what i'm hitting at: If you run the bare system, you
have no problems. If you choose to include some of the accessories
(like HD mount or wifi cards) sold toghether with the net5501
(which suggests that these accessories are supported), you will
run into problems. At least i and seemingly others did.
Attila Kinali
--
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
-- Tirin, The Dispossessed, U. Le Guin
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