[SPARCbook] MHz

[Miles Nordin]

On Mon, 10 Apr 2000, Matthew Haas wrote:

> Nope, more of an obsession to be able to use it for a little longer (doing
> trivial tasks-- not kernel compiles) before it heats up to the point where
> I start to worry about it.

That makes sense.  I think the best solution to your problem is to worry
less.  IMHO the recent flurry of paranoia about overheating sparcbooks is
hogwash.  I have left mine on for literally a week straight, and it spent
at least a day or two at 100% CPU building parts of NetBSD's pkgsrc.  The 
Sparcbook is my main build machine, and I think Todd Whitesel is using a
Tadpole for NetBSD/sparc snapshots.

I have read no reports on this list or warnings in the m anual that
suggest sparcbooks have a ``duty cycle''--the only warning I read was,
``don't close the lid for a long time while it's on--leave it 1" open, or
the TFT can be damaged.'' This is rather standard advice for ANY laptop.  
Even Apple tells their customers to do this in the techinfo library.

If you want to be ```safe,'' use the fold-down feet, don't set it on
insulating fluffy surfaces like beds or rugs, and don't run sloppy ports
like Linux. But stop second-guessing Tadpole engineers that are obviously
a lot smarter than we are about their own design. Aiming fans at your
sparcbook is, IMHO, prudish voodoo lunacy.  Note that the machine has
inside it (1) a temperature sensor, which shuts it down when it gets too
hot, (2) a power-sasving idle instruction, and (3) a dynamic CPU clock
slowdown circuit.  Granted, not all OS's use all features, but Solaris
uses all 3 andn NetBSD has all 3 completed or in progress AFAIK--it puts
things in perspective.  The machine has smarter features inside it than
aiming a room fan at it.

Replacing your board with sa slower speed is questionable at best, because
generally CPU's are rated as to speed chiefly for how fast they can be
clocked before they overheat.  It is not reasonable to assume that a 70MHz
microSPARC II running at rated speed will consume less power than a faster
chip running at rated speed.

The ``Rev. 1.3'' GX CPU board in mine does not have any jumpers on it,
except a solder-pad ``jumper'' to choose 3.3V or 5V memory SIMM's.  Yes,
I've removed it and inspected both sides carefully.

-- 
Miles Nordin / v:+1 720 841-8308 fax:+1 530 579-8680
555 Bryant Street PMB 182 / Palo Alto, CA 94301-1700 / US

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