Altitude?

[Eugene]

On Thu, Sep 06, 2007 at 02:11:33PM CDT, LuKreme <kremels at kreme.com> wrote:
> On 6-Sep-2007, at 00:40, Eugene wrote:
>> On Tue, Sep 04, 2007 at 08:50:12PM CDT, R.L. Grigg <newslists at autonomy.caltech.edu> wrote:
>>> On Sep 4, 2007, at 6:43 PM, Hacker Scot wrote:
>>>>
>>>> - Maximum altitude: 10,000 feet
>>>>
>>>> ??? What components in a computer are altitude sensitive?
>>>
>>> We've been told that the thinner air doesnt have the same cooling
>>> effectiveness so it will likely casue overheating even when the fan blows
>>> on full.
>>
>> The less dense the air is, the less number of "air" molecules,
>> therefore the less amount of matter available to carry away heat
>> via kinetic energy.
>
> I don't buy that argument at all.  It's much more likely to be something 
> like the reduced air pressure increases the chances that the r/w heads on 
> the hard disk will 'crash' to the disc surface, as someone else mentioned.

There are two different threads going on here.

One is about external fans cooling a hard drive, which my comments
are directed towards.

The other is regarding the Bernoulli effect that recording heads
use to float over the platters.  Since the distance of the head
to the platter surface is related to the atmospheric pressure,
hard drives operating at higher altitudes will see their heads
get closer to the platters' surfaces, which means the chances
for a crash increases.  To work in high-altitude environments,
special hard drives must be constructed so that the disks are
specially pressurized and sealed.


-- 
Eugene
http://www.coxar.pwp.blueyonder.co.uk/