[MaxGuru]

I see the specs for the G5 lists its operating limits for temperature and such, but also limits its operating altitude to 10,000 feet. Now I am not going to drag my G5 to the top of Pikes Peak but I was wondering why there was a limit?

The only thing I could imagine being affected by altitude is the new cooling system. The closed loop of liquid could expand and rupture. Are there other components in a G5 that could fail at higher altitudes?

[iCol]

The fluid bearings of the HDD?

[reader50]

Air becomes less dense at higher altitudes, and therefore can cool less. If you go high enough, you reach vacuum, which does not cool at all. However, I would not think 10,000 feet is enough to seriously degrade the cooling system.

It may be a matter of their not testing/calibrating the units for operation above 10,000 feet rather than any expected failure at that altitude.

[Randman]

Plus, you'd need a longer extension cord...

[KS-Jayhawk]

Originally posted by Randman:
Plus, you'd need a longer extension cord...

LOL!

[villalobos]

Originally posted by MaxGuru:
I see the specs for the G5 lists its operating limits for temperature and such, but also limits its operating altitude to 10,000 feet. Now I am not going to drag my G5 to the top of Pikes Peak but I was wondering why there was a limit?

The only thing I could imagine being affected by altitude is the new cooling system. The closed loop of liquid could expand and rupture. Are there other components in a G5 that could fail at higher altitudes?

Every computer from Apple has this limitation. I don't think this is an issue and as said before they probably never tested a computer long enough at higher altitudes to guarantee it works.
Which then reminds me of that commercial for Centrino where I think oen can see two alpinists on top of a mountain using a computer or something like that. Anyhoo, I tried to find some specs on stupid Dell POS website but was unsuccessful.
For what it's worth, my Ibook performs very well in a plane at 37,000 feet.

villa

[MaxGuru]

Originally posted by villalobos:
For what it's worth, my Ibook performs very well in a plane at 37,000 feet.

I believe most airlines keep cabin altitudes around 5000 to 8000 feet. There are towns at over 9000 feet. Pikes Peak is 14,100 feet. I bet the Macs will work above 10K, I am sure they just have not been tested for high altitudes.

[Freeflyer]

Hard drive altitude operating limits to do with the air density.

A hard drive keeps the head off the platter by balancing it on a cushion of air. The speed of the platter turning generates the air pressure that holds the head off. As the air density thins as you go higher, there will come a point where the density is not sufficient to create a reliable cushion, and you risk a head crash, that can render your drive unusable.

This is also why you should never tape over the little hole in the hard drive casing. You would create a pressure inbalance as you change altitude and possible damage the case due to it warping.

I'm guessing that if the limit is 10,000' then there is a healthy margin built in. I used my ipod at 15000 in the himalaya, and also my xdrive for downloading my photos from the digital camera. However, for the few days we were higher (up to 18500) I just used the compact flash cards.

It was this reason that I didn't buy compact flash microdrives for the trip, as they have the same hard drive limitation.

Cheers,

J.

[Shaktai]

Typically all the specs are for "known" safe operating limits. They state them to limit their liability because some folks like to "push the limit". You can probably operate beyond 10,000 feet, or beyond other listed specs (within reason), but Apple won't warranty it or accept responsibility for safe operation.

Besides, it is really tough getting a decent broadband connection above 10,000 feet.

[tooki]

Freeflyer's description is the correct one. Hard drives require air to operate. The other components don't really care.

They make special sealed hard disks for low-air-pressure environments.

tooki

[Rev-O]

Originally posted by reader50:
Air becomes less dense at higher altitudes, and therefore can cool less. If you go high enough, you reach vacuum, which does not cool at all. However, I would not think 10,000 feet is enough to seriously degrade the cooling system.
It may be a matter of their not testing/calibrating the units for operation above 10,000 feet rather than any expected failure at that altitude.

Yes, air becomes less dense, but above 10000 feet the ambient temperature tends to be a bit chilly, which I'd assume would offset the pressure diff...
At any rate, I won't be moving from Parker Colorado to Leadville Colorado now... cross that one off my list...

_Leadville sits in a high mountain valley surrounded by snow-capped peaks. In fact, it's North America's highest incorporated city at a lofty perch of 10,430 feet. With 310 days of sunshine each year and summer temperatures seldom over 80 degrees.

... Seldom over 80 degrees... no sh!t! Every time I've been there it was windy a freezing! They do have Mount Massive golf course tho, which is s'posed to be the highest 9 holer in North America...

[Eug Wanker]

Originally posted by Freeflyer:
Hard drive altitude operating limits to do with the air density.

A hard drive keeps the head off the platter by balancing it on a cushion of air. The speed of the platter turning generates the air pressure that holds the head off. As the air density thins as you go higher, there will come a point where the density is not sufficient to create a reliable cushion, and you risk a head crash, that can render your drive unusable.

This is also why you should never tape over the little hole in the hard drive casing. You would create a pressure inbalance as you change altitude and possible damage the case due to it warping.

I'm guessing that if the limit is 10,000' then there is a healthy margin built in. I used my ipod at 15000 in the himalaya, and also my xdrive for downloading my photos from the digital camera. However, for the few days we were higher (up to 18500) I just used the compact flash cards.

It was this reason that I didn't buy compact flash microdrives for the trip, as they have the same hard drive limitation.

To expand on this... About the MicroDrive (which is also found in the iPod mini):

The Microdrive does need "AIR" to float the heads and typically above 10,000 ft the mass of the air is too low and the drive requires a pressurized environment similar to an aircraft or spacecraft. At high altitude the air bearings begin to loose support from the air molecules needed to provide the "air bearing" for the Negative Air Bearing Surface (NABS) design of the head. If this "air bearing" is removed or lowered (as is the case with low density air at high altitudes) the head damages the media and you could have loss of data. The drive is vented to maintain equal pressure inside and outside to provide the air and to maintain the same pressure. This eliminates the need for sealed and rigid covers that can tolerate pressure differences.

The OEM Functional specification defines the warranty range for operating altitude as 3,000 M or 9,000 ft (3ft/M). If the customer is mountain climbing with a GPS or digital camera above 9,000 ft the drive might have problems. (Mt Fuji ~ +13,000ft, Mt Raineer ~ +14,000 ft). Please note, this is the operating environment. Non operation at high altitudes, including vacuum, have no ill effects on the microdrive. Within passenger aircraft, the cabin is pressurized to 9-10,000 feet hence the drive would experience no difficulty operating in an aircraft cruising at 35-45,000 ft !

BTW, I'm not sure I'd want the average person from Philly to be computing too much at much over 10000 feet, since that's when things like high altitude pulmonary edema start to occur.

[MaxGuru]

Originally posted by Eug Wanker:
BTW, I'm not sure I'd want the average person from Philly to be computing too much at much over 10000 feet, since that's when things like high altitude pulmonary edema start to occur.

I wasn't planning on using my G5 much above my current altitude of 400'. I was just curious about the limitation. I have been to high altitudes in Colorado and in an Air Force altitude chamber. These experiences sparked my interest in the topic. I would like to thank everyone for their enlightening comments.