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Old October 21st, 2006, 07:32 PM   #1
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Altitude Limit for SR1

"You cannot use the camcorder in places where atmospheric pressure is low (above 3000m)."

From Sony's Japanese website.

http://www.sony.jp/products/Consumer.../sr1-info.html

Fortunatly, that's 9900 feet. and commercial airliners pressurize to 8000 feet.

But climbing mountains... that's another story.

Do any other cameras have altitude limits?
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Old October 21st, 2006, 08:31 PM   #2
 
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All hard drive-based camcorders are limited to less than 10 grand MSL.
All hard drive anything is limited to less than 10grand MSL.

General public doesn't know it, but skydivers sure do. Fastest way I know to kill an iPod is to skydive with it in the mountains where you're typically around 15kMSL or higher.
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Old October 22nd, 2006, 02:35 AM   #3
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So do HDDs blow up beyond 3000M?

If it's like that, all hard drives coming in by truck from Salt Lake City to Denver on I-70 would all blow up?
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Old October 22nd, 2006, 08:21 AM   #4
 
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I'll assume you're being facetious.
All HDD manufacturers warn that their products may fail above 10,000 feet above sea level. Read your specifications on most any HDD you own.
What does SLC/Denver have to do with it?
Is that to say your drive will automatically shred if you cross the line? No. I've jumped with several hard drives, I've also spent a lot of time in Telluride where you're at 12k all day. Drives work. But early failure is expected, and it usually comes faster than slower.

http://www.seagate.com/support/disc/...Use&Safety.htm

http://www.westerndigital.com/en/pro...sp?driveid=244

http://www.moosepeterson.com/gear/fortress.html

Read the altitude specs on any of those, or look at your Mac laptop or iPod manual. ALL of them have operational ratings of not higher than 10k. Non-operational rates vary between 15k and 40k.
I've killed one iPod and killed a couple cheaper HDD units in the past. Himalayan climbers have killed laptops and iPods with some degree of regularity.
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Old October 22nd, 2006, 02:56 PM   #5
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So what is the real cause for these failures?
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Old October 22nd, 2006, 05:43 PM   #6
 
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Air pressure causing a shift in distance between the reader and the platter.
If I remember right, anything shifting more than 3 microbars of airpressure creates trouble, but I could easily have that value wrong. I'm sure someone will correct me if I am.
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Old October 23rd, 2006, 06:21 PM   #7
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Remember....read/write heads "fly" on a film of air, so too little pressure and it crashes into the surface.
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Old October 24th, 2006, 06:48 PM   #8
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Jeez, I think the modern day hard drive needs to be redesigned alltogether.

By the way, this image is irony in all ways:

http://www.sonystyle.ca/html/images/...a7_titlein.jpg
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Last edited by Jack Zhang; October 25th, 2006 at 12:42 AM.
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Old July 4th, 2007, 04:16 PM   #9
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Hmm, somebody out there has to have invented an air-tight hard drive pressurized to sea level that can be taken up into high altitudes. For one thing NASA probably has a need for hard drives that can operate in a vacuum.
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Old October 20th, 2007, 01:56 AM   #10
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If things are still like they were a few years ago, hard drives have a small vent to allow pressure equalization and also contain a small amount of dessicant to keep the incoming air from bringing moisture with it. We're talking rather microscopic quantities of course.

I think there may be more to it than just the thinness of the air - we used to have problems with the ability of the thinner air in Denver to effectively transfer heat from air cooled mainframes and there might be some of this at work here too. As I remember, the cooling capability related to the mass of the air.

Also, be sure to recognize the difference between operational and non-operational limits. You can ship at very low pressure as has been pointed out here.
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Old October 21st, 2007, 11:25 AM   #11
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You'll need sealed and pressurized hard drives for high altitudes. From this link:
"The HDD's spindle system relies on air pressure inside the enclosure to support the heads at their proper flying height while the disk rotates. An HDD requires a certain range of air pressures in order to operate properly. The connection to the external environment and pressure occurs through a small hole in the enclosure (about 0.5 mm in diameter), usually with a carbon filter on the inside (the breather filter, see below). If the air pressure is too low, then there is not enough lift for the flying head, so the head gets too close to the disk, and there is a risk of head crashes and data loss. Specially manufactured sealed and pressurized disks are needed for reliable high-altitude operation, above about 10,000 feet (3,000 m)."
For these reasons, video filming on mount Everest must still rely on miniDV tape.
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Old October 21st, 2007, 12:50 PM   #12
 
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Wow. That article on Everest/production is flawed from so many angles, it's hard to know where to begin. Sony has not "discontinued miniDV tape," for starters.
Try shooting in this Everest environment. I'm one of the people on that particular journey; looking forward to shooting, and I'll be carrying one HC5 and one SR7 on the jump.

Either way, as I'd written earlier, HDD units cannot be relied upon above 3000M/10K feet MSL.
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Old October 21st, 2007, 01:27 PM   #13
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This is almost correct, but there are couple of oversimplifications.

Saying that the disk relies on air pressure to keep the heads separated from the disk surface is technically incorrect. The separation is achieved by a thin film of air that is dragged along by friction with the spinning disk. If the disk stopped spinning, the head would contact the surface regardless of the pressure in the enclosure. At high altitudes, the effect is still present, but it would be more analogous to using an excessively thin motor oil in your engine and would lead to the same kind of failure

Actually, the head suspension is pre-loaded to force the heads against the disk with a known force. Quite a few years ago there were experiments using a truly sealed enclosure filled with Helium in order to reduce air friction which is the main cause of heat in the disk. At the time they were thinking of this as a way to get rotational speeds higher without bigger motors and excessive heat buildup. And of course the head suspensions would have required appropriate modification to deal with the lower lubricating effect of the Helium. As data densities increased, the size of the disk itself could be reduced and this was enough to make todays rotation speeds feasible.

Small gyroscopes (including those for camera stabilization) do actually use Helium filled enclosures to enable the extremely high RPM used without high heat.

In the "old days" when disk drives were the size of large refrigerators, the sliders had small vents and high pressure air was actually piped to small holes around the read/write head itself. As things got smaller and lighter, this could be dispensed with.

I think that modern tape drives rely on the same phenomenon to provide some degree of lubrication between the head and the tape so I'd expect somewhat higher wear rates at high alitudes for tape as well. I think we spec the same 3k meter operational altitude limits for our tape drives. Might be wrong on this, though so I'll check it with the engineers on Monday and let you know. None of this means that the drives won't work in Cuzco, Peru (11+k feet), it just means that they'll wear more quickly and warranty claims might be denied.
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Old October 21st, 2007, 07:58 PM   #14
 
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Whether it is correct or not, I'm telling you from several personal experiences that the drives will not work correctly at altitude, if they'll work at all. I'm consistently at unpressurized altitude (18 times over the past 3 days alone) and the drives, whether in a laptop, iPod, or DR60 will either immediately fail, or fail within a very short period of time.
Whether it's air pressure, lubricant, or little green men with an axe to grind, the drives require pressurized enclosures to work in these environments.
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Old October 21st, 2007, 08:30 PM   #15
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Doug,

Sorry - my response wasn't to your post but to the post before it that quoted the Wikipedia article! Yours came in while I was writing mine!

Sorry for any confusion. I certainly agree with you that regular drives are not intended to work at altitude.

On the other hand, neither are tape drives although the failure rate would probably not increase as much as for a disk drive.
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