Special laptop hard drive for aircraft use

There is no way to park a drive that has heads riding on the surface.
That's been the way nearly all disk drives work since the mid-1980s. I
believe the technology was invented by IBM in their San Jose disk facility.




Peter Duniho wrote:
"Stubby" wrote in message
. ..
My understanding is that modern disks have the heads riding in contact
with the surface.
Your understanding is incorrect.

Why is there no defined "Landing Zone" on the current crop of drives?

Non-sequitur.

First, why would you think that "there is no defined 'Landing Zone' on the
current crop of drives"? Second, in what way does the presence or lack
thereof of a "Landing Zone" have to do with whether the heads contact the
surface during normal operation?

The landing zone is a place where the heads can rest when they are not being
used to read or write data from or to the disk platters, and of course to
"park" the heads when the drive is shut down. It has nothing to do with how
the heads are supported when actually accessing the data on the platters.

Pete

"Stubby" wrote in message
. ..
There is no way to park a drive that has heads riding on the surface.

Modern drives don't have heads riding on the surface. They all "fly" above
the surface, on a very thin cushion of air. That's the reason that
high-altitude operation is a problem.

Are you saying that you have a reference that says there is no defined
landing zone on the current crop of drives, and thus you infer that because
of that, the head are in contact with the platters?

I'm really having a hard time trying to figure out what your point is. You
don't appear to understand how modern drives work, but at the same time all
of your posts are so brief, and so seemingly irrelevant to the topic at
hand, it''s difficult to understand what it is you are actually trying to
say.

Pete

On 2006-06-05, Stubby wrote:
There is no way to park a drive that has heads riding on the surface.
That's been the way nearly all disk drives work since the mid-1980s. I
believe the technology was invented by IBM in their San Jose disk facility.

Modern drives are voice-coil actuated and do not need to be "parked" or
"landed". When the power to the voice coil goes away, the head retracts
*completely off the disk surface* into small plastic storage grooves
just off the outer edge of the disk. There may be slight design
differences - but if you take the lid off a hard drive that's what
you'll see (obviously, don't take the lid off a hard drive you want to
keep using).

--
Yes, the Reply-To email address is valid.
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de

I'm a bit of an armchair astronomer so I follow the various astronomy
groups... Astronomers who work at the high altitude observatories
around the world use laptops all the time for data logging, capturing
pictures off the telescope camera, controlling the telescope, etc...
These observatories are above 10,000 feet... The astronomers have no
hard drive problems I am aware of... The OP is repeating old wives
tales without any real knowledge...

denny

On 6 Jun 2006 04:09:55 -0700, "Denny" wrote:

I'm a bit of an armchair astronomer so I follow the various astronomy
groups... Astronomers who work at the high altitude observatories
around the world use laptops all the time for data logging, capturing
pictures off the telescope camera, controlling the telescope, etc...
These observatories are above 10,000 feet... The astronomers have no
hard drive problems I am aware of... The OP is repeating old wives
tales without any real knowledge...

HDD crash due to density altitude is a real problem, as the heads
float above the platter on a cushion of air. Higher DA = less dense
air = easier to contact the platter.

Having said that, I have a 40G drive on my tablet PC. I regularly fly
at 11.5k in an unpressurized, and have had zero problems.

I fly my turbo mooney routinely in the mid-teens and I wasn't even
looking at tablets because of this issue - thanks for pointing it out!


--
wingslevel
Posted at www.flight.org

On Wed, 7 Jun 2006 12:41:46 +1000, wingslevel
wingslevel.290goz@flight_org wrote:


I fly my turbo mooney routinely in the mid-teens and I wasn't even
looking at tablets because of this issue - thanks for pointing it out!

Welcome. It certainly is not a guarantee, but I did want to point
that at least one of us has been using HDDs at reasonable altitudes
for a few years successfully.

I think what we need is a turbo-normalized hard drive.

Yeah, that's the ticket.

"Denny" wrote in message
oups.com...
[...]
These observatories are above 10,000 feet... The astronomers have no
hard drive problems I am aware of... The OP is repeating old wives
tales without any real knowledge...

Drive manufacturers often specifically state a maximum elevation for use of
their drives, because the issue *is* real.

It is true that, with a design maximum elevation of 10K, and a failure mode
that is not immediate, one can use a hard drive above 10K for some period of
time without it crashing (for example, at 10,001 feet you're unlikely to
ever have a problem). But that doesn't mean there's no issue. It just
means the issue isn't generally catastrophic.

And why would you be aware of their hard drive problems anyway? It's not
like the drive is necessarily going to fail *while* above 10K feet. It can
easily be damaged at altitude, and then not actually show signs of failure
until the computer is back at a normal altitude. Do these astronomers
report all of their technical problems, including hardware failures, to you?

Pete