Hard drives on 'Deep Space' missons: any idea why they are never used?

Max Power wrote:
Hard drives on 'Deep Space' missions: any idea why they are never used?

I've no direct knowledge, but would think that the heating/cooling
cycles a deep space probe might encounter would be rather difficult on
a disc drive. It is a rather delicate component - certainly compared
with say magtape and definitely so compared to core I would hazzard
a guess that a disc drive requires environmental conditions not too
far from those desired/required by humans.

rick jones
--
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these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

American wrote:

No, the storage mediums are too allergic to magnetic field disturbances
in the solar radiation field, as well as in the vicinity of Jupiter:

Utter bull****. The magnetic fields in the interplanetary medium
are much weaker than the magnetic field at the Earth's surface,
let alone the magnetic field needed to affect a hard drive.

Paul

Paul F. Dietz wrote:
American wrote:

No, the storage mediums are too allergic to magnetic field disturbances
in the solar radiation field, as well as in the vicinity of Jupiter:

Utter bull****. The magnetic fields in the interplanetary medium
are much weaker than the magnetic field at the Earth's surface,
let alone the magnetic field needed to affect a hard drive.

Paul
Yes but what you are forgetting is particles like neutrinos and gamma
rays. They would destroy magnetic disks. They go through everything,
even the astronauts see light flashes when they close their eyes from
bombardment of the inner eye by particles. Space is a nasty place.

--
Linux is just a fancy name for Windows blocker.

Claude Hopper

Claude wrote:
Paul F. Dietz wrote:

American wrote:


No, the storage mediums are too allergic to magnetic field disturbances
in the solar radiation field, as well as in the vicinity of Jupiter:

Utter bull****. The magnetic fields in the interplanetary medium
are much weaker than the magnetic field at the Earth's surface,
let alone the magnetic field needed to affect a hard drive.

Yes but what you are forgetting is particles like neutrinos and gamma
rays. They would destroy magnetic disks.

I'm not 'forgeting' that, since the message I was responding to
said 'magnetic field disturbances'.

In any case, your idea is also bull****. Neutrinos in space will be
utterly insignificant unless you're operating your hard drive
right next to a supernova (in which case neutrino damage will be
the least of your problems). As for gamma radiation doesn't damage
mangetic disks. It might affect the semiconductors in the drive
controller, but magnetic materials are highly radiation resistant.

Just what is this big source of gamma radiation you're worrying
about, btw? Cosmic radiation doses are mostly from charged particles.

Paul

On Sun, 13 Aug 2006 20:15:45 GMT, Claude wrote:

Paul F. Dietz wrote:
American wrote:

No, the storage mediums are too allergic to magnetic field disturbances
in the solar radiation field, as well as in the vicinity of Jupiter:

Utter bull****. The magnetic fields in the interplanetary medium
are much weaker than the magnetic field at the Earth's surface,
let alone the magnetic field needed to affect a hard drive.

Yes but what you are forgetting is particles like neutrinos and gamma
rays. They would destroy magnetic disks. They go through everything,
even the astronauts see light flashes when they close their eyes from
bombardment of the inner eye by particles. Space is a nasty place.

Yes, and I think Paul knows that better than you do.

First off, neutrinos and gamma rays are not "magnetic field disturbances",
so the idiot who said that magnetic field disturbances would knock out
hard drives in space, was dead wrong. There are magnetic fields in
space, and they do get disturbed from time to time, but the magnitude
of those disturbances is generally too small to be a problem for things
like disk drives.

Second, neutrinos and gamma rays are not problems in space. There are
not enough gamma rays in space to matter. And while there are plenty
of neutrinos in space, they don't matter either, on account of they do
not interact with matter. They will go right through an astronaut, or
a disk drive, without having the slightest effect on it. They are,
basically, ghosts. Takes a huge and very sensitive detector to, every
once in a while, actually notice that one exists.

What is a problem in space, are charged particles. High-energy charged
particles in the form of cosmic rays, and lower-energy charged particles
produced by solar storms and trapped in planetary magnetospheres. These
are not gamma rays, not neutrinos, and not magnetic field disturbances.
They are something completely different.

And while they are a danger, they are a danger that can be measured,
quantified, planned for, and dealt with. They do not prevent us from
sending people, or electronics, into deep space. In particular, they
do not prevent us from sending hard drives into deep space. In fact,
I think as far as the space radiation is concerned, hard drives are
less likely to have a problem than the competing solid-state memory
technologies, that if a hard drive suffers a radiation-induced failure
it would most likely be due to radiation effects on the solid-state
electronics of the drive controller rather than the disk itself.


Which pales in comparison to the fact that the hard drive has moving
parts built to precise tolerances, and is thus not a system you want
to send someplace a billion miles from the nearest repairman if you
can possibly help it. We can make do with solid-state memory, using
redundancy and error-correction, so that's mostly what we do.


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John Schilling wrote:
There are not enough gamma rays in space to matter.

Hopefully it stays that way. If one of these things
http://www.astro.psu.edu/users/nnp/grbphys.html ever goes off nearby,
pointed even a little in our direction, we'd be in deep ****.

mark