From: schillin@spock.usc.edu   
      
   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 bullshit.  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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