[comp.sys.amiga] Disk Errors

jones@uv4.eglin.af.mil (Calvin Jones, III) (03/27/90)

"Ralph A. Foy" <raf@prc.unisys.com> writes:

> Further complication:

> I got around it by just doing a "quick" format, but the idea of a bad
> sector sitting out there has me a little worried... Again, any way to
> handle this without re-prepping the drive? 

S T O P !!!!!
 
Do not pass go, do not collect 200 more bytes of PD software!
 
You are sitting on a time bomb.  Your hard drive has an error (unless 
you are lucky enough to have had a power glitch or something) and the 
error *WILL* show up at some later point.
 
Back up everything and do the low-level format (prep).  Build a 
mountlist that sets up the drive as one big partition and format it 
using the AmigaDos format command with the quick option.  Then use one 
of the PD programs that can read the entire disk surface to verify that 
all bad sectors have been mapped out and the entire disk appears good to 
AmigaDos.
 
In the event that the verification program shows that one or more 
sectors/tracks/cylinders are bad, try another low-level format and try 
to mark them properly.  Then verify again.  If you CAN'T get the verify 
program to come up with a clean disk, you can "manually" map out the bad 
sector, but you will lose a whole cylinder when you do it.  You do this 
by partitioning the drive so that the bad sector(s) lie between your 
partitions.  For example, if you cannot map out errors on tracks 322, 
323, and 402, you might partition:
      DH0:  0-321
      DH1:  324-401
      DH2:  403-nnn (nnn is highest cyl).

Another error that is often made is that users will find that a file on 
their drive has developed a read/write error than can't be recovered.  
When this happens, do *NOT* delete that file! Create a directory on the 
same partition called "badfiles" and rename the file to that directory 
so the OS will not try to use this section of the disk again.  If you 
get very many of these, it's time to do the low-level format again!
 
   --- Cal
   //  Cal Jones - Internet:  <Jones@UV4.Eglin.AF.Mil>
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