The blocks were not bad when I first formatted the disk for MacBSD (under
1.1).  I've run for at least 6 months of light (not constant, say every
weekend or so) use on 1.1 without a single medium error like this.  I
installed a new kernel (NFS_22 I believe) and almost immediately began
seeing this media error.  That is when I reformatted the disk (and ran
several extensive tests on it which reported no errors) and installed
1.2_beta on it.  It ran okay for about a week or so and then the media
errors cropped up again.  The sectors I'm seeing now are quite different
than the ones I first saw.

Also, the errors that I'm seeing a quite random, wouldn't a head crash tend
to effect blocks in one specific location on the disk??  I'm getting at
least 20 bad blocks, wouldn't at least a couple of them be contiguous, or
atleast near each other.  None of them seem to be even very close.  Could
some part of the netbsd kernel other than the scsi driver have changed
between 1.1 and 1.2_beta that might cause a problem like this?  I don't
think they're timing errors because it isn't usually filesystem corruption
its usually the inability to write to or read from the files on disk
("input/output error").

But really, I don't care what's going on (I don't want to assign blame, or
imply that you made a mistake or anything like that), I just want it not to
happen.  Am I safe just running fsck and letting it take care of the bad
blocks when it finds them or should I be doing something more drastic???
This problem is really quite debilitating; I'm loosing a couple files a
day.

Also, aren't modern SCSI drives supposed to automatically remap bad blocks??

Thanks a bunch for your help...

-c


1At 6:04 PM 8/29/96, Scott Reynolds wrote:
>On Thu, 29 Aug 1996, Chris Mason wrote:
>
>> MacOS formatter utils report that indeed these are defective blocks, but
>> when I reformatted the drive the last time trough, the defective block list
>> was reset and the util reported no errors.  In other words, somehow MacBSD
>> is corrupting the disk.
>
>This conclusion is incorrect.  If the blocks were bad before the format,
>there is every reason to believe that the blocks are _still_ bad, whether
>they are marked as such by the formatter utility or not.  Another
>possibility is a head crash on the disk.  In any event, it is simply not
>possible that the SCSI driver -- be it ncrscsi or sbc -- is causing medium
>errors.


 _____________________________________________________________________
|Christopher Mason - cmason@nyx.net  cmason@nando.net  cmason@cmu.edu |
|"You can always count on a murderer for a fancy prose style."-Nabokov|
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~