Messages in this thread |  | | From | "Nicholas J. Leon" <> | Subject | Re: SCSI Sector Size Problem | Date | Fri, 1 Nov 1996 20:24:51 -0500 (EST) |
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Philip Blundell was overheard whispering ... # # On Fri, 1 Nov 1996, Nicholas J. Leon wrote: # # > # mke2fs will do bad-block checking if you use the -c option. This, like # > # MS-DOS reads the entire disk drive during its high-level format. The # > # problem is that this doesn't catch all errors. # > # # > # > It doesn't even catch the errors it reports. I have to disagree, # > mke2fs (with the -c option) doesn't do anything about the bad blocks. # > # > Example: I was reformatting a drive the other day and had a HOST of # > errors. In one window I had a "tail -f /var/log/kernel" running, # > watching the errors appear: # > # > hdb: read_intr: status=0x59 { DriveReady SeekComplete DataRequest Error } # > hdb: read_intr: error=0x40 { UncorrectableError }, LBAsect=306946, sector=306945 # > end_request: I/O error, dev 03:41, sector 306945 # > # > Then after all is said and done, I do a "dd if=/dev/zero of=/dev/hdb" # > and sure enough, I get errors in the exact same locations. # > # > If mke2fs was mapping (or marking) those blocks away, I wouldn't get # > the error again, would I? Or am I missing something vital here? # # You're missing the point. mke2fs doesn't remap the sectors, because # there's no generic way to do it (and many drives can't). Nor can it make # them magically go away. All it does is mark them as bad in the # _filesystem_ so that no data will be stored there. If you do "dd # if=/dev/hdb" you bypass the filesystem layer altogether, and so any bad # blocks marked there will be ignored. #
Oops! The second part of my argument (which I apparently forgot) was that I then remade the filesystem (to compare the bad sectors, *MOSTLY* the same) and then
cat /dev/zero > /mnt/foo
and it also generated the same errors??
Sorry 'bout that! N! ------------------------------------------------------------------------------ Nicholas J. Leon nicholas@binary9.net "Elegance through Simplicity" http://www.binary9.net/nicholas Binary 9 offers free mail and web storage to certain individuals and groups.
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