Messages in this thread |  | | From | Matthias Urlichs <> | Subject | Re: 520 byte sectors - any ideas? | Date | Sun, 26 May 1996 06:45:51 +0100 |
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In linux.dev.kernel, article <01I4OVL7PA02EQOMZW@CRF.IT>, a.vignani@crf.it writes: > > A friend of mine got an IBM662 SCSI hard disk coming from an IBM AS/400 > system and we tried to install and read it on a Linux system, to no avail. > > Seems that these disks are low-level formatted with a 520-byte sector > size, which is correctly recognized by Linux on startup. [...]
Ahh. Somebody else had the bright idea to use 512-byte sectors plus a few bytes for identifying the sector in case of crash.
It's a rather good idea, IMHO, except that it creates problems left and right. (Left: Most disks can only be reformatted witzh powers-of-two sizes, right: disks with weird block sizes don't work most other places.)
It should be possible to modify the SCSI driver to r/w the excess data from/to some Random Area, given either an adapter which can do scatter/gather or somebody who is willing to copy the block around once again, but there's a better solution: Reformat.
> this is an unsupported size; Linux allows only 256,512 and 1024-byte > sectors. There are so many >>9 and <<9 in the code I really doubt it > could be easily modified. > Besides, anything with a sector size != 512 won't boot with LILO.
> Anybody out there had prior encounters with such disks? Any ideas? > Yes. Get a reasonable SCSI control/formatting program and reformat the thing with 512-byte sectors.
Don't ask me which program to use -- whenever I have that problem, I just grab the Mac laptop and startup HDT, a rather nice program to control just about everything your disk can do. -- Matthias Urlichs
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