In <14469.1277.729609.506341@acronym.anu.edu.au> Tim Potter (Tim.Potter@anu.edu.au) wrote:
> Hello. I've got a couple of IBM 35.7 GB DeskStar IDE drives which
> seem to confuse Linux and fdisk as they report >65535 cylinders when
> probed.
> hde: IBM-DPTA-353750, 35772MB w/1961kB Cache, CHS=72680/16/63
> hdf: IBM-DPTA-353750, 35772MB w/1961kB Cache, CHS=72680/16/63
> hdg: IBM-DPTA-353750, 35772MB w/1961kB Cache, CHS=72680/16/63
> Now fdisk gets really confused as the HDIO_GETGEO ioctl returns
> (unsigned short)drive->bios_cyl which is equal to 72680 % 65535 = 7145
> cylinders. This is about 10% of the actual drive capacity.
> It's possible to use the fdisk expert menu to fool around with the CHS
> settings and create a usable partition, but afterwards fdisk *still*
> gets things wrong with respect to the actual number of cylinders on
> the drive although by a slightly different margin - 8191.
> Is there any reason why there is a 32-bit limit on the number of
> cylinders apart from the ATAPI spec? (-: It would be nice to have
> Linux support these drives straight off.
-- cut --
struct hd_geometry {
unsigned char heads;
unsigned char sectors;
unsigned short cylinders;
unsigned long start;
};
-- cut --
Looks like someone should carefully track and fix all places where short is
used for number of cylinders (all IDE, SCSI, etc drivers, [cs]fdsik and so on).
Do you volunteer ?
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This archive was generated by hypermail 2b29 : Sun Jan 23 2000 - 21:00:19 EST