Hello, On 03/09/2010 06:22 PM, Tomasz Palac wrote: >> Using custom geometry is a good way to trick a partitioner which >> partitions based on CHS alignment to align to larger units but it >> isn't meaningful outside of that. If CHS dosen't follow 255*63, a lot >> of code (firmware, BIOS, boot loader, OS...) will just assume CHS is >> incorrect. > > As of firmware, Large Disk Howto states that a lot of SCSI host > adapters are using 64/32 geometry (at least for disks smaller than 8 > GiB). If BIOS supports EDD (INT13h Extensions), then disk geometry > is irrelevant. Yes, the geometry is basically arbitrary values which can be queried using a BIOS call and the reason why SCSI hosts can choose them is they implement BIOS extensions themselves. > If not, then geometry can be read from partition table. >From where? > The only problem with 64/32 geometry is 1 GiB (as opposed to 8 GiB) > limit for boot partition (without using EDD). The same applies to > boot loaders. Modern OSes don't use CHS. For modern OSes, geometry doesn't matter at all. Older ones are the ones having problems (I've been corrected: XP seems okay while 2000 depends on CHS). Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
