Cylinder/Head/Size Hell Is Not Over pixel@mandrakesoft.com $Date: 2002-08-28 07:54:19 -0400 (Wed, 28 Aug 2002) $ Nowadays, you can boot Linux without ever relying on CHS (Cylinder/Head/Size): - CHS information on partition table is obsolete and not used anymore. It was causing the 1024th cylinder limitation: - disallowing partitions above 8GiG. Problem overcome using 28bits Linear Block Addressing (LBA) in partition table. - disallowing to boot on partition above 8GiG (due to int13 limitation used in bootloaders). Problem overcome using int13 extensions (EDD) Logical CHS (Cylinder/Head/Size) and physical CHS are not related anymore. Especially the size of a hard drive is not a multiple of the number of Cylinders. The problem is that many tools still rely somewhat heavily on CHS information. - most tools adjust partitions on cylinder boundary - some tools compute the size of the disk based on CHS (eg: fdisk) Resulting problems in various tools: - last partition not cylinder boundary adjusted, and overrun CHS computed size - fdisk > Total allocated sectors %d greater than the maximum %d - cfdisk (need confirmation) > FATAL ERROR: Bad primary partition %d: Partition ends after end-of-disk or > FATAL ERROR: Bad logical partition %d: Partition ends after end-of-disk - Partition Magic (version?) > Error #109: Partition ends after end of disk - Windows <= 98se, Windows Me (doesn't like it, what error message?) Tools handling it correctly: - parted and so diskdruid in RedHat >= 7.2 (or is it 7.x?) - diskdrake >= Mandrake 8.2 - Windows XP (need confirmation) Tools using the full size of the disk, and so causing pbs with fdisk/cfdisk/...: - diskdrake == Mandrake 8.2 - disagreement between CHS and linear address - parted > "Warning: Unable to align partition properly. This probably means that > another partitioning tool generated an > incorrect partition table, because it didn't have the correct BIOS > geometry. It is safe to ignore,but > ignoring may cause (fixable) problems with some boot loaders. > Ignore Cancel ? C - lilo > Warning: Kernel & BIOS return differing head/sector geometries for device 0x80 > Kernel: 38792 cylinders, 16 heads, 63 sectors > BIOS: 1023 cylinders, 255 heads, 63 sectors > Device 0x2100: Inconsistent partition table, 2nd entry > CHS address in PT: 48:0:1 --> LBA (771120) > LBA address in PT: 48384 --> CHS (3:3:1) > The partition table is *NOT* being adjusted.