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| -rw-r--r-- | docs/Partition-ends-after-end-of-disk.txt | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/docs/Partition-ends-after-end-of-disk.txt b/docs/Partition-ends-after-end-of-disk.txt new file mode 100644 index 000000000..d96167bac --- /dev/null +++ b/docs/Partition-ends-after-end-of-disk.txt @@ -0,0 +1,66 @@ + Cylinder/Head/Size Hell Is Not Over + $Id$ + + + +Nowadays, you can boot Linux without every relying on CHS +(Cylinder/Head/Size): + +- CHS information on partition table is obsolete and not used anymore.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 32bits linear + addressing 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?) + (doesn't like it, what error message?) + - 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 + - parted (what about diskdruid??) + +- 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. + + |