* [9fans] bug report : disk/fdisk
@ 2023-06-10 14:51 ibrahim via 9fans
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From: ibrahim via 9fans @ 2023-06-10 14:51 UTC (permalink / raw)
To: 9fans
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After creating an image file with :
dd
disk/mbr
disk/fdisk
disk/prep
the resulting partition table in the mbr is buggy :
the chs values in the mbr are incompatible with bios.
bios uses the formula (c*H+h)*S+s-1 to calculate the lba values with H=256, S=63 while c (cylinder), h(head), s(sector) are the values from chs entries in the mbr partition table.
disk/fdisk uses the same formula while setting H=64, S=32.
If you write this image to real Hardware (HDD, USB-Sticks) some bios won't boot from such media especially if your boot drive has a size less than 8GB cause for media with sizes less than this size some bios'es use CHS addressing and some verify that sector id's from chs and lba are equal.
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