Alexander Langer writes:
>Wolfgang Solfrank schrieb:

> An extended partition is just as any other MBR partition, having a special
> type (namely 5).  Its first sector is in essence just an MBR, with again up
> to four partitions, but without the code to load the first sector of those
> secondary partitions.  This is the reason that (on PCs) those secondary
> partitions are not bootable (which would be easy to correct if someone would
> modify the standard MBR code to take the offset into account and place it in
> the extended partition's MBR).  

>LILO can boot my Linux, which is on an extended partition!

That's because LILO cheats.  It has the (absolute?) C/H/S addresses of
all the blocks in the target kernel hardcoded into a table in the
bootblock. If you copy a new kernel to the root partition, LILO will
still read in, and jump to, the physical sectors the old kernel used
to reside in.  Unless you rerun lilo to update the c/h/s list, that
is.

Bypassing the MBR and the filesystem semantics this way means LILO is
independent of any given filesystem, and can even boot from secondary
partitions, but the failure modes are just awful.  (It also limits how
big a kernel you can boot and how fragmented it can be.)

[snip]