[syslinux] BIOS disk geometry and Linux 2.6

[ganapathy murali krishnan]

> None that I know of.  I know someone on this list (Murali?) is 
> successfully using it for some installation stuff.

If I remember right something might use the first 4 sectors. I dont 
remember what, and it is only a vague memory. So I use sector 6. Anyway, 
now a days hard disks are large enough that sector 6 is still in track 
0, and track 0 has no use except for the MBR.I use it to decide the 
exact image which isolinux must boot into. I have had no problems with 
that so far.

Here is another sick hack. Isn't the BIOS geometry stored in a fixed 
location in physical memory? Then using /dev/mem you get access to RAW 
virtual memory, and if I recall my OS classes correctly, any virtual 
memory mapping will preserve low memory. So from within linux you get 
access to the BIOS data structures.

However I think, writing a COMBOOT and passing this information in a 
custom boot time option and using it inside linux seems less of a hack.

I always thought that drive 0x80 is either /dev/hda or /dev/sda. Since 
in most cases there is no SCSI drives, the mapping between 0x8{0,1,2,3} 
to /dev/hd{a,b,c,d} was trivial. Hmmm. You always keep learning stuff.

I am really interested in the outcome of this thread, though it doesn't 
apply to me. I just use linux to partition and format all the partitions 
and run the windows installer from DOS.

- Murali