older CHS interface. This works around stupid BIOSs who report that
int13 extensions are present and functional, but fail when you actually
use them. Like Adaptec SCSI BIOSs.
For the bootselector, there was no space to get the CHS info from
the BIOS. Instead, use a flag that can be set by fdisk. fdisk will
set it if one of the partitions on the disk is out of CHS reach
for this disk/BIOS, so that the bootselector will use int13 extensions.
This isn't so bad, because it needs to be configured via fdisk anyway.
Change the mbr manualpage to reflect some shorter error messages.
effect (i386 only of course). Also change one branch in the
bootselector code to an explicit 16 bit one, and check both
the boot menu and partition tables to see if the partition
requested by the user should be booted. This check just in case,
should the bootselector menu and partition table get out of sync
somehow. (mmm, bytesqueezing)
