[syslinux] Custom MBR

[Ferenc Wagner]

YYZ <yyz01 at yahoo.com> writes:

>> So in other words, the MBR would boot a partition designated by data
>> stored on the disk, but instead of using the standard mechanism for
>> this, you'd have it use some new, nonstandard mechanism that nothing
>> else supports.
>
>> Why?
>
> Which partition to boot is encoded within the MBR itself during the
> installation.

The standard mechanism for this is setting the bootable flag.

> There is nothing non-standard about this and this is not incompatible
> with any other software (grub already does this). This “standard”
> approach dates back to the time when one had to rely solely on MBR
> code as boot manager and use fdisk or similar tool while booted in one
> OS to switch to the other OS by activating the other partition. With
> modern multi-boot managers, you can decide at boot time which
> partition to boot and they don’t rely on the active flag in MBR at
> all. The catch is that whenever you start your system, the control
> should somehow get transferred to the boot manager wherever it resides
> (unused sectors of track0, a dedicated boot partition, etc.). This is
> what I’m asking for – I would like to install syslinux on any
> partition of my choice and would like to boot into syslinux regardless
> of which partition is active. From syslinux, I can always boot any
> partition I want by loading its boot sector.

Have a look at the mbr package in Debian.  That has some bells and
whistles, like selecting a partition or floppy at boot time with
timeout to a preset default.
-- 
Regards,
Feri.