[syslinux] Custom MBR

J.H. warthog19 at eaglescrag.net
Fri Dec 12 15:14:22 PST 2008

I guess we are all particularly confused by what your trying to do here.
The MBR that syslinux (extlinux specifically since we are talking about
hard drives here) uses is a whopping 440bytes (roughly) and all it does
is load, look for the active partition and load data off of that
partition.  It can then go and chain load to any other partition you
want, boot up Windows, Linux, etc.  The only bit that doesn't live on
the Partition is that small chunk up in the MBR.  So what advantage does
saving that MBR into the beginning of a partition buy you that you
wouldn't actually want it in the MBR proper?

- John 'Warthog9' Hawley

On Fri, 2008-12-12 at 13:11 -0800, YYZ wrote:
> > 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. 
> 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.
> _______________________________________________
> Syslinux mailing list
> Submissions to Syslinux at zytor.com
> Unsubscribe or set options at:
> http://www.zytor.com/mailman/listinfo/syslinux
> Please do not send private replies to mailing list traffic.

More information about the Syslinux mailing list