On Mon, 18 Dec 1995, Shawn Pearce wrote:

> Lest we not forget how a mac boots - floppy1, then floppy2, then SCSI
> devices.  Starts at the HIGHEST bus, HIGHEST ID, and works down until it
> finds a bootable disk - if the startup disk isn't set, well then, it would
> do just this.  If you make sure that the disk you wanna boot is the highest
> SCSI # on the chain, it'll boot there.
> 
Not quite.

If there is no bootable floppy disks, it boots from the hard disk.
But not necessarily from the disk with the highest id, in fact normally 
you boot the internal disk, i.e. SCSI id 0 even if there are external 
disks with higher SCSI id's.

This may however be changed by using the "Startup disk" control panel to
select another default boot disk. In fact this gives the Macintosh user
a choice of boot device that the PC user does not have.

If the selected hard disk is not present or if it is not bootable, then
the SCSI bus is searched for another bootable disk.

Add to this that in the case of partitioned disks, I think that the Mac
selects the boot partition by taking the first according to a 
lexicographic sorting of their names.

regards
Erik Bertelsen
UNI-C.