[Info-vax] BACKUP/IMAGE/EXCLUDE...?

[Bob Koehler]

In article <001c3c2b$0$19573$c3e8da3 at news.astraweb.com>, JF Mezei <jfmezei.spamnot at vaxination.ca> writes:
> Out of curiosity, when one does BACKUP/IMAGE, backup does backup the
> boot block on the disk and is able to set it properly on the target disk.

   Yes.  You can always restore from such a backup and get a bootable
   disk.
 
> Does anyone know how this is actually done ?

   Yes.  The fellows who write and maintain BACKUP know all.
 
> Does the boot block contain information about the file-id as well as its
> physical location on the disk ?
> 
> Or does Backup lookup the block number pointed by the boot block and
> scans indexf.sys to find which file begins at that block so it can know
> its file ID ?

   Certain files have reserved file-id's.  Generally anything that can't
   fit in one of these gets a pointer from one of these.
 
> I take it that Backup then merely flags the file as being the boot block
> so that in a restore operation, once Backup has written the file, it
> will be reminded to set the boot block to that files new location on the
> disk ?
> 
> 
> What about the EFI partition ?  Does the save set header information
> contain some information about the EFI partition so that backup knows
> NOT to use any of the blocks that will be needed so that by the time it
> gets to creating the ODS5 EFI partition file that needs to be allocated
> on those blocks, those blocks will still be available ?

   Not having an IA64, I've nevfer tried this, but I would be aghast at
   VMS BACKUP if it can't make a bootable disk from a bootable disk.