disklabel writing behavior?

["Thomas Mueller" <mueller6724%bellsouth.net@localhost>]

How does NetBSD disklabel behave when writing a disklabel when the disk 
involved has multiple slices/BIOS partitions?  Does the disklabel go only on 
the NetBSD partition, or can it intrude on another partition where another OS, 
like FreeBSD, Linux or DOS is installed?  Suppose I have a hard disk 
partitioned, with boot manager LILO installed to the MBR:

1: FreeDOS (FAT32) just < 8 GB
2: NetBSD  40 GB
3: Extended partition  50 GB
  5. Linux swap         2 GB
  6. Linux             48 GB
4. FreeBSD             70 GB

Exact partition sizes here are not important, I am just concerned that a change 
to NetBSD disklabel will overwrite the MBR with LILO, might overwrite the 
FreeDOS boot sector, and might write a copy of the NetBSD disklabel to the 
FreeBSD partition.  These concerns are based on actual occurrences even if not 
all details were the same.  I fortunately had a copy of the FreeBSD 
disklabel/bsdlabel saved and was able to restore it.  Further back in time, I 
had an instance where the MBR and DR-DOS 7.03 boot sector were apparently 
messed up; I recovered by booting Linux from the installation CD and rerunning 
lilo, and by booting DR-DOS 7.03 from floppy and running SYS C:

Anyway, it's always a good idea to keep a copy of the partition table and 
disklabels on a separate msdos-formatted disk, can be a floppy or USB stick.

Tom