Accessing 'hidden' sectors on hard drives

[Matthew Dillon]

:I was reading recently about a copy protection scheme that stores data in
:sector 32, which is apparently right after the partition info, correct?
:
:The scheme I am looking at claims to defeat Norton Ghost and yet survive a
:format... probably not low-level.  However, they will not reveal the details
:of where the license info is, except to say it is not 'in the filesystem.'
:
:Do these unused, reserved, or 'system' sectors exist on a UFS/FFS hard disk?
:If I am 'dangerously dedicated,' does that extra space go away?  Is there any
:way a copy protection scheme could be devised under FreeBSD that could access
:that area, or another area beyond the reach of the filesystem?
:
:Jonathon McKitrick
:--
:Hoppiness is a good beer.

    Generally speaking trying to write data in such areas is a very bad
    idea.  It is true that on BSD systems UFS tends to leave more room
    available at the beginning of the filesystem then the disklabel actually
    needs.  There might also be dead space between fdisk slices, or at the
    beginning or end of the physical disk (below the first slice or after the
    last slice).  But relying on such areas for a copy protection mechanism
    is a really bad idea.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>