Re: More info on dd?

From: Valdis.Kletnieksat_private
Date: Fri Sep 27 2002 - 08:36:49 PDT


On Fri, 27 Sep 2002 10:57:44 EDT, "Hooper, Justin" <Hooper_Jat_private>  said:

> real-world applications (block size for instance) and whether or not dd can
> copy only files without slack or unallocated space.

No.

dd can't copy only files if you're using it to copy a disk partition, because
it's copying the raw blocks and has *NO* idea what the data means - it could
be a swap partition, or an ext2 filesystem, or an HFS+ filesystem, or ReiserFS,
or NTFS, or... you get the idea.  If you dd a 2G partition, it's 2G of disk
blocks, and that's it.  If you want to skip slack or unallocated space, you'll
need to mount it as a filesystem and then use filesystem-level tools such as
tar or cpio or backup (this of course means you only get the blocks that are
in the filesystem - forensics work is usually interested in blocks that are
no longer allocated....)
-- 
				Valdis Kletnieks
				Computer Systems Senior Engineer
				Virginia Tech






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