An alternate data path is
a path you define as a secondary storage location for the .dr file
that is created after you run a full backup job.
Symantec recommends you
point the alternate data path to a storage location that is on a
different physical computer or hard drive, including computers that
are attached to a network. Do not use a floppy diskette as the
alternate data path because the .dr file may not fit.
you point the alternative data path to a remote computer, the logon
account that is used to run the full backup must have proper logon
credentials to the remote computer.