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Number   :  53
Date     :  2001-05-17
Author   :  Jim Witherspoon
Subject  :  Using XXCOPY to Back Up to CDRW
Size(KB) :  2


Some thoughts on using XXCOPY to back up to CDRW. I am just going from
memory here, so if I make any misstatements of fact, please correct me!

If at all possible, I'd like to back up to CDRW in such a way that I can
simply copy the files from the CDRW, without having to go through a
"restore" process. This is one thing that attracts me to XXCOPY as a backup
solution.

These days, we have 40GB or bigger HDs, and CDs hold 650 (?) MB. It would
take a lot of CDs to back up a 40GB HD. Because of this, it makes sense to
me to break up the contents of the HD into smaller subsets for backup and
restore. XXCOPY would be good for this, with its many methods for
including/excluding files.

The LFN problem - the way I understand it, files copied to CDs are limited
to 64 character filenames instead of 256 characters allowed by Windows. I
have run into this limitation while using Easy CD Creator, but I haven't
used DirectCD, so I don't know if the same problem exists with DirectCD.

The SFN problem - if I remember correctly, SFNs aren't copied to CDRW at
all. Only the LFN is preserved (with the 64-character limitation).

When I used XCOPY to clone a disk, I ran into the problem that two
directories swapped SFNs on the cloned disk. One of these directories
contained NAVAP.VXD. And because the registry referenced NAVAP.VXD by its
SFN, it was unable to find NAVAP.VXD on the cloned disk! It is because of
this sort of thing that I want to be careful to preserve both LFNs and SFNs
in the process of backup and restore. The registry often refers to files by
their SFNs!

Kan has laid out an ingenious method of duplicating a directory tree,
including the same files, LFNs, SFNs, and date/time stamps - except that all
the "files" in the duplicate structure are zero-byte files! This duplicate
tree could be kept current pretty easily. You could use this duplicate tree
to save LFNs, SFNs, and date/time stamps before you back up to CDs. Then,
when you restore the files from CD, you could use this duplicate tree to
restore the SFNs, by using the /NS switch. Am I right about this, Kan? You
will find this method at the bottom of the "cookbook" page:

http://www.xxcopy.com/xxcopy/xxcopy11.htm

But ... if you lose the "duplicate tree" itself in a disk crash, you
obviously lose the ability to restore the SFNs. So, it would be good to be
able to save the "duplicate tree" itself. You can't save it to the CD - the
SFNs won't be preserved. A floppy may not be big enough to hold the
duplicate tree. A second HD would be.

Also, if you put a duplicate tree of zero-byte files on the same HD, you'll
need to deal with the cyclic copy problem, using the /CCY switch.

I also have the idea of putting the duplicate tree in a ZIP file, but from
what I can tell, only LFNs are stored in a ZIP file. Am I right about that?

jim



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