TITLE:              Backup - Tips and Tricks
DOCUMENT ID:        TID14945
DOCUMENT REVISION:  1
DATE:               01APR94
ALERT STATUS:       Yellow
README FOR:         NA

NOVELL PRODUCT and VERSION:
Novell DOS 7

ABSTRACT:
NA

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ISSUE:

Novell DOS 7 Backup - Tips and Tricks

Q - I was backing up my hard disk to diskette and halfway through the
backup, something went wrong.  I want to start the backup again.  Do
I have to start the whole thing all over again, or can I just pick up
where I left off?

A - Novell DOS 7 does not include parameters for the BACKUP command
to pick up where you left off when doing your backup.  One technique
for accomplishing the same thing is described below.  However,
understanding a little bit how BACKUP works with DOS files is
necessary.

DOS files have several attributes, which describe how DOS treats the
files. These attributes are the following:

     Attribute           Code
     ---------------     ----
     Read only           R
     Hidden              H
     System              S
     Archive needed      A

The attribute you are interested in here in this discussion is the
"Archive needed" attribute.  If this attribute is turned on, it
basically informs DOS that the file has changed since it was backed
up last.  Any time you modify a file, DOS sets the "Archive bit" (the
Archive needed attribute) so that BACKUP recognizes the file has
changed.  When BACKUP is run, any file that is backed up gets the
Archive bit turned off.  This way, DOS can keep track of what files
need to be backed up again.

How does this information help my backup?

Let's assume, for this example, that you want to backup all files on
the hard disk C: drive.  The normal backup command would be the
following:

     C:\> BACKUP C:\*.* /S

This command instructs BACKUP to do a backup of all files in all
subdirectories on the hard disk.  As BACKUP runs, it will turn off
the archive bit of any file that is backed up. Another backup command
might look like this:

     C:\> BACKUP C:\*.* /S /M

This tells BACK UP to do a backup of all files in all subdirectories,
as in the preceding example.  However, this time, only files that
have the archive bit set will be backed up.  So, let's assume that
you issued the first command (without the /M) and the backup errored
out on disk 15.  If you used the second command (with the /M), you
would be able to do a backup again without backing up the files that
were successfully backed up on the first 15 diskettes.

The only problem with this method is that other file may exist on the
hard disk that are not backed up, that might not have the archive
attribute set.  In this case, these files would not get backed up. 
The following is a command to solve this problem:

     C:\> ATTRIB C:\*.* +A /S

This command sets the archive bit on all files on the hard disk C:
drive.  You use this command before doing the BACKUP command.  Now,
if the BACKUP runs successfully, everything is fine.  If BACKUP does
not run successfully, then all files that still have the archive bit
set are the files that did not get backed up.  Any file that does not
have the archive bit set was successfully backed up, because the
BACKUP program turned off the archive bit.  Now, after the backup
errors out, we can use the second BACKUP command (with the /M) and it
will back up the rest of the hard disk.  Every time the backup gets
errors, all we have to do is use this BACKUP command, and you will
get the correct files, that haven't been backed up yet.

In summary, use the following two commands every time you want to do
a backup.  Don't use just the BACKUP command:

     C:\> ATTRIB C:\*.* +A /S
     C:\> BACKUP C:\*.* /S

If you get errors, then you can use the following command to get just
the files that didn't get backed up before the error:

     C:\> BACKUP C:\*.* /S /M

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