Question on Backups

[Shawn F. McDonald]

I am trying to set up a procedure to allow us to do incremental backups.
The reason I am trying to do this is because each day we are currently
running a backup on all of the user's files.  This is approximately 80MB
worth of data and an NCR Tower 32/600 streaming tape drive only supports
50MB tapes. ( I have been told this by many people but I am not sure if this
is true. Any comments? )
	
The problem is that I have to change the tape in the morning and backup
the rest of the files that didn't fit on the first tape.  The causes
our system to run very slow while the overflow is being backed up.

What I wanted to do was start running incremental backups after I
have done a full system backup by cpio'ing the files that have
been modified since the full backup.      

I recently posted this question and I have received many
responses on various methods in which to do this.  Thank you very
much for response.  

Now for my questions (finally):
	
	1)  Which would be better, cpio or tar format?  Keep in mind
	    that I will need to restore some files periodically, not
	    the whole tape.

	2)  If I use cpio, can I keep 'appending' each incremental
	    backup until the tape is full?  I am not sure, but I
	    thought that cpio does not allow this since it writes   
	    the header information to the beginning of the tape 
	    only.

	3)  Anybody out there have any nifty ways to keep track of the
	    amount of memory left on a streaming tape besides keeping
	    a running counter of the sizes of the files backed up and
	    then starting all over again when a new tape is inserted?

If anybody could, I would really appreciate any information, ideas, or
procedures that could accomplish these incremental backups.  BTW,
I DON'T have an extra disk drive to back these up to (maybe if I
wish hard enough), otherwise this would be no problem. Instead I 
have to worry about - tape retension, tape insertion, tape capacity, etc.

------------------------------------------------------------------------
Shawn McDonald				mechsfm at tness1.UUCP
SWBT / Network Mechanization		{!killer,!ihnp4,!petro,..}
San Antonio, TX				(512)377-6226