Should we reuse mag tapes?

[res at ihlpl.UUCP]

In response to:

> >   The question is:  Is it safe to reuse mag tapes  for  important  data  or
> >   should we use brand new tapes when storing critical information?
> >
> >   Would someone have a strong feeling, based on experience or data, one way
> >   or  the other?  I know that the whole idea of using mag tapes is that you
> >   can reuse them a good number of times,  but  I  have  also  heard  people
> >   saying that valuable info should go on virgin tapes.
> 
> It takes a LOT of uses to wear a tape out.  I would guess somewhere in
> the hundred range or so...

While working on a tape controller for the AT&T 3B5 and 3B15 computers
we used one tape for soak testing for many days.  All told, I believe
it racked up on the order of 500 hours of use without exhibiting a
reproducible failure (we had to retire it when it got knocked from atop a 
machine and the reel ended up in three pieces.  The tape was Graham
Ultimag -- expensive, but it did the job for us very nicely.

On the other hand, our Lab Administration people once got a batch of
tape that the Purchasing Department must have got such a deal on.  Ten
passes over the head and the stuff was ready to be scrapped.  After
trying to use it for a short while they shipped it back to the
distributor and got some of the stuff that they ordered in the first
place.

So, how long a tape will last will depend on the initial quality 
(there are lots of good brands out there -- Graham being one of my
personal favorites, but not the only one by any means) and on the care
given the tape when you use it.

					Rich Strebendt
					...!ihnp4!iwsl6!res