8mm tapes

[Warren Jones]

joubert at afc-tci.UUCP (Joubert Berger) writes:

>I have a question about 8mm tapes.  Are there reasons not to use the 
>8mm video tapes (i.e Sony 8mm Video which cost $9.00 vs Sony 8mm Data
>Cartrige which cost $18.00)?

I posed just this question to IBM Link support.
This is the answer I received:

| According to a local tape manufacturer, the main difference between
| the two tape grades is that the data grade is more reliable than the
| video grade.  As you know, IBM sells only data grade tapes.  Tape
| strips are made in large sheets.  The center of these sheets is more
| uniform (consistent) than the outer sections.  The inner section is
| also more durable, has less drop out, and less error detection.  This
| part is used for data grade tapes.  The outer section is used for video
| grade tapes.  Also, the tape case is built better for the data grade
| tapes.  You may want to contact 3M Corporation, or some other tape
| manufacturer for more information on this subject.  Thank you.
| 
| =-=-=-=> 02/18/91 <=-=> 13:17:18 <=-=> MAM/AWAUS     <=-=-=-=
| 

On the other hand, my manager believes that data grade tapes and
video tapes come off the same assembly line, and differ only in
the label and the price.  Because management is very concerned with
shaving pennies, we have been using Sony P6-120MP video cartridges,
which we were able to get in lots of 50 for only about $5.00 each.
Before accepting this, I tested them as thoroughly as possible.
I wrote and read a system backup on one tape ~20 times in sucession,
getting a checksum each time.  No errors.  Of the dozens of tapes
we have made in the past 9 months, I don't believe we've lost a
single bit.  We often overwrite tapes repeatedly.  I'm impressed,
but still not 100% comfortable.  When we had some temporary difficulty
reading one data tape (IBM had cleverly changed the block size of
/dev/rmt0 in the 3002 update), I was told by a manager to procede
on the assumption that the unreadable data was worth $50,000.
Is this true wisdom?  Go figure.

Does anyone else have comments?