SUMMARY: 4mm tape quality, interchange problems/followup questions

From: Marc S. Gibian (
Date: Thu Apr 23 1998 - 08:51:36 CDT

I had asked about problems writing 4mm tape with one generation of Sun 4mm drive
and reading that tape with different generations of Sun 4mm drives. While I did
not get truly definite responses, they have stopped coming in so its time for a

Before getting to the points I got in those replies, let me say that this list
is very good at pointing out what you left out of what otherwise seemed to be a
complete problem description. I was asked with OSes and versions are involved. I
am writting on Solaris 2.5, reading on Solaris 2.5, 2.5.1, and a tape duplicator
of unknown make/model.

1. Given 4mm drives may be DDS-1, DDS-2, or DDS-3, tapes SHOULD be upward
compatible but not backward compatible. Thus, a tape written with the old Sun
drives, which appear to be DDS-1, SHOULD be fine when read by a new drive, which
appear to be DDS-2.

Unfortunately, this is exactly what I have been trying to do and where I see
intermitent failures.

2. One person reported it safer to stick with 120m tapes.

I have seen the failures with both 90m and 120m tapes, so I don't see sticking
with 90m tapes resolving the problems.

3. One person stated that they trust only Verbatim tapes, and have seen problems
with Maxell and other non-Verbatim brands.

I've only tried a few Verbatim tapes, so my experience is too limited to know
whether the intermitent problems we see exist when they are used.

My conclusion is that I should go ahead and try Verbatim on my current tape buy
and see what happens. Two followup questions to speed this buy:

1. Do I buy 120m or 90m tapes? The pricing appears about the same, and I have
not seen any compelling information for either choice. All things being equal, I
wouldn't mind having the extra capacity. But are they equivalent for all
essential purposes OTHER than capacity?

2. What dealer/vendor should I use? I have found a couple of vendors on the
network selling these tapes at roughly $3 a tape. This is much lower than many
other vendors, but tape is tape so long as the brand and model match, right?

My thanks to:

Charlie Mengler <>
Dennis Martens <>
Ron Kelley <rkelly@InfoAve.Net>
"Brandon K. Devlin" <>

Marc S. Gibian
COMSYS Information Technology Services phone: (781) 377-6350
PRISM/TFS email:
                           or is it:
                        well, maybe:
              and if all else fails:

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