Do reliable 8mm (Exabyte drive) tapes exist?

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Chris Metzl » Sat, 03 Sep 1994 08:41:48



Hi.  In my research group, we back up as frequently as we can, but still
run into problems because of the unreliability of our backups.  We use
an Exabyte 8200 8mm drive.  We go through 8mm tapes like crazy, because
they keep dying with media errors after minimal use.

We use pre*ly Maxell and Fuji (112m length) tapes, because that's what
we can get from University Stores or local vendors.  But quite frequently,
these things are dead after only two "backup-catalog" runs.  Today, I needed
to retrieve a file from tape, and had to go three backups back to get it,
because the tapes kept failing with "media errors."  In the past, it's been
impossible to retrieve files, because all the backups of a certain disk were
shot.

Thinking that maybe the Exabyte drive has problems, I replaced it with a new
one.  The problem persists.  I can only presume that I'm buying terrible tapes.
Who makes good ones?  In what lengths?  Where do I find them, and how much
might they cost?

To keep any discussion from cluttering up all three newsgroups I've cross-posted
this to, please email me with any advice you have, and I'll post a summary.

Thanks much.  This is really driving me crazy.

--
Chris Metzler
Department of Physics, University of Michigan           313-764-4607 (office)
Randall Lab, 500 E. University                          313-996-9249 (home)

"If we must err, let us err on the side of personal freedom." -- T. Jefferson

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Peter Whittak » Sat, 03 Sep 1994 23:29:49




>Hi.  In my research group, we back up as frequently as we can, but still
>run into problems because of the unreliability of our backups.  We use
>an Exabyte 8200 8mm drive.  We go through 8mm tapes like crazy, because
>they keep dying with media errors after minimal use.

The Exabyte 8200 drives are less reliable than the Exabyte 8500 drives;
you might want to consider upgrading.  Also, in my experience "media
error" can indicate drive problems.  Since Exabyte drives are repackaged
and sold by everyone from here to Lower Slobovia, vendor quality, and
drive packaging quality, varies greatly.  Another cause of bogus medua
errors, which can lead to the problems you describe, is mentioned below.

An example of vendor quality problems:  one 8mm reseller - who fixed
this problem very quickly once they realized they had it - set up their
drives so that the fans sucked air over the tape heads, resulting in
great big * dust bunnies that caused monstrous grief.  They fixed
this problem so that the dust was expelled instead of sucked in.

Note that if "media errors" continue, you will likely start getting
hardware errors.  This is due to the "flaking scum" described below.
Once you get hardware errors, your heads will need replacing.

Quote:>We use pre*ly Maxell and Fuji (112m length) tapes, because that's what
>we can get from University Stores or local vendors.  But quite frequently,

You might want to try the Exabyte "DATA" grade tapes.  These are tapes
manufactured by Sony and "data certified".  DATA tapes are more
expensive than most others, but they are worth it:  they cause less head
wear and generate fewer errors.

When I looked into DATA tapes, it took me months to get a clear and
cogent story on data certification, and what it boils down to is this:

    1) The tapes are cut from the center of the wide swath of tape
    material, meaning there is less chance of tension-related
    degradation of tape quality during the manufacturing process.

    2) More importantly, the tapes are tested before being packaged and
    shipped.

Point (2) is important for non-obvious reasons.  The first time an 8mm
tape is used, it "flakes" material on your tape heads.  These deposits
wear at the heads, reducing their lifetime.  This can contribute greatly
to drive quality problems, and to "media errors".

With non-DATA tapes, their first use is the first time you back
something up to them.  This means that if you buy a batch on new
non-DATA tapes, you quickly cause scum buildup on the tape heads.  This
can cause tapes written later in the backup cycle to be unreadable.

The advantage of the DATA tapes is that they deposit this scum on
someone else's heads.  Your first use of the tape is the tape's second
use (at least); the much cleaner tape leaves less scum on the heads.

Note that this scum cannot be removed from the heads with cleaning
cartridges:  you must swab the heads with a special (isopropyl ??)
solution.  Note that there are two versions of the tape head cleaning
solution:  one is a carcinogenic CFC, and the other is a relatively
non-toxic, safe, solution.  (We had to investigate the latter as
Northern Telecom, BNR's parent, has very strict chemical use and
environmental policies which prohibit the use of CFCs in company
operations.)

In any case, you should use Exabyte 12 pass cleaning cartridges
regularly (we back up to EXB-8500s six nights a week - that's
4GB+ a night - and clean the drives once a week), and have your
service supplier clean the heads with the aforementioned solution
on a regular basis (I don't remember off-hand how often we do this here;
every six or twelve months comes to mind).

Before we began a regular cleaning regimen and switched to EXB-8500s and
DATA tapes, we had many "media errors" (which eventually resulted in
hardware errors); now we have almost none.

Final note on cleaning:  never use camcorder head cleaners, they will
destroy your heads, and probably void your warranty (if your supplier
has any brains).

pww

--
Peter Whittaker      [~~~~~~~~~~~~~~~~~~~~~~~~~~]   NT Secure Networks

Ph: +1 613 765 2064  [                          ]   Ottawa
FAX:+1 613 765 3520  [__________________________]   K1Y 4H7

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Chris Metzl » Sun, 04 Sep 1994 04:23:45


|>
|> Hi.  In my research group, we back up as frequently as we can, but still
|> run into problems because of the unreliability of our backups.  We use
|> an Exabyte 8200 8mm drive.  We go through 8mm tapes like crazy, because
|> they keep dying with media errors after minimal use.
|>
                 [ and so on ]

A large number of people have sent me replies, and I still need to write
them back and to summarize.  But, many of the people who have written
have wondered if I'm using 8mm video rather than data grade tapes.  I'm
definitely using data grade tapes.

Thanks.

--
Chris Metzler
Department of Physics, University of Michigan           313-764-4607 (office)
Randall Lab, 500 E. University                          313-996-9249 (home)

"If we must err, let us err on the side of personal freedom." -- T. Jefferson

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Julian Moo » Wed, 07 Sep 1994 07:10:57




> Note that this scum cannot be removed from the heads with cleaning
> cartridges:  you must swab the heads with a special (isopropyl ??)
> solution.  Note that there are two versions of the tape head cleaning

Unless you are quite certain you know what you are doing, on no account
swab the heads - you are far more likley to damage them than to clean
them - for one thing you should use a special grade of cotton fibre,
and for lots of other reasons too - not least of which is voiding
warranty (if its still covered, and if you can open the case which I
think uses Torx type screws)

With regard to the general use of Exabytes -

I speak as someone who has used EXB devices extensively in real time
data recording technqiues (and has even consulted on their use) so I
know whereof I speak.

General comments. The MTBF of early serial no 8200's was below the
claimed figure, later models fixed this. There is a bizarre interaction
on older 8200's by which SCSI noise can *appear* to be causing media
errors: I would check that your SCSI is correctly set up - good 0V,
short cables, proper termination etc.  Secondly data grade tapes are a
must, not only do they flake less, there is less general debris from
the manufacturing process.

Also, be very careful about re-writing, an inadequate erasure can cause
problems - special high power bulk erasers are required for external
erasure, but the internal erase bar is usually OK.  Note further that
servo errors are frequent with older ROM versions - check that you have
a good version. Tape tensioning is a frequent cause of problems, and
frequent start-stop operation can wear out parts that the Exabyte
diagnostics and service test routines were not able to detect.

Apart from all that, treated well they work well, but of course later
models work better!

Hope this helps.
--
Julian Moore

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Randy Dav » Fri, 09 Sep 1994 02:09:29


|>Hi.  In my research group, we back up as frequently as we can, but still
|>run into problems because of the unreliability of our backups.  We use
|>an Exabyte 8200 8mm drive.  We go through 8mm tapes like crazy, because
|>they keep dying with media errors after minimal use.
|
|The Exabyte 8200 drives are less reliable than the Exabyte 8500 drives;
|you might want to consider upgrading.
[...]

  Interesting viewpoint.  Any reason for this or data to back it up?
(We have a number of 8200's that have worked fine for years).

  In any event, the original poster doesn't mention anything about cleaning
the drive.  It is imperative that it is cleaned regularly, and would be my
first advice for him to check...


Corporate Network and System Administrator
Megatek Corporation, San Diego, California

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Peter Whittak » Fri, 09 Sep 1994 06:07:39





>|The Exabyte 8200 drives are less reliable than the Exabyte 8500 drives;
>|you might want to consider upgrading.
>  Interesting viewpoint.  Any reason for this or data to back it up?
>(We have a number of 8200's that have worked fine for years).

This was the word from our primary Exabyte reseller about two years ago
- possibly based on word from Exabyte, though I don't remember clearly -
after a long and annoying search into causes of the excessive problems
we were having at the time.

It all depends on your EXB-8200s, of course:  newer ones - those
produced just before or just after EXB-8500s became de rigueur - are
more reliable than the originals.  In any case, the EXB-8500s have a
number of internal improvements - floating heads, uploadable FW, etc.  -
that make them a better bet than the EXB-8200s.

If your EXB-8200s work, great!  You need not spend the money to upgrade.
Some of ours did not, and upgrading was the most effective alternative
for us (while we spent quite some time trying to get the EXB-8200
problems sorted out, we could have spent more; spending more time would
have meant continuing unreliable backups, which we could not afford).

pww

--
Peter Whittaker      [~~~~~~~~~~~~~~~~~~~~~~~~~~]   NT Secure Networks

Ph: +1 613 765 2064  [                          ]   Ottawa
FAX:+1 613 765 3520  [__________________________]   K1Y 4H7

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Marnix A. van_Amme » Fri, 16 Sep 1994 00:11:51




: |>Hi.  In my research group, we back up as frequently as we can, but still
: |>run into problems because of the unreliability of our backups.  We use
: |>an Exabyte 8200 8mm drive.  We go through 8mm tapes like crazy, because
: |>they keep dying with media errors after minimal use.
: |
: |The Exabyte 8200 drives are less reliable than the Exabyte 8500 drives;
: |you might want to consider upgrading.
: [...]

:   Interesting viewpoint.  Any reason for this or data to back it up?
: (We have a number of 8200's that have worked fine for years).

:   In any event, the original poster doesn't mention anything about cleaning
: the drive.  It is imperative that it is cleaned regularly, and would be my
: first advice for him to check...


: Corporate Network and System Administrator
: Megatek Corporation, San Diego, California

I didn't see the original article, but we've had lots of trouble with
Exabyte drives when VIDEO 8mm tapes were used.  You should always use
data grade tapes.


 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Junichi Kuroka » Sat, 17 Sep 1994 15:30:31




 > I didn't see the original article, but we've had lots of trouble with
 > Exabyte drives when VIDEO 8mm tapes were used.  You should always use
 > data grade tapes.
 >

According to what I heard from someone working for a magnetic media
company, using a video 8mm tape on an ExaByte drive can cause a damage
to the internal mechanism of the drive.  It will eventually damage the
tape itself, physically.
--
Junichi Kurokawa
Image and Printing System Products Development Center
Fuji Xerox Co., Ltd.

 
 
 

Do reliable 8mm (Exabyte drive) tapes exist?

Post by Jess Li » Sat, 17 Sep 1994 16:35:48



>: (We have a number of 8200's that have worked fine for years).

>:   In any event, the original poster doesn't mention anything about cleaning
>: the drive.  It is imperative that it is cleaned regularly, and would be my
>: first advice for him to check...


>: Corporate Network and System Administrator
>: Megatek Corporation, San Diego, California

>I didn't see the original article, but we've had lots of trouble with
>Exabyte drives when VIDEO 8mm tapes were used.  You should always use
>data grade tapes.



We have a 3 months old failed 8500C, a 2 months old 8505 which behaves
abnormally sometimes, a broken 8200, and another 8200 which simply refuses
to die.

With the 8500C, I tried Video grade 8mm tapes... DIDNT WORK AT ALL!
dump always quit after writting a few feet into the tape. I have always
used data grade tapes ever since, and till it failed in 3 months.

I ONLY use Exabyte cleaning cartridges to clean the tape drive every
~50 hrs ( thats about every week)

I hope once they refurbish the unit, it will last longer.

happy ExaBiting

--
Jess Liao        

*****************       *******************