Thanks to the following for resonding to my question on TK tape
compatability,
Mitch Bertone, Paul Thompson,Alex Fiedler, Guy Dallaire,
Tim Janes, Karl Marble, Dave Golden and Richard Turner
The original posting,
>We just received several new TZ88 tape drive for data archiving.
>We are running these drives off of Alpha 2100's,DU4.0 and an Alpha 3000,
>DU3.2b.
>
>We were told there was a shortage of TZ88 tapes for these new drives.
>Since we have a number of now outdated TK85K tapes, I decided to try
>archiving to them. I was able to archive and restore at will.
>
>Questions are,
> 1) Has anyone experienced reading/writing with older tapes to the
> new drives.
> 2) Does anyone know of data loss or degardation with time.
> 3) Any compatability problems.
From: Guy Dallaire <dallaire_at_total.net>
Subject: Re: TZ88 Drives
We use TZ87 drives here.
TZ87 and TZ88 drives are compatible with TK85 cartdridges. I don't know if
they can detect them or if you HAVE to press the compatibility button on the
front of the tape drive unit. They probably are INTELLIGENT and I suppose
that this button is used, for example, to write data on a TZ88 tape in a
format that is readable by a TK85 unit.
As for compatibility, I would not bet the farm on reading TK85 cartridges
from an older TK85 unit. My experience with tapes is: If that DATA is REALLY
important to you, read it with the same unit that you wrote it. I see no
problems of using older TK85 cartridges as long as you rewrite to them with
your new unit before reading them with the new unit.
Guy Dallaire
dallaire_at_total.net
From: Mitch Bertone <mbertone_at_gtech.com>
Subject: TZ88 Tape Drives
We have a mixture of TZ88, TZ87 & TZ86 drives.
Yes the THXKD type tape are in short supply, best source is FUJI, which
really makes the DEC tapes. Of course they cost $118.00 each.
No problems using TK85-K in a TZ88 except that you will only get 20 gig
on the tape with compression.
We have had no problems reading a TK85-K tape written in a TZ88 in a
TZ87 drive. When the TZ88 sees a COMPACT III tape (TK85-K) it defaults
to TZ87 mode.(20 gig - compression)
Good luck finding tapes. We were lucky to locate 50, we need 120.
Mitch Bertone
mbertone_at_gtech.com
Subject: Re: TZ88 Drives
The TZ88 supports reading and writing the TZ87 densities
used by the CompacTape III (TK85). The only problem I'd
imagine is a change in the amount of wear, but that's
probably not enough to notice.
From: Karl Marble <marblek_at_city.ci.worcester.ma.us>
Subject: Re: TZ88 Drives
Just curious, what features does the TZ88 offer? We're in the
process of getting a drive from DEC, and if there's a substantial difference
between a TZ88 and a TZ87, I'll prod them into getting a TZ88.
Thanx
Karl Marble
mailto:marblek_at_city.ci.worcester.ma.us
http://www.ultranet.com/~kmarble (My 'at-work' page isn't finished yet)
From: Dave Golden <golden_at_falcon.invincible.com>
Subject: Re: TZ88 Drives
Watch the LEDs on the front of the tape drive. You should notice that
those tapes won't select the highest possible density (this is automatic).
I can't remember what GB size the TK85K's are, I think they're 20 GB
compressed. The data should be just as reliable as if you were writing
with the obsolete drive that those tapes were designed for.
Dave
From: "Tim W. Janes" <janes_at_signal.dra.hmg.gb>
Subject: Re: TZ88 Drives
About 9 months ago we replaced a Ciper 860 DLT stacker (TZ867) with a
Quantum 4700 DLT stacker (TZ887). I continued to use the Compac Tape
III with the higher density drive and all went well for the next 3
months.
We then came to recycle these tapes for a second time on the
DLT4700 and we immediately got a high write error rate (the order of 1
error per tape).
I had several e-mail exchanges with Quantum who could not explain
this and maintained that there should be NO compatibility problem.
The outcome was that we replaced all Compac III Tapes with IV and only
use the III on the old drive - now on an NT system.
I have no means of telling if ours is an isolated incident or not -
certainly Quantum believe that there should not be any problems.
Compac IV are in short supply but the longest delivery I have had to
endure has been 3 weeks so are available with a short wait.
Other than this incident we have been extremely pleased with DLT's now
backing up 100Gbytes per week to them.
Tim.
From: "Fiedler, Alex" <alex.fiedler_at_faulding.com.au>
Subject: RE: TZ88 Drives
This is relevant for us and we eagerly await your summary. We are
presently relying on DEC's claims of compatibility, and haven't ordered
any new media. What we have been told is that the TK85 tapes are fine
except where you require compression.
Alex Fiedler
Faulding Pharmaceuticals
Adelaide, South Australia
From: Paul Thompson <thompson_at_vulcan.edsi.org>
Subject: Re: TZ88 Drives
The Compact Tape IV's are indeed hard to find: supposedly a 4-6mo waiting
list.
Compact Tape III's will work fine, albiet with TZ87 (20G compressed) capacity.
Have not heard of any problems with degradation, etc.
Paul
From: system PRIVILEGED account <root_at_alpha2.ccc.edu>
Subject: Re: TZ88 Drives
We have been using the DECtape III cartridges for some time. In fact,
I've been pushing the guy in charge of purchasing tapes to specify the
III's over the IV's due to the availability problem (it's been taking as
long as two months for the IV's to come in while we can get III's within a
week -- plus we really don't need the 40GB capacity... yet.). The III's
work fine. As far as degradation over time, I'm not sure if our
experience will help but some of our tapes contain vdumps from January '96
and can be read with no problem. Some of these older tapes were in use
for some time for VMS backups before we started using them.
Richard N. Turner |
turnerr_at_metamor.com |
***************************************************************************
Summary - Personal 2 cents
I have written to and retrieved from the TK85 tapes with no observable
problems - so far. Tim Janes mentioned his problems started when he
recycled the tapes, I haven't done this yet, but I will try that. The
tape unit itself does adjust for density and the only problem with the III
tapes is max of 20Gb, not much of a problem on our 3000, the 2100 may pose
a problem, time will tell.
Once again, thanks for all the responses.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
___ ___ ____
/__\\ /__\\ /____\ Harvey Miotke Jr.
// //_ // Detroit Water & Sewerage Dept.
// \__\ // __ 303 S.Livernois
//__// //__// //___// Detroit, Michigan 48209
\__omputer \__ervices \___roup (313) 297-5835 FAX (313) 297-5805
miotke_at_mms.water.ci.detroit.mi.us
Received on Wed Oct 30 1996 - 22:45:05 NZDT