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Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!inria!irisa!decouty
From: decouty@irisa.UUCP (Bertrand Decouty)
Newsgroups: comp.sys.pyramid,comp.periphs
Subject: Re: S159 Cartridge tape
Keywords: Reliability, helical scan recording
Message-ID: <669@irisa.UUCP>
Date: 21 Sep 88 14:16:28 GMT
References: <459@Terra.cc.brunel.ac.uk> <40260@pyramid.pyramid.com>
Organization: I.R.I.S.A., Rennes, Fr
Lines: 38

In article <40260@pyramid.pyramid.com> csg@pyramid.pyramid.com (Carl S. Gutekunst) writes:
	[ text deleted]
>While these drives are interesting, they are hardly a panacea. The big problem
>is reliability. The drives are rated at "10,000 hours, 10% duty cycle," which
    ^^^^^^^^^^^
>means that to achieve a 10,000 hour life you cannot use the drive more than 2
>hours and 2 minutes per day. That's a little more than a gigabyte per day. If
>you have more than that, the drive will wear out sooner. Sure enough, when we
>ran the drives continuously, they died consistently in about two months.
                ^^^^^^^^^^^^
>
>

Could you be more precise, please? Is it 10% continuously or not?
Because doing a back-up of 500 MBytes of a local disk on a Sun 3 can take
as long as 1 hour but the same back-up of a *remote* disk take 3 times more!

Which method is the best for big back-up (near a full tape, 1.7 GB for a 90mn
tape): 3 hours continuously or 3 times 1 hour separated by 1 idle hour?
(it is an example).
Is there any people having such an experience of large and long back-up?

It seems to me that many people are interested by Exabyte-like products
but few people really uses it for more than 500 MB back-up, so we have no
idea of real reliability: dump failure, hardware failure...

Thanks for any info.


    ----- Bertrand DECOUTY @ INRIA-IRISA (Centre de Rennes) -----
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