ADSM-L

Re: finding end of tape after rewind

1996-03-22 17:52:27
Subject: Re: finding end of tape after rewind
From: Paul Zarnowski <VKM AT CORNELLC.CIT.CORNELL DOT EDU>
Date: Fri, 22 Mar 1996 17:52:27 EST
On Fri, 22 Mar 1996 13:03:01 PST Greg Tevis said:
>John...this is probably due to the 8mm technology which is
>limited in functional richness (not to mention slow performance
>and low reliability)...3490/3590 type drives (and others) have
>fast search capabilities that adsm exploits to rush to various
>parts of the tape....many devices(especially 8mm) don't have
>this ability so you have to read (slowly) through to the end of
>tape...greg tevis

I don't think this is true for the newer 8mm drives.  8200s are pretty
old technology at this point.  We have 8500c drives, which aren't as old
as 8200s, but are still older than the newer drives, and we do not
experience the problem that John describes.  I also happen to know that
the 8500 drives support the SPACE command, which allows you to position
the tape without doing sequential (slow) reads.  And ADSM uses it.

Actually, after re-reading John's original mailfile, I wonder if something
else isn't going on.  John, are you dismounting tape volumes before you
halt the server, or are you just halting the server with tape volumes
still mounted in the drives?  If the latter, you might try dismounting
the volume before doing the halt.

..Paul
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