Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!killer!kcdev!gentry
From: gentry@kcdev.UUCP (Art Gentry)
Newsgroups: comp.sys.att
Subject: Re: 9track on 3b2
Summary: needs streaming bit set
Keywords: 9track, 3b2, backups
Message-ID: <792@kcdev.UUCP>
Date: 27 Jun 89 15:31:09 GMT
References: <125@bdofed.UUCP>
Organization: AT&T Kansas City, MO.
Lines: 27

In article <125@bdofed.UUCP>, nickerso@bdofed.UUCP (b) writes:
>
> [problem description/layout deleted]
> 
> 	Has anyone else had any experience with the 9track on a 3b2?  Our
> contacts at AT&T say that the throughput should be much higher.  It seems
> that the drive is stopping and starting as it writes (an indication that
> the buffering can't keep up with the drive???) which means it has to back up
> so that it can get the tape to the right speed at the right time.  Not exactly
> a time saver!
> 
The AT&T 9track drive is really a Hewlett Packard 7980 drive that AT&T has
OEMed.  I have a couple on an HP9000/850.  This is a streaming tape drive, but
you need to have the right bit set in the driver to put it into streaming mode.
Sounds like you have one of two possible problems: 1) the bit is not set and
the drive is running in start/stop mode or 2) your backup utility is not
feeding data to the drive fast enough to keep it streaming.  The drive will
only stream as long as there is data in the buffer to feed it.  If it runs
out of data, the tape will stop, wait for the buffer to hit x percentage full
and then backup/re-stream to dump that data.  If the buffer empties again, it
starts the process all over again.

-- 
| R. Arthur Gentry     AT&T Communications     Kansas City, MO     64106 |
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