Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!att!ihaxa!ihlpy!wolfordj
From: wolfordj@ihlpy.ATT.COM (452is-Wolford)
Newsgroups: comp.sys.att
Subject: Re: 9track on 3b2
Message-ID: <12905@ihlpy.ATT.COM>
Date: 27 Jun 89 22:51:01 GMT
References: <125@bdofed.UUCP>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 50

From article <125@bdofed.UUCP>, by nickerso@bdofed.UUCP (b):
> Hello World!
> 	Hi.  We're having trouble with backups on a 9track.  We have two
> 3b2s (a 622 and a 700).  We have the tape unit on the 700 and ethernet
> between the two.  We have /dev mounted under RFS on the 622.  The problem
> is that the backups are taking FOREVER! (well, almost :-)  The backup of
...
...
> 	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!
> 
> 		Bill
> 
> nickerso@bdofed
> Etobicoke Board of Education
> 1 Civic Centre Ct, Etobicoke, Ontario
> (416)394-7182

YEP, think of what you are doing.  Taking the information off the of the
disk (ie 
1 - going through the disk controller, 
1A - to the SCSI controller
2 - to the 3B2, 
3 - to the networking card
4 - through the network
5 - to the networking card
6 - to the 3B2
7 - to the SCSI controller
8 - and to the 9 track controller

Steps 3 - 6 are removed from the process if you don't have the take mounted
over a lan.

Think about it.  Have questions send mail and I will give a more
detailed explaination of "why" this occurs and that little you do
could make the tape drive on the RFS'ed machine to stream.

Jeff Wolford
att!iwsag!jww
att!ihlpy!wolfordj

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