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Path: utzoo!linus!philabs!seismo!harpo!floyd!cmcl2!rna!dan
From: dan@rna.UUCP
Newsgroups: net.periphs
Subject: Magtape capacities vs densities ?
Message-ID: <190@rna.UUCP>
Date: Tue, 3-Jan-84 15:41:53 EST
Article-I.D.: rna.190
Posted: Tue Jan  3 15:41:53 1984
Date-Received: Wed, 4-Jan-84 05:07:27 EST
Lines: 20


	A question for those with 6250bpi magtape drives:
	How much can you actually put on a 2400 foot reel ?

	The DEC Peripherals Handbook says 145 Mb for their TU78 with
8kb records. They also say 40Mb at 1600 bpi for 8kb records.
	Our Kennedy 9100 can put somewhere around 43Mb on a 2400 foot
tape.
	How much can put put on and with what record sizes ? How much
variability is there (I imagine tape length to be somewhat variable
between manufacturers) ?

					Thanks,
					Dan Ts'o
					...cmcl2!rna!dan

P.S.
	The question is immediately relevant to changing partitions
on our 4.2BSD. Do people still do image copy backups or is another
method almost as fast ?