From owner-freebsd-questions Tue Dec 14 13:57: 4 1999 Delivered-To: freebsd-questions@freebsd.org Received: from benge.graphics.cornell.edu (benge.graphics.cornell.edu [128.84.247.43]) by hub.freebsd.org (Postfix) with ESMTP id A3B3315192 for ; Tue, 14 Dec 1999 13:56:57 -0800 (PST) (envelope-from mkc@benge.graphics.cornell.edu) Received: from benge.graphics.cornell.edu (mkc@localhost) by benge.graphics.cornell.edu (8.9.3/8.9.3) with ESMTP id QAA31551; Tue, 14 Dec 1999 16:56:54 -0500 (EST) (envelope-from mkc@benge.graphics.cornell.edu) Message-Id: <199912142156.QAA31551@benge.graphics.cornell.edu> To: Adon Cc: freebsd-questions@FreeBSD.ORG Subject: Re: DDS-4 set density woes In-Reply-To: Message from Adon of "Tue, 14 Dec 1999 16:11:28 EST." Date: Tue, 14 Dec 1999 16:56:54 -0500 From: Mitch Collinsworth Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >it is nominally compressed (gzip default). in the past, i have seen that gzip(1) says: The default compression level is -6 (that is, biased towards high compres- sion at expense of speed). I would not call this "nominal". >the hardware compression can squeeze some bits out of this. however, >perhaps you are right. i should try the backup without >hardware compression. one or the other, not both. >my real question is concerning 'mt density' command. it seems to do well your initial message said "my problem is ..." so that seemed like the obvious issue to address. >nothing. i also have an exabyte 8mm drive. for that drive, the density >shows up as simply "default". attempts to change it were also useless. I'll offer an educated guess, not having actually used a dds4 drive or even mt on a freebsd box. The dds drives are capable of detecting what type of tape you give them by looking at the holes on the underside edge farthest from the hinge. If mt is confused about the tape type I wouldn't worry too much about that. As far as hardware compression there are probably only two choices - on or off. You should be able to control compression from software but it doesn't always work. If by testing you can determine that turning compression on/off isn't gaining you anything (with uncompressed files!) then you need to double-check the switch settings on the drive and at that point start questioning the software. Hope this helps. -Mitch To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message