Date: Thu, 25 Feb 1999 19:32:11 -0600 From: David Kelly <dkelly@hiwaay.net> To: mi@aldan.algebra.com Cc: questions@FreeBSD.ORG, tapesupport@seagate.com Subject: Re: disabling compression on Seagate DAT (Arhive Python) drive Message-ID: <199902260132.TAA52025@nospam.hiwaay.net> In-Reply-To: Message from Mikhail Teterin <mi@misha.cisco.com> of "Thu, 25 Feb 1999 15:48:07 EST." <199902252048.PAA22091@misha.cisco.com>
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Mikhail Teterin writes: > The manual says it is possible to do by a MODE SELECT command > from the host computer, but provides no specifics. Can someone, > please, share the knowledge? Ideally, I need an argument for > FreeBSD-2.2.6's scsi(8) command. First, I'd suggest an upgrade to 3.1-stable is in order. The mt(1) utility now supports enabling/disabling compression. A minor nit is the new CAM sa driver implements "mount sessions" and resets to defaults when it thinks the mount session ends. No way to chose your defaults. If that is out of the question, then there is a "DC-Passthru" jumper and/or DIP switch on the Seagate drive which selects the compression state at power up. Under older FreeBSD's this means you don't have a means to enable compression. But reading a compressed tape will automagically work. What I'm concerned about is that once you have read a compressed tape the drive will stay in compressed mode when you create a new tape. Its not supposed to be possible to switch compression modes in the middle of a tape. While we are CC:'ing Seagate on this (I'm a good Seagate customer with about 100 Seagate HD's and 15 Seagate tape drives at work) I'd like to know how one can query a drive to learn 1) what compression mode is on the tape, and 2) the error rate on the tape that was just read or written. The only way I've found to prove a tape is compressed or not is to attempt to read with a DDS drive which doesn't support compression. Doesn't do me any good if its a DDS-2 or DDS-3 tape as my DDS-1 drives are the only ones that don't support compression. -- David Kelly N4HHE, dkelly@nospam.hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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