Date: Tue, 14 Dec 1999 16:11:28 -0500 (EST) From: Adon <ahwang@fas.harvard.edu> To: Mitch Collinsworth <mkc@Graphics.Cornell.EDU> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: DDS-4 set density woes Message-ID: <Pine.OSF.4.10.9912141608360.5936-100000@is04.fas.harvard.edu> In-Reply-To: <199912142102.QAA31206@benge.graphics.cornell.edu>
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it is nominally compressed (gzip default). in the past, i have seen that the hardware compression can squeeze some bits out of this. however, perhaps you are right. i should try the backup without hardware compression. my real question is concerning 'mt density' command. it seems to do 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. thanks, adon On Tue, 14 Dec 1999, Mitch Collinsworth wrote: > > >i have a HP SureStore DAT40i (HP C5683A C908). it is a DDS-4 drive that > >purports to write to smaller formats such as DDS-2 or DDS-3. my problem > >is when i try to write to a DDS-2 tape. in its default configuration, i > >cannot write the full capacity of the tape (4 GB uncompressed). with > >hardware compression turned on, i get about 3.6 GB on a tape. > > Is the data you're writing already compressed before it goes to the > tape? Hardware compressing a file that is already software compressed > will actually end up making it bigger rather than smaller. From your > numbers above it sounds like this might be what's happening here. > > -Mitch > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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