Date: Wed, 10 Jan 1996 16:36:01 +0100 (MET) From: grog@lemis.de (Greg Lehey) To: se@ZPR.Uni-Koeln.DE (Stefan Esser) Cc: hackers@freebsd.org (FreeBSD Hackers) Subject: DDS-2 (was: I would like your comment on this configuration) Message-ID: <199601101536.QAA14334@allegro.lemis.de> In-Reply-To: <199601091616.AA10078@Sysiphos> from "Stefan Esser" at Jan 9, 96 05:16:13 pm
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Stefan Esser writes: > > On Jan 9, 17:20, didier@omnix.fr.org wrote: >} Subject: I would like your comment on this configuration >} >} Mother Board: ASUS P/I-P55TP4XE Rev 2.1 bios #401A0-0106 (Award) >} Processor: Pentium 133 >} Cache: 512k PB >} Memory: 128Mb 60ns (DRAM) >} SCSI: Adaptec 2940W >} Hard disks: 2 x Seagate Barracuda Fast Wide SCSI 2 Go >} Video: Miro 20SV (S3-964, 2Mb VRAM) >} DAT: Conner 4326 4/8 Gb > > I'd definitely choose the HP1533A ! > > It is some three times faster than the Conner, > i.e. does 514KB/s (times compression factor). I haven't tried the Conner, but I haven't got anything like that speed out of a 1533A (especially considering that you appear to be using normal DDS tapes). But you (Didier) should be aware that the claim 4/8 GB is: (4: hope, occasionally seen; 8: blatant lie). On those tapes, with a normal mix, I get about 3.5 GB. > Doing backups, I see some 800KB/s to 1100KB/s written to tape > (depending on whether the data had been compressible or mostly > compressed archives). > > > Regarding DDS-2: I've heard multiple times, that DDS-2 tapes are not > reliable. And since somebody had recorded nuclear physics data on > DDS-2 tapes and had found no way to read back more than a few MB, I > tried myself and now would never again trust 120m DDS-2 tapes. I've been using a 1533A for several months now, and have had no problems with the tapes. You do need to keep the heads clean, though, otherwise you'll see the problems you describe. I make a daily backup of about 7 GB, and read the tape back in daily just to be sure. On the other hand, I *have* seen (and reported on) problems with the SCSI tape driver. I have the 1533A on a BSDI box, so I can't say how FreeBSD reacts to that, but it doesn't like my old unmarked HP tapes on the 35480A. Greg
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