Date: Sun, 29 Mar 1998 12:55:45 -0800 (PST) From: Simon Shapiro <shimon@simon-shapiro.org> To: Ustimenko Semen <semen@iclub.nsu.ru> Cc: FreeBSD-scsi@FreeBSD.ORG Subject: RE: SDT-7000 and other DDS-2 tapes Message-ID: <XFMail.980329125545.shimon@simon-shapiro.org> In-Reply-To: <Pine.BSF.3.96.980325154953.25252A-100000@iclub.nsu.ru>
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On 25-Mar-98 Ustimenko Semen wrote: > On Wed, 25 Mar 1998, Simon Shapiro wrote: >> On 25-Mar-98 Ustimenko Semen wrote: >> > >> > Have somebody succesfuly used SDT-7000 under FreeBSD? >> >> Yes. Two of them in shared mode on a DPT controller. >> > Wow! And it realy gives 600kb/s (I have only 150, and not proper > capacity). Tell me, pls, is it -CURRENT, and what blocksize and density > do you use? And dmesg:) My tests hover around 1-1.2MB/Sec for CPIO or DUMP (But, important BUT below). Here is a fragment of dmesg from sendero sd80: Direct-Access 23834MB (48813696 512 byte sectors) pt5 at scbus5 target 7 lun 0 pt5: <DPT PM3334UDW 07LI> type 3 fixed SCSI 2 pt5: Processor sd88 at scbus5 target 8 lun 0 sd88: <DPT CMN-0-RIGHT 07LR> type 0 fixed SCSI 2 sd88: Direct-Access 23834MB (48812544 512 byte sectors) scbus6 at dpt1 bus 2 worm6 at scbus6 target 4 lun 0 worm6: <YAMAHA CDR100 1.10> type 4 removable SCSI 2 worm6: Write-Once st6 at scbus6 target 5 lun 0 st6: <SONY SDT-7000 0195> type 1 removable SCSI 2 st6: Sequential-Access density code 0x13, 512-byte blocks, write-enabled pt6 at scbus6 target 7 lun 0 pt6: <DPT PM3334UDW 07LI> type 3 fixed SCSI 2 pt6: Processor IMPORTANT BUT: The SCSI tape drive is DANGEROUSLY next to useless! If the system uses ANY block size other than 512 bytes, you will silently produce trash tapes. Here are some details: * Do NOT use dump(1). Dump uses blocking that are a multiple of 1K. This produces tapes that cannot be read; The data is trash, there are no EOF maks on the tape, etc. * CPIO must be factored with -C 512, or you will get the same trash problems. * When you run at 512 byte blocks, throughput becomes akin to RS-232C. It is very, very slow. The danger lies in the dumping/writing process NOT producing ANY indication of failure. Things just zoom along nicely. The problem arises when you try to READ the tapes. There will be nothing but trash there. BTW, My answr got delayed, as I had to dump some 30GB of data to tapes, as part of disks upgrade. It took that long to finish (4 days). ---------- Sincerely Yours, Simon Shapiro Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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