Date: Tue, 12 Mar 1996 02:26:17 -0700 (MST) From: Alan T Krantz <atk@alumni.cs.colorado.edu> To: joerg_wunsch@uriah.heep.sax.de, rgrimes@GndRsh.aac.dev.com Cc: fcawth@jjarray.umd.edu, freebsd-hardware@freebsd.org, freebsd-scsi@freebsd.org Subject: Re: Slow Toshiba 6.7X cdrom drive. Message-ID: <199603120926.CAA06253@alumni.cs.colorado.edu>
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||From owner-freebsd-scsi@freefall.freebsd.org Mon Mar 11 22:06:52 1996 ||> ||> As Fred Cawthorne wrote: ||> > ||> > I just purchased a Toshiba 3701B 6.7X scsi drive. I have the 3401 and I ||> > like it, and the price was good... Has anyone else had problems getting ||> > this drive to work at full speed?? I get 300K/sec with a 486-66 and ||> > an Ultrastor 14f controller. I get 500K/sec with a 1542CF on a P-90 ||> > system. I can get 1MB/sec with an NCR scsi controller on the pentium system. ||> > What's going on here? ||> ||> Just for reference: i get 330 KB/s (only) from the 3401 on a 486/33 ||> with a Buslogic BT472A (EISA) controller (raw `dd' throughput). The ||> controller is known to get about 5 MB/s from the Seagate Hawk that's ||> also in the machine. ||Try the 3 following dd commands, I found that xfer rates on multispin ||cdrom drives is heavily block size dependent. ||dd if=/dev/rcd0a of=/dev/null bs=512 ||dd if=/dev/rcd0a of=/dev/null bs=2048 ||dd if=/dev/rcd0a of=/dev/null bs=8192 ||Many drives will due there highest rate with the 8K I/O, a few others ||seem to like the 2K I/O. ||-- ||Rod Grimes rgrimes@gndrsh.aac.dev.com ||Accurate Automation Company Reliable computers for FreeBSD Out of curiosity I tried this (P-100, NCR810 with FreeBSD 2.0 ) and got 300mb with 4092 and 615mb with 8192 for a Toshiba XM-3601TA 0725. (512 and 1024 were illegal block sizes). Also got around 4 megabyte for a Fuji M1606S-512 which seems a little high... atk
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