Date: Mon, 11 Mar 1996 18:39:50 -0800 (PST) From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com> To: joerg_wunsch@uriah.heep.sax.de Cc: fcawth@jjarray.umd.edu, freebsd-scsi@FreeBSD.org, freebsd-hardware@FreeBSD.org Subject: Re: Slow Toshiba 6.7X cdrom drive. Message-ID: <199603120239.SAA13266@GndRsh.aac.dev.com> In-Reply-To: <199603112246.XAA00663@uriah.heep.sax.de> from "J Wunsch" at Mar 11, 96 11:46:04 pm
next in thread | previous in thread | raw e-mail | index | archive | help
> > 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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199603120239.SAA13266>