From owner-freebsd-scsi Sun Jul 13 00:52:04 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id AAA10159 for freebsd-scsi-outgoing; Sun, 13 Jul 1997 00:52:04 -0700 (PDT) Received: from misery.sdf.com (misery.sdf.com [204.244.210.193]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id AAA10148 for ; Sun, 13 Jul 1997 00:52:00 -0700 (PDT) Received: from tom by misery.sdf.com with smtp (Exim 1.62 #1) id 0wnJMx-0002CJ-00; Sun, 13 Jul 1997 00:46:59 -0700 Date: Sun, 13 Jul 1997 00:46:58 -0700 (PDT) From: Tom Samplonius To: "Jin Guojun[ITG]" cc: asami@cs.berkeley.edu, crb@Glue.umd.edu, freebsd-scsi@freebsd.org Subject: Re: NCR SCSI controllers In-Reply-To: <199707130403.VAA24519@george.lbl.gov> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-scsi@freebsd.org X-Loop: FreeBSD.org Precedence: bulk On Sat, 12 Jul 1997, Jin Guojun[ITG] wrote: > } Not a problem. I used 11 disks on a 3940UW, and was able to max out > }both channels. With drives being able to sustain 7MB writing, this is > }getting easier to do. > > When you say to sustain 7MB writing, do you mean using a single disk? I guess. Of course. > Because I can get 15MB writing over three disks via single NCR SCSI channel That isn't very fast. > (just wide, not ultra-wide). So, 3940UW supposes to have 30MB in writing and > 35MB in reading. This will be seen in NCR-875 when the driver is ready (S.E). Huh? 3940UW performance is related to the drive performance. If the drives are willing, you will be able max the channels. In fact, I was able to do this on a 3940UW (actually worked out 39MB/s). I have no idea where this 30MB writing, and 35MB reading stuff is coming from. It is misinformation. I believe it was just one person's results on one array. Given the right disk array, you will easily max the both channels of a 3940UW. > Otherwise, the 7MB writing rate sounds not right. > > -Jin > > > Tom