From owner-freebsd-current Sun Feb 9 18:37:34 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id SAA01954 for current-outgoing; Sun, 9 Feb 1997 18:37:34 -0800 (PST) Received: from dfw-ix5.ix.netcom.com (dfw-ix5.ix.netcom.com [206.214.98.5]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id SAA01946 for ; Sun, 9 Feb 1997 18:37:28 -0800 (PST) Received: from silvia.HIP.Berkeley.EDU (wck-ca5-13.ix.netcom.com [199.35.213.173]) by dfw-ix5.ix.netcom.com (8.6.13/8.6.12) with ESMTP id SAA07133; Sun, 9 Feb 1997 18:36:54 -0800 Received: (from asami@localhost) by silvia.HIP.Berkeley.EDU (8.8.5/8.6.9) id SAA21100; Sun, 9 Feb 1997 18:36:51 -0800 (PST) Date: Sun, 9 Feb 1997 18:36:51 -0800 (PST) Message-Id: <199702100236.SAA21100@silvia.HIP.Berkeley.EDU> To: rlb@mindspring.com CC: freebsd-current@freebsd.org In-reply-to: <32FD295D.41C67EA6@mindspring.com> (message from Ron Bolin on Sat, 08 Feb 1997 20:33:17 -0500) Subject: Re: AHC Driver Throughput Question From: asami@vader.cs.berkeley.edu (Satoshi Asami) Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk * Am I wrong in thinking that purchasing a Ultra-Wide SCSI-3 drive ^ ! * with an advertised max throughput of 40MB/sec would not be * fully realized using the current driver? You are half right. The adapter is able to work in 40MB/s mode (20MHz, 16-bit wide). However, a single drive will not give you anywhere near 40MB/s in terms of sustained throughput. (It's a different story if you read the same block repeatedly but you don't need a disk to do that.) You will need at least 2 of today's fastest drive before you start feeling the limitation of the Fast-Wide bus. Satoshi