From owner-freebsd-current Sun Feb 9 03:51:24 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id DAA12807 for current-outgoing; Sun, 9 Feb 1997 03:51:24 -0800 (PST) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id DAA12787 for ; Sun, 9 Feb 1997 03:51:16 -0800 (PST) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id MAA18596; Sun, 9 Feb 1997 12:51:12 +0100 Received: (from j@localhost) by uriah.heep.sax.de (8.8.5/8.6.9) id MAA12789; Sun, 9 Feb 1997 12:46:07 +0100 (MET) Message-ID: Date: Sun, 9 Feb 1997 12:46:07 +0100 From: j@uriah.heep.sax.de (J Wunsch) To: rlb@mindspring.com (Ron Bolin) Cc: freebsd-current@freebsd.org Subject: Re: AHC Driver Throughput Question References: <32FD295D.41C67EA6@mindspring.com> X-Mailer: Mutt 0.55-PL10 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: <32FD295D.41C67EA6@mindspring.com>; from Ron Bolin on Feb 8, 1997 20:33:17 -0500 Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk As Ron Bolin wrote: > I have an Adaptech 2940UW controller. I am interested in purchasing > an Ultra-Wide SCSI-3 drive with the capability of 40MB/sec throughput. > > After giving the driver source a quick look, it appears the Ultra > and Wide are supported, but not together since the max throughput > registered by the driver is 20MB/sec in 16 bit mode of operation. You're confusing MHz and MB/s. (Peak) throughput = sync rate * bus width. So either a 10 MHz 32-bit bus or a 20 MHz 16-bit bus would yield you 40 MB/s peak rate. (I'm not sure whether 32-bit does already work though.) -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)