From owner-freebsd-hackers Mon Apr 1 02:54:23 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id CAA16456 for hackers-outgoing; Mon, 1 Apr 1996 02:54:23 -0800 (PST) Received: from paloalto.access.hp.com (daemon@paloalto.access.hp.com [15.254.56.2]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id CAA16451 for ; Mon, 1 Apr 1996 02:54:22 -0800 (PST) Received: from fakir.india.hp.com by paloalto.access.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA212396051; Mon, 1 Apr 1996 02:54:16 -0800 Received: from localhost by fakir.india.hp.com with SMTP (1.37.109.16/15.5+ECS 3.3) id AA014696294; Mon, 1 Apr 1996 16:28:14 +0530 Message-Id: <199604011058.AA014696294@fakir.india.hp.com> To: Kees Jan Koster Cc: hackers@freebsd.org Subject: Re: HDD cpu usage (IDE vs. SCSI). In-Reply-To: Your message of "Mon, 01 Apr 1996 11:03:46 +0200." <199604010903.LAA07931@deimos.spase.nl> Date: Mon, 01 Apr 1996 16:28:14 +0530 From: A JOSEPH KOSHY Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk kjk> I was told that cpu usage of SCSI disks was lower than that of IDE disks. [snip] This is generally true if the controller is a bus mastering device. However some of the cheaper SCSI controllers require CPU intervention to read the data from their internal buffers into system memory. These are probably as heavy on CPU as IDE. Would some system experts care to comment? Koshy