From owner-freebsd-current Tue Sep 15 03:31:12 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id DAA05564 for freebsd-current-outgoing; Tue, 15 Sep 1998 03:31:12 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from bright.fx.genx.net (bright.fx.genx.net [206.64.4.154]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id DAA05558 for ; Tue, 15 Sep 1998 03:31:10 -0700 (PDT) (envelope-from bright@hotjobs.com) Received: from localhost (bright@localhost) by bright.fx.genx.net (8.9.1/8.8.8) with SMTP id GAA01711; Tue, 15 Sep 1998 06:32:14 -0500 (EST) (envelope-from bright@hotjobs.com) X-Authentication-Warning: bright.fx.genx.net: bright owned process doing -bs Date: Tue, 15 Sep 1998 06:32:13 -0500 (EST) From: Alfred Perlstein X-Sender: bright@bright.fx.genx.net To: Mike Smith cc: freebsd-current@FreeBSD.ORG Subject: Re: Download of FreeBSD 3.0-SNAP In-Reply-To: <199809150940.CAA00565@word.smith.net.au> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 15 Sep 1998, Mike Smith wrote: > I don't think anyone would disagree with this; my point was simply that > disks are effectively nondeterministic, so by definition you can't have > an "optimal" solution. > > I've seen assorted drive literature describing different caching > policies on modern drives, and I think it's probably in our interest > not to try too hard to outsmart the disk these days, as it's busy > trying to outsmart us. > > If you really wanted to play games with the queue sorter, you might > want to go for a minimal distance insertion policy rather than a strict > ladder sort. As Kirk pointed out, there's plenty of room for > experimentation in this field. 8) you can easily starve processes far from the insertion point using an algorithm like that, in fact you can almost DOS a machine unless some sort of quantum is invlolved to compromise locallity over time elapsed since a read/write has been queued. Alfred Perlstein - Programmer, HotJobs Inc. - www.hotjobs.com -- There are operating systems, and then there's FreeBSD. -- http://www.freebsd.org/ 3.0-current To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message