From owner-freebsd-questions Wed Oct 24 23:48:37 2001 Delivered-To: freebsd-questions@freebsd.org Received: from mailg.telia.com (mailg.telia.com [194.22.194.26]) by hub.freebsd.org (Postfix) with ESMTP id 7521C37B407 for ; Wed, 24 Oct 2001 23:48:30 -0700 (PDT) Received: from d1o913.telia.com (d1o913.telia.com [195.252.44.241]) by mailg.telia.com (8.11.6/8.11.6) with ESMTP id f9P6mTl17372 for ; Thu, 25 Oct 2001 08:48:29 +0200 (CEST) Received: from ertr1013.student.uu.se (h185n2fls20o913.telia.com [212.181.163.185]) by d1o913.telia.com (8.8.8/8.8.8) with SMTP id IAA09206 for ; Thu, 25 Oct 2001 08:48:28 +0200 (CEST) Received: (qmail 1188 invoked by uid 1001); 25 Oct 2001 06:48:27 -0000 Date: Thu, 25 Oct 2001 08:48:27 +0200 From: Erik Trulsson To: Chris Pearce Cc: freebsd-questions@freebsd.org Subject: Re: Harddrive reporting wrong RPM Message-ID: <20011025084827.A1152@student.uu.se> Mail-Followup-To: Chris Pearce , freebsd-questions@freebsd.org References: <01102519212300.00352@Ferox> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <01102519212300.00352@Ferox> User-Agent: Mutt/1.3.22.1i Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Thu, Oct 25, 2001 at 07:21:23PM +1300, Chris Pearce wrote: > Hey, > > I recently installed FreeBSD4.3, and I noticed my > harddrive seems to be running slower than it has > done under Windoze and Linux. I ran 'disklabel ad0' > and it told me that my rpm of my HD is 3600, which > is wrong; the drives only 9 months old. I think that FreeBSD does not really know anything about how many rpm the disk has. The 3600 I believe is only a default value to be used in case no further information is available. > > If I run 'disklabel -e ad0' and changed the rpm > manually, will it speed up the drive, or could it > damage it instead? (Thought I'd better check before > I tried.....) Neither probably. I don't think the rotational speed of the harddisk can be controlled by software. > > Is there any other ways to speed up the HD, like > doing something funky with DMAs? Turning on write-caching should give a noticable performance boost. This was, by default, turned off in 4.3. To check if write caching is on or off do: sysctl -a | grep ata.wc This should display a line like hw.ata.wc: 0 If it is a "1" instead of "0" then write caching is already turned on. To enable write caching if it is not enabled you will need to add the line hw.ata.wc="1" to the file /boot/loader.conf and then reboot. A warning though: With write caching enabled you run the risk of losing more data or leaving the disk in an inconsistent state if the computer should crash. Search the mailing-list archives for much more discussion on this. -- Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message