From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1PgYGE-0000hy-Mq for garchives@archives.gentoo.org; Sat, 22 Jan 2011 07:51:51 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 31B2DE0A6F; Sat, 22 Jan 2011 07:50:12 +0000 (UTC) Received: from mail-gw0-f53.google.com (mail-gw0-f53.google.com [74.125.83.53]) by pigeon.gentoo.org (Postfix) with ESMTP id ED4EEE0A6F for ; Sat, 22 Jan 2011 07:50:11 +0000 (UTC) Received: by gwb10 with SMTP id 10so1282649gwb.40 for ; Fri, 21 Jan 2011 23:50:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:message-id:date:from:user-agent:mime-version:to :subject:references:in-reply-to:content-type :content-transfer-encoding; bh=V4YVIzbHNRTOEhDzjIDsPxlZNgM5gS/N6sqbGnSFhcc=; b=NY18Tj1Awco0LnnBv6GwDsFbSYeVk1oDNFNz2InkpiMR+QIi5oDi3FX4hA0E8Vjopp dM9TZm8yfduayoSFiIO8jRqx43Mv+avsK/sVg8NimJl76aX4mdKtvst+1QlhzGiWbR7h Q0nXDiGQF62ORXz2Ds7swttdwhbT2Kqyz7C3c= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; b=mHZOol2nvU7JtKL1iqGD/G0wPKnllyGCC+pxt+uCc3vsmsh7WcrDJeFbtehHaBKOVN Udk1ZYmcaIikPROCJx00hc5FHKWZ8m/97I9tB2lc8aYll1ONlmdiElxWfkBZgXsOwQHl vBoqTgCIl6sW8bdqShMoyu/SmeeuEy0rhlHE4= Received: by 10.90.97.6 with SMTP id u6mr1980481agb.42.1295682611204; Fri, 21 Jan 2011 23:50:11 -0800 (PST) Received: from [192.168.2.5] (adsl-0-115-233.jan.bellsouth.net [65.0.115.233]) by mx.google.com with ESMTPS id b19sm12662139ana.7.2011.01.21.23.50.09 (version=SSLv3 cipher=RC4-MD5); Fri, 21 Jan 2011 23:50:10 -0800 (PST) Message-ID: <4D3A8C30.9050201@gmail.com> Date: Sat, 22 Jan 2011 01:50:08 -0600 From: Dale User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20101212 Gentoo/2.0.11 SeaMonkey/2.0.11 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: AHCI/IDE-question References: <20110121184507.GC5787@solfire> <20110121201150.GC5878@solfire> <4D39EE7D.6070603@gmail.com> <201101220006.02377.alan.mckinnon@gmail.com> <4D3A0929.6080606@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Archives-Salt: X-Archives-Hash: c0264996d99e8605701020b02ada967c Nikos Chantziaras wrote: > On 01/22/2011 12:31 AM, Dale wrote: >> Alan McKinnon wrote: >>> My notebook works like that too. >>> >>> Hard disk works fine when everything is set to AHCI, but then the >>> system won't >>> boot from CD. So I enabled the IDE driver and the IDE driver for >>> CD-ROMs. >>> >>> My take on this is that Dell had a vast stock of cheap-skate CD-ROM >>> hardware >>> and used them up. The engineering logic would have been "it doesn't >>> matter >>> that we use the slow interface for that device, it's still faster than >>> we can >>> get the data off the media." >>> >> >> And I thought there was something weird with me on this one. o_O I did >> switch it back to AHCI after I got done booting the CD thingy. I really >> can't tell any difference in speed between the two and neither could >> hdparm -tT either. > > hdparm measures raw throughput when reading continuously from one > position to another. AHCI improves performance when the disk needs to > read from several different places, which is the case in every day > use. It does this by providing a feature similar to what SCSI > provides: native command queuing (NCQ). You can read about what this > is and why we want it here: > > http://en.wikipedia.org/wiki/Native_Command_Queuing > Other than copying a file and using time to measure how long it takes, what is the best test of a hard drive's speed? Also, does or can the kernel override the BIOS setting? I think it uses AHCI no matter what is in the BIOS. It seems it would be at least some difference in speed. Nice link. The picture explained it best. I'm sort of simple. lol Dale :-) :-)