From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: ATA standard vs. speed Date: Sun, 4 Mar 2012 14:48:06 +0100 Message-ID: <20120304144806.4bef0256@endymion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from zoneX.GCU-Squad.org ([194.213.125.0]:33877 "EHLO services.gcu-squad.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754398Ab2CDOIn (ORCPT ); Sun, 4 Mar 2012 09:08:43 -0500 Received: from jdelvare.pck.nerim.net ([62.212.121.182] helo=endymion.delvare) by services.gcu-squad.org (GCU Mailer Daemon) with esmtpsa id 1S4BnH-0001oX-Kl (TLSv1:AES128-SHA:128) (envelope-from ) for linux-ide@vger.kernel.org; Sun, 04 Mar 2012 14:48:11 +0100 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org Hi all, After reading http://en.wikipedia.org/wiki/Parallel_ATA#Features_introduced_with_each_ATA_revision it seemed clear to me that there was a direct relation between the operating speed of a (P)ATA hard disk drive and the version of the ATA standard it implemented. However I see the following in my kernel logs on an old machine (kernel 2.6.34, Intel ICH5 controller): ata1: PATA max UDMA/100 cmd 0xeff0 ctl 0xefe4 bmdma 0xef90 irq 18 ata2: PATA max UDMA/100 cmd 0xefa8 ctl 0xefe0 bmdma 0xef98 irq 18 ata2.00: HPA unlocked: 40018511 -> 40020624, native 40020624 ata2.00: ATA-6: Maxtor 52049H4, DAC10SC0, max UDMA/100 ata2.00: 40020624 sectors, multi 16: LBA ata1.00: HPA unlocked: 78175679 -> 78177792, native 78177792 ata1.00: ATA-5: MAXTOR 6L040J2, A93.0300, max UDMA/133 ata1.00: 78177792 sectors, multi 16: LBA While the second disk matches the wikipedia table (ATA-6 introduced UDMA/100), the first one doesn't: UDMA/133 wasn't supposed to exist in standard ATA-5. Digging old logs, I also found this (same machine, same kernel, different drive): ata2.00: ATA-4: WDC WD102AA, 05.05B05, max UDMA/66 Here again, UDMA/66 wasn't supposed to exist in standard ATA-4. Can anyone explain this mystery to me? Thanks, -- Jean Delvare