From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: AHCI should try to claim all AHCI controllers Date: Wed, 01 Nov 2006 09:37:49 -0500 Message-ID: <4548B13D.6070501@rtr.ca> References: <45482BA7.6070904@pobox.com> <1162383783.11965.116.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([64.26.128.89]:23310 "EHLO mail.rtr.ca") by vger.kernel.org with ESMTP id S2992512AbWKAOhv (ORCPT ); Wed, 1 Nov 2006 09:37:51 -0500 In-Reply-To: <1162383783.11965.116.camel@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Linus Torvalds , Jeff Garzik , Conke Hu , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Andrew Morton Alan Cox wrote: > Ar Maw, 2006-10-31 am 21:22 -0800, ysgrifennodd Linus Torvalds: >> (We had the same issue with "PCI IDE controller". Some PCI IDE controllers >> are clearly exactly that from a programming interface standpoint, but >> because they support RAID in hardware, they claim to be RAID controllers, >> since that is more "glamorous". Gaah ;^). > > Actually its far uglier than that. With one exception they don't support > hardware raid mode, they use the RAID class tag to stop other OS drivers > grabbing the interface or seeing it directly as un-raided software raid. Note that a lot of the software raid controllers actually have full hardware RAID acceleration in the chipset (single block command is automatically remapped across several drives of a RAID 0/1/10 configuration, reducing bus transactions and bandwidth requirements. But they still require a driver do perform the RAID management, and are thus not true "hardware" RAID. But they are higher on the food chain than total "pretend" RAID devices. Cheers