Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756097AbZDLOXt (ORCPT ); Sun, 12 Apr 2009 10:23:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752570AbZDLOXj (ORCPT ); Sun, 12 Apr 2009 10:23:39 -0400 Received: from rtr.ca ([76.10.145.34]:37903 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372AbZDLOXi (ORCPT ); Sun, 12 Apr 2009 10:23:38 -0400 Message-ID: <49E1F967.9090106@rtr.ca> Date: Sun, 12 Apr 2009 10:23:35 -0400 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.21 (X11/20090318) MIME-Version: 1.0 To: Alan Cox Cc: Grant Grundler , Linus Torvalds , Jeff Garzik , Linux IDE mailing list , LKML , Jens Axboe , Arjan van de Ven Subject: Re: Implementing NVMHCI... References: <49E0D47B.9070205@garzik.org> <20090411203246.513a0892@lxorguk.ukuu.org.uk> <20090412002527.631a5a89@lxorguk.ukuu.org.uk> In-Reply-To: <20090412002527.631a5a89@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1447 Lines: 35 Alan Cox wrote: .. > Alternatively you go for read-modify-write (nasty performance hit > especially for RAID or a log structured fs). .. Initially, at least, I'd guess that this NVM-HCI thing is all about built-in flash memory on motherboards, to hold the "instant-boot" software that hardware companies (eg. ASUS) are rapidly growing fond of. At present, that means a mostly read-only Linux installation, though MS for sure are hoping for Moore's Law to kick in and provide sufficient space for a copy of Vista there or something. The point being, it's probable *initial* intended use is for a run-time read-only filesystem, so having to do dirty R-M-W sequences for writes might not be a significant issue. At present. And even if it were, it might not be much worse than having the hardware itself do it internally, which is what would have to happen if it always only ever showed 4KB to us. Longer term, as flash densities increase, we're going to end up with motherboards that have huge SSDs built-in, through an interface like this one, or over a virtual SATA link or something. I wonder how long until "desktop/notebook" computers no longer have replaceable "hard disks" at all? Cheers -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/