From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754563AbXLDVyb (ORCPT ); Tue, 4 Dec 2007 16:54:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752214AbXLDVyX (ORCPT ); Tue, 4 Dec 2007 16:54:23 -0500 Received: from wa-out-1112.google.com ([209.85.146.179]:64884 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751565AbXLDVyX (ORCPT ); Tue, 4 Dec 2007 16:54:23 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=uqIrfqfdQbU0xjHnN2i8sNsXVdw5vZRnWO2MpYB35p1Ho2W0qCe6xNkpx2txHbAVgIbMvyZZ9dlZN4yo3BxwdvvgdxePhBuuUhHQUSFwXZbv6HlaYSVmbQREhEpEYdr9/6X06EFPyLWn04Yr2W9OGyvNgQgWfxea1lqMQbE5S/4= Message-ID: <6934efce0712041354n47c11d6ckbc7f4aa1e7c85f@mail.gmail.com> Date: Tue, 4 Dec 2007 13:54:21 -0800 From: "Jared Hulbert" To: "Alan Cox" Subject: Re: solid state drive access and context switching Cc: "Chris Friesen" , linux-kernel@vger.kernel.org In-Reply-To: <20071204203536.2bf6d025@the-village.bc.nu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <47548BF4.3010907@nortel.com> <20071203230629.725f4c7a@the-village.bc.nu> <6934efce0712040954v74cf0b4bk19b49988bc828233@mail.gmail.com> <20071204203536.2bf6d025@the-village.bc.nu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > microseconds level and an order of magnitude higher bandwidth than > > SATA. Is that fast enough to warrant this more synchronous IO? > > See the mtd layer. Right. The trend is to hide the nastiness of NAND technology changes behind controllers. In general I think this is a good thing. Basically the changes in ECC and reliability change very rapidly in this technology. Having custom controller hardware to handle this is faster than handling it in software and makes for a nice modular interface. We don't rewrite our SATA drivers and filesystem everything the magnetic media switches to a new recording scheme, we just plug it in. SSD's are going to be like that even if they aren't SATA. However, the MTD layer is more about managing the chips themselves, which is what the controllers are for. Maybe I'm missing something but I don't see it. We want a block interface for these devices, we just need a faster slimmer interface. Maybe a new mtdblock interface that doesn't do erase would be the place for? > > BTW - This trend toward faster, lower latency busses is marching > > forward. 2 examples; the ioDrive from Fusion IO, Micron's RAM-module > > like SSD concept. > > Very much so but we can do quite a bit in 10,000 processor cycles ... > > Alan >