From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: Implementing NVMHCI... Date: Fri, 1 May 2009 00:51:53 +0200 Message-ID: <20090430225153.GA14784@logfs.org> References: <20090412091228.GA29937@elte.hu> <6934efce0904141052j3d4f87cey9fc4b802303aa73b@mail.gmail.com> <1239777470.3390.164.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1239777470.3390.164.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org To: Artem Bityutskiy Cc: Jared Hulbert , Linus Torvalds , Szabolcs Szakacsits , Alan Cox , Grant Grundler , Linux IDE mailing list , LKML , Jens Axboe , Arjan van de Ven , David Woodhouse List-Id: linux-ide@vger.kernel.org On Wed, 15 April 2009 09:37:50 +0300, Artem Bityutskiy wrote: >=20 > I briefly glanced at the doc, and it does not look like this is an > interface to expose raw NAND. E.g., I could not find "erase" operatio= n. > I could not find information about bad eraseblocks. >=20 > It looks like it is not about raw NANDs. May be about "managed" NANDs= =2E I'm not sure whether your distinction is exactly valid anymore. "raw NAND" used to mean two things. 1) A single chip of silicon without additional hardware. 2) NAND without FTL. Traditionally the FTL was implemented either in software or in a constroller chip. So you could not get "cooked" flash as in FTL withou= t "cooked" flash as in extra hardware. Today you can, which makes "raw NAND" a less useful term. And I'm not sure what to think about flash chips with the (likely crappy) FTL inside either. Not having to deal with bad blocks anymore is a bliss. Not having to deal with wear leveling anymore is a lie. Not knowing whether errors occurred and whether uncorrected data was left on the device or replaced with corrected data is a pain. But like it or not, the market seems to be moving in that direction. Which means we will have "block devices" that have all the interfaces o= f disks and behave much like flash - modulo the crap FTL. J=C3=B6rn --=20 Courage is not the absence of fear, but rather the judgement that something else is more important than fear. -- Ambrose Redmoon