From owner-freebsd-fs Sun Jan 12 13:52: 8 2003 Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DA29C37B401 for ; Sun, 12 Jan 2003 13:52:06 -0800 (PST) Received: from pohoda.cz (pohoda.pohoda.cz [194.228.111.151]) by mx1.FreeBSD.org (Postfix) with SMTP id 1A1B943F65 for ; Sun, 12 Jan 2003 13:52:05 -0800 (PST) (envelope-from plusik@pohoda.cz) Received: (qmail 15336 invoked from network); 12 Jan 2003 21:52:10 -0000 Received: from plusik@pohoda.cz by pohoda.cz by uid 513 with qmail-scanner-1.15 ( Clear:. Processed in 0.058297 secs); 12 Jan 2003 21:52:10 -0000 Received: from saturn.netcore.cz (HELO localhost.localdomain) (212.67.74.6) by pohoda.pohoda.cz with SMTP; 12 Jan 2003 21:52:09 -0000 Received: by localhost.localdomain (Postfix, from userid 1000) id E27C21CBAF4; Sun, 12 Jan 2003 22:52:02 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by localhost.localdomain (Postfix) with ESMTP id E0B6D1CBAF3; Sun, 12 Jan 2003 22:52:02 +0100 (CET) Date: Sun, 12 Jan 2003 22:52:02 +0100 (CET) From: Tomas Pluskal X-X-Sender: plusik@localhost.localdomain To: Terry Lambert Cc: David Schultz , Bruce Evans , Subject: Re: seeking help to rewrite the msdos filesystem In-Reply-To: <3E21D9F0.A2AA9F0@mindspring.com> Message-ID: <20030112222759.R23717-100000@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Thank you all for your comments. I would like to state here, that I have no experience with filesystem development at all (well, now I have a bit :) You told me to look at the cd9660 code, so I did my best to do it like it's in cd9660... I only partially understand what the code really does. By the way, is there any documentation for these things anywhere ? I mean it is quite hard to understand what pcbmap(), bread(), cluster_read() etc. and their parameters really mean, just by reading the code... If I understand it right, when I assume the file is not fragmented, it is just a performance issue - it would make the FS slow on fragmented files, but should not break anything. Is this correct? If any of you could suggest a better solution (in a way that I could understand it :), I can work on it. Tomas On Sun, 12 Jan 2003, Terry Lambert wrote: > > FWIW, I had the same question, but I haven't had time to really > stare at some FS instances from a working Windows box from the > FreeBSD side of things, to know how bad this really is, so I > thought that this might be on purpose. > > I don't expect he'd ever see it at all, given his intended usage. > > I think that it's not that bad (really), but will lose about 50% > of the performance improvement on a file that's partially fragged, > but still contains contiguous blocks in it. On a generally fragged > file, you're not going to trigger the code at all. I'm not really > sure a cluster can start at a non-boundary, anyway (this is what I > need to looks at examples to see), so it may be a total non-issue. > > -- Terry > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message