From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse To: "Eric W. Biederman" In-Reply-To: References: Content-Type: text/plain Message-Id: <1075099329.17157.97.camel@lapdancer.baythorne.internal> Mime-Version: 1.0 Date: Mon, 26 Jan 2004 06:42:09 +0000 Content-Transfer-Encoding: 7bit cc: linux-mtd@lists.infradead.org Subject: Re: Q: Filesystem choice.. List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, 2004-01-25 at 14:53 -0700, Eric W. Biederman wrote: > The old papers on jffs2 would make it unacceptable as it reserves > 5 erase blocks. It's got slightly different heuristics now -- a proportion of total size, plus a proportion of total _blocks_. That was done primarily to deal with NAND flash, where we need _more_ blocks reserved, but it should also have helped with small NOR flashes. You blatantly don't _need_ to reserve five erase blocks to let you rewrite the contents of the remaining, erm, one erase block full of data. You can tune this; it's not a mount option but it's relatively simple to change in the code. > And I don't know if yaffs or yaffs2 is any better. They're for NAND, not NOR flash. > In addition boot time is important so it would be ideal if I did not > to read every byte of the ROM chip to initialize the filesystem. There have been efforts to improve JFFS2 performance in this respect. It still reads the _header_ from each node of the file system, but doesn't actually checksum every node any more. -- dwmw2