On 31.05.2011 17:42, Ross Younger wrote: > Running a non-NAND-aware filesystem on NAND is a very bad idea.
Is there any NAND-aware filesystem with eCos-compatible license? I only know of jffs2 - yaffs2 is GPL or (a lot of) $$$ and ubifs is also GPL. Actually I am seeing this situation as a major drawback to eCos - nowadays just about any device uses NAND for larger storage... > Even reading a NAND page can, once in a while, cause a bit in-flash to > flip (the "read disturb" effect). If your filesystem doesn't periodically > refresh its contents, files and/or filesystem metadata which is frequently > read but never changed will gradually rot. Hmm, does jffs2 handle this? I don't remember seeing something like this in the code, but maybe I did not look at recent enough one. > Now, the public JFFS2 tree has had support for NAND flash since 2003. > It looks like the version in eCos dates from around that time, though > has its NAND support disabled; there's an argument to be made that this > perhaps ought to be put right some time. AFAIK when this was discussed there was some architectural problem - Linux's jffs2 uses mtd layer and that code is GPL, so it needs to be written from scratch: http://www.cygwin.com/ml/ecos-discuss/2008-07/msg00055.html -- Stano -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
