YAFFS team, After investigating some corrupt files in our Android app, I think I've narrowed the problem down to YAFFS. The same code on a FAT fs performs as expected. First, it looks like RandomAccessFile.setLength(), which translates to ftruncate(), can fail silently. For example, I can set the file length to much more space than is available, and I don't get an error. I'm not sure why else ftruncate() fails, but we've seen cases where the actual file length (as reported by "ls -l") is less than it should be. RandomAccessFile.length(), which seeks to the end of the file, returns the requested value, which is much longer than the available space. I even tried writing and reading the last byte, and I still didn't get an error. Finally, File.length(), which uses stat, returns 0 for the length, and the available space reported by "df" doesn't go down. :-( As a workaround, I'm going to append bytes to the end of the file instead of using ftruncate(), but I thought I should bring these issues to your attention. Thanks, Bob