Al writes: In fact I distrust filesystems, OS's, data busses, etc., more than I distrust the rotating rust. And the more expensive or complicated the filesystems, OS's, and data busses become, the less I feel I should trust them. Many years ago I had a hard drive whose write gate failed "safe". You mean I just verified the cache instead of the media? I don't think I am putting excessive faith in bunzip2 -v, md5, and sha1, but you could try to convince me otherwise. Silent corruption of data is my worst fear of all. It's even worse than when Mr. Bemis's glasses break at the end of that Twilight Zone episode - it's more like he opened all the books and found them blank. Finding out the data wasn't there where I expected it, is far more disappointing than knowing it's there but I can't see it. Tim.