henry (07/20/82)
I can't speak for the 4BSD version of dump, but two independent analyses that I know about (one mine) have concluded that using V6 or V7 dump(8) on a live filesystem is not safe, period. physics!gill's problem sounds like the first one we found: going in through the /dev entries for a file system bypasses all that nice machinery that makes sure everybody always has a consistent view of things like inodes and indirect blocks.