I occasionally did tech support for field investigators acquiring evidence from hard disks, and have had an interest in digital forensics for many years due to acquaintances in law enforcement. It was because of this that we sent a request to Stefan Fleischmann, the author of WinHex, to add the "!" (not) feature to its Hex search, so we could rapidly move through countless sectors of zero bytes using "!00" when searching for anything that was not zero. For a floppy full of F6 bytes, you could use "!F6"; you get the idea. My name also appeared in one of Stefan's templates.
In the field of Data Recovery, I've been involved with [TestDisk] for many years.
Some here may find my pages about the early IBM PC diskettes of interest: Hidden Bytes from the Past: A Forensic Examination of the IBM® Personal Computer™ DOS Version 1.00 (1981) Diskette. (Other mirror sites are available; Google my full name below.)
Daniel B. Sedory