I occasionally do tech support for field investigators acquiring evidence from hard disks, and have had an interest in digital forensics for many years due to some acquaintances in law enforcement.
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 me.)
Daniel B. Sedory