Re: Compaq 'security'?
"You had to know the original virtual cylinder/head/sector values "
Which were usually written on the top of the drive.
For old enough drives, they weren't. I used to carry around a book with thousands of CHS values for various drives in it.
Plus, for added laughs, people would often put the wrong number of heads or sectors in. So the drive would sort-of work, but not all of it would be accessible. And they would then get cross when you tried to upgrade their PC. "How can I have lost all my files?????"