3) Mark I, V, VI, X or XI disk packs
I'm not familiar with those model names but I suspect I might know them as a
"Memorex brand 2315 cartridge" or "Memorex brand 3330 pack" or
similar.
Was Memorex the first maker of IBM-compatible packs? Where did Caelus come in the scheme?
For a while in the mid-2000's there was a Memorex brand USB keychain drive, which I
swear was styled to look exactly like a miniature little disk pack. Not a very efficient
of pocket space but wow, did it look like an old disk pack :-).
4) A Data Mark module
Help refresh my memory... Data Mark was Memorex's version of the IBM 3348? Head and
positioner inside the cartridge?