I wouldn't have thought they were that rare or valuable, although I guess there aren't many left in working order.
If I recall correctly, the Hyperdrive was rather unusual for a third party product, in that it:
a) required internal modifications to the Mac
B) didn't void warranty!
The manufacturer had come to some arrangement with Apple and had their product blessed with special holy water from Cupertino or something, because Apple's service manuals actually mentioned it as an upgrade that was "ok". This was really unusual, because with the "closed box" arrangement of the Mac and Apple's exchange program for repairing boards, they were much less tolerant of any modifications to the machine than other manufacturers at the time.
I'm pretty sure I have an old Hyperdrive board kicking around under my house somewhere that I ripped out of a Mac after the original ST-506 interface hard drive failed. It connected with the Mac logic board via a piggyback plug that went over the 68000 CPU.
If I recall correctly, the Hyperdrive was rather unusual for a third party product, in that it:
a) required internal modifications to the Mac
B) didn't void warranty!
The manufacturer had come to some arrangement with Apple and had their product blessed with special holy water from Cupertino or something, because Apple's service manuals actually mentioned it as an upgrade that was "ok". This was really unusual, because with the "closed box" arrangement of the Mac and Apple's exchange program for repairing boards, they were much less tolerant of any modifications to the machine than other manufacturers at the time.
I'm pretty sure I have an old Hyperdrive board kicking around under my house somewhere that I ripped out of a Mac after the original ST-506 interface hard drive failed. It connected with the Mac logic board via a piggyback plug that went over the 68000 CPU.