The only Model
1/III/4 that came stock with DS drives was the 4D. Any other
DS setup was third-party. The stock III/4 controllers (both the add-on in
the III and early 4 and the built-in on the gate-array 4) had no problems
with DS drives.
Does that imply that merely substituting DS drives would make a 4 DS
capable, or were there some other modifications necessary?
I had a gate-array Model 4 that I installed two DSQD drives in without
any other modification (other than replacing the floppy cable that used
missing connectors for drive select).