Variation #2 - Drives Supported if a Switch block is Fitted
If a switch block were to be fitted, the switches would be set according to the drive/s attached.
Switches 1 and 2 configure drive 0.
Switches 3 and 4 configure drive 1.
The information in the above table was sourced from the book: Upgrading and Repairing PCs, Scott Mueller, 5th Edition, page 761/762/763
That matches well with what SpeedStor software reports.
On a computer with variation #2 of the controller fitted, if I activate SpeedStor's ROMLIST switch ( i.e. A:\>sstor /romlist ), the result is: