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.


Switch Settings

Switches 1 and 2 configure drive 0.
Switches 3 and 4 configure drive 1.

Table
Address		 Switch Settings
for C:		 Drive Characteristics Comment
0 1=on  2=on  Cylinders = 306  /  Heads = 2  /  WPC = 0  /  a step rate of 3 ms is valid  milliseconds, not microseconds
1 1=on  2=off  Cylinders = 375  /  Heads = 8  /  WPC = 0  /  step pulses per here are valid  
2 1=off  2=on  Cylinders = 306  /  Heads = 6  /  WPC = 256  /  step pulses per here are valid  
3 1=off  2=off  Cylinders = 306  /  Heads = 4  /  WPC = 0  /  step pulses per here are valid  What gets selected if no switch block


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:

Table Cylinders Heads WPC Control
0 306 2 0 0
1 375 8 0 5
2 306 6 256 5
3 306 4 0 5