An adapter device driver command line contains three classes of parameters:

• Adapter Device Driver Parameters
  Adapter device driver parameters apply to all adapters and units managed by an adapter device driver unless overridden by adapter parameters or unit parameters.
  
• Adapter Parameters
  Adapter parameters begin with the (/A) switch and identify a specific adapter card. Parameters following the (/A) switch apply only to the adapter card indicated.
  
• Unit Parameters
  Unit parameters apply specific units on an adapter.

Note: In some cases, a parameter may appear as both an Adapter parameter and a Unit parameter. If the host adapter hardware supports specifying a parameter on a per-unit basis, then it is recommended that the adapter device driver support both the per-Adapter and per-Unit forms of the parameter.