SetOSDefault
DefOSPtr pb ; pointer to a 2-byte DefOSRec parameter block returns none
SetOSDefault specifies what operating system is the default. pb is the address of a 2-byte DefOSRec structure. It contains the following fields:
Out-In Name Type Size Offset Description
Notes: The general application of this call is when a partitioned drive is loaded
with more than one operating system.