HelpPC 2.10	Quick Reference Utility	Copyright 1991 David Jurgens
DOS Undocumented Interrupts, Functions and Structures        INT 15,20   PRINT.COM Critical Region Flag (DOS 3.x+)        INT 21,1F   Get pointer to current drive parameter table        INT 21,32   Get pointer to drive parameter table        INT 21,34   Get address to DOS critical flag (INDOS flag)        INT 21,37   Get/set switch char        INT 21,4B   EXEC/Load and execute (Function 1 undocumented)        INT 21,50   Set current process id (DOS 2.x)        INT 21,51   Get current process id (DOS 2.x)        INT 21,52   Get pointer to DOS "INVARS"        INT 21,53   Generate drive parameter table        INT 21,55   Create new PSP        INT 21,58   Get/set memory allocation strategy (DOS 3.x+)        INT 21,5D   Critical error information (DOS 3.x+)        INT 21,60   Get fully qualified file name (DOS 3.x+)        INT 21,64   Set device driver look ahead  (DOS 3.3+)        INT 21,69   Get/set disk serial number (DOS 4.0+)        INT 21,F8   Set INT 21 OEM handler        INT 28      DOS idle loop/scheduler        INT 29      Fast character output        INT 2E      Execute command using base level COMMAND.COM        BCB         Batch Control Block        DTA         Disk Transfer Area  (partially undocumented)        MCB         Memory Control Block        PSP         Program Segment Prefix Layout (partially undocumented)        SFT         System File Table        - the above items are undocumented with respect to IBM/Microsoft          and should be not be used unless one fully understands the          repercussions        - several functions are version dependant and OEM specific
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