AH = ECh
ES = segment of virtual screen
Desc: Determine the address of the virtual screen to which the program should write instead of the actual video memory, so that the multitasked programs do not interfere with each other's output
Notes: Screen address can change if task-switching is on!. Identical to AH=FCh
See Also: INT 10/AH=FEh - AH=FCh"DoubleDOS" - INT FC"DoubleDOS"
Category: DOS-Based Task Switchers/Multitaskers - Int 21h - D