INT 2F - OS/2 compatibility box - SWITCHING DOS TO BACKGROUND
AX = 4001h
Note:   called by OS/2 when the DOS box is about to be placed in the background
and the video driver should save any necessary state
SeeAlso: AX=4005h

See also: 2F4002

2F4001 - OS/2 compatibility box - SWITCHING DOS TO BACKGROUND