INT 2F - DBLSPACE.BIN - "DeactivateDrive" - UNMOUNT COMPRESSED DRIVE
        AX = 4A11h
        BX = 0006h
        DL = drive number (0=A:) to unmount
Return: AX = status (0000h,0102h) (see AX=4A11h/BX=0001h)
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=0005h

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