INT 2F U - DOS 3.2+ - SET DISK INTERRUPT HANDLER AH = 13h DS:DX -> interrupt handler disk driver calls on read/write ES:BX = address to restore INT 13 to on system halt (exit from root shell) or warm boot (INT 19) Return: DS:DX set by previous invocation of this function ES:BX set by previous invocation of this function Notes: IO.SYS hooks INT 13 and inserts one or more filters ahead of the original INT 13 handler. The first is for disk change detection on floppy drives, the second is for tracking formatting calls and correcting DMAsee Direct Memory Access boundary errors, the third is for working around problems in a particular version of IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911.'s ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs. BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. before the first call, ES:BX points at the original BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. INT 13; DS:DX also points there unless IO.SYS has installed a special filter for hard disk reads (on systems with model byte FCh and BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. date "01/10/84" only), in which case it points at the special filter most DOS 3.2+ disk access is via the vector in DS:DX, although a few functions are still invoked via an INT 13 instruction during Windows 3.1 startup this function seems to be used to temporarily point DOS to a dummy handler in WDCTRL.386 which always halts the system with a fatal error message. If DS hasn't changed on return from the function, Windows will display the error message "Invalid DOS version". this is a dangerous security loophole for any virus-monitoring software which does not trap this call ("INT13", "Nomenklatura", and many Bulgarian viruses are known to use it to get the original ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs. entry point) the preloadable Novell DOS 7+ SECURITY.BIN driver $SECURE$ traps this call. BUG: Novell DOS 7 IBMBIO.COM before 1995-05-08 trashed AX on return from this function. VGACOPY by Thomas Mönkemeier's VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. Software GmbH crashed due to this. Later releases of Novell DOS 7 preserved the contents of the AX register. SeeAlso: INT 13/AH=01h,INT 19,INT 9D"VIRUS"