## Virtual Device Driver Reference for OS/2

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### BIOS Support

Since the BIOS INT 16h service only references the BIOS data area for keystrokes, the BIOS continues to provide this service.

The BIOS INT 09h interrupt service routine, however, is emulated within the virtual keyboard device driver. When the INT 09h vector is invoked, the virtual keyboard device driver passes the character to the physical device driver, which translates the character according to the current translation table.

It is possible for an application or a DOS memory-resident program to hook the INT 09h vector. Often, such applications simply monitor keystrokes, and pass them on to the previously-hooked interrupt service routine. In this case, the virtual keyboard device driver emulation code still runs and translates scan codes according to the current translation table. Otherwise , if an application that has hooked INT 09h fails to pass the scan code on, then the scan code is not translated, or placed into the BIOS data area by the virtual keyboard device driver.