Casio IT-2000W - Manual (Page 102)

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7.6 Virtual Keyboard Driver
7.6.1 Function
The Virtual Keyboard Driver (VKD.386) is a driver that enables access to the keyboard controller
on Windows (refer to Chapter 6 "Keyboard Controller"). This driver is only called from the system
library. Since this driver has no chance of being directly called from the application program, the
user does not have to be aware of its existence. Some of the system libraries use the functions of the
keyboard controller. However, Windows applications cannot directly access the hardware.
Therefore, they use this virtual keyboard driver to access the keyboard controller assuming that it is
a virtual machine. The relationship between the virtual keyboard driver and application programs is
shown in the following diagram.
Fig. 7.4
Application Program
System Library
Virtual Keyboard Driver
Windows
Keyboard Controller