Introduction - If you have any usage issues, please Google them yourself
Memory of the basic idea of the presence of the procedure is to remain in the memory process has been, and continue to the implementation of specific command. However, the presence of how memory was enforced? In general, the memory resident programs by modifying the BIOS or DOS interrupt to the system to achieve the scale. For example, modifications to the scale location 16H interrupt (interrupt reception of the keyboard keys, in the DOS, the button pressed, the interrupt will be called), to point to my program, if this button is pressed, then I implemented procedures.