内存驻留程序的基本思想就是让程序一直停留在内存中，不断的执行特定的命令。但内存驻留如何被执行呢？一般地，内存驻留程序都是通过修改BIOS或DOS的系统中断向量表来实现的。比如修改向量表中16H位置的中断（这个中断接收键盘的按键，在DOS中，按键按下，这个中断就会被调用），让其指向我的程序，这时若有按键被按下，则执行的是我的程序。-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.