UI Management Application Interface just as drivers provide a way for applications to make use of hardware subsystems without having to know every detail of the hardware's operation, application program interfaces ( APIs ) let application programmers use functions of the computer and operating system without having to directly keep track of all the details in the CPU's operation. Let's look at the example of creating a hard disk file for holding data to see why this can be important. A programmer writing an application to record data from a scientific instrument might want to allow the scientist to specify the name of the file created. The operating system might provide an API function named MakeFile/COPY CON for creating files. When writing the program, the programmer would insert a line that looks like this: MakeFile [1, %Name, 2] In this example, the instruction tells the operating system to creat...