Introduction to I/O Devices

Before delving into the main content of this part of the course (on persistence), we first introduce the concept of an input/output (I/O) device and show how the operating system might interact with such an entity. I/O is quite critical to computer systems, of course. Imagine a program without any input (it produces the same result each time); now imagine a program with no output (what was the purpose of it running?). Clearly, for computer systems to be interesting, both input and output are required. And thus, our general problem:

CRUX: HOW TO INTEGRATE I/O INTO SYSTEMS

How should I/O be integrated into systems? What are the general mechanisms? How can we make them efficient?