Operating System Concepts, 8th Edition

CHAPTER 13

I/O Systems

 

13.1 Overview

13.2 I/O Hardware

13.3 Application l/O Interface

13.4 Kernel I/O Subsystem

13.5 Transforming I/O Requests to Hardware Operations

13.6 STREAMS

13.7 Performance

13.8 Summary

Practice Exercises

Exercises

Wiley Plus

Bibliographical Notes

 

The two main jobs of a computer are I/O and processing. In many cases, the main job is I/O, and the processing is merely incidental. For instance, when we browse a Web page or edit a file, our immediate interest is to read or enter some information, not to compute an answer.

The role of the operating system in computer I/O is to manage and control I/O operations and I/O devices. Although related topics appear in other chapters, here we bring together the pieces to paint a complete picture of I/O. First, we describe the basics of I/O hardware, because the nature of the hardware interface places constraints on the internal facilities of the operating system. Next, we discuss the I/O services provided by the operating system and the embodiment of these services in the application I/O interface. Then, we explain how the operating system bridges the gap between the hardware interface and the application interface. We also discuss the UNIX System V STREAMS mechanism, which enables an application to assemble pipelines of driver code dynamically. Finally, we discuss the performance aspects of I/O and the principles of operating-system design that improve I/O performance.

CHAPTER OBJECTIVES

• To explore the structure ...