Principle of Input/Output Software Goals of I/O Software Key Issues in the Design of I/O Software (page 352): Device independence Uniform naming Error handling Synchronous (blocking) versus asynchronous (interrupt-driven) transfer Buffering Shared and dedicated devices: the O.S must be able to handle both shared and dedicated devices in a way that avoids problems. Input / Output Layers (Figure 5.11, page 356) User-Level I/O Software Device-Independent I/O Software Device drivers Interrupt handlers Hardware Functions done in the device independent software: (Figure 5.13, Page 361) Main functions of each layer (Figure 5.17, page 368) Chapter 5 Questions 1 a) b) c) 2. What are the key concepts used in the design of I/O software? What are the four layers in which I/O software are structured? What is the function of each of these layers? Do exercise 14, page 430.