Principle of Input/Output Software

Goals of I/O Software

Key Issues in the Design of I/O Software (page 343):

    ; 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 348)

     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 353)

    Main functions of each layer (Figure 5.17, page 360)

     Chapter 5 Questions

1

    a) What are the key concepts used in the design of I/O software?

     b) What are the four layers in which I/O software are structured?

    c) What is the function of each of these layers?

2. Do exercise 11, page 428-429.