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24. External Devices and Their Types

The chapter discusses various input/output (I/O) devices and modules, explaining their roles in computer systems, including human-readable and machine-readable devices. It further elaborates on the memory hierarchy, the function of the I/O module, and different methods of data transfer such as programmed I/O, interrupt-driven I/O, and direct memory access (DMA). Additionally, it highlights the importance of error detection and synchronization in device communication.

Sections

External Devices and Their Types

This section covers external devices, categorizing them into human-readable, machine-readable, and storage devices, and explains their roles in computer functionality.

24.1 Section Overview

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24.1.1 Human Readable Devices

This section discusses human-readable devices and their functions, exemplifying how data is input and output through various devices like keyboards, screens, and printers.

24.1.2 Machine Readable Devices

This section introduces machine-readable devices, their functions, and their importance in monitoring and controlling computational processes.

24.1.3 Storage Devices

This section discusses different types of storage devices, their hierarchy, and the role of I/O modules in managing data transfers between devices and the processor.

24.1.4 Memory Hierarchy

This section explores the memory hierarchy in computing, emphasizing the different types of memory and devices used for data storage, processing, and communication.

24.1.5 Communication Devices

The section details the various communication devices and their roles, including human-readable and machine-readable devices, storage devices, and the I/O modules used for data transfer.

24.1.6 I/O Module Overview

This section provides an overview of Input/Output (I/O) modules, detailing their functions, the types of devices they interface with, and the steps involved in data transfer between the CPU and these devices.

I/O Module Functions

This section explains the functions of Input/Output (I/O) modules in relation to how they interact with the processor and various I/O devices.

24.2 Section Overview

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24.2.1 Control and Timing

This section discusses control and timing in input/output modules, highlighting their functions, including CPU communication and data buffering.

24.2.2 CPU Communication

This section discusses the communication between the CPU and various input/output devices through the I/O module, outlining different device categories and data transfer processes.

24.2.3 Device Communication

This section covers the communication between devices and the computer, detailing types of devices, their role in system operations, and the hierarchy of data storage.

24.2.4 Data Buffering

This section discusses the concept of data buffering and the hierarchy of memory within a computer system.

24.2.5 Error Detection

This section discusses the diverse I/O devices, their purposes, and the mechanisms involved in data transfer between the processor and these devices.

I/O Steps

This section outlines the steps involved in input/output (I/O) processing in computer systems, highlighting the roles of various modules and devices.

24.3 Section Overview

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24.3.1 I/O Processing Flow

This section discusses the flow of input/output processing in computers, focusing on human-readable and machine-readable devices, the memory hierarchy, and the role of I/O modules.

Top Level Block Diagram of I/O Module

This section provides an overview of the I/O module's structure and functions, including examples of input and output devices.

24.4 Section Overview

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24.4.1 Connection to Processor

This section discusses the interaction between processors and various input/output devices, exploring the concepts of memory hierarchy, device control, and the role of I/O modules.

24.4.2 Registers and Logic Circuits

This section covers the organization of storage devices and input/output (I/O) modules in computer systems, including memory hierarchies and I/O communication processes.

I/O Module Decisions

This section delves into the functionality of I/O modules, including device types, memory hierarchy, and data transfer techniques.

24.5 Section Overview

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24.5.1 Device Properties Management

This section explores the management of device properties, focusing on the different types of devices, their functions, and how the I/O modules interact with them.

24.5.2 Device Support Options

This section discusses various device support options including human-readable devices, machine-readable devices, and the memory hierarchy relevant to I/O operations.

24.5.3 Control Decisions

This section discusses control decisions in computing, focusing on input/output (I/O) modules, their functions, and the importance of data transfer between devices and processors.

Input/Output Techniques

This section explores input/output (I/O) techniques, highlighting the differences between human-readable and machine-readable devices, as well as the various methods of I/O data transfer.

24.6 Section Overview

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24.6.1 Programmed I/O

This section discusses Programmed Input/Output (I/O) methods, including the operation of I/O modules and the interaction between the CPU and I/O devices.

24.6.2 Interrupt Driven I/O

This section discusses the mechanisms of interrupt-driven I/O, highlighting the importance of I/O modules in coordinating communication between CPUs and various I/O devices.

24.6.3 Direct Memory Access (DMA)

This section elaborates on Direct Memory Access (DMA) and its significance in facilitating efficient data transfer between memory and input/output devices, minimizing processor involvement.

Learning Objectives

  • I/O devices are categorized into human-readable and machine-readable, with specific roles in data input and output.

  • Understanding of memory hierarchy including registers, cache, main memory, and storage devices.

  • I/O modules are responsible for controlling, timing, buffering data, and error detection in device communication.

Key Concepts

I/O Module

A hardware component that manages communication between the CPU and I/O devices, controlling timing, buffering, and error detection.

Memory Hierarchy

The structure that organizes memory from fastest to slowest, including registers, cache, main memory, and hard disks.

Direct Memory Access (DMA)

A method that allows hardware devices to access the main memory independently of the CPU, enabling efficient data transfers.

Programmed I/O

A method of data transfer where the CPU actively checks the status of I/O devices, potentially wasting processor time.

Interruptdriven I/O

A method where the CPU can perform other tasks while waiting for I/O operations to complete, leading to more efficient use of resources.

Practice Exercises

Total Questions

3

Estimated Time

6 min

Passing Score

70%

Instructions

  • Read each question carefully
  • You can use hints if you need help
  • Complete all questions before submitting