UU-BCA-SEM-1-Introduction to Informative Technology-Unit 2

UNIT – 2 COMPUTER ORGANIZATION, MEMORY AND STORAGE STRUCTURE

2.0 Learning Objectives

  • Explain definitions of peripheral devices.

  • Describe types of input devices (punched cards, keyboards, mouse, digitizers, scanners) and output devices (printers, plotters, video display terminals, microfilms).

  • Discuss common peripheral devices, their designs, features, advantages, and disadvantages.

  • Gain practical proficiency in using these devices.

2.1 Introduction

  • Computer hardware includes physical parts like electronic ICs, magnetic storage media, and mechanical devices.

  • Peripheral devices connect the computer with the external world.

2.2 Basic Computer Organization

  • Common characteristics across different computers: hardware and software.

  • Key elements of computing process:

    1. Hardware

    2. Software

    3. Data

    4. People

    5. Procedures

  • These elements must work efficiently together to accomplish tasks.

Hardware

  • Physical parts of the computer, can be touched.

  • Divided into four major categories:

    1. Processor

    2. Memory

    3. Input and Output Devices

    4. Storage Devices

Processor

  • Processes data into information; consists of:

    • Arithmetic Logic Unit (ALU)

    • Control Unit

  • Microprocessor is used in personal computers, consisting of interconnected circuits.

Memory

  • Loaded with software and data, primarily RAM (Random Access Memory), which is volatile.

  • Other memory types include ROM (Read Only Memory), which is non-volatile.

  • Measurement of memory storage:

    • Kilobyte (KB) ~ 1000 bytes

    • Megabyte (MB) ~ 1000 KB

    • Gigabyte (GB) ~ 1000 MB

2.3 Input Devices

Types of Input Devices:

  1. Punch Cards:

    • Used to record data in standard codes.

    • Advantages: Cheap, reliable.

    • Disadvantages: Cannot be reused, require careful handling.

  2. Keyboard:

    • Most common input device.

    • Facilitates data entry and editing.

    • Comprises keys for letters, numbers, and functions.

  3. Mouse:

    • Pointing device that enhances input efficiency.

    • Types include mechanical, optical, and optomechanical.

  4. Other Devices:

    • Light pen for CAD applications.

    • Joystick for video games.

    • Touch screen and digitizers to convert graphics to digital formats.

  5. Scanners:

    • Optical Scanner: Uses light sensors to read data.

    • Optical Mark Reader (OMR) and Optical Character Reader (OCR) for reading marks and characters.

2.4 Output Devices

  • Communicate information from the computer:

  1. Printers: Produce hard copies with categories:

    • Impact Printers: Use mechanical force, e.g., dot matrix.

    • Non-Impact Printers: Use inkjet and laser technologies.

  2. Plotters: For drawings and graphs, including X-Y and drum plotters.

  3. Video Display Terminals: Display information immediately and consist of monitors and keyboards.

2.5 Central Processing Unit (CPU)

  • Performs data processing operations, made up of:

    • Processor unit (ALU, registers)

    • Control unit

  • Executes instruction cycles:

    • Fetch, Interpret, Process, Write Data

  • Contains special registers for various tasks:

    • Memory Address Register (MAR), Memory Buffer Register (MBR), Instruction Register (IR).

2.6 The System Bus Architecture

  • A set of wires for moving data, with types being:

    • Data Bus: Carries data, bidirectional.

    • Address Bus: Carries memory addresses, unidirectional.

    • Control Bus: Transmits control signals from the CPU.

2.7 Memory or Storage Unit

  • Primary Storage: RAM, volatile; store temporary data.

  • Secondary Storage: Non-volatile storage, such as magnetic tapes and disks.

  • Characteristics of storage units:

    • Access time, Storage capacity, Cost.

2.8 Let Us Sum Up

  1. Peripheral devices essential for data communication.

  2. Input/output interfaces convert user data into machine-readable form.

  3. Common input devices include punched cards, keyboards, and mice.

  4. Various output devices provide results through printers and display terminals.

2.9 Keywords

  • Peripheral Devices: Communicate between the computer system and the outside world.

  • ROM: Non-volatile memory, stores permanent data.

2.10 Some Useful Books

  • Reference titles for further reading on computer organization and architecture.

2.11 Answer to Check Your Progress

  1. Computer Organization vs. Computer Architecture.

  2. Classifications of microprocessors based on data size.

2.12 Terminal Questions

  1. Write short notes on various input and output devices.