Chapter 1: Introduction to Computer System
1.1 Introduction to Computer System
A computer is an electronic device that accepts data (input), processes it, and produces an output.
A computer system includes hardware (physical components) and software (programs and applications).
The main components of a computer system include:
Central Processing Unit (CPU)
Memory (Primary and Secondary)
Input/Output Devices
Storage Devices
1.1.1 Central Processing Unit (CPU)
The CPU, often referred to as the “brain” of the computer, executes instructions and processes data.
The CPU is made up of:
Arithmetic Logic Unit (ALU): Handles arithmetic and logical operations.
Control Unit (CU): Directs the flow of data within the computer.
Registers: Temporary storage areas within the CPU used for quick access to data during processing.
1.1.2 Input Devices
Input devices are tools used to send control signals to a computer, allowing users to input data.
Examples include:
Keyboard, Mouse, Scanner, Touch Screen.
Specialized input tools like braille keyboards for visually impaired users.
1.1.3 Output Devices
Output devices display or output the data processed by the computer in human-understandable form.
Common examples:
Monitor, Printer, Speakers, and 3D Printers (used in various fields, including manufacturing and medicine).
1.2 Evolution of Computer Systems
Computer systems have advanced from simple calculators to highly complex processors over time.
Von Neumann Architecture: Fundamental design that includes the CPU, memory, input/output devices, and communication channels.
Timeline of Key Developments in Computing Technology
Abacus: The earliest mechanical device for calculations.
Pascaline: Blaise Pascal’s early mechanical calculator.
Analytical Engine: Developed by Charles Babbage, considered the first concept of a modern computer.
ENIAC/EDVAC: Early computers using Von Neumann’s concept of stored programs.
Integrated Circuits: Revolutionized computer size and efficiency by combining multiple electronic circuits on a single chip.
Microprocessors: Enabled the creation of personal computers by integrating the CPU on a single chip.
1.3 Computer Memory
1.3.1 Units of Memory
Computers store and process data using binary digits (bits). Bits are grouped into larger units:
Nibble: 4 bits
Byte: 8 bits
Larger memory units include:
Kilobyte (KB), Megabyte (MB), Gigabyte (GB), Terabyte (TB), and beyond.
1.3.2 Types of Memory
Primary Memory:
RAM (Random Access Memory): Volatile memory that temporarily holds data for quick access.
ROM (Read-Only Memory): Non-volatile memory storing essential programs that cannot be modified easily.
Cache Memory:
A high-speed memory between the CPU and RAM that stores frequently accessed data to improve processing speed.
Secondary Memory:
Non-volatile memory with large storage capacity, used for long-term data storage. Examples include Hard Disk Drives (HDD), Solid-State Drives (SSD), and CDs/DVDs.
1.4 Data Handling in Computers
1.4.1 Data Capturing, Storage, and Retrieval
Data Capturing: Collecting digital data from sources like barcode readers, sensors, and social media.
Data Storage: Saving captured data in files or databases for future use. Large organizations use data servers to manage vast amounts of data.
Data Retrieval: Accessing stored data for processing as needed.
1.4.2 Data Deletion and Recovery
Data Deletion: Removing data entries or freeing up storage without fully erasing data, which allows potential recovery.
Data Recovery: Recovering accidentally deleted or corrupted data using special tools, provided the data has not been overwritten.
1.5 Software in Computer Systems
1.5.1 Definition and Need for Software
Software: A set of instructions that tells the computer how to operate. Hardware requires software to function.
Categories of Software:
System Software: Manages the core operations of the computer (e.g., Operating System, Device Drivers).
Application Software: Performs specific tasks for the user (e.g., Word Processors, Web Browsers).
Programming Tools: Assist in software development (e.g., Compilers, Text Editors).
1.5.2 System Software
Operating Systems: Enable interaction with the computer and manage other programs.
System Utilities: Maintenance tools like disk defragmenters and anti-virus programs.
Device Drivers: Allow the operating system to communicate with hardware peripherals.
1.5.3 Application Software
General Purpose Software: Used by a broad audience for common tasks (e.g., Microsoft Word, Adobe Photoshop).
Customised Software: Tailor-made software to meet specific organizational or individual needs (e.g., School Management Systems).
1.5.4 Proprietary vs. Open Source Software
Proprietary Software: Commercial software with restricted access to the source code (e.g., Microsoft Windows).
Open Source Software (FOSS): Free software with accessible source code, encouraging collaboration (e.g., Linux, Mozilla Firefox).
Summary of Key Concepts
A computer system combines hardware and software to process data.
The CPU executes instructions and processes data, assisted by memory and storage devices.
Software acts as an intermediary between hardware and users, with various types catering to different functions.
Modern computers are integral to daily life, continually evolving with technological advancements.
