1.1
Introduction
to Computer
This unit introduces the foundational concepts of computing.
We will define what a computer is, its fundamental functions, and the
components that make up a complete computer system.
What is a Computer?
A computer is an electronic device,
operating under the control of instructions stored in its own memory, that can
be programmed to accept data (input), process that data according to specified
rules (processing), produce information (output), and store the information for
future use.
At its core, a computer is a machine designed to perform
calculations and logical operations at high speed.
The Four Basic Functions of a Computer
Every computer, regardless of its size or
type, performs four basic functions:
i.
ii.
Processing: This is
the "brain" of the operation. The computer's Central Processing Unit
(CPU) takes the input data and performs operations on it. This can be anything
from a simple mathematical calculation to complex logical comparisons.
iii.
Output: This is the
process of presenting the processed data (now called information) back to the
user or to another device. Output can be in a human-readable form (like text on
a monitor or a printed document) or in a machine-readable form (like a file
saved to a drive).
iv.
Storage: This is the
computer's memory. It has two main types:
a.
Primary Storage (RAM):
Temporary memory that holds data and instructions while the CPU is actively
working with them. It is fast but volatile (its contents are lost when the
power is turned off).
b.
Secondary Storage:
Long-term, non-volatile memory that stores data and programs for future use
(e.g., hard drives, SSDs, USB flash drives).
Basic Components
of a Computer System
A complete, functioning computer system
requires three essential elements:
i.
Hardware: These are
the physical, tangible parts of the computer that you can see and touch. This
includes:
o
Input Devices:
(e.g., keyboard, mouse, scanner)
o
Output Devices:
(e.g., monitor, printer, speakers)
o
Processing Devices:
(e.g., Central Processing Unit - CPU)
o
Storage Devices:
(e.g., Hard Disk Drive - HDD, Solid-State Drive - SSD, RAM)
ii.
Software: This is
the set of non-physical instructions (programs) that tell the hardware what to
do. Software is broadly divided into two categories:
o
System Software:
Manages the computer's basic functions (e.g., the Operating System like
Windows, macOS, or Linux).
o
Application Software:
Programs designed to help users perform specific tasks (e.g., Microsoft Word,
Google Chrome, games).
iii.
User: This is the
person operating the computer. The user provides the input and benefits from
the output, completing the system's purpose.
1.2
History
& Computer Generation
Computers have evolved dramatically since their inception. This evolution is often categorized into "generations,"
each marked by a significant technological advancement that made computers
smaller, faster, more reliable, and more powerful.
i.
First Generation (1940s -
1950s)
o
Key Technology: Vacuum
Tubes.
o
Characteristics:
These were the first-ever computers. They were massive, often taking up an
entire room. They used thousands of vacuum tubes, which generated immense heat,
consumed a lot of power, and were prone to frequent failures. Programming was
done in machine language (binary 0s and 1s).
ii.
o
Key Technology:
Transistors.
o
Characteristics:
Transistors replaced vacuum tubes. They were significantly smaller, faster,
more reliable, and more energy-efficient. This generation also saw the
development of assembly languages, which were easier to use than machine
language.
o
Examples: IBM 1401,
DEC PDP-1.
iii.
Third Generation (Mid-1960s -
Mid-1970s)
o
Key Technology:
Integrated Circuits (ICs), or "microchips."
o
Characteristics: ICs
placed many transistors onto a single silicon chip. This drastically increased
the computer's speed and efficiency while making them even smaller. For the
first time, computers began to use keyboards and monitors, which interacted
with operating systems.
o
Examples: IBM
System/360.
iv.
Fourth Generation (Mid-1970s -
Present)
o
o
Characteristics:
This generation saw the development of the microprocessor—a single chip that
contains the entire CPU. This innovation made the personal computer (PC)
possible, bringing computing power to individuals and small businesses. This
era also introduced Graphical User Interfaces (GUIs) and computer networking.
o
Examples: Apple II,
IBM PC, and virtually all modern personal computers.
v.
Fifth Generation (Present &
Beyond)
o
Key Technology:
Artificial Intelligence (AI) and Parallel Processing.
o
Characteristics:
This generation is less defined by a single hardware change and more by
function and application. It focuses on concepts like artificial intelligence,
machine learning, natural language processing, and parallel processing (using
many CPUs simultaneously to solve complex problems).
o
Examples: AI-driven
systems (like this one), quantum computers, and modern supercomputers.
1.3
Types
of Computer
Computers come in many shapes and sizes,
classified based on their processing power, size, and intended use.
o
Definition: The
largest, fastest, and most expensive computers in the world. They are often
comprised of thousands of processors working in parallel.
o
Use: Used for
extremely complex, calculation-intensive tasks such as scientific research
(e.g., weather forecasting, climate modeling, nuclear simulations, and genome
sequencing).
o
Definition: Large,
powerful, and highly reliable computers designed for high-volume, secure
transaction processing.
o
Use: The backbone of
large organizations like banks (for processing millions of transactions),
airlines (for reservation systems), and governments. They are known for their
extreme reliability, security, and ability to run for decades without failure.
iii.
Minicomputers (Midrange
Computers)
o
Definition: A class
of multi-user computers that filled the gap between mainframes and
microcomputers.
o
Use: This term is
largely historical. Minicomputers were used as servers for businesses and
departments that needed to support multiple users but could not afford a
mainframe. Today, high-end servers fulfill this role.
iv.
Microcomputers (Personal
Computers)
o
Definition: The most
common type of computer, designed for a single user (hence "personal
computer").
o
Use: Used for a vast
range of everyday tasks, including word processing, browsing the internet,
communication, gaming, and multimedia.
o
Examples:
§ Desktops: Designed to stay in one location.
§ Laptops/Notebooks: Portable, all-in-one computers.
§ Tablets & Smartphones: Also forms of microcomputers,
optimized for portability and touch-based interaction.