FOC UNIT-I Introduction to Computers .pdf

Fundamentals of Computers Unit-I BCA Semester I
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Notes by Dr. Chandrakantha T S, Vagdevi College of BCA, Melinakuruvalli, Thirthahalli-577 432
📚 For more notes and resources, visit: https://sites.google.com/view/chandrakanthats/bca
Unit-I: Introduction to Computers
Computer Definition
• A computer is a programmable electronic device that accepts input, processes data
according to given instructions, stores information, and produces output at high speed
and with great accuracy.
• The word computer comes from “compute,” meaning to calculate. It is also called a data
processor as it stores, processes, and retrieves data.
• Data is raw material used as input to data processing and information is processed data
obtained as output.
Examples of Computers:
1. Desktop Computer – Used in homes, offices, and schools (Example: Dell, HP).
2. Laptop – Small and portable (Example: Lenovo, MacBook).
3. Server – Gives data or services to other computers (Example: Web server).
4. Supercomputer – Very powerful, used for research and weather study (Example: PARAM
(India), Summit (USA)).
5. Embedded Computer – Used inside machines like washing machines, ATMs, and smart
TVs.

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Characteristics of Computers
A computer is a fast, accurate, and reliable electronic machine. key characteristics are:
1. Automatic Operation: Works automatically after loading a program.
Example: Printer prints pages without manual help.
2. High Speed: Performs millions or billions of instructions per second.
Example: Generates reports quickly.
3. Accuracy: Produces correct results if input and instructions are correct.
Example: Used in banking and scientific calculations.
4. Diligence: Can work continuously without getting tired.
Example: Web servers operate 24/7.
5. Versatility: Can perform different types of tasks.
Example: Typing, programming, video editing.
6. Large Memory: Can store huge data and programs for later use.
Example: Cloud servers store data for millions of users.
7. No Intelligence: Cannot think or make decisions by itself.
Example: Calculator gives wrong result if input is wrong.
8. No Emotions: Cannot feel or respond emotionally.
Example: Computer does not sympathize with mistakes.

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History of Computers
• Computers have developed from simple mechanical machines to modern electronic
systems.
• The history of computers can be divided into two main eras:
i)Mechanical Devices (17th Century)
Started in the 17th century using gears, wheels, and levers, these machines performed basic
arithmetic but had limited speed and flexibility.
1. Blaise Pascal (France, 1642): Invented Pascaline, the first mechanical adding machine.
2. Gottfried Wilhelm von Leibniz (Germany, 1671): Invented the Stepped Reckoner, a
calculator capable of multiplication.
3. Charles Babbage (England, 1822 / 1842) – Called Father of Modern Computers:
Designed the Difference Engine for computing mathematical tables and proposed the
Analytical Engine, a fully automatic mechanical computer for arithmetic operations.
4. Christopher Latham Sholes (USA, 1868): Developed keyboard machines for typing
and data input.
5. Herman Hollerith (USA, 1890): Created the punched card system for data processing.
ii)Modern Digital Systems (20th Century)
Began in the 20th century using electronic components like vacuum tubes, transistors, and ICs,
making computers fast, programmable, versatile, and introducing the stored-program concept,
with major developments in the USA and UK.

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1. Atanasoff-Berry Computer (ABC) (1942) – First electronic digital computer using
binary logic; designed by John Atanasoff and Clifford Berry for solving linear equations.
2. Harvard Mark I (1944) – First electromechanical programmable computer built at
Harvard University; used relays and switches to perform calculations automatically.
3. ENIAC (Electronic Numerical Integrator and Calculator) (1946) – First general-
purpose fully electronic computer; used vacuum tubes and could perform thousands of
calculations per second.
4. EDVAC (Electronic Discrete Variable Automatic Computer) (1949) – Introduced the
stored-program concept, allowing instructions and data to be stored in memory, during
World War II to calculate artillery firing tables.
5. EDSAC (Electronic Delay Storage Automatic Calculator) (1949) – First computer to
execute a program stored in memory; used mercury delay line memory.
6. Manchester Mark-I (1949) – Early stored-program computer prototype developed at
the University of Manchester; laid the foundation for modern computers
7. UNIVAC-I (Universal Automatic Computer-I) (1951) – First commercial digital
computer; used for business and government applications like census data.
8. IBM 701 (1952) – IBM’s first scientific computer designed for engineering and defense
calculations.
9. IBM 650 (1953) – First mass-produced commercial computer; widely used in
universities and businesses.

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Computer Generations
The term "generation" in computer technology refers to a step in the evolution of hardware,
software, speed, size, cost, and performance.
1. First Generation (1942–1955): Computers used vacuum tubes and were mainly for scientific
calculations.
Hardware: Vacuum tubes, punch cards
Software: Machine & assembly languages
Features: Bulky, slow, unreliable
Examples: ENIAC, EDVAC, UNIVAC-I, IBM 701
2. Second Generation (1955–1964): Computers used transistors and supported high-level
programming languages.
Hardware: Transistors, magnetic core memory
Software: High-level languages (FORTRAN, COBOL)
Features: Faster, smaller, reliable, batch processing
Examples: IBM 7030, UNIVAC LARC, Honeywell 400
3. Third Generation (1964–1975): Computers used Integrated Circuits (ICs), introducing
minicomputers.
Hardware: Small-Scale Integration & Medium-Scale Integration ICs (SSI & MSI),
magnetic disks
Software: Time-sharing OS, high-level languages
Features: User-friendly, commercial use increased
Examples: IBM 360/370, PDP-8(Programmed Data
Processor), PDP-11, CDC 6600
4. Fourth Generation (1975–1989): Computers used VLSI (Very Large-Scale Integration) chips
and microprocessors for personal computing.
Hardware: VLSI chips, microprocessors, hard/floppy disks
Software: GUI (Graphical User Interface) OS (Windows), C/C++, UNIX
Features: Affordable, general-purpose, object-oriented programming
Examples: IBM PC, Apple II, TRS-80, CRAY-1, VAX 9000

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5. Fifth Generation (1989–2025 / Current): Computers are powerful, portable, and support AI,
cloud computing, multimedia, and smart devices.
Hardware: ULSI (Ultra-Large-Scale Integration) chips, multicore processors, SSDs,
notebooks
Software: Internet, Java, Python, AI tools
Features: AI-enabled, portable, multimedia, cloud computing
Examples: iPhone, iPad, Pentium PCs, PARAM, IBM SP/2
6. Sixth Generation (2025–Future / Emerging): Computers will use quantum and brain-
inspired technologies for ultra-fast, intelligent computing.
Hardware: Quantum computers, neuromorphic chips, 6G/Edge devices
Software: Deep learning, neural networks, AGI frameworks, quantum algorithms
Features: Self-learning AI, brain-like computing, ultra-fast, secure, energy-efficient
Examples: Google Sycamore, IBM Quantum, Intel Loihi, future AGI systems
Anatomy of Computer
A computer system is made of several interconnected units that work together to process data and
provide meaningful output.
The main components are:
1. Input Units: Input units allow users to provide data and instructions to the computer for
processing.
Examples: Keyboard (to type), Mouse (to select), Scanner (to convert documents), Microphone
(audio input), Camera/Webcam (images/videos).

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2. Central Processing Unit (CPU=ALU+CPU): The CPU is the brain of the computer,
processing all instructions.
It has two main parts:
a) Arithmetic and Logic Unit (ALU): Performs arithmetic (+, - . x, /) and logical operations
(AND, OR, comparisons)
b) Control Unit (CU): Directs operations, fetches instructions from memory, decodes and
executes them using the ALU
Examples: Intel Core i7, AMD Ryzen 9, Apple M2, and Qualcomm Snapdragon are popular CPUs
used in computers and smartphones.
3. Storage Units: Storage units are used to store data, instructions, and results.
There are main two types:
a) Primary Storage (Main/ Volatile/ Temporary Memory)
• It is the high-speed memory directly accessed by the CPU, used to store data and
instructions during execution.
• It is temporary (Volatile) in nature and loses data when power is off.
• Examples: RAM (Random-Access Memory), ROM (Read Only Memory) Registers,
Cache Memory.
b) Secondary Storage (External/Non-volatile/ Permanent Memory)
• It is permanent storage used to store the operating system, software, and user data.
• It retains(Non-volatile) information even when power is off, offering large capacity but
slower access than primary memory.
• Examples: Hard Disk Drive (HDD), Solid State Drive (SSD), Optical Discs (CD/DVD),
USB Flash Drive, Memory Card.
4. Output Devices: Output devices present processed information in a human-readable form
such as text, images, or sound.
Examples: Monitor (visual display), Printer (hard copy), Speaker (audio output), and Projector
(large-screen display).

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Types of Computers
• Computers are classified by size, speed, processing power, and purpose.
• By size, they include supercomputers, mainframes, minicomputers, workstations, personal
computers, and microcomputers.
• By function, they can be general-purpose (perform multiple tasks) or special-purpose
(designed for specific tasks).
• By data processing, they are classified as analog computers (process continuous data),
digital computers (process discrete data), or hybrid computers (combine features of both
analog and digital).
The main types are:
1. Supercomputer (Special-purpose): Extremely high-performance computer, largest and
fastest, used for complex scientific calculations and simulations.
Examples: PARAM (India), Summit (USA), Fugaku (Japan)
2. Mainframe (General-purpose): High-performance, large computer used for large-scale
data processing and supporting multiple users simultaneously.
Examples: IBM Z Series, UNIVAC, Hitachi Z800

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3. Workstation (General-purpose): High-performance single-user computer designed for
technical and scientific tasks such as CAD(Computer-Aided Design), graphics, and
simulations.
Examples: Lenovo ThinkStation, Dell Precision, HP Z Series
4. Minicomputer (General-purpose): Medium-performance, mid-sized computer
supporting multi-user and multitasking operations in medium-sized businesses.
Examples: PDP-11, VAX, IBM AS/400
5. Personal Computer (PC) (General-purpose): Moderate-performance computer for
individual use, user-friendly and suitable for daily tasks.
Examples: HP Pavilion, Dell Inspiron, Apple MacBook, Lenovo IdeaPad
6. Microcomputer (Special-purpose): Low-performance, compact and low-cost computer
used in embedded systems, portable devices, and small electronics.
Examples: Raspberry Pi, Arduino, Smartwatches, Gaming Consoles (PlayStation, Xbox)
7. Analog Computer (Special-purpose): Processes continuous data, mainly used in
scientific and engineering calculations.
Examples: Speedometers, Thermometers
8. Digital Computer (General-purpose): Processes discrete data, widely used in personal,
commercial, and industrial applications.
Examples: Laptop, Desktop, Smartphone
9. Hybrid Computer (Special-purpose): Combines features of analog and digital computers
to process both continuous and discrete data.
Examples: Industrial process control systems, Medical imaging machines
10. Embedded Computer (Special-purpose): A small computer built into other devices to
perform dedicated functions automatically.
Examples: Washing machines, ATMs, Smart TVs, Traffic signals

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Types of Software
Computer software is a set of programs that tell the computer how to perform tasks. It is mainly
divided into System Software and Application Software.
I) System Software: Helps manage the computer system and provides a platform for
application software.
It includes:
1)System Management Software: Manages hardware and system resources.
a) Operating System (OS): Manages hardware and software resources.
Example: Windows 10/11, Linux, Android
b) Device Drivers: Allow the OS to communicate with hardware devices.
Example: Printer driver, Audio driver,Graphics card driver
c) Utility Programs: Perform maintenance tasks like file management, antivirus, backup.
Example: Disk Cleanup, Norton Antivirus
2)Software Development Tools: Helps programmers develop software.
a) Linker and Loader: Combines program modules and loads into memory.
Example: GNU Linker (ld)
b) Debugger: Helps find and fix errors in programs.
Example: GDB (GNU Debugger)
c) Language Translators: Converts code from high-level language to machine language.
Example: Compiler, Interpreter, Assembler

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II) Application Software: Helps users perform specific tasks.
1)General-purpose Software: Used for common tasks by all users.
Example: MS Word, Excel, PowerPoint, Web Browsers
2)Special-purpose Software: Designed for specific tasks or industries.
Example: Tally (accounting), AutoCAD (engineering), Photoshop (graphics)
Computer Languages
Computer languages are used to give instructions to a computer. Based on abstraction from
hardware, they are classified into three types:
1. Machine-Level Language: A low-language of binary code (0s and 1) directly executed by the
computer’s processor.
Features:
• Fastest to execute
• Hardware-dependent(can’t run on different systems).
• Difficult to write, read, and debug
Example:
10110100 00000001 (Binary instruction for a processor)

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2. Assembly-Level Language: A middle-level language using symbolic codes (mnemonics) to
represent machine instructions, converted by an assembler.
Features:
• Easier to read than machine language
• Still hardware-specific
• Requires an assembler to convert it into machine code
Example:
MOV R1, 03 ; Move the value 03 into register R1
MOV R2, 02 ; Move the value 02 into register R2
ADD R3, R2, R1 ; Add the values in R2 and R1, store the result in R3 (R3 = R2 + R1)
3. High-Level Language: A high-level language human-readable, portable programming
language that requires a compiler or interpreter to run.
Features:
• Easy to learn and use
• Portable and hardware-independent (can run on different systems).
• Requires compiler or interpreter to convert into machine code
Examples: C – System programming, Python – General-purpose, data science, Java – Web and
enterprise applications
Sample Code in Python:
a = 5
b = 3
sum = a + b
print("Sum is:", sum)

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Languages Translators
• Languages Translators/Languages processor are System software that converts code from
human-readable language into machine code that the computer can execute.
• There are three main types of translators:
1. Assembler: A translator that converts assembly language instructions (mnemonics) into
machine code for the computer to execute.
Features:
• Translates one mnemonic instruction at a time.
• Output is fast and efficient.
• Still hardware-dependent.
Example:
MOV A, 05H ; Assembly code
↓
10110000 00000101 ; Machine code (Binary)
2. Compiler: A translator that converts an entire high-level language program into machine code
before execution, producing an executable file.
Example Languages & Tools: C/C++ → GCC, Turbo C; Java → javac + JVM

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Features:
• Translates the whole program before execution.
• Faster execution after compilation.
• Reports all errors (e.g. syntax errors) after full translation.
• Generates an executable file (.exe).
Example:
→SUM = A + B (High-Level Language)
→ Compiler → 10110000 00000001 (Machine Code, saved as sum.exe)
→ Run sum.exe SUM = 8 (Output)
3. Interpreter: A translator that converts and executes high-level language code line-by-line
without creating a separate machine code file.
.
Example Languages & Tools: Python → Python Interpreter, JavaScript → Node.js
Features:
• Slower than compiler (no pre-compilation).
• Stops immediately on first error.
• Good for debugging and learning.
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FOC UNIT-I Introduction to Computers .pdf

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FOC UNIT-I Introduction to Computers .pdf