Index

 COMPUTER

│

├── 1. Introduction to Computer

│   ├── Definition of Computer

│   ├── Characteristics of Computer

│   ├── Advantages and Disadvantages

│   ├── Applications of Computer

│   └── History / Generations of Computer

│

├── 2. Types of Computer

│   ├── Analog Computer

│   ├── Digital Computer

│   ├── Hybrid Computer

│   ├── Micro Computer

│   ├── Mini Computer

│   ├── Mainframe Computer

│   └── Super Computer

│

├── 3. Functional Units of Computer

│   ├── Input Unit

│   ├── Processing Unit

│   │   ├── ALU

│   │   ├── CU

│   │   └── Registers

│   ├── Memory Unit

│   └── Output Unit

│

├── 4. Hardware

│   ├── Input Devices

│   │   ├── Keyboard

│   │   ├── Mouse

│   │   ├── Scanner

│   │   ├── MICR

│   │   ├── OCR

│   │   ├── OMR

│   │   ├── Joystick

│   │   └── Light Pen

│   │

│   ├── Output Devices

│   │   ├── Monitor

│   │   ├── Printer

│   │   ├── Plotter

│   │   ├── Speaker

│   │   └── Projector

│   │

│   ├── Storage Devices

│   │   ├── Primary Storage

│   │   │   ├── RAM

│   │   │   ├── ROM

│   │   │   └── Cache

│   │   └── Secondary Storage

│   │       ├── Hard Disk

│   │       ├── SSD

│   │       ├── CD/DVD

│   │       ├── Pen Drive

│   │       └── Floppy Disk

│   │

│   └── Processing Devices

│       ├── CPU

│       └── GPU

│

├── 5. Software

│   ├── System Software

│   │   ├── Operating System

│   │   ├── Utility Program

│   │   └── Language Translator

│   │       ├── Compiler

│   │       ├── Interpreter

│   │       └── Assembler

│   │

│   ├── Application Software

│   │   ├── General Purpose

│   │   └── Customized Software

│   │

│   └── Programming Software

│

├── 6. Programming Language

│   ├── Machine Language

│   ├── Assembly Language

│   ├── High Level Language

│   └── 4GL / 5GL

│

├── 7. Operating System

│   ├── Functions of OS

│   ├── Types of OS

│   ├── Windows

│   ├── Linux

│   ├── DOS

│   └── Android

│

├── 8. Number System

│   ├── Decimal

│   ├── Binary

│   ├── Octal

│   ├── Hexadecimal

│   └── Conversion

│

├── 9. Computer Memory

│   ├── Bit, Nibble, Byte

│   ├── KB, MB, GB, TB

│   ├── RAM

│   ├── ROM

│   └── Cache

│

├── 10. Computer Graphics

│   ├── Pixel

│   ├── Resolution

│   ├── CGA

│   ├── EGA

│   ├── VGA

│   └── SVGA

│

├── 11. Computer Network

│   ├── LAN

│   ├── MAN

│   ├── WAN

│   ├── PAN

│   ├── Topology

│   ├── Internet

│   ├── Intranet

│   └── Extranet

│

├── 12. Internet and Email

│   ├── WWW

│   ├── Website

│   ├── Webpage

│   ├── Browser

│   ├── Search Engine

│   ├── Email

│   └── Social Media

│

├── 13. Cyber Security

│   ├── Virus

│   ├── Worm

│   ├── Trojan

│   ├── Antivirus

│   ├── Firewall

│   └── Hacking / Cracking

│

├── 14. Database

│   ├── Data

│   ├── Information

│   ├── DBMS

│   ├── RDBMS

│   └── SQL

│

├── 15. Microsoft Office

│   ├── MS Word

│   ├── MS Excel

│   ├── MS PowerPoint

│   ├── MS Access

│   └── Outlook

│

└── 16. Recent Technology

    ├── AI

    ├── Robotics

    ├── Cloud Computing

    ├── IoT

    └── Blockchain

Terminologies

 Basic Terminolgies

Computer – An electronic device that accepts data, processes it, and gives output.

Data – Raw facts and figures without meaning.

Information – Processed and meaningful data.

Processing – The act of converting data into information.

Instruction – A command given to a computer.

Program – A set of instructions to perform a task.

Hardware – Physical parts of a computer that can be touched.

Software – A collection of programs and instructions.

Firmware – Permanent software stored in ROM.

Liveware / Peopleware – The human users who operate the computer.

User – A person who uses the computer.

Input – Data entered into a computer.

Output – Result produced by the computer.

Storage – Place where data/information is kept.

Device – Any hardware component attached to a computer.

System – A combination of related parts working together.

Application – Software designed for specific tasks.

Utility – Software used for maintenance and protection.

File – A collection of related data stored together.

Folder / Directory – A place to store files.

Icon – A small graphical symbol representing a file/program.

Desktop – The main screen of an operating system.

Window – A rectangular area showing a program or file.

Taskbar – Bar showing running programs, usually at the bottom.

Booting – The process of starting a computer.

Rebooting – Restarting the computer.

Login / Logon – Entering credentials to access a system.

Logout / Logoff – Exiting from a system account.

Password – Secret code used for security.

Username – Name used to identify a user.

 Functional Unit Terminolgies

Input Unit – Accepts data and instructions from the user.

Output Unit – Displays or prints the processed result.

Memory Unit – Stores data, instructions, and results.

Control Unit (CU) – Controls and coordinates all operations of the computer.

Arithmetic Logic Unit (ALU) – Performs arithmetic and logical operations.

Central Processing Unit (CPU) – The brain of the computer; consists of CU and ALU.

Register – Small and fastest memory inside CPU.

Accumulator (AC) – Register used to store intermediate arithmetic results.

Program Counter (PC) – Holds the address of the next instruction.

Instruction Register (IR) – Stores the current instruction being executed.

Memory Address Register (MAR) – Stores the address of memory location to access.

Memory Data Register (MDR) / MBR – Stores data being transferred to/from memory.

Cache Memory – Very fast memory between CPU and RAM.

Bus – Pathway for data transfer inside the computer.

Data Bus – Carries data between components.

Address Bus – Carries memory addresses.

Control Bus – Carries control signals.

Clock – Generates timing signals for operations.

Clock Speed – Number of cycles per second, measured in Hertz.

Machine Cycle – Complete process of instruction execution.

Fetch Cycle – Fetching instruction from memory.

Decode Cycle – Interpreting the instruction.

Execute Cycle – Performing the instruction.

Store Cycle – Storing the result back in memory.  Basic Terminolgies

CPU – The brain of the computer that processes instructions.

Microprocessor – A CPU on a single integrated chip.

Processor – Another name for CPU.

Core – An individual processing unit inside a CPU.

Single-Core Processor – CPU with one core.

Dual-Core Processor – CPU with two cores.

Quad-Core Processor – CPU with four cores.

Octa-Core Processor – CPU with eight cores.

Thread – A sequence of instructions handled by a CPU.

Multithreading – Running multiple threads simultaneously.

Clock – Produces pulses to synchronize operations.

Clock Speed – Number of cycles per second (Hz, GHz).

Cycle – One complete pulse of the clock.

Instruction Cycle – Time to complete one instruction.

Machine Cycle – Basic operation cycle of CPU.

Fetch – Getting instruction from memory.

Decode – Understanding the instruction.

Execute – Performing the instruction.

Store – Saving the result.

Register – Small, high-speed storage inside CPU.

Accumulator – Stores arithmetic results temporarily.

Program Counter (PC) – Holds address of next instruction.

Instruction Register (IR) – Holds current instruction.

MAR – Holds memory address.

MDR / MBR – Holds data being transferred.

Cache Memory – Fast memory to speed up CPU access.

L1 Cache – Smallest and fastest cache.

L2 Cache – Larger but slower than L1.

L3 Cache – Shared cache among cores.

Heat Sink – Removes heat from CPU.

Fan / Cooler – Cools the processor.

GPU – Specialized processor for graphics.

Coprocessor – Assists CPU in special tasks.

Overclocking – Running CPU faster than standard speed.

Underclocking – Running CPU slower to save power.

Instruction Set – Collection of commands CPU understands.

x86 – Common CPU architecture by Intel / AMD.

ARM – Power-efficient CPU architecture used in phones.

64-bit Processor – Can process 64 bits at once.

32-bit Processor – Can process 32 bits at once.

Memory Storage

1. Memory – Place where data and instructions are stored in a computer.
2. Storage – Long-term saving of data for future use.
3. Primary Memory – Main memory directly accessed by CPU.
4. Secondary Memory – Permanent storage used for saving data long-term.
5. RAM (Random Access Memory) – Temporary memory that stores data while computer is running.
6. ROM (Read Only Memory) – Permanent memory that stores essential startup instructions.
7. Cache Memory – Very fast memory between CPU and RAM to speed up processing.
8. Register – Smallest and fastest memory inside CPU.
9. Virtual Memory – Memory technique using hard disk as extra RAM.

Types of RAM

10. DRAM (Dynamic RAM) – Needs constant refreshing; used in main memory.
11. SRAM (Static RAM) – Faster and does not need refreshing; used in cache.

Types of ROM

12. PROM – Programmable once; cannot be erased.
13. EPROM – Can be erased using UV light and reprogrammed.
14. EEPROM – Can be electrically erased and rewritten.

Secondary Storage Devices

15. Hard Disk (HDD) – Magnetic storage device with large capacity.
16. SSD (Solid State Drive) – Faster storage using flash memory.
17. USB Flash Drive – Portable storage device.
18. Memory Card – Small storage used in phones/cameras.
19. Optical Disk – CD, DVD, Blu-ray storage using laser.
20. Magnetic Tape – Tape-based storage used for backup.

Memory Units

21. Bit – Smallest unit of data (0 or 1).
22. Nibble – 4 bits.
23. Byte – 8 bits.
24. Kilobyte (KB) – 1024 bytes.
25. Megabyte (MB) – 1024 KB.
26. Gigabyte (GB) – 1024 MB.
27. Terabyte (TB) – 1024 GB.

Access Types

28. Random Access – Data accessed in any order (RAM).
29. Sequential Access – Data accessed in order (Magnetic tape).
30. Direct Access – Data accessed directly by location (HDD).

Other Important Terms

31. Volatile Memory – Loses data when power is off (RAM).
32. Non-Volatile Memory – Keeps data even when power is off (ROM, HDD).
33. Buffer Memory – Temporary storage during data transfer.
34. Flash Memory – Fast, rewritable non-volatile memory.
35. Swap Space – Part of disk used as virtual RAM.
36. Formatting – Setting up a disk so it can store files and folders.
37. File System – Method used to organize and manage files (e.g., FAT32, NTFS).
38. Low-Level Formatting – Creates physical tracks and sectors on the disk (done by manufacturer).
39. High-Level Formatting – Creates file system and directory structure (done by user/OS).
40. Partitioning – Dividing a disk into separate logical sections.
41. Partition – A divided section of a hard disk.
42. Boot Sector – First sector of a disk that contains boot information.
43. Sector – Smallest storage unit on a disk.
44. Track – Circular path on a disk where data is stored.
45. Cluster – Group of sectors treated as one unit for storage.
46. Quick Format – Removes file system structure quickly without deep checking.
47. Full Format – Deletes data and checks disk for errors.
48. Erase – Removing all data from storage.
49. Volume – Formatted storage area with a file system.
50. Allocation Table (FAT) – Table that keeps track of file locations.
51. NTFS – Advanced file system used in modern Windows systems.
52. Bad Sector – Damaged part of disk that cannot store data.
53. Disk Cleanup – Removing unnecessary files to free space.
54. Disk Defragmentation – Rearranging fragmented data for faster access.
55. Mounting – Making a storage device accessible to the system.

Input Device

1. Input Device – Hardware used to enter data and instructions into a computer.
2. Keyboard – Used to type text, numbers, and commands.
3. Mouse – Pointing device used to move cursor and select items.
4. Scanner – Converts printed documents into digital form.
5. OCR (Optical Character Recognition) – Converts scanned text into editable text.
6. OMR (Optical Mark Recognition) – Reads shaded marks in forms or answer sheets.
7. MICR (Magnetic Ink Character Recognition) – Reads special ink used in bank cheques.
8. Barcode Reader – Reads product information using barcode lines.
9. QR Code Reader – Reads two-dimensional QR codes.
10. Joystick – Used mainly for gaming and controlling movement.
11. Light Pen – Pen-like device used to draw or select on screen.
12. Touch Screen – Screen that works by touching directly.
13. Microphone – Converts sound into digital input.
14. Webcam – Captures video and images as input.
15. Trackball – Stationary pointing device controlled by rolling a ball.
16. Graphics Tablet – Used for drawing digitally with a pen.
17. Touchpad – Small touch-sensitive surface used in laptops.
18. Biometric Devices – Input using human features (fingerprint, face, iris).
19. Fingerprint Scanner – Reads fingerprint patterns for security.
20. Voice Input System – Converts spoken words into computer commands.

Output Device

1. Output Device – Hardware that shows or produces results from a computer.
2. Monitor / VDU – Displays text, images, and video on screen.
3. Printer – Produces hard copy (paper output) of data.

• Key related terms:

  • Printer – Device that converts soft copy into hard copy.
  • Hard Copy – Printed output on paper.
  • Soft Copy – Digital output on screen.

  Types of Printers:

  • Impact Printer – Prints by striking an ink ribbon (noisy).
  • Non-Impact Printer – Prints without striking (quiet).

  Impact Printers:

  • Dot Matrix Printer – Prints using pins forming dots on paper.
  • Daisy Wheel Printer – Uses wheel with characters for printing (old type).
  • Line Printer – Prints a full line at once (used in big systems).

  Non-Impact Printers:

  • Inkjet Printer – Sprays tiny ink droplets to print.
  • Laser Printer – Uses laser and toner for fast, high-quality printing.
  • Thermal Printer – Uses heat to print (used in receipts).

  Printer Concepts:

  • Resolution – Quality of print measured in DPI (dots per inch).
  • DPI (Dots Per Inch) – Number of dots printed per inch.
  • Cartridge – Ink container in printer.
  • Toner – Powder used in laser printers.
  • Spooler – Software that manages print jobs.
  • Print Queue – List of documents waiting to print.
  • Duplex Printing – Printing on both sides of paper.
  • Printing Speed – Measured in PPM (pages per minute).
  • Printer Driver – Software that controls printer operation.
4. Speaker – Outputs sound from the computer.
5. Headphones – Personal audio output device.
6. Plotter – Prints large-scale drawings like maps and designs.

• Plotter (Computer Fundamentals) – An output device used to print large and high-precision graphics like maps, engineering drawings, and architectural designs.

  Key related terms:

  • Plotter – A device that draws images on paper using pens or ink.
  • Hard Copy Output – Physical print produced on paper.
  • Vector Graphics – Graphics made of lines and shapes used by plotters.

  Types of Plotters:

  • Drum Plotter – Paper moves on a rotating drum while pen draws.
  • Flatbed Plotter – Paper remains fixed; pen moves over it.
  • Inkjet Plotter – Uses inkjet technology for large prints.
  • Cutting Plotter – Cuts materials instead of printing (used in stickers, designs).

  Plotter Components:

  • Pen/Marker – Drawing tool used in plotter.
  • Paper – Medium where output is drawn.
  • Carriage – Moves the pen across paper.
  • Motor System – Controls movement of pen and paper.

  Important Concepts:

  • Resolution – Quality/detail of output drawing.
  • Precision – Accuracy in drawing fine lines.
  • CAD (Computer Aided Design) – Software used with plotters.
  • Large Format Printing – Printing on big sheets (A1, A0).
  • Graphic Plotting – Process of drawing technical diagrams.
  • Vector Output – Output based on mathematical lines instead of pixels.
7. Projector – Displays computer output on a large screen or wall.
8. Monitors

• Monitor (Computer Fundamentals) – An output device that displays information from a computer on a screen in visual form (soft copy).

  Key related terms:

  • Monitor – Screen used to display text, images, and video.
  • VDU (Visual Display Unit) – Another name for monitor.
  • Soft Copy – Digital output shown on screen.

  Types of Monitor:

  • CRT Monitor – Old bulky monitor using cathode ray tube technology.
  • LCD Monitor – Flat screen using liquid crystal display.
  • LED Monitor – Improved LCD using LED backlight for better brightness.
  • OLED Monitor – Advanced display with better color and contrast.
  • Plasma Display – Older large screen technology used in TVs.

  Monitor Components:

  • Screen/Display Panel – Main surface where output appears.
  • Pixel – Smallest dot on screen that forms images.
  • Resolution – Number of pixels on screen (e.g., 1920×1080).

  • Resolution (Computer Fundamentals) – The clarity or sharpness of an image displayed on a screen or printed output, measured by the number of pixels.

    Key related terms:

    • Resolution – Number of pixels displayed on a screen or image.
    • Pixel – Smallest unit (dot) that forms a digital image.
    • Display Resolution – Screen quality measured in width × height (e.g., 1920 × 1080).
    • Screen Resolution – Total number of pixels a monitor can display.
    • Image Resolution – Quality of a digital image based on pixel density.
    • Printer Resolution – Quality of print output measured in DPI.
    • DPI (Dots Per Inch) – Number of dots printed per inch in printers.
    • PPI (Pixels Per Inch) – Number of pixels per inch in screens/images.
    • HD (High Definition) – Basic high-quality resolution (1280 × 720).
    • Full HD (FHD) – 1920 × 1080 resolution.
    • 4K Resolution – Ultra high definition (3840 × 2160).
    • 8K Resolution – Very high resolution (7680 × 4320).
    • Aspect Ratio – Ratio of width to height (e.g., 16:9).
    • Screen Density – How closely pixels are packed together.
    • Clarity – Sharpness of image depending on resolution.
    • Graphics Quality – Visual detail level shown on screen.
  • Refresh Rate – How many times screen updates per second (Hz).
  • Response Time – Time taken for pixel to change color.

  Monitor Concepts:

  • Aspect Ratio – Width to height ratio of screen (e.g., 16:9).
  • Color Depth – Number of colors a screen can display.
  • Brightness – Intensity of light from screen.
  • Contrast Ratio – Difference between darkest and brightest colors.
  • Graphic Card (GPU) – Hardware that sends output to monitor.
  • Display Driver – Software that controls monitor output.
  • Touch Monitor – Monitor that also works as input device.
9. LCD Monitor – Thin flat-screen display using liquid crystal technology.
10. LED Monitor – Improved LCD using LED backlighting.
11. CRT Monitor – Old bulky monitor using cathode ray tube.

• CRT Monitor (Cathode Ray Tube Monitor) – An old type of monitor that displays images using an electron beam on a phosphorescent screen.

  Key related terms:

  • CRT Monitor – Bulky display device used before LCD/LED monitors.
  • Cathode Ray Tube (CRT) – Vacuum tube technology used to produce images.
  • Electron Beam – Stream of electrons that creates images on screen.
  • Phosphor Screen – Coating inside screen that glows when hit by electrons.
  • Phosphorescence – Light emitted from screen after electron impact.
  • Raster Scan – Method of drawing image line by line on screen.
  • Refresh Rate – Number of times image is redrawn per second.
  • Screen Flicker – Temporary blinking effect due to low refresh rate.
  • Resolution – Image clarity based on pixel-like dots formed.
  • Color Gun – Electron beams for Red, Green, Blue (RGB) colors.
  • Shadow Mask – Helps align colors accurately on screen.
  • Bulky Design – Large and heavy structure of CRT monitors.
  • High Power Consumption – Uses more electricity than modern monitors.
  • Heat Generation – Produces more heat during operation.
  • Analog Display – Works using analog signals, not digital.
  • Curved Screen – Slightly curved glass display surface.
  • De-Gaussing – Removing magnetic distortion in CRT screen.
  • Magnetic Interference – Can affect display quality.
  • CRT TV – Television version of CRT monitor.
  • Obsolete Technology – Replaced by LCD/LED monitors today.
12. Inkjet Printer – Prints by spraying ink on paper.
13. Laser Printer – Uses laser technology for fast and high-quality printing.
14. Dot Matrix Printer – Prints using pins and ink ribbon (impact printer).
15. 3D Printer – Creates physical 3D objects from digital design.
16. Braille Printer (Embosser) – Prints tactile output for visually impaired users.
17. Sound Card Output – Converts digital sound into audible audio.
18. Video Card Output – Sends graphics/video to monitor.
19. Haptic Device – Gives vibration/force feedback as output.
20. Smart Display Devices – Output through smart TVs or smart panels.
21. Soft Copy Output – Output shown on screen (digital form).

Types of Computer

Types of Computer (Computer Fundamentals) – Computers are classified based on size, working principle, and purpose.

1. Based on Working Principle

1. Analog Computer – Works with continuous signals (used in speed, temperature measurement).
2. Digital Computer – Works with binary data (0 and 1), most common type.
3. Hybrid Computer – Combination of analog and digital computer.

2. Based on Size and Capacity

4. Microcomputer – Small personal computer (PC, laptop).
5. Minicomputer – Medium-sized computer used by organizations.
6. Mainframe Computer – Large computer used by big companies for bulk data processing.
7. Supercomputer – Fastest and most powerful computer used in scientific research.

3. Based on Purpose

8. General Purpose Computer – Used for multiple tasks (word, internet, games).
9. Special Purpose Computer – Designed for a specific task (ATM, traffic control).

4. Modern/Advanced Types

10. Workstation – High-performance single-user computer for design and engineering.
11. Server Computer – Provides services to other computers in a network.
12. Embedded Computer – Built inside devices like washing machines, cars, etc.

Number System

Number System – A method of representing numbers using symbols and a base.

Base (Radix) – Total number of digits used in a number system.

Digit – A single symbol used to form numbers.

Decimal System – Number system with base 10 (0–9).

Binary System – Number system with base 2 (0 and 1).

Octal System – Number system with base 8 (0–7).

Hexadecimal System – Number system with base 16 (0–9, A–F).

Binary Digit (Bit) – Smallest unit of data (0 or 1).

Nibble – A group of 4 bits.

Byte – A group of 8 bits.

Word – A group of bits processed as a unit by CPU.

Positional Value – Value of a digit based on its position.

Place Value – Weight of a digit in a number system.

MSB (Most Significant Bit) – Leftmost bit with highest value.

LSB (Least Significant Bit) – Rightmost bit with lowest value.

Binary Number – A number written in base 2.

Octal Number – A number written in base 8.

Hex Number – A number written in base 16.

Conversion – Changing number from one system to another.

Binary to Decimal – Converting base 2 number into base 10.

Decimal to Binary – Converting base 10 number into base 2.

Binary Addition – Adding binary numbers using rules of 0 and 1.

Binary Subtraction – Subtracting binary numbers using borrow method.

Weighted Number System – Each digit has a positional weight.

Non-weighted System – Digits have no positional weight (rare).

Overflow – When result exceeds storage capacity.

Underflow – When value is too small to represent.

Base Conversion – Process of changing number base.

Complement – Method used in subtraction (1’s and 2’s complement).

1’s Complement – Inverting all bits (0 ↔ 1).

2’s Complement – 1’s complement + 1, used for subtraction.

Operating System

Operating System (OS) – System software that acts as an interface between user and computer hardware.

Kernel – Core part of OS that controls CPU, memory, and devices.

Shell – Interface between user and OS (CLI or GUI).

Booting – Process of starting or loading the operating system.

Cold Booting – Starting computer from completely off state.

Warm Booting – Restarting the computer while it is already ON.

Multitasking – Running multiple programs at the same time.

Multiprogramming – Multiple programs kept in memory and executed one by one.

Multiprocessing – Using more than one CPU to execute tasks.

Time Sharing – Multiple users share CPU time simultaneously.

Real-Time OS – OS that gives instant response to inputs.

Single User OS – Supports only one user at a time.

Multi User OS – Supports multiple users at the same time.

GUI (Graphical User Interface) – OS interface with icons and graphics.

CLI (Command Line Interface) – Text-based command interface.

File Management – Organizing, storing, and retrieving files.

Process Management – Handling execution of programs.

Memory Management – Managing primary memory (RAM).

Device Management – Controlling input/output devices.

Security Management – Protecting system from unauthorized access.

System Call – Request from program to OS for services.

Driver – Software that controls hardware devices.

Utility Program – Helps in maintenance (antivirus, disk cleanup).

Deadlock – Situation where processes block each other.

Spooling – Storing data temporarily for devices like printer.

Buffering – Temporary storage during data transfer.

Paging – Memory management technique dividing memory into pages.

Segmentation – Dividing memory into logical sections.

Virtual Memory – Using disk space as extended RAM.

Scheduler – OS component that decides process execution order.

File Database

File Related Terms

1. File – A collection of related data stored under a name.
2. Filename – Name given to a file for identification.
3. File Extension – Indicates file type (e.g., .txt, .jpg).
4. Folder / Directory – A container used to store files.
5. Subdirectory – Folder inside another folder.
6. Path – Location of a file in storage.
7. File System – Method used by OS to manage files.
8. File Management – Organizing, storing, and retrieving files.
9. Sequential File – Data stored and accessed in order.
10. Direct File – Data accessed directly using address.
11. Indexed File – File accessed using an index table.
12. Read Operation – Opening and viewing a file.
13. Write Operation – Saving data into a file.
14. Append – Adding data at the end of a file.
15. Delete File – Removing a file from storage.
16. Rename File – Changing file name.
17. File Permission – Rights like read, write, execute.
18. Backup – Copy of file for safety.
19. Restore – Recovering backed-up file.
20. File Compression – Reducing file size.

Database Related Terms

21. Database – Organized collection of related data.
22. DBMS (Database Management System) – Software to manage databases.
23. Table – Data arranged in rows and columns.
• Table – Collection of related data organized in rows and columns.
• Row (Record) – A single entry in a table containing full data of one item.
• Column (Field) – A category of data in a table (attribute).
• Field – Smallest unit of data in a table (one column value).
• Record – Complete set of fields in one row.
• Cell – Intersection of a row and column (single value).
• Attribute – Another name for column/field.
• Tuple – Another name for row/record (database term).
• Primary Key – Unique field that identifies each record.
• Foreign Key – Field that connects one table to another.
• Schema – Structure/design of a table.
• Data Type – Type of data stored in a column (text, number, date).
• Heading – Name of each column.
• Entity – Object or thing about which data is stored.
• Relation – Another name for table in DBMS.
• Degree – Number of columns in a table.
• Cardinality – Number of rows in a table.
• Null Value – Empty or unknown data in a cell.
• Index – Structure used to speed up data search.
• Query Result Table – Output table generated after a database query.
24. Query – Request to retrieve or manipulate data.
1. Query – A command used to interact with a database to get or modify data.
2. SQL (Structured Query Language) – Language used to write database queries.
3. SELECT Query – Used to retrieve data from a table.
4. INSERT Query – Used to add new data into a table.
5. UPDATE Query – Used to modify existing data.
6. DELETE Query – Used to remove data from a table.
7. WHERE Clause – Condition used to filter data in a query.
8. ORDER BY – Sorts query result in ascending or descending order.
9. GROUP BY – Groups similar data together in query results.
10. JOIN Query – Combines data from two or more tables.
11. INNER JOIN – Returns matching records from both tables.
12. LEFT JOIN – Returns all records from left table and matching from right.
13. RIGHT JOIN – Returns all records from right table and matching from left.
14. FULL JOIN – Returns all records from both tables.
15. Condition – Rule used to filter data in query.
16. Expression – Combination of fields and operators in query.
17. Result Set – Output generated after executing a query.
18. Subquery – Query inside another query.
19. Command – Instruction written in SQL.
20. Transaction Query – Query that ensures complete execution of operations.
21. Data Redundancy – Repetition of same data.
25. Data Integrity – Accuracy and consistency of data.
• Data Integrity – Accuracy and consistency of data in a database.
• Accuracy – Data is correct and error-free.
• Consistency – Same data remains uniform in all places.
• Validity – Data follows defined rules and format.
• Reliability – Data can be trusted for use.
• Entity Integrity – Each table must have a unique primary key.
• Referential Integrity – Relationship between tables remains valid using foreign keys.
• Domain Integrity – Data must be within allowed range/type.
• Primary Key – Ensures uniqueness of each record.
• Foreign Key – Maintains relationship between tables.
• Constraints – Rules applied to data (NOT NULL, UNIQUE, etc.).
• Data Validation – Checking data before storing it.
• Error Checking – Detecting mistakes in data.
• Duplicate Data – Repeated data that reduces integrity.
• Data Redundancy – Unnecessary repetition of data.
• Normalization – Process of reducing redundancy and improving integrity.
• Consistency Check – Ensuring data is same across system.
• Transaction Integrity – Ensuring complete and correct execution of database operations.
• Backup Integrity – Ensuring backup data is correct and usable.
• Security Control – Protecting data from unauthorized changes.
26. Data Security – Protection of data from unauthorized access.
27. Normalization – Process of organizing data efficiently.
• Normalization – Process of dividing large tables into smaller related tables to avoid duplication.
• Redundancy – Repetition of the same data in multiple places.
• Anomaly – Problem caused by poor database design (insert, update, delete errors).
• Insertion Anomaly – Problem when adding data due to missing fields.
• Update Anomaly – Problem when updating data causes inconsistency.
• Deletion Anomaly – Loss of important data when deleting a record.
• Functional Dependency – Relationship where one attribute depends on another.
• Primary Key – Unique identifier used to maintain table structure.
• Foreign Key – Connects two related tables.
• Candidate Key – Possible attributes that can become primary key.
• Composite Key – Primary key made using more than one field.
• 1NF (First Normal Form) – No repeating groups; atomic values only.
• 2NF (Second Normal Form) – Removes partial dependency.
• 3NF (Third Normal Form) – Removes transitive dependency.
• BCNF (Boyce-Codd Normal Form) – Stronger version of 3NF.
• Table Decomposition – Splitting large tables into smaller ones.
• Dependency – One field depends on another field.
• Attribute – Column in a table.
• Tuple – Row in a table.
• Schema – Structure/design of database tables.
28. Relationship – Connection between tables.
29. ER Diagram – Visual representation of database structure.
• ER Diagram – Graphical representation of database structure.
• Entity – Real-world object or thing (e.g., Student, Teacher).
• Attribute – Property or characteristic of an entity (e.g., Name, Age).
• Relationship – Connection between entities (e.g., Student studies Course).
• Entity Set – Collection of similar entities.
• Attribute Set – Collection of attributes of an entity.
• Primary Key – Unique identifier of an entity.
• Composite Attribute – Attribute that can be divided (e.g., Full Name → First + Last).
• Simple Attribute – Cannot be divided further (e.g., Age).
• Derived Attribute – Calculated from other attributes (e.g., Age from DOB).
• Multi-valued Attribute – Can have multiple values (e.g., Phone Numbers).
• Weak Entity – Entity that depends on another entity for identification.
• Strong Entity – Entity that can exist independently.
• Cardinality – Relationship type between entities (1:1, 1:M, M:M).
• One-to-One (1:1) – One entity relates to one other entity.
• One-to-Many (1:M) – One entity relates to many entities.
• Many-to-Many (M:M) – Many entities relate to many entities.
• Participation Constraint – Whether entity must participate in relationship.
• Total Participation – All entities must participate in relationship.
• Partial Participation – Some entities participate in relationship.
• ER Model – Conceptual model used before database creation.
• Rectangles – Represent entities in diagram.
• Ovals – Represent attributes.
• Diamonds – Represent relationships.
30. DBA (Database Administrator) – Person who manages database.
31. Transaction – A complete unit of database operation.
32. Backup (Database) – Copy of database for safety.
• Transaction – A group of operations treated as one unit (all succeed or all fail).
• Atomicity – Either all operations happen or none happen.
• Consistency – Database remains in a valid state after transaction.
• Isolation – One transaction does not affect another running transaction.
• Durability – Once completed, changes are permanent.
• ACID Properties – Four rules that ensure safe transactions (Atomicity, Consistency, Isolation, Durability).
• Commit – Saves all changes made by a transaction permanently.
• Rollback – Cancels a transaction and restores previous state.
• Savepoint – Temporary checkpoint within a transaction.
• Transaction Log – Record of all database changes.
• Concurrent Transaction – Multiple transactions running at the same time.
• Deadlock – Situation where two transactions wait for each other forever.
• Commit Point – Stage where transaction is successfully completed.
• Failure – Error that causes transaction to stop or rollback.
• Read Operation – Retrieving data in transaction.
• Write Operation – Modifying data in transaction.
• Undo – Reversing changes of a transaction.
• Redo – Reapplying changes after failure.
• Consistency Check – Ensures rules are not violated after transaction.
• Transaction Manager – System component that controls transactions.
33. Recovery – Restoring lost database data.
34. Concurrency – Multiple users accessing database at same time. 

Networking

Network – A group of interconnected computers.

Networking – Process of connecting computers to share resources.

Node – Any device connected in a network.

Host – A computer that provides or uses network services.

Client – A device that requests services from a server.

Server – A computer that provides services or data.

Peer – A computer that acts as both client and server.

LAN (Local Area Network) – Network within a small area like school or office.

• LAN – Local Area Network used for small-area communication.
• Local Area – Limited area such as home, school, or office.
• Network – Group of connected computers sharing resources.
• Node – Any device connected in a LAN (PC, printer, etc.).
• Server – Central computer that provides services in LAN.
• Client – Computer that uses services from server.
• Peer-to-Peer Network – LAN where all computers are equal.
• Client-Server Network – LAN with central server control.
• Topology – Layout of LAN (Star, Bus, Ring, etc.).
• Ethernet – Common technology used in LAN.
• Switch – Device that connects multiple computers in LAN.
• Hub – Simple device that broadcasts data to all devices.
• Router – Connects LAN to other networks or internet.
• Bandwidth – Data transfer capacity of LAN.
• Transmission Media – Cable or wireless used in LAN.
• UTP Cable – Common twisted pair cable used in LAN.
• Wi-Fi – Wireless LAN technology.
• MAC Address – Unique hardware address of LAN device.
• IP Address – Logical address of device in LAN.
• File Sharing – Sharing data between computers in LAN.
• Printer Sharing – Using one printer by multiple computers.
• Resource Sharing – Sharing hardware/software in LAN.
• Protocol – Rules for communication (TCP/IP).
• Latency – Delay in LAN communication.
• LAN Speed – Usually high compared to WAN.

MAN (Metropolitan Area Network) – Network covering a city area.

MAN – Network that covers a city or large town.

Metropolitan Area – Area larger than LAN but smaller than WAN.

LAN – Smaller network that connects to form MAN.

WAN – Larger network that connects multiple MANs.

Node – Any device connected in MAN.

Backbone Network – High-speed main network of MAN.

Fiber Optic Cable – Common high-speed medium used in MAN.

Wireless MAN (WiMAX) – Wireless technology used for MAN.

ISP (Internet Service Provider) – Provides MAN/WAN connectivity.

Router – Connects different LANs in MAN.

Switch – Connects devices within LANs in MAN.

Bridge – Connects two LANs inside MAN.

Bandwidth – Data transfer capacity of MAN.

Transmission Media – Cable or wireless used for communication.

Public Network – MAN often uses shared infrastructure.

Private MAN – MAN owned by an organization or government.

Cable TV Network – Example of MAN.

City Network – Government or city-wide communication system.

High Speed Connection – MAN is faster than WAN.

Coverage Area – Usually 5 km to 50 km range

WAN (Wide Area Network) – Network covering large areas like countries.

WAN – Wide Area Network covering large distances.

Wide Area – Large geographical region (country or world).

LAN – Small network that connects into WAN.

MAN – City-level network that connects to WAN.

Internet – The largest example of WAN.

Node – Any device connected in WAN.

Router – Device used to connect different networks in WAN.

Gateway – Connects different types of networks in WAN.

ISP (Internet Service Provider) – Provides WAN connectivity to users.

Leased Line – Dedicated connection used in WAN.

Satellite Communication – Wireless method used in WAN.

Fiber Optic Cable – High-speed medium used in WAN.

Microwave Transmission – Wireless communication used in WAN.

Packet Switching – Method of sending data in small packets.

IP Address – Unique address of devices in WAN.

DNS (Domain Name System) – Converts domain names to IP addresses.

Latency – Delay in data transmission over WAN.

Bandwidth – Amount of data transferred in WAN.

Protocol (TCP/IP) – Rules for communication in WAN.

Public Network – WAN is mostly public and global.

Global Connectivity – WAN connects the whole world.

Internet Backbone – Main high-speed network of WAN.

Cloud Network – Internet-based WAN services.

Security Firewall – Protects WAN from threats.

Data Transmission – Process of sending data across WAN.

PAN (Personal Area Network) – Very small network around a person.

Internet – Global network of interconnected computers.

Internet – Worldwide network of connected computers.

Network of Networks – Internet connects many LANs, MANs, and WANs.

WAN – Internet is the largest form of WAN.

TCP/IP – Main protocol used for internet communication.

IP Address – Unique address of each device on internet.

Domain Name – Human-readable name of website (e.g., google.com).

DNS (Domain Name System) – Converts domain names into IP addresses.

WWW (World Wide Web) – Collection of websites on the internet.

Web Browser – Software used to access internet (Chrome, Firefox).

Web Server – Stores and delivers web pages.

URL (Uniform Resource Locator) – Address of a web page.

HTTP/HTTPS – Protocols used to access websites.

Hyperlink – Clickable link to navigate between pages.

Search Engine – Tool to find information (Google, Bing).

ISP (Internet Service Provider) – Company that provides internet access.

Modem – Device that connects computer to internet.

Router – Distributes internet to multiple devices.

Bandwidth – Speed/amount of data transfer.

Upload – Sending data to internet.

Download – Receiving data from internet.

Cloud Computing – Storing and accessing data via internet.

Email – Electronic mail service over internet.

Social Media – Platforms like Facebook and X.

Cyber Security – Protection of internet systems and data.

Firewall – Security system that protects network.

Cookies – Small data stored by websites in browser.

Cache – Temporary storage for faster browsing.

Streaming – Watching/using media in real-time over internet.

FTP (File Transfer Protocol) – Used to transfer files online.

E-commerce – Buying and selling goods over internet.

Intranet – Private network within an organization.

Intranet – Private internal network of an organization.

Private Network – Access is restricted to employees or members only.

Organization Network – Used inside companies, schools, offices.

LAN-Based System – Usually built on Local Area Network.

TCP/IP – Protocol used for communication inside intranet.

Web Browser – Used to access intranet websites.

Intranet Server – Stores internal data and applications.

Firewall – Protects intranet from external access.

User Authentication – Login system for authorized access.

Internal Communication – Used for messaging within organization.

File Sharing – Sharing documents inside organization.

Database Access – Internal data storage and retrieval.

Employee Portal – Website inside intranet for staff use.

Email System – Internal email service.

Restricted Access – Only authorized users can enter.

Security Policy – Rules to protect internal data.

Intranet Website – Internal web pages of organization.

Local Hosting – Data stored on local servers.

Intranet vs Internet – Intranet is private, Internet is public.

Extranet Connection – Controlled access extension of intranet.

Extranet – Controlled access network for outsiders and organization.

Topology – Arrangement of computers in a network.

Bus Topology – All devices connected in a single line.

Star Topology – Devices connected through a central hub/switch.

Ring Topology – Devices connected in a circular path.

Mesh Topology – Every device connected to every other device.

Hybrid Topology – Combination of different topologies.

Protocol – Rules for communication between devices.

TCP/IP – Main protocol used in internet communication.

IP Address – Unique address of a device in network.

MAC Address – Hardware address of a network device.

DNS (Domain Name System) – Converts domain names into IP addresses.

URL (Uniform Resource Locator) – Address of a web page.

HTTP/HTTPS – Protocol used for web communication.

FTP (File Transfer Protocol) – Used to transfer files.

Bandwidth – Amount of data transfer capacity.

Router – Device that connects different networks.

Switch – Device that connects computers within a network.

Hub – Simple device that broadcasts data to all devices.

Modem – Converts digital signals to analog and vice versa.

Gateway – Connects different types of networks.

Firewall – Security system that protects network.

Bandwidth – Speed of data transfer.

Latency – Delay in data transmission.

Packet – Small unit of data sent over network.

Packet Switching – Method of sending data in packets.

Transmission Media – Medium used to send data (cable/wireless).

Security

Security – Protection of computer resources and information.

Cyber Security – Protection of systems from digital attacks.

Information Security – Safeguarding data from unauthorized access.

Authentication – Verifying identity of a user (login/password).

Authorization – Giving permission to access resources.

Username – Identity name used to access system.

Password – Secret code used for security.

Biometric Security – Security using fingerprints, face, iris, etc.

Encryption – Converting data into unreadable form for safety.

Decryption – Converting encrypted data back to original form.

Firewall – System that blocks unauthorized network access.

Antivirus – Software that detects and removes viruses.

Malware – Harmful software that damages systems.

Virus – Malicious program that spreads and harms files.

Worm – Self-replicating malware that spreads automatically.

Trojan Horse – Harmful program disguised as useful software.

Spyware – Software that secretly collects user data.

Adware – Software that shows unwanted advertisements.

Ransomware – Malware that locks data and demands money to unlock it.

Rootkit – Malware that hides itself and gives hacker control of system.

Keylogger – Records keystrokes to steal passwords and data.

Botnet – Network of infected computers controlled by attacker.

Backdoor – Secret entry point into a system bypassing security.

Logic Bomb – Malware activated by a specific condition or time.

Payload – Part of malware that performs harmful action.

Infection – Process of malware entering a system.

Propagation – Spreading of malware to other systems.

Antivirus – Software used to detect and remove malware.

Firewall – Blocks unauthorized access to prevent malware attack.

Quarantine – Isolating infected files from system.

Scan – Checking system for malware.

Threat – Any potential danger to computer system.

Phishing – Fake attempts to steal personal information.

Hacking – Unauthorized access to a system.

Ethical Hacking – Legal testing of system security.

Backup – Copy of data for recovery in case of loss.

Recovery – Restoring lost or damaged data.

Access Control – Restricting who can use system resources.

Security Policy – Rules for protecting systems and data.

Digital Signature – Electronic verification of identity.

SSL/TLS – Secure protocols for safe internet communication.

Two-Factor Authentication (2FA) – Extra security step using OTP or device.

Firewall Rules – Conditions used to allow/block network traffic.

Data Breach – Unauthorized access to sensitive data.

Programming

Programming – Writing a set of instructions for a computer.

Program – A collection of instructions that performs a task.

Programming Language – Language used to write programs (C, Java, Python).

Source Code – Human-readable instructions written by programmer.

Machine Code – Binary code (0s and 1s) understood by computer.

High-Level Language – Easy-to-understand language (C, Java, Python).

Low-Level Language – Close to machine language (Assembly).

Algorithm – Step-by-step solution to a problem.

Flowchart – Diagram that represents algorithm visually.

Pseudo Code – Simple English-like representation of program logic.

Compiler – Converts entire program into machine code at once.

Interpreter – Converts and executes code line by line.

Assembler – Converts assembly language into machine code.

Syntax – Rules of writing a programming language.

Variable – Named storage location for data.

Constant – Value that does not change during program execution.

Data Type – Type of data (int, float, char, etc.).

Operator – Symbol used for operations (+, -, *, /).

Loop – Repeating a set of instructions.

Conditional Statement – Decision-making statement (if, else).

Function – Block of code that performs a specific task.

Array – Collection of similar data items.

Debugging – Finding and fixing errors in program.

Bug – Error in a program.

Execution – Running a program.

IDE (Integrated Development Environment) – Software for writing programs.

Runtime Error – Error during program execution.

Compile Time Error – Error detected during compilation.

Logic Error – Wrong output due to incorrect logic.

Algorithm Efficiency – Measure of program performance.

Internet

1. Internet – Global network of interconnected computers used for communication and information sharing.
2. WWW (World Wide Web) – Collection of websites accessed through internet.
3. Web Browser – Software used to access internet (Chrome, Firefox).
4. URL – Address of a web page.
5. ISP (Internet Service Provider) – Company that provides internet access.
6. IP Address – Unique address of a device on internet.
7. DNS – Converts domain names into IP addresses.
8. HTTP/HTTPS – Protocol used for web communication.
9. Download – Receiving data from internet.
10. Upload – Sending data to internet.

2. Cloud Computing

11. Cloud Computing – Using internet to store, manage, and process data instead of local computer.
12. Cloud – Remote servers used for data storage and services.
13. SaaS (Software as a Service) – Software provided over internet (e.g., Gmail).
14. PaaS (Platform as a Service) – Platform for developing applications online.
15. IaaS (Infrastructure as a Service) – Virtual hardware resources over internet.
16. Cloud Storage – Online storage of files (Google Drive).
17. Virtualization – Creating virtual resources using cloud.
18. Scalability – Ability to increase/decrease resources easily.
19. Pay-as-you-go – Payment based on usage.
20. Backup – Storing data safely in cloud.
21. Data Center – Large facility that stores cloud servers.
22. Public Cloud – Cloud services available to everyone.
23. Private Cloud – Cloud used by a single organization.
24. Hybrid Cloud – Combination of public and private cloud.
25. Cloud Security – Protection of data stored in cloud.

3. IoT (Internet of Things)

26. IoT (Internet of Things) – Network of physical devices connected to internet that can collect and exchange data.
27. Smart Device – Device that can connect and communicate via internet.
28. Sensor – Device that collects data from environment.
29. Actuator – Device that performs action based on data.
30. Smart Home – Home devices controlled through internet.
31. Wearable Devices – Smart devices worn on body (smartwatch).
32. Automation – Automatic control of devices without human input.
33. Machine-to-Machine (M2M) – Devices communicating with each other.
34. Smart City – City using IoT for traffic, lighting, and services.
35. Embedded System – Computer system built inside devices.
36. Data Collection – Gathering information from sensors.
37. Remote Monitoring – Controlling devices from anywhere.
38. Connectivity – Devices connected via Wi-Fi, Bluetooth, etc.
39. Cloud Integration – IoT devices storing data in cloud.
40. Smart Agriculture – Using IoT in farming systems.