Basic Computer Fundamentals -Easy Notes for Beginners

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Introduction to Computer?


The word Computer comes from the word Compute, which means to count or to calculate.
A computer is an electronic device that takes input from the user, processes the data, and gives the desired result(output). It performs both mathematical and non-mathematical operations. 
                                     A computer follows the principle of GIGO (Garbage In, Garbage Out), which means if incorrect input is given, the output will also be incorrect. 

Characteristics of Computer:

  1. Speed: Computers work very fast. They can perform millions or even billions of instructions in one second. Tasks that take hours for humans can be completed in seconds or milliseconds.             Example: Solving thousands of mathematical problem in a few seconds. 
  2. Accuracy : A computer is highly accurate. It gives correct results if the input is correct. Errors occur only when incorrect data or instructions are given. 
  3. Automation: Once a computer is given instructions or a program, it works automatically. It does not need human intervention during processing. 
  4. Versatility: A computer can perform different types of tasks. It can be used for typing documents, playing games, watching videos, doing calculations, sending emails, and more. 
  5. Diligence: A computer never gets tired or bored. It can work continuously for long hours without losing speed or accuracy. 
  6. Storage: A computer can store a large amount of data such as documents, images, videos, and programs. This data can be stored for many years and can be easily retrieved when needed. 

Limitations of Computer:

  1. No Self-Intelligence: Computers do not have their own intelligence. They cannot think or take decisions on their own. 
  2. No Thinking and Decision-Making Power: Computers cannot think or understand like humans. They only follow pre-defined instructions. 
  3. No Feelings or Emotions: Computers do not have feelings such as happiness, sadness, or anger. 
  4. Limited Learning Ability: Computers cannot learn on their own like humans. However, with the help of Artificial Intelligence (AI) and Machine Learning(ML), they can learn from data and improve their performance. 

Applications Areas of Computers

  1.  Education: Computers are used in schools and colleges for teaching, learning, online classes, and preparing projects. 
  2. Business: Computers help in maintaining records, preparing bills, managing accounts, and communication.
  3. Banking: Banks use computers to store customer data, provide online banking services, ATM operations, and money transfers.
  4. Healthcare: Hospitals use computers to maintain patient records, perform medical tests, and assist in diagnosis and treatment.
  5. Communication: Computers help people communicate through emails, video calls, and social media platforms. 
  6. Booking: Computers are used for online booking of tickets such as trains, buses, flights and hotel reservations. 
Types of Computers according to the Size.
1. Micro Computers: A microcomputer is also known as a personal computer (PC). It is a small computer designed for individuals use. It uses a microprocessor as its central processing unit(CPU). Microcomputers are commonly used in homes, schools, and offices for tasks such as typing documents, browsing the internet, learning, and entertainment. Examples of microcomputers include desktop computers, laptops, tablets, and smartphones. 
2. Mini Computers: A minicomputer is a medium-sized computer that is more powerful than a microcomputer but smaller than a mainframe computer. It can supports multiple users at the same time. Minicomputer are used in small and medium organizations for task such as data processing , database management and scientific applications. 
3. Main Frame Computers: A main frame Computers is a very large and powerful computer used by big organization. It can process a huge amount of data and support hundreds of thousands of users at the same time. Main Frame Computers are generally used in banks, government offices, airlines, and large companies for data processing and record management. 
4. Super Computers: A supercomputer is the fastest and most powerful type of computer. It can perform very complex calculations at extremely high-speed. Super Computers are used for tasks such as weather forecasting, scientific research, space exploration, and nuclear research.

Categories of Computers:
Computer can be classified into two categories:
Hardware: Hardware is the physical components that we can touch, feel, & view are called Hardware. In simple words hardware is the physical parts of the computer.
Example: Keyboard, Mouse, Scanner, RAM, ROM, Microprocessor, Hard disk, Pen drive, Monitor, etc. 
 Software: Software is a set of programs or instructions that tells the computer what to do. In other words Software is a collection of programs that perform specific tasks. 
Note: 
  • Program : A program is a set of instructions to perform a specific task. P
  • Programs are written in a programming language like C,C++, JAVA, Python, etc.
  • A programmer is a person who writes programs or instructions for a computer . 
Software are generally are two types: 
1. System Software: 

Output Devices: An Output device is a device that shows the result of processed input data on screen(Soft copy), paper(Hard copy), or as audio.
Example: Monitor, Projector, Plotter, Printer, Speakers.
 Monitor: A Monitor is a primary soft-copy output device that displays processed data generated by the computer in the form of text, graphics, and video on a visual display unit(VDU).
There are three types of Monitors:
  1. CRT(Cathode Ray Tube) Monitor: An old type of monitor that is large and heavy.
  2. LCD(Liquid Crystal Display): Monitors provide clear images, but sometimes image quality may reduce at extreme viewing angles.
  3. LED(Light Emitting Diode): LED monitor gives brighter and clearer pictures with better contrast. It consumes less power and provides better images quality than LCD.
 Projector: A projector is an output device that displays images, videos, or presentations from a computer onto a large screen or wall so many people can see it at the same time.
Uses of a Projector are Teaching in classrooms, office presentations, watching movies and videos and meeting and seminars. 
Printer: A printer is a peripheral output device that converts digital data from a computer into a hard copy format by printing text, graphics, or images onto paper using ink or toner.
Printer are mainly of two types:
1. Impact Printers: An Impact printer prints by striking an ink ribbon onto paper and produces noisy, low-quality output. It is used in railways, banks, and offices.
Example: Dot Matrix Printer


Storage Device: A Storage device is a hardware component of a computer used to store data, information, and programs either temporarily or permanently. 

Memory Stores data in two ways:

1. Volatile Memory: Volatile memory is also known as temporary memory that means once computer off  data will be lost. 
2. Non-Volatile Memory: Non-Volatile memory is also known as permanent memory. It means that once data is stored in this memory, it remains available even when the computer is turned on or off..

Types of Computer Memory/Storage : Computer memory is divided into two main types: 

1. Primary Memory (Main Memory): Primary memory is the memory that is directly accessed by the CPU. It stores data and instructions that are currently being used by the computer. 
There are two types of Primary Memory:
  • RAM(Random Access Memory)
  • ROM (Read Only Memory)
What is RAM(Random Access Memory)? 
RAM is a volatile memory inside the computer that is used to store data temporarily so that it can be quickly accessed by the processor. 
Types of RAM:
There are mainly types of RAM:
SRAM(Static Random Access Memory): No refresh, Fast & Costly
DRAM(Dynamic Random Access Memory): Refresh needed, slow & Cheap

ROM(Read Only Memory):ROM is a non-volatile memory that stores important programs such as the booting program. These programs are installed by the manufacturer and help in starting the computer. 
Example of ROM Use: 
  • Computer BIOS
  • Calculator Programs
  • Washing machine control system
  • Mobile firmware
  • ATM machine software
Types of ROM : There are mainly three types of ROM:
  1. PROM(Programmable Read Only Memory): PROM is a type of ROM that can be programmed only once and after that the data can be read, not changed or erased.
  2. EPROM(Erasable Programmable Read Only Memory): EPROM is a type of ROM that can store data even when the power is off, and its data can be erased using UV light and written again.
  3. EEPROM(Electrical Erasable Programmable Read Only Memory): EEPROM is a type of non-volatile memory that can store data even when power is off, and its data can be erased and rewritten using electricity. 
2. Secondary Memory: Secondary Memory is also called external memory or auxiliary storage, that is used to store data, information, and programs permanently for a long period of time. It provides large storage space and is slower than primary memory. 
Hard Disk, Pen Drive (USB Flash Drive), CD, DVD, Blu-Ray, Memory Card(SD Card)
Note: 
  • A hard disk is a secondary storage device used to store data permanently in a computer.
  • A Pen drive is a portable secondary storage device used to store and transfer data.
  • A CD is an optical storage device used to store data in digital form.(Storage capacity is 700 MB)
  • A DVD is an optical storage device used to storage large amounts of data in digital for.(Storage capacity is 4.7 GB)
  • A Blu-ray Disc is an optical storage device used to store very large amounts of high-definition data. Storage capacity is 25 GB to 50 GB
  • A memory card is a small portable storage device used to store data in digital devices like Mobile phones and Cameras.
  • Solid State Drives(SSDs): Similar to HDDs, but use flash memory instead of spinning disks, offering faster read and write speeds. 
  • Cloud Storage: Data stored and accessed over the internet. Ex: Google Drive, Dropbox, Microsoft One drive,etc.

Measurement of Computer's Memory

Bit: A bit is the smallest unit of data in a computer, which can have of either 0 or 1..
Byte: A byte is a group of 8 bits. It is commonly used to store a single character, such as letter, number, or symbols.
For example: 'A' = 1 byte, '5' = 1 byte , '@' = 1 byte 

Unit of Computer Memory Measurement 
1 bit = 0,1 (binary digit)
4 bits = 1 nibble
8 bits = 1 byte
1024 byte = 1 KB (Kilobyte)
1024 KB = 1 MB (Megabyte)
1024 MB = 1 GB (Gigabyte)
1024 GB = 1 TB (Terabyte)
1024 TB = 1 PB(Petabyte)
Computer Coding System: A computer coding system is a method used to represent data (like letters, numbers, and symbols) in a form that a computer can understand. 
Example : Letter A= 65(in ASCII) = 01000001(in binary)
Common Coding Systems
ASCII(American Standard Code for Information Interchange): ASCII is a coding system used to represent letters, numbers , and symbols in computers using numbers.
Ex: A= 65, B= 66, a=97, 0=48

Number System: A number system is a way of representing numbers using a set of digits or symbols. 
Types of Number system: 
1. Decimal Number System: The decimal system is a system with base 10, which uses 10 digits (0-9). The decimal number system is commonly used in daily life. 
Ex: (79)10, (1243)10
2. Binary Number System: The binary number system uses only two digits 0 and 1 and has a base of 2.
Ex- (101)2, (101110)2
3. Octal Number System: The Octal number system uses digit from 0 to 7 and has base of 8.
Ex- (17)8 , (25) 8
4. Hexadecimal Number System: The hexadecimal number system uses 16 symbols (0-9 and A-F). and has a base of 16.
A-10, B-11, C-12, D-13, E-14, F-15
Ex- (ABC)16, (2FA)16

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