Download Notes - Computer System - SEE Computer Science - Grade IX 2082

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1.1 Introduction to Computer Systems: 

 1.1.1 Definition and features of computer system 

 1.1.2 Application areas of computer systems. 

 1.1.3 Functions of a computer system: Input, Process, Output, Storage (IPOS) with Basic Block Diagram. 

 1.2 Input Devices: Overview of input devices: Mouse, Keyboard, Joystick, Microphone, Scanner, Webcam, Touchscreen, Touchpad. 

 1.3 Central Processing Unit (CPU) 

1.3.1 Function of the CPU 

 1.3.2 Components of the CPU: Control Unit, Arithmetic and Logic Unit, and Memory Unit. 

 1.4 Motherboard and Data Bus 

 1.4.1 Explanation of the motherboard's role in connecting components. 

 1.4.2 Understanding the data bus and its importance in data transfer. 

 1.5 Memory (Primary and Secondary) 

 1.5.1 Definition and function of memory 

 1.5.2 Units of memory measurement 

 1.5.3 Types of memory: primary and secondary memory and their comparison. 

 1.5.4 Example of primary memory: RAM, ROM, Cache, Register. 

 1.5.5 Example of secondary memory (Storage devices): Hard disk drive (HDD), Solid State Drive (SDD), Optical Discs (CD/DVD), Flash Memory 

 1.5.6 Function and characteristics of each type of memory. 

 1.6 Output Devices 

 1.6.1 Overview of output devices: 

 1.6.2 Display unit: LED and LCD Monitor, 

 1.6.3 Printer: Laser, Ink-jet, Dot-matrix and 3D Printer, 

 1.6.4 Overview of Ports: USB/Type C, HDMI, VGA, Ethernet, Audio port. 

 1.7 Computer Software 

 1.7.1 Concept and its types 

 1.7.2 Open sources and proprietary software 

 1.7.3 Compare features of System and Application software 

 1.7.4 Introduction to Mobile and Web Application

1.1  Introduction to Computer Systems

 

1.1.1 Definition and features of computer system

The word “Computer” comes from the Latin word Computare, which means “to calculate”. A computer is an electronic device that accepts data as input, processes it according to given instructions, stores data and results, and produces meaningful information as output.

Features of a Computer

 

1. Automatic

A computer works automatically once instructions are given through software. Once a program is started, the computer performs tasks automatically without human intervention. Example: Printing 1000 pages continuously without monitoring.

 

2. Speed

A computer system can perform millions of calculations per second. It completes tasks much faster than humans. The table below shows the speed of the computer in different units of time.

Unit of Time	Part of second	Power of 10
Millisecond	1/1000	One Thousand (10-3)
Microsecond	1/1000000	One Millionth (10-6)
Nanosecond	1/1000000000	One Billionth (10-9)
Picosecond	1/1000000000000	One Trillionth (10-12)
Femtosecond	1/1000000000000000	One Quadrillionth (10-15)

 

3. Accuracy

A computer provides accurate results if correct data and instructions are given. Errors occur only due to wrong input or programs. The incorrect output produced due to incorrect input is referred to as Garbage In Garbage Out (GIGO). Errors due to hardware or software faults are called bugs.

 

4. Storage

A computer can store a large amount of data, information, and programs for future use.1 Byte = 1 character.

1 Bit = 1 or 0	4 bits = 1 Nibble
8 bits = 1 Byte	1024 bytes = 1 KB	KB-Kilobyte	EB-Exabyte
1024 KB = 1 MB	1024 MB = 1 GB	MB-Megabyte	ZB-Zettabyte
1024 GB = 1 TB	1024 TB = 1 PB	GB-Gigabyte	YB – Yottabyte
1024 PB = 1 EB	1024 EB = 1 ZB	TB-Terabyte
1024 ZB = 1 YB		PB-Petabyte

 

5. Diligence

A computer can work continuously for a long time without getting tired or losing efficiency. The capability of a computer to perform a task repeatedly without losing speed and accuracy for a long time is known as diligence.

 

6. Versatility

A computer system can perform different types of tasks such as calculations, document creation, internet browsing, and multimedia work. Versatility refers to the capability of doing various kinds of tasks.

 

7. No Intelligence

A computer cannot think or make decisions on its own. It works strictly according to the instructions provided by the user.

 

 

1.1.2 Application Areas of Computer Systems

Computers are very powerful and versatile. They help people work faster, correctly, and more efficiently. With computers, people can prepare documents, spreadsheets, presentations, and graphics. They can also enjoy modern facilities like instant messaging, video chatting, email, online shopping, ticket booking, banking, and getting the latest news. Today, computers are used in almost every field of life. Some important applications are:

 

Education

Computer systems are used in education for teaching and learning purposes. Teachers use computers to prepare teaching materials and presentations, while students use them for learning through the internet, online classes, and educational software. Computers are also used to keep student records and examination results.

 

Communication

Computers play a vital role in communication. They are used to send and receive information through email, video conferencing, chatting, and social media platforms. Computers make communication faster, easier, and global.

 

Entertainment

Computers are used in entertainment for playing games, watching movies, listening to music, animation, and video editing. They provide digital entertainment through multimedia and online platforms.

 

Banking

In the banking sector, computers are used for maintaining customer records, processing transactions, online banking, ATM services, and generating bank statements. Computer systems have increased accuracy, speed, and security in banking services.

 

Medicine and Healthcare

Computer systems are widely used in hospitals and healthcare centers. They are used to maintain patient records, assist in medical diagnosis, operate medical equipment, and manage hospital systems. Computers are also used in medical research.

 

Scientific research

Computers are used in scientific research to analyze large amounts of data, conduct simulations, weather forecasting, and space research. They help scientists perform complex calculations accurately and quickly.

 

Business

In business organizations, computers are used for accounting, billing, payroll processing, inventory management, record keeping, and communication. They help in efficient management and decision making.

 

Agriculture

Computers are used in agriculture for weather forecasting, crop management, data analysis, and modern farming techniques. They help farmers increase productivity and efficiency.

 

Transportation

Computers are used in transportation systems for ticket booking, traffic control, navigation, and managing transport schedules. They help reduce human errors and improve safety.

 

Government Offices

Government offices use computer systems for census data, record keeping, tax systems, e-governance services, and public administration. Computers improve efficiency and transparency in government services.

 

 

1.1.3 Functions of a computer system: Input, Process, Output, Storage (IPOS) with Basic Block Diagram.

 

A computer system performs its work through four basic functions known as the IPOS cycle. IPOS stands for Input, Process, Output, and Storage. These functions work together to convert data into meaningful information.

 

The block diagram of the IPOS cycle of the computer system as:

 

1. Input

Input is the process of entering raw data and instructions into the computer system.
Input devices such as keyboard, mouse, scanner, and microphone are used to provide data to the computer.

 

2. Process

Processing is the operation performed on the input data according to the given instructions.
The CPU (Central Processing Unit) processes data by performing arithmetic and logical operations to convert data into information.

 

3. Output

Output is the result produced after processing the data.
Output devices like monitor, printer, and speaker are used to display or produce the processed information.

 

4. Storage

Storage refers to saving data, programs, and results for future use.
A computer uses primary memory (RAM, ROM) and secondary memory (HDD, SSD, pen drive) to store information.

 

 

1. The word “Computer” is derived from which word? [k]

A. Compute                B. Calculus                 C. Computare ✅                   D. Calculation

2. A computer is best defined as: [k]

A. A mechanical device                      B. An electronic device that processes data ✅
C. A thinking machine                                    D. A communication tool

3. Which feature allows a computer to work without human intervention once started? [k]

A. Speed                     B. Accuracy                C. Automatic ✅                    D. Versatility

4. Performing millions of calculations per second shows which feature? [u]

A. Accuracy                B. Speed ✅               C. Storage                               D. Diligence

5. Wrong output due to wrong input is called: [k]

A. Bug                         B. Virus                       C. GIGO ✅                           D. Malware

6. A computer working continuously for long hours shows: [u]

A. Accuracy                B. Speed                      C. Diligence ✅                     D. Versatility

7. A computer editing videos, calculating results, and browsing the internet shows: [a]

A. Speed                     B. Accuracy                C. Versatility ✅                    D. Storage

8. Which feature proves that a computer cannot think on its own? [k]

A. Speed                     B. Accuracy                C. Automatic                          D. No intelligence ✅

9. Which unit represents one billionth of a second? [k]

A. Microsecond          B. Millisecond            C. Nanosecond ✅                 D. Picosecond

10. Which unit represents one trillionth of a second? [k]

A. Nanosecond           B. Microsecond          C. Picosecond ✅                   D. Femtosecond

11. Sending emails and video calls belongs to: [k]

A. Entertainment        B. Business                 C. Communication ✅           D. Research

12. Online shopping and billing are examples of computer use in: [u]

A. Business ✅          B. Education               C. Agriculture             D. Government

13. Weather forecasting mainly uses computers in: [u]

A. Entertainment        B. Agriculture             C. Communication     D. Scientific research ✅
14. Computers reduce human error most effectively in: [ HA]
A. Entertainment        B. Manual work          C. Automated systems ✅      D. Games

15. IPOS stands for: [K]

A. Input, Program, Output, Storage               B. Input, Process, Output, Storage ✅
C. Instruction, Process, Output, Speed           D. Input, Processing, Object, System

16. Entering data into the computer is called: [K]

A. Processing              B. Output                    C. Input ✅                D. Storage

17. Which device is used for input? [K]

A. Monitor                  B. Printer                    C. Keyboard ✅         D. Speaker

18. Which part processes data in a computer system? [K]

A. Output device        B. CPU ✅                 C. Input device           D. Storage device

19. Arithmetic and logical operations are done by: [U]

A. CU                          B. Register                  C. ALU ✅                 D. ROM

20. The processed result displayed to the user is called: [K]

A. Input                       B. Output ✅              C. Storage                   D. Processing

21. Saving data for future use is called: [K]

A. Input                       B. Processing              C. Output                    D. Storage ✅

22. Which memory is volatile? [U]

A. ROM                      B. HDD                                   C. SSD                        D. RAM ✅

23. Which stage converts data into information? [A]

A. Input                       B. Storage                   C. Processing ✅        D. Output

24. Which statement best explains the term “Garbage In, Garbage Out (GIGO)” in a computer system? [HA]

A. Computer always produces correct output B. Computer can correct wrong input automatically
C. Wrong input leads to wrong output ✅                 D. Computer makes decisions on its own

25. In the basic block diagram of a computer system, which component directly controls and coordinates all operations? [A]

A. Input Unit              B. Output Unit            C. Storage Unit           D. Central Processing Unit (CPU) ✅

 

Short Questions

 

What is computer? Explain why a computer is called an automatic machine.

What is GIGO? How does diligence differentiate a computer from humans?

What is versatility? Explain accuracy as a feature of a computer system.

Why is a computer said to have no intelligence?

Explain the importance of storage in a computer system.

How do computers help farmers in agriculture?

Explain the use of computers in business organizations.

 

Long Questions

 

Draw and Explain the functions of a computer system with reference to the IPOS cycle.

Define a computer system and Explain any five features of a computer system.

Explain the application of computer systems in different fields.

Describe the role of computers in education and communication.

Explain the use of computers in banking and healthcare sectors.

Explain how computers are useful in business and government offices.

 

1.2 Input Devices

 

Input devices are hardware components of a computer system used to enter data and instructions into the computer. They convert human-readable data into machine-readable form for processing.

 

Examples of Input Devices:

Mouse

Keyboard

Joystick

Microphone

Scanner

Webcam

Touchscreen

Touchpad

 

Mouse

A mouse is a handheld pointing input device used to select and control objects on the computer screen. It is mainly used with GUI-based systems for pointing, clicking, dragging, and scrolling. It has left, right, and scroll buttons.

 

Keyboard

A keyboard is an input device used to enter text, numbers, and commands into a computer by typing. A standard keyboard has 104 keys and the most common layout is QWERTY, named after the first six keys of the top row. Types of Keys on a Keyboard: Alphabet keys: A to Z, Numeric keys: 0 to 9 and mathematical symbols, Function keys: F1 to F12, Cursor movement keys: Arrow keys

Special purpose keys: Enter, Spacebar, Shift, Ctrl, Alt, Delete

 

Joystick

A joystick is an input device mainly used for playing video games and simulation systems. It consists of a movable stick that detects direction and movement and has buttons for game control.

 

Microphone

A microphone is an input device used to enter sound or voice into a computer. It converts sound waves into digital signals and is used for voice recording, online meetings, and video conferencing.

 

Scanner

A scanner is an input device used to convert printed documents or images into digital form. It is commonly used for digitizing text and photographs.

 

Webcam

A webcam is an input device used to capture live images and videos. It is mainly used for video calls, online classes, and video conferencing.

 

Touchscreen

A touchscreen is an input device that allows users to give input by touching the display screen directly. It is commonly used in smartphones, tablets, and ATMs.

 

 

Touchpad

A touchpad is a touch-sensitive pointing input device commonly found on laptops. It is used to control the cursor and works like a mouse.

 

📘 1.2 Input Devices - MCQs

1. Which task is most efficiently performed using a mouse?

A. Typing a document            B. Recording sound    C. Dragging and dropping icons ✅   D. Scanning text

2. The main purpose of a keyboard is to:

A. Capture images                  B. Enter text and commands ✅        C. Record sound            D. Control cursor

3. Function keys on a keyboard are labeled as:

A. A1–A12                              B. Ctrl keys                             C. F1–F12 ✅            D. Arrow keys

4. A joystick is mainly used for:

A. Typing        B. Playing games and simulations ✅  C. Scanning documents       D. Video conferencing

5. A microphone is used to input:

A. Images                               B. Text                                    C. Sound ✅                           D. Video

6. A scanner converts:

A. Digital data into paper                                                       B. Paper documents into digital form ✅
C. Sound into text                                                                   D. Video into images

7. A touchscreen accepts input through:

A. Keyboard only                   B. Mouse only                        C. Touch on screen ✅            D. Voice

8. A touchpad is commonly found in:

A. Desktop computers            B. Printers                               C. Laptops ✅                        D. Servers

9. Which input device does not require physical movement on a surface?

A. Mouse                                B. Touchpad                            C. Joystick                  D. Touchscreen ✅

10. A standard keyboard generally has:

A. 84 keys                               B. 90 keys                               C. 104 keys ✅                       D. 120 keys

11. QWERTY is called so because:

A. It is fastest layout                                                               B. It is the newest layout
C. It is named after first six top-row letters ✅                     D. It is named after inventor

12. Which device is used for video calling as video input?

A. Keyboard                           B. Mouse                                C. Webcam ✅                       D. Scanner

13. Which input device is built into most laptops for cursor control?

A. Joystick                              B. Touchpad ✅                     C. Scanner                  D. Microphone

14. Touchpad performs the same function as a:

A. Keyboard                           B. Mouse ✅                          C. Scanner                  D. Speaker

15. Which of the following is NOT an input device?

A. Mouse                                B. Keyboard                            C. Scanner                  D. Printer ✅

16. Which device acts as both input and output device?

A. Mouse                                B. Keyboard                            C. Touchscreen ✅                 D. Scanner

17. Which input device is MOST suitable for entering hand-drawn pictures into a computer?

A. Mouse                                B. Scanner ✅                        C. Keyboard                D. Webcam

18. Which input device reduces the need for both keyboard and mouse?

A. Touchpad                           B. Scanner                              C. Touchscreen ✅                 D. Joystick

19. Which input device is generally used in laptops instead of an external pointing device?

A. Mouse                                B. Touchpad ✅                     C. Joystick                  D. Scanner

20. Which input device is MOST suitable when a user needs to interact with a computer without using any physical buttons or keys?

A. Mouse                                B. Keyboard                            C. Touchscreen ✅                 D. Scanner

What are input devices? Write any two functions of a mouse.

What is a keyboard? Name any four types of keys found on a keyboard.

What is a joystick? How is a touchpad different from a mouse?

Define a mouse. What is a microphone used for?

What is a scanner? Write two uses of a webcam.

1.3 Central Processing Unit (CPU)

The Central Processing Unit (CPU) is the brain of the computer system that controls all operations of the computer and processes data and instructions.

It is responsible for receiving data from the input unit, executing instructions provided by the user, and generating output information.

Intel CPUs (e.g., Intel Core i5, i7, i9), AMD CPUs (e.g., Ryzen series, EPYC), Apple CPUs(M1, M2), ARM CPUs ((e.g., Qualcomm Snapdragon, MediaTek)), etc. are popular examples of CPUs.

 

1.3.1 Function of the CPU

 

i. Fetching: Retrieves data and instructions from memory (RAM).

ii. Decoding: Interprets the instructions to understand required actions.

iii. Executing: Performs calculations, data movement, or hardware interaction.

iv. Storing: Stores results back into memory or sends them to output devices.

v. Managing Interrupts: Handles hardware and software interruptions to ensure smooth processing.

 

In short with Example (25 + 10):

·        Fetch → Get the problem from memory.

·        Decode → Understand it’s an addition.

·        Execute → Do 25 + 10 = 35.

·        Store → Save result (35) in memory to display.

·        Manage Interrupts → Handle side tasks (e.g., notifications).

 

Example (Working of CPU):

1. The CPU fetches instructions from memory.
2. The Control Unit decodes the instructions.
3. The Arithmetic Logic Unit executes the instructions.
4. The results are stored in registers or sent to memory/output devices.

📌 This is the fetch–decode–execute cycle.

 

1.3.2 Components of the CPU: Control Unit, Arithmetic and Logic Unit, and Memory Unit.

 

Control Unit (CU)

The Control Unit (CU) controls the working of all parts of the computer system. It controls the movement of data inside as well as outside the CPU. The CU communicates between the registers and the ALU and between the CPU and all input, output, and storage devices. It directs all parts of the computer system to perform their tasks.

 

Arithmetic Logic Unit (ALU)

The Arithmetic Logic Unit (ALU) performs all arithmetic and logical operations. Arithmetic operations include addition, subtraction, multiplication, and division. Logical operations include greater than, less than, and not equal comparisons.

 

Memory Unit (MU)

The Memory Unit (MU) stores data, instructions, and results required during processing. In the CPU, the Memory Unit mainly consists of registers, which are small, high-speed memory units. Registers store immediate data, instructions, and results while processing data.

 

Registers

Registers are small, fast memory units inside the CPU. They are used to store immediate data, instructions, and results temporarily during data processing.

The speed of a computer depends mainly on its microprocessor.

1. CPU stands for: ⭐

A. Central Program Unit                    B. Computer Processing Unit
C. Central Processing Unit ✅           D. Control Processing Unit

2. The CPU is also known as the: ⭐

A. Heart of the computer                    B. Memory of the computer
C. Brain of the computer ✅              D. Storage of the compute

3. Which unit performs arithmetic and logical operations? ⭐

A. Control Unit                       B. Memory Unit         C. Arithmetic Logic Unit ✅ D. Input Unit

4. Fetching refers to: ⭐

A. Performing calculations                                                    B. Storing results
C. Retrieving data and instructions from memory ✅           D. Sending output to devices

5. Which unit controls the movement of data inside and outside the CPU? ⭐

A. ALU                       B. Memory Unit                     C. Control Unit ✅     D. Register

6. Registers are:

A. Large storage devices                                                        B. Input devices
C. Small high-speed memory units inside CPU ✅               D. Output devices

7. Which function ensures smooth processing by handling interruptions? ⭐

A. Executing                           B. Storing                   C. Decoding    D. Managing interrupts ✅

8. The speed of a computer mainly depends on its: ⭐

A. Keyboard               B. Monitor                  C. Microprocessor ✅            D. Printer

9. Which of the following are examples of CPUs?

A. Intel, AMD, Apple, ARM ✅                    B. Mouse, Keyboard, Scanner
C. RAM, ROM, HDD                                     D. Printer, Monitor, Speaker

10. The CPU receives data from which unit? ⭐

A. Output unit                         B. Storage unit            C. Input unit ✅D. Control unit

11. Decoding in CPU means: ⭐

A. Performing calculations                            B. Translating instructions into machine language
C. Interpreting fetched instructions ✅         D. Storing results

12. Managing interrupts is done to ensure: ⭐

A. Faster typing                                                          B. Better storage        

C. Smooth and efficient processing ✅                     D. More memory

13. Registers are mainly used to store: ⭐

A. Permanent data                                                      B. Backup files          

C. Immediate data and instructions ✅                      D. Output information only

14. Which statement is CORRECT about the microprocessor? ⭐

A. It is an input device                                   B. It controls only output devices
C. It contains CU, ALU, and registers ✅     D. It stores data permanently

15. Which of the following tasks is performed during the execution stage? ⭐

A. Retrieving instructions from RAM                                    B. Interpreting instructions
C. Performing calculations and data movement ✅              D. Storing instructions permanently

 

Define Central Processing Unit (CPU).  Write any two examples of CPUs.

Explain the functions of the CPU.

Explain the components of the CPU.

Explain the working of the CPU.

Describe the Control Unit and Arithmetic Logic Unit.

 

1.4 Motherboard and Data Bus

 

1.4.1 Explanation of the motherboard's role in connecting components.

 

Motherboard

 

Motherboard is the main circuit board of a computer that connects, controls, and allows communication between all hardware components like CPU, memory, storage, and input/output devices.

It is also called the system board or PCB (Printed Circuit Board).

 

Role of Motherboard

The motherboard acts as the main circuit board of a computer. It serves as the foundation of the computer system and connects all major components like the CPU, memory, and peripherals, allowing them to communicate and work together. Hence, it is called the backbone of the computer.

 

The motherboard acts as a central connector hub in a computer system. It manages connections in the following ways:

 

i. Physical Connections:
Sockets hold major components like the CPU and RAM. Expansion slots allow installation of devices such as graphics cards and network cards, and ports are used to connect external devices like monitor, keyboard, and printer.

 

ii. Electrical Connections:
The motherboard distributes power from the PSU to all components through circuits and voltage regulators. Data is transferred using electrical signals through internal pathways.

 

iii. Communication Hub:
Chipsets such as Northbridge and Southbridge control communication between the CPU, RAM, and peripherals. Internal buses like PCIe and SATA enable fast data transfer between components.

 

1.4.2 Understanding the data bus and its importance in data transfer.

A bus is a set of electronic pathways or connected lines that is used to transfer data, addresses, and control signals between the internal components of a computer system.

 

Types of buses

 

Data Bus

A data bus is a set of electronic lines that is used to transfer actual data between the CPU, memory, and peripheral devices in a computer system.

The data bus is important because it ensures fast and smooth data transfer, and the width of the data bus affects the speed and performance of the computer system.

 

Address Bus

An address bus is a communication pathway that carries the address of memory locations from the CPU to the memory, indicating where data is to be read or written.

 

Control Bus

A control bus is a set of lines that transfers control and timing signals between computer components to coordinate and manage operations such as read, write, and interrupt.

 

 

1. What is the motherboard of a computer?
a) An input device                              b) The main circuit board of a computer ✅
c) A storage device                             d) An output device

2. The motherboard is also known as:
a) Hard disk                                        b) Control board
c) System board or PCB ✅            d) Expansion board

3. Which component holds the CPU on the motherboard?
a) Port                         b) Slot             c) Socket ✅              d) Bus

4. Which of the following supplies power to the motherboard?
a) CPU                        b) RAM           c) PSU ✅                  d) ROM

5. How many main types of buses are there in a computer system?
a) One                         b) Two             c) Three ✅               d) Four

6. Why is the motherboard called the backbone of the computer?
a) It stores data permanently
b) It connects and allows communication between components ✅
c) It performs calculations
d) It provides internet connection

7. Which of the following is an example of a physical connection on the motherboard?
a) Chipset                   b) PSU            c) CPU socket ✅      d) Data signal

8. What is the main role of chipsets like Northbridge and Southbridge?
a) Store data                b) Supply power
c) Control communication between components ✅
d) Display output

9. What does the width of a data bus decide?
a) Size of memory                              b) Amount of data transferred at once ✅
c) Type of software used                    d) Number of peripherals

10. Which bus carries the address of memory locations?
a) Data bus                  b) Control bus             c) Expansion bus        d) Address bus ✅

11. If a computer transfers data faster, which bus feature is mainly responsible?
a) Narrow data bus                 b) Wider data bus ✅           c) Control bus signals     d) Address bus length

12. Which bus helps the CPU decide where data should be stored in memory?
a) Data bus                              b) Control bus             c) Address bus ✅                 d) System bus

13. A signal to read or write data is carried by which bus?
a) Data bus                  b) Address bus            c) Control bus ✅                 d) Expansion bus

14. Connecting a graphics card to the motherboard uses:
a) Socket                     b) Expansion slot ✅            c) Port             d) Bus width

15. Which bus is responsible for transferring actual data between the CPU, memory, and peripheral devices?

a) Address bus            b) Control bus             c) Data bus ✅                      d) Expansion bus

 

1. Why is the motherboard called the backbone of the computer?

2. Define motherboard and explain its role in connecting computer components.

3. Explain the motherboard as a central connector hub.

4. What is a bus? Explain the types of buses used in a computer system.

5. Define data bus and explain its importance in data transfer.

 

1.5.1 Definition and function of memory

 

Memory is a computer storage system used to store data, instructions, and results either temporarily or permanently during processing.

 

The function of memory is to store data, instructions, and results for use by the CPU during processing so that the CPU can work efficiently.

 

Type of Memory

a. Primary memory and

b. Secondary memory

 

1.5.2 Units of memory measurement

 

Computer memory and storage are measured in bits and bytes.

 

Unit	Symbol	Description
Bit	b	The smallest unit of memory, stores either 0 or 1
Nibble	—	A group of 4 bits.
Byte	B	A group of 8 bits, represents one character (e.g., a letter/number).
Kilobyte	KB	1024 bytes
Megabyte	MB	1024 KB
Gigabyte	GB	1024 MB
Terabyte	TB	1024 GB

 

1.5.3 Types of memory: primary and secondary memory and their comparison.

 

Primary memory (Main Memory / Internal Memory)

Primary memory is the main memory of a computer system that stores data and instructions currently being used by the CPU. It is directly accessed by the CPU and is used during the processing of data.

 

Secondary memory, (Storage devices or auxiliary or backup memory)

Secondary memory is a type of memory used to store data and instructions permanently for future use. It has a large storage capacity, is not directly accessed by the CPU, and retains data even when the power is switched off.

 

Primary Memory	Secondary Memory
Primary memory is the main memory of a computer used to store data and instructions currently needed by the CPU.	Secondary memory is used to store data and instructions permanently for future use.
Directly accessed by the CPU	Not directly accessed by the CPU
Very fast	Slower compared to primary memory
Limited storage capacity	Very large storage capacity
Mostly volatile (data is lost when power is off)	Non-volatile (data is not lost when power is off)
Examples: RAM, ROM, Cache, Register	Examples: Hard Disk, SSD, Pen Drive, CD/DVD

 

 

 

 

 

1.5.4 Example of primary memory: RAM, ROM, Cache, Register

 

Types of Primary Memory:

 

1. RAM (Random Access Memory)

RAM is a temporary memory that stores data and instructions currently being used by the CPU. It is volatile in nature, so data is lost when the power is switched off.

 

2. ROM (Read Only Memory)

ROM (Read Only Memory) is a non-volatile memory that permanently stores instructions needed to start the computer and load the operating system. It is non-volatile, meaning data is not lost when the power is turned off.

Programs stored in ROM are written during manufacturing and are known as firmware, such as the BIOS (Basic Input Output System), which helps in booting the computer.

 

3. Cache Memory

Cache memory is a very fast memory that stores frequently used data and instructions to improve the performance of the CPU. It is located between the CPU and main memory and reduces the time required to access data.

 

4. Register

Registers are the smallest and fastest memory units located inside the CPU that temporarily store data and instructions during processing.

 

RAM (Random Access Memory)	ROM (Read Only Memory)
RAM is a temporary memory that stores data and instructions currently used by the CPU.	ROM is a permanent memory that stores instructions needed to start the computer and load the operating system.
It is volatile in nature, so data is lost when the power is switched off.	It is non-volatile, meaning data is not lost when the power is turned off.
Used during processing	Used during startup
Faster than ROM	Slower than RAM
Data can be read and written	Data is mostly read-only

 

Types of RAM

 

1. DRAM (Dynamic Random Access Memory)

DRAM is a type of RAM that stores data temporarily and needs to be refreshed repeatedly to retain data. It is slower than SRAM but has a larger storage capacity and is commonly used as the main memory of a computer.

 

2. SRAM (Static Random Access Memory)

SRAM is a type of RAM that stores data without frequent refreshing. It is faster and more reliable than DRAM but has a smaller capacity and is more expensive, so it is mainly used as cache memory.

 

SRAM (Static Random Access Memory)	DRAM (Dynamic Random Access Memory)
SRAM is a type of RAM that stores data without the need for frequent refreshing.	DRAM is a type of RAM that stores data temporarily and needs continuous refreshing.
Very fast and more expensive	Slower than SRAM and less expensive
Smaller storage capacity	Larger storage capacity
Consumes less power and more reliable	Consumes more power due to refreshing and less reliable compared to SRAM

Types of ROM:

 

1. PROM (Programmable Read Only Memory)

PROM is a type of ROM that is programmed only once after manufacturing. Once data is written into PROM, it cannot be changed or erased. It is used when permanent data storage is required.

 

2. EPROM (Erasable Programmable Read Only Memory)

EPROM is a type of ROM that can be erased using ultraviolet (UV) light and reprogrammed. It allows data to be modified, but the chip must be removed from the computer for erasing.

 

3. EEPROM (Electrically Erasable Programmable Read Only Memory)

EEPROM is a type of ROM that can be erased and reprogrammed electrically without removing it from the computer. It is more flexible and commonly used in modern systems.

 

PROM	EPROM	EEPROM
Programmable Read Only Memory	Erasable Programmable Read Only Memory	Electrically Erasable Programmable Read Only Memory
PROM is a type of ROM that can be programmed only once after manufacturing.	EPROM is a type of ROM that can be erased and reprogrammed using ultraviolet light.	EEPROM is a type of ROM that can be erased and reprogrammed electrically.
Programmed only once	Can be programmed multiple times	Can be programmed multiple times
Cannot be erased	Erased using UV (ultraviolet) light	Erased using electrical signals
Not reusable	Reusable after erasing	Highly reusable
Not applicable	Must be removed from the computer for erasing	No need to remove from the computer

 

1.5.5 Example of secondary memory (Storage devices): Hard disk drive (HDD), Solid State Drive (SDD), Optical Discs (CD/DVD), Flash Memory

 

Hard Disk Drive (HDD)

A Hard Disk Drive (HDD) is a secondary storage device used to store data, programs, and files permanently in a computer system. It is a non-volatile memory, so data is not lost when the power is switched off. HDD stores data on magnetic disks and has a large storage capacity, making it suitable for long-term data storage.

The speed of a hard disk is measured in Revolutions Per Minute (RPM), which usually ranges from 5400 to 7200 rpm in common computers.

 

SSD (Solid State Drive)

A Solid State Drive (SSD) is a secondary storage device used to store data, programs, and files permanently in a computer system. It is a non-volatile memory and stores data using flash memory instead of magnetic disks. SSDs are faster, quieter, and more reliable than hard disk drives.

SSDs are widely used in laptops, notebooks, and ultrabooks for high performance.

HDD (Hard Disk Drive)	SSD (Solid State Drive)
HDD is a secondary storage device that stores data using magnetic disks.	SSD is a secondary storage device that stores data using flash memory.
Has moving parts like rotating disks	Has no moving parts
Slower data access and consumes more power	Faster data access and consumes less power
Less durable, produce noise, cheaper	More durable, silent, more expensive

Optical Storage Disc

An Optical Storage Disc is a secondary storage device used to store data permanently using laser light technology. Data is read and written on the disc with the help of a laser beam. It is a non-volatile storage, so data is not lost when the power is switched off.

Common examples include CDs (Compact Discs), DVDs (Digital Versatile Discs), and Blu-ray Discs.

 

CD (Compact Disc)

A CD (Compact Disc) is an optical storage disc used to store data permanently. It uses laser technology to read and write data. A CD is a non-volatile storage device, so the data stored on it is not lost when the power is switched off.

 

A CD (Compact Disc) is an optical storage disc used to store data permanently. It uses laser technology to read and write data. A CD is a non-volatile storage device, so the data stored on it is not lost when the power is switched off.

A standard CD is 12 cm in diameter, 1 mm thick, and weighs about 18 g. The storage capacity of CD is 700MB.

 

DVD (Digital Versatile Disc)

A DVD (Digital Versatile Disc) is an optical storage disc used to store data permanently. It uses laser technology to read and write data. A DVD has a larger storage capacity than a CD, making it suitable for storing videos, software, and large data files.

A DVD is an optical storage disc developed in 1995 by Philips, Sony, Toshiba, and Panasonic. A DVD drive is required to read and write data on DVDs.

Storage Capacities:

• Single Side, Single Layer: 4.7 GB
• Single Side, Double Layer: 8.5 GB
• Double Side, Single Layer: 9.4 GB
• Double Side, Double Layer: 17.08 GB

 

CD (Compact Disc)	DVD (Digital Versatile Disc)
Uses laser technology to read and write data	Uses advanced laser technology to read and write data
Stores about 700 MB of data	Stores 4.7 GB or more of data
Lower data density and Slower data access speed	Higher data density and Faster data access speed
Usually single layer	Can be single-layer or double-layer
Used for music, small software, and documents	Used for movies, videos, large software, and data
Lower video quality and Older technology	Better video quality and More advanced than CD

 

Blu-ray Disc

A Blu-ray Disc is an optical storage disc used to store large amounts of data permanently. It uses a blue-violet laser, which allows it to store more data than CDs and DVDs. It is commonly used for high-definition videos and large data storage.

 

Flash Memory

Flash memory is a type of non-volatile memory used to store data permanently. It stores data in electronic form and does not require power to retain data. Flash memory is widely used in devices such as pen drives, memory cards, and solid state drives (SSD).

 

Pen Drive

A pen drive is a portable secondary storage device that uses flash memory to store data permanently. It is a non-volatile memory, so data is not lost when power is switched off. A pen drive connects to a computer through a USB port and is used for storing and transferring data.

 

Cloud Storage

Cloud storage is a type of online storage system that allows users to store data on remote servers accessed through the internet instead of storing it on a local device. It enables users to access, share, and manage data from anywhere using an internet connection. Examples: Google Drive, Dropbox, Microsoft OneDrive, Amazon S3

 

Comparison Between HDD, SSD, and Flash Memory

 

HDD (Hard Disk Drive)	SSD (Solid State Drive)	Flash Memory
HDD is a secondary storage device that stores data using magnetic disks.	SSD is a secondary storage device that stores data using flash memory chips.	Flash memory is a type of non-volatile memory used to store data electronically.
Magnetic storage (rotating platters)	Flash memory (electronic chips)	Flash memory (electronic)
Has moving parts	No moving parts	No moving parts
Slower data access speed	Very fast data access speed	Faster than HDD but slower than SSD
Less durable due to moving parts	More durable and shock-resistant	Highly durable
Consumes more power	Consumes less power	Consumes very little power
Not portable	Less portable	Highly portable
Used in traditional desktop computers	Used in modern laptops and high-speed systems	Used in pen drives, memory cards, USB devices

 

1.5.6 Function and characteristics of each type of memory

 

Type of Memory	Function	Characteristics
Primary Memory	Stores data and instructions currently required by the CPU for processing.	• Directly accessed by CPU • Fast in speed • Limited storage capacity • Mostly volatile
RAM (Random Access Memory)	Temporarily stores data and instructions during execution of programs.	• Volatile memory • Data lost when power is off • Fast access speed • Used during processing
ROM (Read Only Memory)	Stores instructions needed to start the computer and load the operating system.	• Non-volatile memory • Permanent storage • Mostly read-only • Stores firmware (BIOS)
Cache Memory	Stores frequently used data and instructions to improve CPU performance.	• Very fast memory • Located between CPU and RAM • Small capacity • Expensive
Register	Stores data and instructions temporarily inside the CPU during processing.	• Smallest and fastest memory • Located inside CPU • Very limited capacity
Secondary Memory	Stores data and programs permanently for future use.	• Non-volatile memory • Large storage capacity • Slower than primary memory • Not directly accessed by CPU

 

1. Memory in a computer is used to
A. Control hardware                           B. ✓ Store data, instructions, and results
C. Perform calculations                      D. Display output

2. The smallest unit of memory is
A. Byte            B. Nibble                    C. ✓ Bit                      D. Word

3. A group of 4 bits is called
A. Byte            B. ✓ Nibble                C. Word                       D. Register

4. A byte consists of
A. 4 bits          B. 6 bits                      C. ✓ 8 bits                  D. 16 bits

5. 1 KB is equal to
A. 1000 bytes              B. 512 bytes    C. ✓ 1024 bytes          D. 2048 bytes

6. Which memory is directly accessed by the CPU?
A. Secondary memory            B. Optical memory     C. ✓ Primary memory            D. Flash memory

7. Which memory loses data when power is switched off?
A. ROM                      B. HDD           C. SSD            D. ✓ RAM

8. Which of the following is non-volatile memory?
A. RAM                      B. Cache         C. ✓ ROM                  D. Register

9. BIOS is stored in
A. RAM                      B. Cache         C. ✓ ROM                  D. Register

10. Cache memory is used to
A. Store files permanently                 B. Increase storage capacity
C. ✓ Speed up CPU processing         D. Backup data

11. Registers are
A. Secondary storage devices            B. ✓ Located inside CPU
C. Slower than RAM                          D. Used for permanent storage

12. Which memory has the fastest access speed?
A. RAM                      B. Cache                     C. ✓ Register              D. SSD

13. Which memory is mostly read-only?
A. RAM                      B. ✓ ROM                  C. Cache                     D. Register

14. Firmware refers to programs stored in
A. RAM                      B. HDD                       C. ✓ ROM                  D. Cache

15. Which memory is volatile?
A. ROM                      B. HDD                       C. SSD            D. ✓ RAM

16. DRAM stands for
A. Direct RAM                       B. ✓ Dynamic Random Access Memory
C. Digital RAM                      D. Dual RAM

17. Which RAM needs refreshing?
A. SRAM                    B. ✓ DRAM                C. ROM                      D. Cache

18. Which RAM is faster?
A. DRAM                   B. ✓ SRAM                C. ROM                      D. Flash

19. PROM can be programmed
A. Multiple times       B. ✓ Only once                       C. After UV erase                   D. Electrically

20. EPROM is erased using
A. Electrical signals   B. Heat                        C. ✓ UV light             D. Magnet

21. EEPROM is erased using
A. UV light                 B. Heat                        C. ✓ Electrical signals                        D. Magnet

22. Which memory is permanent?
A. RAM                      B. Cache                     C. Register                  D. ✓ ROM

23. Which is secondary memory?
A. Cache                     B. Register                  C. RAM                      D. ✓ Hard disk

24. HDD stores data using
A. Laser                      B. Flash memory                    C. ✓ Magnetic disks               D. Electric charge

25. HDD speed is measured in
A. Mbps                      B. GHz                        C. ✓ RPM                   D. ns

26. SSD stores data using
A. Magnetic disks                   B. Laser                      C. ✓ Flash memory                D. Registers

27. Which storage has no moving parts?
A. HDD                       B. ✓ SSD                    C. CD              D. DVD

28. Optical discs use
A. Magnetism             B. Electricity              C. ✓ Laser technology                       D. Heat

29. Standard CD storage capacity is
A. 4.7 GB                    B. 8.5 GB                    C. ✓ 700 MB              D. 1 TB

30. Which memory helps reduce CPU access time?
A. RAM                      B. HDD                       C. ✓ Cache                 D. ROM

31. Data currently being processed is stored in
A. ROM                      B. HDD                       C. ✓ RAM                  D. CD

32. Booting instructions are stored in
A. RAM                      B. ✓ ROM                  C. Cache                     D. HDD

33. Which memory is fastest but smallest?
A. RAM                      B. Cache                     C. ✓ Register              D. SSD

34. Which is NOT primary memory?
A. RAM                      B. Cache                     C. Register                  D. ✓ HDD

35. Which device is best for portability?
A. HDD                       B. SSD            C. ✓ Pen drive            D. DVD

36. A laptop boots faster mainly due to
A. RAM size               B. ✓ SSD                    C. CD drive                D. Cache size

37. Which memory retains data without power?
A. RAM                      B. Cache                     C. ✓ ROM                  D. Register

38. Which storage is used for HD movies?
A. CD                          B. DVD                       C. ✓ Blu-ray               D. Pen drive

39. Which memory is slower than RAM?
A. Cache                     B. Register                  C. ✓ ROM                  D. SRAM

40. Which storage is cloud-based?
A. HDD                       B. SSD            C. Pen drive                D. ✓ Google Drive

41. Which memory consumes more power due to refreshing?
A. SRAM                    B. ✓ DRAM                C. ROM                      D. Cache

42. Which is more durable?
A. HDD                       B. ✓ SSD                    C. CD                          D. DVD

43. Which memory is used during execution of programs?
A. ROM                      B. HDD                       C. ✓ RAM                  D. CD

44. Which memory is inside CPU?
A. RAM                      B. Cache                     C. ✓ Register              D. HDD

45. Which optical disc has highest capacity?
A. CD                          B. DVD                       C. ✓ Blu-ray               D. Pen drive

46. Which memory is erased using UV light?
A. PROM                    B. ✓ EPROM              C. EEPROM               D. ROM

47. Which memory does not need refreshing?
A. DRAM                   B. ✓ SRAM                C. RAM                      D. Cache

48. Which is correct order of speed (fast → slow)?
A. RAM → Cache → Register                      B. HDD → RAM → Cache
C. ✓ Register → Cache → RAM                   D. Cache → Register → RAM

49. Which storage is best for long-term backup?
A. RAM                      B. Cache                     C. ✓ HDD                   D. Register

50. Which memory is closest to CPU?
A. RAM                      B. Cache                     C. ✓ Register              D. SSD

51. Which is true about SSD?
A. Uses magnetic disks                      B. Has moving parts
C. ✓ Faster and silent             D. Needs RPM

52. Which storage is accessed via internet?
A. HDD                       B. SSD            C. ✓ Cloud storage                 D. CD

53. Which memory is used only during startup?
A. RAM                      B. ✓ ROM                  C. Cache                     D. HDD

54. Which memory stores OS files permanently?
A. RAM                      B. ✓ HDD / SSD                    C. Cache         D. Register

55. Which memory type balances speed and cost best?
A. Register                  B. Cache                     C. ✓ RAM                  D. SSD

1.     (A1) Why is RAM called volatile memory? Explain with a suitable example.

2.     (A1) How does cache memory improve the performance of the CPU?

3.     Differentiate between SRAM and DRAM based on working principle and usage.

4.     (A1) Why is ROM essential for booting a computer system?

5.     (A1) Explain the role of cache memory between CPU and RAM.

6.     (A1) A system crashes suddenly. Which type of memory data will be lost and why?

 

7.     (A1) Define computer memory. Explain its functions and importance in a computer system.

8.     (A1) Explain primary memory. Describe its types with suitable examples.

9.     Define secondary memory. Explain different types of secondary storage devices with examples.

10.  (A1) Explain RAM and ROM in detail. Compare them.

11.  (A1) Explain the types of RAM. Describe SRAM and DRAM with differences.

12.  Explain ROM and its types: PROM, EPROM, EEPROM.

13.  Explain Hard Disk Drive (HDD) and Solid State Drive (SSD). Compare them.

14.  Explain optical storage devices: CD, DVD, Blu-ray Disc with capacities.

15.  (A1) Compare Primary memory and Secondary memory.

 

 

1.6 Output Devices

1.6.1 Overview of output devices:

 

An output device is a hardware component that receives data from the computer and converts the processed information into a human-readable form such as text, images, sound, or video. Common output devices include monitors, printers, speakers, and headphones.

 

1.6.2 Display unit: LED and LCD Monitor,

 

Monitor (Visual Display Unit – VDU)

A monitor is an primary output device that displays processed information from the computer in visual form. It shows text, images, graphics, and videos on the screen, allowing users to see the results of processing. The output seen on a monitor is known as a soft copy because it is temporary and can only be viewed on screen. Monitors come in two main types based on color capabilities: monochrome and color monitors

 

LED and LCD Monitors

 

LCD (Liquid Crystal Display)

An LCD monitor is a flat-panel output device that displays information using liquid crystal technology. It controls liquid crystals to allow light to form images on the screen. LCD monitors are thin, lightweight, and consume less power than CRT monitors.

 

LED (Light Emitting Diode) Monitor

An LED monitor is a flat-panel output device that uses light-emitting diodes for backlighting to display images on the screen. It provides better brightness, higher contrast, and consumes less power compared to LCD monitors. LED monitors are thin, lightweight, and widely used in modern computers and televisions.

 

LCD Monitor	LED Monitor
LCD stands for Liquid Crystal Display, which is a type of display technology that uses liquid crystals to produce images on the screen.	LED stands for Light Emitting Diode, which uses light emitting diodes as a source of backlighting for the display.
LCD monitors are comparatively thicker and bulkier due to the use of fluorescent lamps.	LED monitors are thinner and lighter in design because LEDs require less space.
The picture quality of LCD monitors is average and suitable for basic use.	LED monitors provide better picture quality with sharper and more vivid images.
LCD monitors generate more heat due to higher power consumption.	LED monitors generate less heat because of efficient backlighting technology.
LCD monitors are mostly found in older computer systems and televisions.	LED monitors are widely used in modern computers, laptops, and televisions.

 

1.6.3 Printer: Laser, Ink-jet, Dot-matrix and 3D Printer,

 

Printer

A printer is an output device that produces a hard copy of information generated by a computer. It converts processed digital data into a permanent printed form such as text, images, or graphics on paper. Printers are commonly used in homes, schools, and offices for printing documents, reports, and photographs.

 

 

 

 

 

 

Types of Printers:

 

Impact Printer

An impact printer is a type of printer that produces output by physically striking an inked ribbon against the paper to print characters or images. These printers are generally noisy and are commonly used where multiple copies are required. Examples: Dot Matrix Printer, Daisy Wheel Printer, Line Printer

 

Non-Impact Printer

A non-impact printer is a type of printer that produces output without any physical contact between the printer and the paper. It uses modern technologies such as inkjet or laser printing, resulting in quieter operation and better print quality. Examples: Inkjet Printer, Laser Printer, Thermal Printer

 

Laser Printer

A laser printer is a type of non-impact printer that uses laser technology and toner powder to produce high-quality printed output. It works by forming an image on a drum using a laser beam and transferring toner onto paper, which is then fixed by heat. Laser printers are fast, quiet, and widely used in offices for printing large volumes of documents.

 

Inkjet printer

An inkjet printer is a type of non-impact printer that uses liquid ink to produce printed output. It works by spraying tiny droplets of ink onto paper through small nozzles to form text and images. Inkjet printers are quiet, affordable, and commonly used in homes and small offices for printing documents and photos.

 

Dot matrix printer

A dot matrix printer is a type of impact printer that produces printed output by striking an inked ribbon against paper using pins. It works by forming characters and images as patterns of small dots. Dot matrix printers are noisy, slow, and commonly used where continuous paper and multiple copies are required. It is still used for printing bills, receipts, and carbon copy documents.

 

3D printer

A 3D printer is a type of printer that creates three-dimensional objects from a digital design. It works by depositing material layer by layer, such as plastic or resin, to build a physical object. 3D printers are used in industries, education, and healthcare for making models, prototypes, and customized products.

 

 

Inkjet Printer	Laser Printer
Inkjet printer is a non-impact printer.	Laser printer is also a non-impact printer.
Uses liquid ink sprayed through tiny nozzles onto paper.	Uses a laser beam to form an image and toner powder to print.
Produces high-quality color prints and is better for photos.	Produces sharp text and clear graphics suitable for documents.
Printing speed is relatively slow	Printing speed is faster compared to inkjet printers.
Initial cost is lower.	Initial cost is higher.
Ink cartridges are expensive, increasing running cost.	Toner lasts longer, reducing cost per page.

 

Speaker

A speaker is an output device that produces sound output from a computer. It converts digital audio signals generated by the computer into audible sound that can be heard by the user. Speakers are commonly used to listen to music, voice, alarms, and other audio output from the computer system.

 

 

Plotter

A plotter is an output device used to produce large-sized and accurate drawings such as maps, charts, and engineering or architectural designs. It creates images using continuous lines, which makes it suitable for detailed graphical work. Plotters are commonly used in fields where high precision is required.

 

Laser Printer	Dot Matrix Printer
Laser printer is a non-impact printer.	Dot matrix printer is an impact printer.
Uses a laser beam and toner powder to print.	Uses pins to strike an inked ribbon against paper.
Produces high-quality and sharp output.	Produces low-quality output made of dots.
Very fast printing speed.	Slow printing speed.
Operates quietly.	Produces a lot of noise during printing.
Initial cost is higher but Cost per page is low.	Initial cost is lower but Cost per page is low.
Produces single copy at a time.	Can produce multiple copies at once.

 

 

Impact Printer	Non-Impact Printer
An impact printer is a printer that produces output by physically striking an inked ribbon against the paper.	A non-impact printer is a printer that produces output without any physical contact between the printer and the paper.
Uses mechanical force to strike pins or characters onto the ribbon and paper.	Uses modern technologies such as ink spray, laser beam, or heat to print.
Produces a lot of noise during operation due to striking action.	Operates quietly because there is no physical striking.
Print quality is generally low and characters are formed using dots.	Print quality is high with clear text and graphics.
Printing speed is slow.	Printing speed is fast.
Dot matrix printer, Daisy wheel printer.	Laser printer, Inkjet printer, Thermal printer.

 

 

Soft Copy	Hard Copy
A soft copy is the digital form of output that is displayed on electronic devices.	A hard copy is the physical form of output produced on paper or other materials.
Exists in electronic form only.	Exists in physical and tangible form.
Cannot be physically touched.	Can be physically touched and stored.
Produced using devices like monitor, projector, and speaker.	Produced using devices like printer and plotter.
Not permanent unless saved digitally.	Permanent and can be stored for a long time.

 

1.6.4 Overview of Ports: USB/Type C, HDMI, VGA, Ethernet, Audio port.

 

Peripheral Devices (Exam-Type Answer)

Peripheral devices are external hardware devices that are connected to a computer to provide input, output, or storage functions. These devices are not part of the main processing unit but help the computer system work effectively by allowing users to interact with it.

Common examples of peripheral devices include keyboard, mouse, monitor, printer, speaker, and external storage devices.

 

 

 

 

 

Hardware Ports (Exam-Type Answer)

Hardware ports are physical connection points on a computer that are used to connect peripheral devices to the system. They allow data and signals to be transferred between the computer and external devices such as keyboards, printers, monitors, and storage devices.

Common examples of hardware ports include USB ports, HDMI ports, VGA ports, audio ports, and Ethernet ports.

 

USB Port

A USB port is a hardware port used to connect external devices to a computer and transfer data between them. It is commonly used to connect devices like keyboard, mouse, pen drive, and printer. Versions are USB 2.0, USB 3.0, USB-C (faster transfer rates)

 

Type-C Port

A Type-C port is a modern USB port used for fast data transfer, video output, and power delivery. It has a reversible connector, meaning it can be plugged in either direction, and is commonly used in smartphones, laptops, and modern computers.

 

HDMI

HDMI (High-Definition Multimedia Interface) is a hardware port used to transmit high-quality audio and video signals from a computer to display devices such as monitors, TVs, and projectors.

 

VGA Port

A VGA (Video Graphics Array) port is a hardware port used to transmit analog video signals from a computer to display devices such as monitors and projectors.

 

Ethernet Port

An Ethernet port is a hardware port used to connect a computer to a wired network or the internet using an Ethernet cable, enabling fast and reliable data communication.

 

Audio Port

An audio port is a hardware port used to connect audio devices such as speakers, headphones, or microphones to a computer for sound input and output.

 

50. Which printer uses pins and ribbon?
A. Inkjet                      B. Laser                      C. ✓ Dot matrix                      D. 3D printer

U & A LEVEL (Understanding + Application)

1. Why is a printer called a hard copy output device?

K LEVEL (Knowledge Based)

1. Define output devices. Explain their functions and importance in a computer system.
2. What is a monitor? Explain its types and uses.
3. Define a printer. Explain its role as an output device.
4. Explain the types of printers with suitable examples.
5. What is an impact printer? Explain its working and examples.
6. What is a non-impact printer? Explain different types of non-impact printers.
7. Explain laser printer, inkjet printer, and dot matrix printer.
8. Define peripheral devices. Explain their types with examples.
9. What are hardware ports? Explain different types of ports used in a computer.
10. Explain USB, HDMI, VGA, Ethernet, and Audio ports with their uses.

 

🟢 K-LEVEL (Knowledge) MCQs (1–20)

1. Which of the following is an output device?
A. Keyboard               B. Mouse                    C. ✓ Monitor              D. Scanner

2. Output devices mainly convert digital data into
A. Binary form           B. Machine language              C. ✓ Human-readable form    D. Electrical signals

3. Which device produces hard copy output?
A. Monitor                  B. Speaker                  C. ✓ Printer                D. Projector

4. Which printer is an impact printer?
A. Laser printer          B. Inkjet printer          C. ✓ Dot matrix printer          D. Thermal printer

5. Which output device produces sound?
A. Monitor                  B. Printer                    C. ✓ Speaker              D. Plotter

6. LCD stands for
A. Light Crystal Display                    B. Liquid Color Display
C. ✓ Liquid Crystal Display              D. Light Crystal Device

7. LED monitor uses which backlight?
A. Fluorescent lamps              B. Gas lamps              C. ✓ Light emitting diodes     D. Halogen lamps

8. Which printer uses toner powder?
A. Inkjet                      B. Dot matrix              C. ✓ Laser printer                  D. 3D printer

9. VGA port transmits
A. Audio signals                     B. Digital video                      C. ✓ Analog video      D. Network signals

10. HDMI carries
A. Only video             B. Only audio             C. ✓ Audio and video             D. Only data

11. USB stands for
A. Universal System Bus                                B. Unified Serial Bus             

C. ✓ Universal Serial Bus                              D. Universal Speed Bus

12. Which port is used for wired internet?
A. USB                        B. HDMI                     C. ✓ Ethernet              D. VGA

13. Audio ports are used to connect
A. Monitor                  B. Printer                    C. ✓ Speakers and microphones        D. Scanner

14. Which is a peripheral device?
A. CPU                        B. RAM                      C. ✓ Printer                D. ALU

15. Which printer can print multiple copies at once?
A. Laser printer                      B. Inkjet printer                      C. ✓ Dot matrix printer            D. Thermal printer

16. Which monitor is thinner and energy efficient?
A. CRT                        B. LCD                        C. ✓ LED                    D. Plasma

17. Which output device shows soft copy?
A. Printer                    B. Plotter                    C. ✓ Monitor              D. Dot matrix printer

18. Which printer sprays liquid ink?
A. Laser                      B. ✓ Inkjet                  C. Dot matrix              D. 3D printer

19. Type-C port has which feature?
A. Single direction     B. Slow speed             C. ✓ Reversible connector     D. Analog signal

20. Which device creates 3-D objects?
A. Laser printer          B. Plotter                    C. ✓ 3D printer                      D. Inkjet printer

21. Which printer is best for photo printing at home?
A. Laser printer          B. ✓ Inkjet printer      C. Dot matrix printer              D. Line printer

22. A noisy printer that uses ribbon is
A. Laser                      B. Inkjet                      C. ✓ Dot matrix                      D. Thermal

23. Which port is best for connecting a TV to a laptop?
A. USB                        B. VGA                       C. ✓ HDMI                             D. Ethernet

24. A device used to hear music from a computer is
A. Printer                    B. Monitor                  C. ✓ Speaker                          D. Scanner

25. Which printer is suitable for office bulk printing?
A. Inkjet                      B. Dot matrix              C. ✓ Laser                              D. 3D printer

26. Which monitor technology consumes less power?
A. CRT                        B. LCD                        C. ✓ LED                                D. Plasma

27. Which port is commonly used for pen drives?
A. HDMI                     B. VGA                       C. ✓ USB                                D. Ethernet

28. For online meetings, which output device is needed?
A. Printer                    B. Monitor                  C. ✓ Speaker                          D. Plotter

29. Which device is used to print large engineering drawings?
A. Inkjet printer          B. Laser printer          C. ✓ Plotter                            D. Dot matrix printer

30. Which port connects headphones?
A. USB                        B. VGA                       C. Ethernet                              D. ✓ Audio port

31. Which printer gives the best text clarity?
A. Inkjet                      B. Dot matrix              C. ✓ Laser                              D. Thermal

32. Which device allows user interaction visually?
A. Speaker                  B. Printer                    C. ✓ Monitor                          D. Plotter

33. Which printer does NOT strike the paper?
A. Dot matrix             B. ✓ Inkjet                  C. Line printer                        D. Daisy wheel

34. Which port supports charging and data together?
A. VGA                       B. HDMI                     C. ✓ USB Type-C                   D. Ethernet

35. Which printer uses heat to fix toner?
A. Inkjet                      B. ✓ Laser                  C. Dot matrix                          D. 3D printer

36. Which combination is fully output related?
A. Keyboard, mouse, scanner                        B. CPU, RAM, ROM
C. ✓ Monitor, printer, speaker                       D. USB, HDMI, VGA

37. Which printer has the lowest print quality?
A. Laser                      B. Inkjet                      C. ✓ Dot matrix                      D. Thermal

38. Which port transmits only analog signals?
A. HDMI                     B. USB                        C. ✓ VGA                               D. Ethernet

39. Which device converts electrical signals into sound?
A. Monitor                  B. ✓ Speaker              C. Printer                    D. Plotter

40. Which printer is both fast and quiet?
A. Inkjet                      B. Dot matrix              C. ✓ Laser                  D. Line printer

41. A modern laptop may NOT include which port?
A. USB-C                    B. HDMI                     C. ✓ VGA                   D. Audio

42. Which printer is best for carbon copy printing?
A. Inkjet                      B. Laser                      C. ✓ Dot matrix          D. Thermal

43. Which device is NOT a peripheral?
A. Printer                    B. Monitor                  C. Speaker                  D. ✓ CPU

44. Which output device is used for presentations?
A. Printer                    B. Speaker                  C. ✓ Projector            D. Scanner

45. Which port provides the fastest data transfer?
A. VGA                       B. HDMI                     C. Ethernet                  D. ✓ USB Type-C

46. Which printer builds objects layer by layer?
A. Laser                      B. Inkjet                      C. ✓ 3D printer          D. Dot matrix

47. Which output device gives permanent output?
A. Monitor                  B. Speaker                  C. ✓ Printer                D. Projector

48. Which monitor technology is oldest?
A. LED                        B. LCD                        C. ✓ CRT                    D. OLED

49. Which port connects router to computer?
A. USB                        B. HDMI                     C. ✓ Ethernet              D. VGA

 

1.7 Computer Software

1.7.1 Concept and its types

Software refers to a collection of programs, instructions, and related data that directs a computer to perform specific tasks. It enables the user to interact with computer hardware and controls the overall operation of the computer system. Without software, hardware cannot function meaningfully.

 

Types of Software

System Software

Application Software

 

System Software

System software is a type of software that manages and controls the computer hardware and provides a platform for running application software. It is responsible for the proper functioning of the computer system and acts as an interface between the hardware and the user. Examples: Operating system, device drivers, utility software.

 

Types of System Software

 

1. Operating System

An operating system manages computer hardware and software resources and provides an interface between the user and the computer. Examples: Windows, Linux, macOS

The operating system performs important functions such as process management, memory management, file management, and device management. It also controls input and output operations and ensures that different programs run properly without interfering with each other.

 

Functions of Operating System

• Process Management: Controls the execution of programs and manages CPU usage.
• Memory Management: Allocates and deallocates memory to different programs.
• File Management: Organizes, stores, and retrieves files and folders.
• Device Management: Controls and coordinates input and output devices.
• User Interface: Provides an interface for user interaction with the computer.
• Security Management: Protects the system from unauthorized access.

 

2. Device Drivers

Device drivers are system programs that allow the operating system to communicate with hardware devices such as printers, keyboards, and monitors.

 

3. Utility Software

Utility software helps in the maintenance, protection, and efficient functioning of a computer system.

It helps improve the performance of the computer by performing tasks such as disk management, virus protection, file backup, and system cleanup.

Examples: Antivirus programs, disk cleanup, backup tools.

4. Language Translators

Language translators convert programs written in high-level or assembly language into machine language so that the computer can understand them. Examples: Compiler, Interpreter, Assembler

 

Types of Language Translators

 

1. Compiler

A compiler translates the entire program at once from a high-level language into machine language. It produces an error list after compiling the whole program. Example: C, C++

 

2. Interpreter

An interpreter translates and executes the program line by line. It stops execution when an error is found.

Example: Python, JavaScript

 

3. Assembler

An assembler translates programs written in assembly language into machine language. Example: Assembly language programs

 

Assembler	Compiler	Interpreter
An assembler translates assembly language programs into machine language.	A compiler translates a high-level language program into machine language all at once.	An interpreter translates and executes a high-level language program line by line.
Translates the entire program at once	Translates the entire program at once	Translates one line at a time
Errors are shown after translation	Errors are displayed after compiling the whole program	Errors are shown immediately line by line
Execution is fast	Execution is fast	Execution is slow
Generates object code	Generates object code	Does not generate object code
Requires less memory	Requires more memory	Requires less memory
Program runs after translation	Program runs after compilation	Program runs during translation
Assembly language	C, C++	Python, JavaScript

 

Application Software

Application software is a type of software designed to perform specific tasks for the user. It helps users carry out activities such as word processing, calculations, data management, and internet browsing according to their needs. Examples:
Word processors, spreadsheets, web browsers, media players.

 

Types of Application Software

 

Packaged Application Software

Packaged application software is ready-made software developed for general users to perform common tasks. It can be used by many users without modification. Examples: MS Word, MS Excel, PowerPoint, web browsers.

 

Customized Application Software

Customized application software is software that is specially developed to meet the specific requirements of a particular user or organization. It is designed according to their needs and work processes. Examples: Banking software, hospital management system, school management system.

 

 

 

Packaged Application Software	Customized Application Software
Packaged application software is ready-made software developed for general users to perform common tasks.	Customized application software is specially developed software designed to meet the specific needs of a particular user or organization.
Designed to meet the needs of many users.	Designed to meet the needs of a specific user or organization.
Less flexible as features are fixed.	Highly flexible as it is developed according to user requirements.
Generally cheaper as development cost is shared among many users.	Generally more expensive due to custom development.
Available immediately for use.	Requires more time for development and testing.
Limited modification possible.	Can be easily modified as per user requirements.
MS Word, MS Excel, PowerPoint, Web browsers.	Banking software, Hospital management system, School management system.

 

1.7.2 Open sources and proprietary software

 

Open Source Software (OSS)

Open Source Software (OSS) is software whose source code is freely available to users, allowing them to study, modify, and distribute the software according to its license. Examples: Linux, Mozilla Firefox, LibreOffice, Apache.

.

Proprietary Software

Proprietary software is software that is owned by an individual or a company, where the source code is not available to users and the software can be used only under specific license terms. Examples: Microsoft Windows, MS Word, Adobe Photoshop.

 

Open Source Software (OSS)	Proprietary Software
Open source software is software whose source code is freely available for users to view, modify, and distribute.	Proprietary software is software whose source code is owned by a company and is not accessible to users.
Source code is open and accessible to everyone.	Source code is closed and restricted.
Users are allowed to modify and improve the software.	Users are not allowed to modify the software.
Mostly free of cost.	Usually paid software.
Can be freely used, shared, and distributed under license terms.	Usage is restricted by license agreements.
Highly flexible and customizable.	Less flexible and cannot be customized by users.
Developed collaboratively by a community of developers.	Developed and maintained by a single company or organization.
Security issues can be identified and fixed by the community.	Security updates depend only on the software company.
Linux, Mozilla Firefox, LibreOffice	Microsoft Windows, MS Word, Adobe Photoshop

 

 

 

 

 

 

 

 

1.7.3 Compare features of System and Application software

System Software	Application Software
System software is software that controls and manages the computer hardware and system resources.	Application software is software designed to help users perform specific tasks.
Its main purpose is to operate and control the computer system.	Its main purpose is to solve user-specific problems or perform tasks.
System software is essential for the functioning of the computer.	Application software depends on system software to run.
Interacts indirectly with the user.	Interacts directly with the user.
Starts running when the computer is switched on.	Runs only when the user starts it.
Installed automatically during system setup.	Installed according to user needs.
Without system software, the computer cannot function.	Without application software, the computer can still function but cannot perform user tasks.
Operating system, device drivers, utility software.	MS Word, Excel, web browsers, media players.
Mostly general-purpose and system-oriented.	Task-oriented and user-specific.
Not easily modified by users.	Can be modified or replaced easily.

 

1.7.4 Introduction to Mobile and Web Application

 

Web Application

A web application is a software application that runs on a web server and is accessed through a web browser using the internet. It allows users to perform tasks and interact with data without installing the software on their local computer.

Examples: Gmail, Google Docs, Facebook, online banking systems.

 

Mobile App

A mobile application (mobile app) is a software application designed to run on smartphones and tablets. It allows users to perform specific tasks or access services directly on their mobile devices. Mobile apps are usually downloaded from app stores and can work online or offline.

Examples: WhatsApp, Instagram, Google Maps, YouTube.

 

Mobile App	Web App
A mobile app is a software application designed to run on smartphones and tablets.	A web app is a software application that runs on a web server and is accessed through a web browser.
Must be downloaded and installed from an app store.	No installation required; accessed through a browser.
Platform-dependent (Android or iOS specific).	Platform-independent; works on any device with a browser.
Can work online or offline.	Mostly requires an internet connection.
Faster and smoother performance.	Performance depends on browser and internet speed.
Uses device storage and accessed by tapping the app icon.	Uses server storage and accessed using a URL in a browser.
Needs to be updated manually via app store.	Updates automatically on the server.
WhatsApp, Instagram, Google Maps.	Gmail, Google Docs, online banking websites.

 

 

 

 

 

 

 K-LEVEL (Knowledge) MCQs (1–20)

1. Software is a collection of
A. Hardware components       B. Input devices          C. ✓ Programs and instructions            D. Output devices

2. Which software controls computer hardware?
A. Application software         B. ✓ System software             C. Utility software      D. Web application

3. Which of the following is system software?
A. MS Word                B. Google Chrome                  C. ✓ Operating System          D. Photoshop

4. Application software is mainly used to
A. Control memory    B. Manage devices     C. ✓ Perform user tasks         D. Boot the computer

5. Which is an example of proprietary software?
A. Linux                      B. LibreOffice            C. ✓ Microsoft Windows       D. Mozilla Firefox

6. Open Source Software allows users to
A. Only use software              B. Only copy software            C. ✓ View and modify source code
D. Buy license compulsorily

7. Which software is usually free and community developed?
A. Proprietary software          B. ✓ Open source software    C. Utility software      D. Application software

8. A web application runs on
A. Local computer      B. Mobile device only            C. ✓ Web server                     D. BIOS

9. Which is a mobile application?
A. Google Docs          B. Gmail                     C. ✓ WhatsApp                      D. Wikipedia

10. Operating System acts as an interface between
A. User and software              B. CPU and RAM       C. ✓ User and hardware   D. Input and output devices

11. Which is NOT a function of OS?
A. Memory management        B. File management   C. ✓ Word processing            D. Device management

12. Utility software is used for
A. Programming                     B. User interaction     C. ✓ System maintenance                  D. Gaming

13. Antivirus software is an example of
A. Application software         B. ✓ Utility software              C. System software     D. Web software

14. A compiler translates
A. Assembly language            B. ✓ High-level language       C. Machine language              D. Binary code

15. An interpreter works
A. All at once              B. ✓ Line by line        C. After execution                  D. Without errors

16. An assembler translates
A. High-level language          B. ✓ Assembly language        C. Machine language  D. Binary code

17. Packaged software is
A. Custom-built          B. ✓ Ready-made software    C. Free software         D. Hardware-specific

18. Customized software is developed for
A. All users     B. General purpose     C. ✓ Specific user/organization         D. Entertainment

19. Which software starts when computer boots?
A. Application software         B. Utility software      C. ✓ Operating System          D. Web application

20. Which is NOT application software?
A. MS Excel               B. Photoshop              C. ✓ Device driver     D. PowerPoint

21. Which software is best for writing documents?
A. OS              B. Utility software                  C. ✓ Word processor              D. Device driver

22. Which OS function allocates RAM to programs?
A. File management   B. ✓ Memory management    C. Process management         D. Device management

23. Which software protects a computer from viruses?
A. Compiler                B. OS              C. ✓ Antivirus            D. Browser

24. Which translator helps in debugging easily?
A. Compiler                B. Assembler              C. ✓ Interpreter                      D. Loader

25. Which software allows users to browse the internet?
A. Utility software      B. OS              C. ✓ Web browser                  D. Firmware

26. Which app requires installation on phone?
A. Web app     B. ✓ Mobile app         C. OSS D. Utility software

27. Which software is best for accounting in a company?
A. Packaged software             B. ✓ Customized software     C. Utility software                  D. OS

28. Which OS feature allows multiple programs to run?
A. File management               B. ✓ Process management                 C. Security      D. Booting

29. Which software updates automatically via server?
A. Mobile app             B. ✓ Web app             C. Packaged software             D. Utility software

30. Which software helps compress files?
A. Application software         B. ✓ Utility software              C. OS  D. Translator

31. Which is a disadvantage of proprietary software?
A. Free to use             B. Source code available        C. ✓ Restricted modification D. Community support

32. Which software is used to manage files and folders?
A. Utility software      B. Application software          C. ✓ Operating System          D. Compiler

33. Which translator produces object code?
A. Interpreter              B. ✓ Compiler            C. Assembler  D. Loader

34. Which software is platform-independent?
A. Mobile app             B. ✓ Web app             C. OS              D. Utility software

35. Which software depends on system software to run?
A. OS              B. Utility software                  C. ✓ Application software                  D. Firmware

36. Without system software, a computer will
A. Run slowly             B. Partially work                     C. ✓ Not function       D. Open applications

37. Which combination is correct?
A. Linux – Proprietary           B. Windows – OSS     C. ✓ LibreOffice – OSS         D. MS Word – OSS

38. Which translator executes during translation?
A. Compiler                B. Assembler              C. ✓ Interpreter          D. Loader

39. Which software is best for frequent feature updates?
A. Packaged software             B. Customized software         C. ✓ Web application D. Proprietary software

40. Which software gives maximum user control?
A. Proprietary software          B. ✓ Open source software    C. Utility software      D. Firmware

41. Which software is closest to hardware?
A. Application software         B. Utility software      C. ✓ System software             D. Web app

42. Which software can work offline after installation?
A. Web app                 B. ✓ Mobile app                     C. OSS            D. Browser

43. Which translator is fastest in execution?
A. Interpreter              B. ✓ Compiler            C. Assembler              D. Loader

44. Which software manages I/O devices?
A. Utility software      B. ✓ Operating System          C. Application software          D. Web app

45. Which software is usually paid and licensed?
A. OSS                        B. ✓ Proprietary software      C. Utility software      D. Web software

46. Which software is developed for general users?
A. Customized software         B. ✓ Packaged software         C. Firmware    D. Translator

47. Which software helps recover lost data?
A. Application software         B. ✓ Utility software  C. OS  D. Compiler

48. Which translator shows errors one by one?
A. Compiler    B. Assembler  C. ✓ Interpreter          D. Loader

49. Which software enables multitasking?
A. Application software         B. Utility software      C. ✓ Operating System          D. Web app

50. Which software does NOT require installation?
A. Mobile app             B. Packaged software             C. ✓ Web application             D. Utility software

 

1. Define software. Explain its types with suitable examples.
2. What is system software? Explain its types in detail.
3. Define application software. Explain its types with examples.
4. What is an operating system?  Explain the functions of an operating system.
5. Differentiate between system software and application software.
6. What is utility software? Explain its functions and examples.
7. Explain language translators and their types.
8. Compare assembler, compiler, and interpreter.
9. Differentiate between open source software and proprietary software with examples.
10. Compare packaged application software and customized application software.
11. Explain web applications and mobile applications with examples.

 

1. Which component is considered the brain of the computer?
A. RAM                      B. Motherboard                      C. ✓ CPU                    D. Hard disk

2. Which input device is mainly used for selecting options on the screen?
A. Keyboard               B. Scanner                              C. ✓ Mouse                D. Microphone

3. Which unit of CPU performs logical decisions?
A. Control Unit           B. ✓ ALU                                C. Register                  D. Cache

4. Which bus is responsible for carrying control signals like read and write?
A. Data bus                 B. Address bus                        C. ✓ Control bus        D. Expansion bus

5. Which memory is used to store data permanently?
A. RAM                      B. Cache                     C. ✓ Secondary memory        D. Register

6. Which type of ROM can be erased electrically?
A. PROM                    B. EPROM                  C. ✓ EEPROM                       D. Mask ROM

7. Which output device produces soft copy output?
A. Printer                    B. Plotter                    C. ✓ Monitor              D. Dot matrix printer

8. Which printer uses pins and ribbon for printing?
A. Inkjet printer                      B. Laser printer          C. ✓ Dot matrix printer          D. 3D printer

9. Which port is commonly used to connect a monitor to a CPU?
A. USB                        B. Ethernet                  C. ✓ HDMI                 D. Audio port

10. Which of the following is a peripheral device?
A. CPU                        B. RAM                      C. ✓ Printer                D. ALU

11. Which software is required to run application software?
A. Utility software      B. ✓ System software             C. Web application     D. Firmware

12. Which function of OS manages files and folders?
A. Memory management        B. Device management  C. ✓ File management   D. Process management

13. Which translator does NOT generate object code?
A. Compiler                B. Assembler              C. ✓ Interpreter          D. Loader

14. MS Excel is an example of:
A. System software                B. Utility software      C. ✓ Application software      D. Open source software

15. Which application requires a web browser to run?
A. Mobile app             B. Desktop app           C. ✓ Web app             D. Packaged software

Download Notes - Computer System - SEE Computer Science - Grade IX 2082