1.1 Introduction to Computer System 

Computer Science is the study of computer system.

Computer is an electronic device which process rawdata into meaningful information.



Computer system is combination of hardware and software which makes it to work.

Computer system components are the parts which make it to work.

COMPUTER is common operating machine that process userdata for technological and educational research.

Features/characteristics of  a computer system: ASASDV 

  • Automatic: Operates without human input.
  • Speed: Process data quickly.
  • Accuracy: Correct output but GIGO.
  • Storage: Stores data.
  • Diligence: Works repeatedly without mistakes.
  • Versatile: wide range of tasks.
Application of computer system ABCDEF
  • Agriculture 
  • Banking 
  • Communication 
  • Digital marketing 
  • Education 
  • Facebook 
Function of computer system: 
IPOS Block Diagram 
1.2 Input device 
  • Keyboard: Types letter. 
  • Mouse: Point on screen. 
  • Joystick: Control game. 
  • Microphone: Capture sound.
  • Scanner: Convert physical to digital.
  • Webcam: Captures image and videos.
  • Touchscreen: Interact by touching.
  • Touchpad: Moves cursor with finger.
1.3 Central processing unit process data which communicates on the databus from devices connected to the motherboard.

CPU functions 
  • Fetching: Gets an instruction from memory
  • Decoding: Understand what the instruction means.
  • Executing: Carries out the instruction.
  • Storing: Save the result to memory.
  • Managing interrupts: Responds to request which need immediate.
CPU Components 
  • ALU does all math and logic.
  • CU manages other parts what to do.
  • MU stores data and instruction for quick access.


1.4 Motherboard and databus
Motherboard circuits enable CPU to process data from other components.
Databus is a set of wires on the motherboard which communicates data between CPU and other components.

1.5 Computer Memory 
Primary memory is the main storage by CPU for active processing.
  1. SRAM (Static Random Access Memory): Very fast.
  2. DRAM (Dynamic Random Access Memory): Slow. 
  3. PROM (Programmable ROM): Only one time written.
  4. EPROM (Erasable PROM): Erase with ultra voilet light and then reprogramme.
  5. EEPROM (Electrically EPROM): Electrically erase and reprogramme.
  6. Firmware 
  7. Cache Memory: Small, fast, store for frequently access.
  8. CPU Register: High speed storage in CPU for current running.
Secondary memory use for permanent storage.
  1. HDD (Hard Disk Drive): High capacity and low cost.
  2. SSD (Solid State Drive): Uses flash memory, faster.
  3. Magnetic Tap: Large scale data storage.
  4. CD-ROM: Written once.
  5. DVD (Digital versatile Disc): High storage capacity.
  6. Cloud storage: Stores data on remote server.
  7. USB Flash Drive: Small, portable.
  8. SD Card (Secure Digital Card): {portable memory card.
1.6 Output Devices

Display Unit:
LED Monitor (Light emitting diode): offering high brightness.
LCD Monitor (Liquid crystal Display): Create an image.

Printer:
Laser printer uses laser beam to create an image on a drum then transfer to paper.
Ink-jet printer: Sprays droplets of liquid ink onto paper.
Dot-matrix printer: create an image from a pattern of dots.
3D printer creates three dimensional solid objects.

1.7 Computer Software is a set of programs.
Computer software is classified into two types:
1. System Software operates basic tasks:

a. Operating system software is the system software that controls and manages the overall operation of a computer.

b. Language processor (translator) is system software that translates program written in assembly language or high label language into machine language.
Three types processor: Assembler, compiler and interpreter.

c. Utility software uses for specific tasks as transfer files, search, disk management.

d. Device driver software is a set of programs to control and manage the specific devices.

2. Application software uses user needs:

a. Package or general purpose application software readymade software developed for all general users as MS office, google meet.

b. Customised or tailored software is the application software which is designed to fulfil the specific requirements of an office.

3. Open source software is a free source code to use/change/share.
Propritary software is a private, licenced.

4. Mobile and web application software is designed to work as touchscreen, GPS, camera, social media.
Practical Task
a. Demonstrate computer system and parts
b. Demonstrate various input/output and storages devices.
c. Use different ports to connect peripheral devices

Practical Task 
a. Demonstrate computer system and parts 
b. Demonstrate various input/output and storages devices.
c. Use different ports to connect peripheral devices


Activities 
• Engage students with visuals, animations, and interactive learning resources.
• Demonstrate disassembling and reassembling computers to understand 
hardware components by the teacher.
• Explore hardware and software in everyday devices and appliances.
• More student engagement activities, tech-related topics, and discussion
• Visit or observe a physical and virtual computer laboratory and its 
applications.

Ex.1.1
1. Write the full forms of the following abbreviations

i.EC: Electronic Commerce
ii. MHz: Megahertz
iii. GHz: Gigahertz
iv. ms: Millisecond
v. ns: Nanosecond
vi. ps: Picosecond
vii.Fs: Femtosecond
viii.GIGO: Garbage In, Garbage Out
ix. RAM: Random Access Memory
x. IPOS: Input, Processing, Output, Storage
xi. ATM: Automated Teller Machine
xii. CT scans: Computed Tomography scans

2. Choose the correct answer

a. Which fraction of a second is equivalent to one millionth of a second?
Ans: ii) Microsecond


b. Incorrect input results in incorrect output. It is referred to as ....
Ans: iii) GIGO


c. How many kilobytes are in one megabyte?
Ans: iv) 1024


d. Repeatedly working capability of computers is known as ..........
Ans: iii) diligence


e. What is the primary function of the CPU in a computer system?Ans: iii) Arithmetic and logic operations

3. Short answer the following question.

a) Define the Computer.
Ans: A computer is an electronic device that accepts raw data as input, processes it according to a set of instructions, and produces meaningful information as output.


b) How do IPOS work?
Ans: It works sequentially: Data is entered (Input), manipulated by the CPU (Processing), presented to the user (Output), and saved for future use (Storage).


c) What is GIGO?
Ans: GIGO stands for Garbage In, Garbage Out. It means if you feed incorrect or invalid data into a computer, it will naturally produce incorrect results.

d) List any four computer features.
Ans: High speed, high storage capacity, accuracy, and diligence.


e) Why is a computer called a diligence machine?
Ans: Because it can perform repetitive tasks for hours without getting tired, bored, or losing accuracy.


f) List four computer-related uses.
Ans: Online banking, data analysis, digital graphics designing, and software development.


g) Identify distinct computer storage units.
Ans: Bit, Byte, Kilobyte (KB), Megabyte (MB), Gigabyte (GB), and Terabyte (TB).

4. Long answer the following questions.

a) Explain the working principles of computers with a block diagram and explain it in detail.
Ans: A computer works on the IPOS cycle. The Input Unit takes data; the Central Processing Unit (CPU) (consisting of the ALU, CU, and Memory Registers) processes and controls the data; the Storage Unit retains it; and the Output Unit displays the final result.


b) Describe the use of computers in the education field.
Ans: Computers are used in education for managing online classes, conducting multimedia presentations, researching information on the internet, and maintaining student administrative records.

Ex. 1.2-8

1: Full Forms

i. CPU:Central Processing Unit
ii. BIOS:Basic Input Output System
iii. HDD: Hard Disk Drive
iv. SSD: Solid State Drive
v. RAM: Random Access Memory
vi. CU: Control Unit
vii. USB: Universal Serial Bus
viii. ALU: Arithmetic Logic Unit
ix. MU: Memory Unit
x. PCB: Printed Circuit Board
xi. BIOS: Basic Input Output System
xii. ROM: Read Only Memory
xiii. PSU: Power Supply Unit
xiv. CMOS: Complementary Metal-Oxide-Semiconductor
xv. CD: Compact Disc
xvi. DVD: Digital Versatile Disc
xvii. KB: Kilobyte
xviii. MB: Megabyte
xix. GB: Gigabyte
xx. TB: Terabyte
xxi. YB: Yottabyte
xxii. PB: Petabyte
xxiii. SRAM: Static Random Access Memory
xxiv. DRAM: Dynamic Random Access Memory
xxv. VRAM: Video Random Access Memory
xxvi. EPROM: Erasable Programmable Read-Only Memory
xxvii. EEPROM: Electrically Erasable Programmable Read-Only Memory
xxviii. rpm: revolutions per minute
xxix. VDU: Visual Display Unit
xxx. LED: Light Emitting Diode
xxxi. LCD: Liquid Crystal Display
xxxii. CPS: Characters Per Second
xxxiii. LCM: Liquid Crystal Module
xxxiv. PPM: Pages Per Minute
xxxv. Mbps: Megabits per second
xxxvi. HDMI: High-Definition Multimedia Interface
xxxvii. LAN: Local Area Network

2. Choose the correct answer.
i. What is the primary function of the CPU in a computer system?
Ans:(c) Arithmetic and logic operations

ii. Which of the following is a volatile memory in a computer system?
Ans: b. Random Access Memory (RAM) & d. Cache Memory

iii. What does the term “BIOS” stand for in a computer system?
 Ans: a. Basic Input Output System
iv. Which of the following is a secondary storage device?
Ans: c. USB Flash Drive

v. What is the role of the motherboard in a computer system?
Ans: b. Connect all hardware components and provide communication between them

vi. What is the role of a monitor as an output device in a computer system?
Ans: b. Monitors provide a visual display of digital information such as text, images, and videos.

vii. What is the role of microphones as an input device in a computer system?
Ans: b. Microphones record audio input, allowing for voice commands or communication.
viii. What is the primary function of a printer as an output device?
Ans: c. Produce a hard copy of digital documents or images
ix. What is the primary function of a microprocessor in a personal computer?
Ans: c. Execute instructions and perform calculations

3. Short answer the following questions.

a. What is the primary function of the CPU in a computer system?
The primary function of the Central Processing Unit (CPU) is to fetch, decode, and execute instructions, and to perform arithmetic and logical calculations on data. It acts as the "brain" of the computer.

b. Explain the difference between RAM and ROM in terms of functionality.
RAM (Random Access Memory): It temporarily holds data and programs currently being used by the CPU. It is volatile (loses data when powered off) and supports both read and write operations.
ROM (Read Only Memory): It permanently stores essential startup instructions (like the BIOS). It is non-volatile (retains data without power) and is typically read-only.

c. How does a hard drive differ from RAM in terms of data storage?
RAM is temporary (volatile) storage that holds active data for immediate CPU access. It operates at very high speeds.
A Hard Drive (HDD/SSD) is permanent (non-volatile) storage used to save operating systems, programs, and user files long-term, even when the computer is turned off.

d. What is the role of a motherboard in a computer system?
The motherboard acts as the main circuit board that connects all internal hardware components (such as the CPU, RAM, hard drive, and power supply) and allows them to communicate with each other.

e. Explain the concept of cache memory and its importance in CPU performance.
Cache memory is a small, extremely high-speed volatile memory located directly inside or close to the CPU. It stores frequently used instructions and data so the CPU doesn't have to wait to fetch them from the slower RAM, significantly speeding up overall system processing.

f. Define the term “bus” in the context of computer architecture.
A bus is a collection of parallel wires or communication pathways used to transfer data, instructions, and control signals between different components inside a computer system (e.g., between the CPU, memory, and peripherals).

g. What is the purpose of an input device in a computer system? Provide examples.
The purpose of an input device is to allow users to enter data and control commands into the computer system, converting real-world signals into digital format.
Ex: Keyboard, Mouse, Scanner, Microphone.

h. What is a peripheral device, and how does it enhance a computer system?
A peripheral device is any auxiliary hardware component that connects to the computer externally (or internally via expansion slots) but is not part of the core CPU or memory architecture. It enhances the system by adding new functionalities, such as printing documents (Printer), capturing video (Webcam), or enabling external storage (USB drive).

4. Long answer the following questions.

a. Explain the architecture of a computer system, detailing the functions of the CPU, memory, input/output devices, and storage.
A basic computer system follows the Von Neumann architecture, dividing functions into four core blocks:
CPU: The processing unit divided into the ALU (for math/logic) and CU (for directing operations).
Memory (Primary Memory/RAM): The high-speed working space that holds active data for immediate processing.
Input/Output Devices: Input units (like keyboards) feed data into the system, while Output units (like monitors) display processed information to the user.
Storage (Secondary Memory): Permanent storage (HDDs/SSDs) that safely retains files, software applications, and the Operating System long-term.

b. What is the role of an operating system in managing and coordinating the various components of a computer system with examples? Analyze the functions of an operating system.
The Operating System (OS) acts as an intermediary interface between the computer hardware and the user/applications. Examples include Windows, Linux, and macOS.
Core Functions:
Processor Management: Allocates CPU time to different running tasks.
Memory Management: Tracks and coordinates RAM allocation among software applications.
File Management: Organizes, names, and stores files into structured directories.
Device Management: Uses device drivers to communicate and coordinate with connected hardware peripherals (printers, keyboards).

c. Differentiate between primary and secondary memory.
Primary Memory (e.g., RAM, ROM):
Nature: It is internal memory that is directly accessed by the CPU. It is mostly volatile (like RAM), meaning it loses data when power is turned off.
Speed & Capacity: It operates at extremely fast speeds but features a smaller storage capacity (typically 8GB - 32GB).
Purpose: It holds data, programs, and instructions currently in active use or needed to boot the system.
Secondary Memory (e.g., SSD, HDD, USB Flash Drive):
Nature: It is external or auxiliary memory that cannot be accessed directly by the CPU. It is non-volatile, meaning it retains data permanently.
Speed & Capacity: It operates at a slower speed compared to primary memory but offers a massive storage capacity (typically 256GB - 2TB+).
Purpose: It is used for permanent long-term storage of user files, media, applications, and the operating system.

d. Describe the role of cache memory, RAM, and storage devices. How do they contribute to overall system performance?
These three components form a memory hierarchy designed to balance speed, cost, and capacity:
Cache Memory holds instantaneous, tiny bits of data for the CPU core to prevent processing bottlenecks.
RAM acts as the immediate staging ground, holding active software applications so they run smoothly without lagging.
Storage Devices house files permanently when they are not in active use.
Performance Impact: A system performs optimally when data flows quickly from storage to RAM, and then to Cache. If RAM or Cache is insufficient, the CPU is forced to wait for slow secondary storage devices, dropping overall system efficiency.

e. Explain the architecture of a CPU in detail.
The CPU consists of three main foundational units that work together to execute instructions:
Control Unit (CU): The coordinator that manages and directs the flow of signals throughout the system. It fetches instructions from memory, decodes them, and tells other units what to do.
Arithmetic and Logic Unit (ALU): The execution engine that performs all mathematical operations (addition, subtraction) and logical decisions (AND, OR, comparisons).
Registers: Internal, ultra-fast storage locations within the CPU chip itself used to hold tiny instruction words, intermediate computational results, and execution addresses immediately during calculations.

1.9 Ex.
1. Write the full forms of the following abbreviations:
i. OS: Operating System
ii. CUI: Character User Interface(or Command User Interface)
iii. DOS: Disk Operating System
iv. GUI: Graphical User Interface
v. SPSS: Statistical Package for the Social Sciences
vi. OSS: Open Source Software
vii. SQL: Structured Query Language
viii. HTML: HyperText Markup Language
ix. CSS: Cascading Style Sheets

2. Choose the correct answer.

i. What is the purpose of an operating system in a computer system?
Ans:a. Manage hardware resources and provide a user interface
ii. Which type of software is designed to perform a specific task, such as word processing or spreadsheet calculations?
Ans:b. Application software
iii. What is software?
Ans: b.Instructions that tell a computer what to do
iv. Which of the following is an example of application software?
Ans:a. Microsoft Word
 v. What is the role of the operating system?
Answer:b. To manage hardware and software resources
vi. Which of the following is not software?Ans:a. Keyboard

3. Short answer the following question.

a. What does the term “open source” mean in software?
Ans: It means the software's source code is publicly available for anyone to inspect, modify, and distribute for free.
b. How does open-source software differ from proprietary software?
Ans: Open-source software is free and its source code is public (e.g., Linux), whereas proprietary software is privately owned, commercial, and its source code is hidden (e.g., Windows).
c. What is system software, and what role does it play in a computer system?
Ans: System software is a collection of programs designed to operate and control the computer hardware. Its primary role is to serve as a platform for running application software.
d. Define application software and provide examples of common applications.
Ans: Application software consists of programs developed to help users perform specific productive or recreational tasks.
Examples: Microsoft Word, Google Chrome, VLC Media Player.
e. What is the purpose of utility software, and give examples of utilities?
Ans: The purpose of utility software is to analyze, configure, optimize, and maintain the computer system.
Examples: Antivirus software, Disk Defragmenter, WinRAR.

4. Long answer the following question.

a. Explain the types of computer software with their respective functions.
Ans: Computer software is mainly divided into two types:
System Software: Manages core system hardware and resources. (Functions: Background management, file system handling, memory allocation).
Application Software: Designed for users to execute specific tasks. (Functions: Text editing, web browsing, data calculation).
b. Differentiate between system software and application software with respective roles in a computer system.
Ans:
System Software
Primary Role: It acts as an interface between computer hardware and the user, managing core system resources.
Execution: It runs automatically in the background from the moment the computer starts up.
Dependency: It is completely independent and can function without application software.
Examples: Operating Systems like Linux and Windows, Device Drivers.
Application Software
Primary Role: It helps end-users perform specific tasks or solve specific problems.
Execution: It runs only when explicitly opened and executed by the user.
Dependency: It is highly dependent and cannot run without the underlying system software.
Examples: MS Word, Photoshop, Google Chrome.
c. Differentiate between open source and proprietary software models with examples of everyday applications that we use.
Ans:
Open Source Software 
Source Code: The source code is public, allowing anyone to view, modify, and share it.
Cost: It is generally free of cost to download and use.
Flexibility: Highly flexible as users can customize it according to their requirements.
Examples: Android OS, Mozilla Firefox, VLC Media Player.
Proprietary Software
Source Code: The source code is closed and strictly restricted by the parent company or owner.
Cost: It requires a license fee or subscription fee to use legally.
Flexibility: Restrictive; users are not permitted to change or redistribute the code.
Examples: Microsoft Windows, macOS, Microsoft Office.
d. Explain the concept of utility software and its role in enhancing the performance and functionality of a computer system.
Ans: Utility software is a specialized type of system software designed to maintain, optimize, and protect a computer system.
Its role in enhancing performance includes:
Optimization: Reorganizes fragmented files on hard drives (Defragmentation) to speed up file access.
Maintenance & Cleanup: Deletes temporary files and system clutter to free up disk space.
Security: Detects and removes malware/viruses to safeguard system stability.