Computer Notes – Grade 10
National Curriculum Pakistan - NCP
Chapter 1: Computer System
This comprehensive guide covers essential computer science concepts for Grade 9, including data representation, number systems, operating systems, software types, file management, and programming tools.
Q1. How is Data Represented in a Computer?
Data in a computer is represented in binary form, i.e., using 1s and 0s. For example, in the hexadecimal system, 1010 represents A, and 1011 represents B. In ASCII code, the letter A is represented as 01000001.
Q2. What Are Data Types?
Different types of data are represented in various ways in machine language. Common data types include:
- Integers: Whole numbers without decimals, e.g., 23, 34, 45.
- Floating Point Numbers: Numbers with decimal points, e.g., 123.34, 445.56.
- Characters: Represented using encoding schemes like ASCII. For example, “A” is 65 in ASCII.
- Boolean Values: Represent
trueorfalseusing 1 or 0 respectively.
Q3. What Are Numbering Systems?
Numbering systems are methods of representing numbers using specific digits and symbols. They simplify arithmetic operations such as addition, subtraction, multiplication, and division.
Q4. What Is a Number?
A number is a mathematical value used for counting, measuring, or labeling. Examples include 34, 45, and -45.
Q5. Types of Numbering Systems
- Decimal Number System (0-9)
- Binary System (0, 1)
- Octal Number System (0-7)
- Hexadecimal Number System (0-9, A-F)
Q6. What Is the Decimal Number System?
The decimal system, also known as denary, uses ten digits: 0 to 9. It is called the base 10 system because it consists of 10 digits, e.g., (7)10.
Q7. What Is the Binary System?
The binary system has only two digits: 0 and 1. It is known as the base 2 system, e.g., (1)2.
Q8. What Is the Octal Number System?
The octal system consists of eight digits: 0 to 7. It is based on 8, e.g., (5)8.
Q9. What Is the Hexadecimal System?
The hexadecimal system is based on 16. It includes digits from 0–9 and letters A–F, e.g., (5)16.
Q10. How to Convert from Any Number to Decimal?
To convert a number from any number system to the decimal system (base 10), follow these steps:
- Convert each digit of the number to its decimal equivalent.
- Use base 10 arithmetic by multiplying each digit by the base raised to the power of its position (starting from right to left, beginning at 0).
- Add all the results to get the final decimal number.
Example: Convert 1011 from binary (base 2) to decimal:
(1×2³) + (0×2²) + (1×2¹) + (1×2⁰) = 8 + 0 + 2 + 1 = 11
So, 10112 = 1110.
Q11. How Do We Do Binary Addition?
Binary addition is performed using only two digits: 0 and 1. The rules for binary addition are simple and similar to decimal addition but with a different carry logic:
| Binary Operation | Result | Carry |
|---|---|---|
| 0 + 0 | 0 | 0 |
| 0 + 1 | 1 | 0 |
| 1 + 0 | 1 | 0 |
| 1 + 1 | 0 | 1 (carry) |
Note: When the result exceeds 1 in binary, a carry is generated to the next higher bit position, just like in decimal addition when the result exceeds 9.
Q12. How Do We Do Binary Subtraction?
Binary subtraction is the process of subtracting binary digits (bits) using specific rules. It is similar to decimal subtraction but with only two digits: 0 and 1. The rules for binary subtraction are:
| Binary Operation | Result | Borrow |
|---|---|---|
| 0 − 0 | 0 | 0 |
| 0 − 1 | 1 | 1 (borrow) |
| 1 − 0 | 1 | 0 |
| 1 − 1 | 0 | 0 |
Note: A borrow is taken when subtracting a larger bit from a smaller one, just like in decimal subtraction.
Q13. What Are Coding Schemes?
Coding schemes are standardized methods used by computers to convert and represent data in a form they can understand, usually in binary (0 and 1).
Q14. Why Are Coding Schemes Used?
- Data Representation: They convert human-readable characters into binary codes for computer understanding.
- Standardization: They provide a consistent way to represent data across all devices and platforms.
- Efficiency: They use fixed-length binary codes for optimized data storage and processing.
- Communication: They ensure compatibility in data exchange between different computer systems.
Q15. What Is an Operating System?
An operating system (OS) is system software that manages computer memory, processes, hardware, and software. It acts as an interface between the user and the hardware.
Q16. What Are the Main Tasks Performed by the Operating System?
- Process Management
- Memory Management
- File Management
- Device Management
- Network Management
- Security Management
Q17. What Are the Types of Operating Systems?
- Batch Processing
- Multiprogramming
- Multitasking
- Time Sharing
- Real-Time
- Multiprocessor
- Distributed
- Embedded
Q18. What Is a Process?
A process is a program in execution. For example, when a Word document is opened and running, it is considered a process.
Q19. What Are the States of a Process?
- Start/New State: The process is created and ready to be executed.
- Ready State: The process is waiting for CPU allocation to begin execution.
- Running State: The process is currently being executed by the CPU.
- Blocked/Waiting State: The process is waiting for some resource or input/output operation.
- Terminated State: The process has finished execution and is removed from memory.
Q20. What Is a Thread?
A thread is a smaller unit of a process. A process can have multiple threads running simultaneously, performing different tasks.
Q21. What Is the Difference Between Process and Thread?
| Process | Thread |
|---|---|
| A process is an independent program in execution. | A thread is a lightweight sub-process within a process. |
| Each process has its own memory space. | Threads share the memory space of the process they belong to. |
| Inter-process communication is slower. | Inter-thread communication is faster. |
| More resource-intensive to create and manage. | Less resource-intensive and easier to manage. |
Q22. What Are Folders or Directories and Their Types?
Folders or directories are containers used to organize and store files in a hierarchical structure. They help manage data efficiently.
Types of Directories:
- Single-Level Directory
- Two-Level Directory
- Tree-Structured Directory
Q23. What Are Files?
A file is the smallest unit of data storage in a computer, representing a collection of bytes saved on a disk. Files come in various types, including text, executable, image, and more.
Q24. What Are File Allocation Methods?
File allocation methods determine how files are stored on disk space. The main types include:
- Contiguous Allocation
- Linked Allocation
- Indexed Allocation
Q25. What Are the File Operations?
- Create: Making new files or directories.
- Open: Accessing files for reading or writing.
- Read: Retrieving data from a file.
- Write: Adding or modifying content in a file.
- Delete: Removing a file or directory.
- Rename: Changing the name of a file or directory.
Q26. What Are Software and Its Categories?
Software is a collection of programs, data, and instructions that guide a computer in performing specific tasks.
Types of Software:
- System Software: Controls and manages hardware operations (e.g., Operating Systems).
- Application Software: Helps users perform specific tasks (e.g., MS Word, browsers).
- Programming Software: Provides tools to write, test, and debug programs (e.g., compilers, editors).
- Driver Software: Enables communication between the hardware and system (e.g., printer drivers).
Q27. What Are the Differences Between All the Software Types?
| Software Type | Description | Example |
|---|---|---|
| System Software | Manages hardware and core system functions. | Windows, Linux, macOS |
| Application Software | Performs specific tasks for users. | MS Word, Chrome, Photoshop |
| Programming Software | Used by developers to create and test software. | GCC, Code::Blocks, Visual Studio |
| Driver Software | Enables hardware and OS communication. | Printer driver, Graphics card driver |
Q28. What Are Application Patches?
An application patch is a piece of software designed to update, fix, or improve an existing software program or its associated data.
Q29. What Are the Key Applications of Patches?
Key uses of software patches include:
- Fix Bugs: Correct errors and glitches in the application.
- Improve Security: Address vulnerabilities to prevent security breaches.
- Enhance Performance: Optimize speed and efficiency.
- Add Features: Introduce new tools or functions to the software.
Q30. What Features Can Be Added in Software?
Common features that can be added to software through updates or patches include:
- Security Patches: Updates to protect against cyber threats.
- Game Updates: New levels, characters, or bug fixes in games.
- New Features: Additional functionality to enhance user experience.
Q31. What Is Software Hosting?
Software hosting is the process of deploying, maintaining, and providing remote access to software applications via servers, allowing users to run programs over the internet or a local network.
Q32. What Are the Types of Software Hosting?
There are several types of software hosting, including:
- On-Premises Hosting: Software is installed and maintained on the organization’s own hardware.
- Shared Hosting: Multiple applications or websites are hosted on the same server.
- Dedicated Hosting: A server is fully dedicated to one application or user.
- Cloud Hosting: Applications are hosted on cloud infrastructure for scalability and flexibility.
Explanation of each type may vary in textbooks.
Q33. What Are the Components of Programming Software?
Programming software consists of tools and utilities used to write, test, and manage code. Components include:
- Text Editors: Simple tools for writing and editing code. Examples: VS Code, Notepad++.
- IDEs (Integrated Development Environments): Full-featured platforms combining editors, debuggers, and compilers. Example: Visual Studio.
- Compilers: Programs that convert high-level code into machine-readable code.