CBSE Class 9 Foundation of Information Technology Chapter 2: Computer System Organisation NCERT Solutions

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CBSE Class 9 Information Technology chapter 2, Computer System Organisation, introduces the essential building blocks of a computer. You'll learn about various input devices, such as keyboards and webcams, and their specific functions. The chapter also clarifies the vital distinctions between primary memory (like RAM) and secondary memory (like hard drives), focusing on aspects like volatility and storage size. It explains the importance of cache memory in boosting processing speed. Additionally, you'll explore different memory units, ordered by their storage capacity, and understand fundamental terms like 'bit' and 'byte'. These explanations are designed to help you understand computer hardware organisation, preparing you for exams and building a solid IT foundation.

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BoardCBSE
ClassClass 9
SubjectFoundation of Information Technology
Session2026
LanguageEnglish
TypeNCERT Solutions
Chapter2. Computer System Organisation

Chapter summary

NCERT Solutions for Class 9 Foundation of Information Technology, Chapter 2, "Computer System Organisation," cover essential hardware components. The solutions explain various input devices, the distinction between primary and secondary memory, and the function of cache memory. They also detail memory units and their ordering by capacity, alongside definitions of bits and bytes. This chapter focuses on understanding the basic structure and organisation of a computer system, crucial for foundational IT knowledge.

Learning outcomes

  • Identify and describe common computer input devices.
  • Differentiate between primary and secondary memory, including their characteristics.
  • Explain the purpose and advantage of cache memory.
  • Understand and order memory units by storage capacity.
  • Define key terms like bit and byte.
  • Explain the function of a webcam.

Topics covered

Paper topics

  • Input Devices
  • Keyboard
  • Webcam
  • Optical Character Recognition (OCR)
  • Memory Types
  • Primary Memory (RAM)
  • Secondary Memory
  • Cache Memory
  • Storage Units
  • Bit
  • Byte
  • Memory Card

Important topics

  • Difference between Primary and Secondary Memory
  • Role and Advantage of Cache Memory
  • Understanding Memory Units (Bit, Byte, KB, MB, TB)
  • Common Input Devices and their Functions

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Questions and Solutions

Question 1.

Name the most commonly used input device.
Solution: The keyboard is the most commonly used input device. It allows users to enter text, numbers, commands, and other data into the computer system, making it essential for interaction and control.

Question 2.

Explain the main advantage and disadvantage of an () device.
Solution: The main advantage of an () device is its ability to accurately scan and interpret characters printed on paper, converting them into machine-readable digital text. However, a significant disadvantage is its limitation to recognizing only a specific set of characters or fonts, and it may struggle with unusual or low-quality print.

Question 3.

Why do we use a webcam?
Solution: A webcam is used for capturing a series of digital images or video streams in real-time. These images or video feeds are then transferred to a computer, where they can be processed, stored, or displayed, commonly used for video conferencing, online communication, and surveillance.

Question 4.

Name the memory (Primary/Secondary) with the following features:
  • If current is interrupted, data is lost.
  • Before a program is ready to run, the program is loaded into this memory, which allows the CPU directly access the program.
Solution: The memory described is Primary Memory, specifically RAM (Random Access Memory). RAM is volatile, meaning it loses its contents when the power supply is interrupted. It is also the memory where programs are loaded from secondary storage to be directly accessed and executed by the CPU.

Question 5.

Write any one advantage of cache memory.
Solution: One significant advantage of cache memory is its speed. If the data the CPU needs is found in the cache (a cache hit), the CPU can access it very quickly without having to use the slower motherboard's system bus to fetch it from the main memory (RAM). This greatly speeds up data processing.

Question 6.

Which disc is created using laser beam?
Solution: A ROM (Read-Only Memory) disc, such as a CD-ROM or DVD-ROM, is created using a laser beam during the manufacturing process to etch the data onto the disc's surface.

Question 7.

Give one difference between primary and secondary memory.
Solution: The primary difference lies in their volatility and capacity. Primary memory (like RAM) is volatile, meaning it loses data when power is off, and typically has a smaller storage capacity. Secondary memory (like hard drives) is non-volatile, retaining data without power, and offers much larger storage capacities.

Question 8.

Arrange the following memory units in ascending order of their storage capacities: Kilobyte, Byte, Terabyte, Megabyte, Geopbyte
Solution: The memory units arranged in ascending order of their storage capacities are: Byte, Kilobyte (KB), Megabyte (MB), Terabyte (TB), Geopbyte (GB). Note: Geopbyte is not a standard unit; assuming it refers to Gigabyte (GB), the order would be Byte, KB, MB, GB, TB. If 'Geopbyte' is intended as a unit larger than Terabyte, the order remains relative based on standard prefixes. For standard units: Byte < Kilobyte < Megabyte < Gigabyte < Terabyte.

Question 9.

Where can a memory card be used?
Solution: A memory card can be used in a wide variety of portable electronic devices. Common examples include digital cameras, smartphones, camcorders, portable audio players, video players, Personal Digital Assistants (PDAs), gaming consoles, and laptops, providing expandable storage.

Question 10.

Define the term byte. Differentiate between a bit and a byte.
Solution: A byte is a fundamental unit of digital information storage in computing. A bit (binary digit) is the smallest unit of data and can have a value of either 0 or 1. A byte is a collection of 8 bits, typically used to represent a single character, such as a letter, number, or symbol.

Short Answer Type Questions

Question 1.

Differentiate between Magnetic Ink Character Recognition (MICR) and Optical Mark Recognition (OMR).
Solution:
  • MICR stands for Magnetic Ink Character Recognition. It is used to read characters printed with special magnetic ink, commonly found on bank cheques. The system uses a magnetic reader to detect the magnetic properties of the ink.
  • OMR stands for Optical Mark Recognition. It is used to detect the presence or absence of a mark in a specific position on a form, such as in multiple-choice tests where you fill in bubbles. It works by sensing reflected light from the paper.

Common mistakes

  • Confusing volatile and non-volatile memory characteristics.
  • Incorrectly ordering memory units by size.
  • Not understanding the specific use cases for different input devices.
  • Misinterpreting the role of cache memory in system performance.

Revision tips

  • Create flashcards for memory units and their order.
  • Draw diagrams to illustrate the difference between primary and secondary memory.
  • Practice identifying input devices based on their descriptions.
  • Summarize the advantages of cache memory in your own words.

Practice MCQs

Q1. Which input device is most commonly used for typing commands and data?

Q2. What is the main disadvantage of an () device?

Q3. Which type of memory loses its data when the power is interrupted?

Q4. What is the primary advantage of cache memory?

Q5. A 'byte' is typically composed of how many 'bits'?

Frequently asked questions

What are the main input devices discussed in Chapter 2 of Class 9 Foundation of IT?

Chapter 2 discusses devices like the keyboard, webcam, and () devices as common input methods for a computer system.

What is the key difference between primary and secondary memory?

Primary memory (like RAM) is volatile and faster, used for active programs and data, while secondary memory is non-volatile, slower, and used for long-term storage of large amounts of data.

Why is cache memory important in a computer system?

Cache memory is important because it stores frequently used data and instructions, allowing the CPU to access them much faster than from the main memory, thereby improving overall system performance.

How are memory units like Byte, Kilobyte, and Megabyte related?

A byte is made up of 8 bits. A Kilobyte (KB) is approximately 1024 bytes, and a Megabyte (MB) is approximately 1024 Kilobytes. They represent increasing capacities of digital storage.

Where can a memory card be used?

Memory cards are versatile and can be used in various devices such as digital cameras, cell phones, camcorders, portable audio players, gaming consoles, and laptops.

Important links

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