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Q&A-KCSE Computer Studies Paper 1

State the types of storage devices used in a computer

  1. Primary Storage (Memory):

    • Random Access Memory (RAM): This is a volatile memory used to store data and instructions that the CPU (Central Processing Unit) can access quickly. RAM is essential for running applications and the operating system. However, its contents are lost when the computer is powered off.
    • Read-Only Memory (ROM): ROM is a non-volatile memory that stores essential firmware and instructions necessary for the computer's boot-up process. It retains its contents even when the power is turned off.
    • Cache Memory: Cache is a small and fast memory located closer to the CPU. It stores frequently accessed data to speed up the processing.
  2. Secondary Storage (Mass Storage):

    • Hard Disk Drive (HDD): HDDs use magnetic storage to store data on rotating platters. They provide relatively large storage capacities and are commonly used in computers and laptops for long-term data storage.
    • Solid-State Drive (SSD): SSDs use NAND flash memory to store data, offering faster read and write speeds than HDDs. They are more durable and consume less power, making them increasingly popular in modern computers.
    • Optical Discs: CDs, DVDs, and Blu-ray discs are examples of optical storage media. They are mainly used for distribution of software, music, movies, and archival purposes.
    • USB Flash Drives: Also known as thumb drives or pen drives, these portable storage devices use flash memory to store data and can be easily connected to a computer's USB port.
    • Memory Cards: Memory cards, such as SD cards and microSD cards, are used in various devices like cameras, smartphones, and tablets to store data, photos, videos, etc.
    • External Hard Drives: These are HDDs or SSDs contained within an external enclosure, allowing users to expand their computer's storage capacity or create backups.

Explain the difference between the sequential and parallel computational models.

Any four of:
Sequential:
Individual instructions are executed one after another
Flow control is accomplished by jump/branch/goto instructions
Results are usually achieved less quickly than parallel processing (do
not award twice)
Parallel:
Individual instructions can be routed to different processors for
simultaneous execution
Results are usually achieved quicker than sequential instruction (do not
award twice)
Requires multi-core processors or multiple microprocessors
Tasks may be split into different parts with each part executed on a
different processor
Results need to be merged back together after completion

State the name of the storage space used by the operating system when there is insufficient RAM

  • virtual memory

Journalists are issued with laptops when they start working at a magazine publishing company. The company only uses free open-source software (FOSS).

  • 2.1.1 Explain the concept of open source in the context of FOSS. (2)
  • 2.1.2 Give ONE example of a free operating system the company could install on a laptop. (1)
  • 2.1.3 State TWO disadvantages of using free open-source software.

The laptops are equipped with either an HDD or an SSD.

  • 2.2.1 Users of laptops equipped with HDDs are advised to defragment the HDD regularly.
  • Briefly explain what defragmentation is. (2)
  • 2.2.2 Write out the abbreviation SSD in full. (1)
  • 2.2.3 Explain why an SSD accesses the data faster than an HDD.

The journalists can access their data remotely using virtualisation or Software
as a Service (SaaS).
2.3.1 Define the term virtualisation. (1)
2.3.2 Office365 is an example of SaaS.
(a) Except for remote data access, state TWO benefits of using
SaaS. (2)
(b) Describe how the license model of SaaS works. (2)

  • 2.4 The company takes precautionary measures to protect the magazine's data.
  • 2.4.1 An incremental backup strategy has been implemented to safeguard data. Explain how an incremental backup strategy works. (2)
  • 2.4.2 The company considers installing biometric readers on all the laptops. How would a biometric reader help safeguard the data on a laptop?

 

2.1.1 Explain the concept of open source in the context of FOSS. (2)

  • Is a software whose source available and user can modify and redistribute

Give ONE example of a free operating system the company could install on a laptop. (1)

  • Linux
  • FreeBSD
  • ReactOS
  • Android
  • ChromeOS
  • OpenSolaris

2.1.3 State TWO disadvantages of using free open-source software.

  • Lack of support
  • Security risks
  • Compatibility issues
  • Hidden costs

Identify four events that take place during the fetch-execute cycle

  • An instruction is retrieved from the memory
  • The instruction is decoded
  • The instruction is executed
  • the program counter is incremented

What is secondary storage?

  • A non-volatile store of data

Describe the difference between a barcode and A quick Response code (QR code)

  • A barcode is one-dimensional while a QR code is two dimensional
  • Barcodes are a set of vertical lines and QR code contains squares
  • QR codes can be read from any angle . Barcode is only above or below and lined up horizontally

Explain how an SSD stores data

Uses transistors( resistors and capacitors) . It can be implemented by the use of NAND or NOR gates. Data is stored on the chip as a charge

State the uses of 3D printers

  • Making prosthetic limbs for patients
  • Making items which allow precise reconstructive surgery
  • Making light-weight plane wings
  • Making sculptures

List four input devices used to capture data by way of scanning                 

Optical Mark Recognition; Optical Character Recognition; Magnetic Ink Character Recognition ; Optical Bar Recognition

Giving answers as readers is also acceptable, that is, Optical Character Readers, Magnetic Ink Character Readers; Optical Mark Readers

 

Explain two computer hardware features that may be considered when selecting a laptop computer to be used in developing a KCSE computer studies project (4mks)

Multimedia Capability - A laptop with strong multimedia capabilities is essential for a computer studies project submitted on CD-RW. This ensures that the laptop can efficiently handle multimedia content, providing a seamless experience in creating and presenting project materials.

Processor Speed - Opting for a laptop with a high processor speed is crucial. This feature enables the smooth execution of multiple applications simultaneously, enhancing overall project efficiency and reducing processing delays.

Hard Disk Capacity - Consider a laptop with ample hard disk capacity, as the Microsoft Office suite used in computer projects requires significant space for the installation and storage of project files. A spacious hard drive ensures that there is sufficient room for data and applications.

Main Memory Capacity - Given that students often work with multiple programs concurrently during a project, it's important to choose a laptop with an adequate main memory size. A smaller main memory may result in performance issues, hindering the seamless operation of various software applications during project development.

 

A typical computer’s main memory consists of both volatile and non-volatile memory.

a)  i)  Explain what is meant by the term volatile memory                                                            (1mark)

  • Memory content is lost when the power is turned off

ii) What is normally stored in the non-volatile part of a computer’s main memory                       (1mark)

  • The Computer’s BIOS

b) Explain why having cache memory can improve the performance of the CPU                         (2mks)

  • Frequently used data/instructions are store in the cache; Meaning they don’t have to be fetched from the main memory;
  • Data/instructions stored in the cache memory can be accessed faster (than data/instructions stored in the main memory) MAX 2

Describe the role of the registers and system clock within the fetch-execute cycle.

  • Registers are small amounts of memory available that hold data fetched from memory or data waiting to be stored in memory. A temporary holding place for the instruction that has been fetched.
  • The system clock purpose is to determine the pace of the cycle, each tick of the clock a part of the fetch-execute cycle occurs. Regulates the timing and speed of a computers systems functions.

Identify which processor in the PC systems below is likely to process instructions more efficiently. Justify your answer.

  • Processor X: Intel® Core™ i7 processor (3.8 - 5.0 GHz, quad core)
  • Processor Y: Intel® Core™ i5 (2.9 - 4.7GHz, dual core)

  • Processor X is likely to process instructions more efficiently as firstly it has the i7 CPU which is a faster processor as well as the quad core which processes quicker and the higher GHz versus Processor Y

What is a backup?

A backup is a copy of data that can be used if the original data is lost.