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Q&A-KCSE Computer Studies Paper 1

Explain the difference between
(i) serial and parallel,
(ii) simplex and duplex
modes of data transmission.

  • Serial is the transmission of data one bit at a time/through one wire
  • Parallel is the transmission of data more than one bit at a time/many wires
  • Simplex is the transmission of data in one direction only
  • Duplex is the transmission of data in both directions simultaneously
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Peter has installed internet on his home computer in order to use it for browsing. State three ways in which he would prevent viruses from infecting his computer.                                                        (3 marks)

  • Installing the latest versions of antivirus software
  • Avoiding downloads from untrusted sites
  • Scanning removable storage media for viruses before use
  • Scanning attachments for viruses before opening or downloading
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Differentiate between logical and physical network topology

Physical topology - the physical arrangement of nodes of a computer network

Examples

  • bus topology
  • ring topology
  • mesh topology
  • star topology

Logical topology- the way data flows in a network

Examples

  • Ethernet
  • Ring
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A company is developing a computer for use in schools.
(a) All computers have a CPU, memory and storage.
(i) Identify the type of physical storage that uses electronic circuits.

 

Solid state
 

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(iii) John von Neumann proposed the concept of a stored program.
   State the two items he proposed to store in main memory.

 Data

Instructions

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What is meant by RAID technology?

RAID (Redundant Array of Independent Disks) technology refers to a method of combining multiple physical disk drives into a logical unit to improve performance, data availability, and data redundancy. RAID technology is commonly used in storage systems to provide fault tolerance, data protection, and increased storage performance.

The primary purpose of RAID is to create a more reliable and robust storage solution by spreading data across multiple drives and implementing various data redundancy techniques. This helps to mitigate the risk of data loss and system downtime in case of drive failures.

There are different levels or configurations of RAID, each offering different features and trade-offs. The most commonly used RAID levels are:

  1. RAID 0 (Striping): Data is split evenly across multiple drives, resulting in increased performance as data can be accessed from multiple drives simultaneously. However, there is no redundancy, so if one drive fails, data loss can occur.

  2. RAID 1 (Mirroring): Data is duplicated or mirrored across two drives, providing redundancy. If one drive fails, the other drive can still function and serve the data. RAID 1 offers data protection but does not offer increased performance.

  3. RAID 5 (Striping with Parity): Data and parity information are striped across multiple drives, providing both increased performance and fault tolerance. Parity information allows for the recovery of data in case of a single drive failure. RAID 5 requires a minimum of three drives.

  4. RAID 10 (Combination of Mirroring and Striping): RAID 10 combines elements of RAID 1 and RAID 0. It involves mirroring data across two sets of drives and then striping the mirrored sets for increased performance and fault tolerance. RAID 10 provides high levels of data redundancy and performance but requires a minimum of four drives.

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Distinguish between a client-server and a peer-to-peer network

  • In a client-server network, every device is either a client or a server whereas in a peer-to-peer network each computer has equal responsibility and each has the ability to work as both a server and a client
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Explain the term website as used in the internet

  • A collection of related webpages under the same domain name
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State ways in which a network manager can use to ensure that the network is secure

  • Encrypt network traffic
  • Use of Firewall(s)
  •  Anti-virus software
  • Password protect the database
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Define Domain integrity

Domain integrity - ensures that all data in  a field contain valid values

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Define the following terms as used in the internet

HTTPS/HTTP: this is a protocol that is used to send data to web pages across the Internet

Uniform Resource Locator (URL):   a text-based version of a web address

Internet Service provider /ISP  - his is the company that provides a user with a connection to the Internet

browser - Software/application that allows users to view web pages / render HTML -

cookie - a text file (stored by a web browser) that contains data about a user’s browsing habits/details/preferences

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When data is transmitted it is subject to corruption. Explain how a parity check could be used to determine whether corruption has taken place.

  • Extra bit on each data-byte that
  •  Does not transmit data
  • Makes the number of ones in a byte always even or always odd
  • Error in the transmission of a bit will make the even/odd wrong
  • The problem of two errors in one byte not being found
  • Parity block
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