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Q&A-KCSE Computer Studies Paper 1

Distinguish between Incremental and Full backup


Incremental:

  • Only the changes need to be backed up
  • The software/OS/settings are unlikely to have changed between backups
  • Small number of files likely to be used/edited between backups
  • Take less time to backup
  • Each backup will take less memory space to store

Full:

  • Backup all the data/files and software
  • It might not take a significant time to back up entire system
  • He might only have a small number of files to be backed up each time
  • Safer as have more past versions to revert to
  • User may have changed settings on computer
  • Faster to restore the backup
  • Needs to do a full before he can do an incremental
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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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A school intends to install a computer network. Explain three challenges that the school may experience after the installation (KCSE 2021 Computer Studies Q19(b))

Network Failure - when the network becomes faulty or the network is down, users may not access network resources hence operations of an organization may be brought to a standstill

Security Issues:  A computer network can be accessed thus there is an increased chance of hacking

The rapid spread of viruses: Viruses can easily spread to terminals of a computer network which may be very expensive to clear

Cultural and moral effects: adult content may be shared in a networked environment which may be of negative impact on teenagers

 

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Viruses, pharming and phishing are all examples of potential Internet security issues.
Explain what is meant by each of these three terms.

Virus

  • - program/software that replicates/copies itself
  • – can delete or alter files/data stored on a computer
  •  – can make the computer “crash”/run slow

Pharming -

  • malicious code/software installed on a user’s hard drive/actual webserver
  •  – this code redirects user to a fake website (without their knowledge)
  •  – to obtain personal/financial information/data

Phishing

  • - legitimate-looking emails sent to a user
  • – as soon as the recipient opens/clicks on the link in the email/attachment …
  • – … the user is directed to a fake website (without their knowledge)
  • – To obtain personal/financial information/data
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Explain how virtual memory can compensate for the limited  RAM capacity in a computer.

  • VM is used when RAM is full  i.e part of the secondary storage used as (temporary) RAM/VM
  • Data from RAM is moved to the secondary storage/VM (to make space in RAM)
  • RAM can then be filled with new data
  • When data in VM is needed it is moved back to RAM
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Defining  blocking of text as used in  word processing

  • Refers to selecting a group of text eg word, sentence or even a paragraph in order to work with it as a whole
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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
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Define the term variable as used in programming

A variable is a memory location used to store a value

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Explain how the techniques of

(i) verification,
(ii) validation
are used to ensure that the stored data is as accurate as possible.

Dual input of data

  • Two inputs are compared by the system and any discrepancies are reported (and not stored.)
  • Data input once, either printed out or checked on the screen and  errors corrected

 Rules are given to the processor

  • Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

  • Provides only valid inputs, so no other validation is required
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What is a source code as used in computer programming?

  • It is a program written in a high level langauage
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State three different methods that allow people to communicate using the Internet. In each case, give a different benefit for the stated method.

emails: – fast delivery of messages (to recipient’s mail box)
– able to send attachments
– can store messages for later use
– auto-translation no language problems
– can open email at a convenient time
video conferencing/calling/chat:
– removes need to travel (saves time and money)
– allows face to face discussions
– works in real time (only allow once)
VoIP: – much cheaper than normal international calls
– direct communication between people
– works in real time (only allow once)
chat rooms/instant messaging:
– instantaneous reply
– anyone can join in
social networking:
– can ensure only your “friends” are in communication
– usually free to join and use
– talk to (multiple) friends at the same time

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Maranda 2024 Mock CRE Paper 2

1. a) Based on Deutro-Isaiah, describe the Messiah. (7mks)

The Messiah would be despised/ rejected

The Messiah would be treated harshly/ arrested/sentenced to death

The Messiah would be reconciling people through His suffering

The death of the Messiah would bring forgiveness of sins of humankind

The Messiah would endure suffering/humiliation without complaining/ would suffer innocently

The Messiah would have nothing attractive

The Messiah would be humble/simple

The Messiah would be highly honored

The Messiah would succeed in His work

He would be despised, rejected, wounded oppressed and afflicted 

He endured pain and suffering which would have been ours. 

Because of our sins he was wounded 

We are healed by the punishment he suffered He was treated harshly but he never said a word 

He was put in the grave with the wicked 

He was buried with the rich even though he did not commit a crime 

He took the place of many sinners and prayed that they might be forgiven.

 

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What is an Operating System?

  • It refers to a system software that provides a platform for installation and execution of an application software and also manages the computer hardware
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State  the advantages and Disadvantages of GUI

Advantages

  • It is intuitive
  • Easy to navigate
  • Uses menus, pointers and icons thus easy to learn and use
  • It lets the user exchange data between different software applications
  • The user does not have to learn complicated commands

Disadvantages

  • Takes a lot of memory
  • A lot of processor power is needed
  • Takes up a larger amount of hard disk space than other interfaces
  • They need significantly more memory (RAM) to run than other interface types

 

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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

 

Give one application of each type of data transmission. Each application must be different

Parallel

  • sending data from a computer to a printer
  •  internal data transfer (buses)

Serial

  • connect a computer to a modem
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State three features of the fifth generation computers (3mks)    [2017 paper 1]

  • Artificial intelligence
  • Parallel processing
  • Natural language processing
  • quantum computing
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Describe two effects on society of an increase in the use of the Internet for e-commerce.

  • loss of jobs as some traditional shops/banks close
  • lower profits for companies that do not get involved with e-commerce
  • decline of leisure shopping as goods are bought on-line
  • city centres becoming deserted as shops/banks close down
  • gap between rich and poor widening as richer get savings from
  • shopping on-line
  • more people choosing to interact with computers rather than people
  • increase in small businesses
  • less pollution/travelling
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Give two characteristics of each of the system development methodologies listed below.

(a) Linear/Cascade/Waterfall

(b) Iterative Methodology

(a) Linear/Cascade/Waterfall

  • a project is divided into stages or phases
  • it is sequential, each stage needs to be completed before moving on
  • clear goals are set for each stage

(b) Iterative Methodology

  • effective in producing a working prototype in a short period of time
  •  involves extensive user input and testing
  • based on build – test – evaluate process, the philosophy is re-build until users are completely satisfied
  • features user input throughout the process which enables ongoing, responsive changes to be made to the design.
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Describe what is meant by shareware.

 the trial version of software for a limited time/number of uses with limited features  free of charge

If a full version is required need to pay a fee/sign up

When the trial is over user is asked to pay/sign up

Protected by copyright

Type of software licence
 

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