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Q&A-KCSE Computer Studies Paper 1

 Lucy wrote: “I should validate the input into my database by typing in the same data twice”.Why was her statement incorrect?

  • she had actually described verification
  • data could be incorrect, therefore same incorrect data typed in twice
  • accept description of validation process e.g. range check
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Differentiate between bus topology and star topology of networks. What are the advantages and disadvantages of star topology over bus topology

  • Bus topology is characterised by common transmission media shared by all the connected nodes
  • Star topology is characterised by a central switching node connected directly to each of the multiple nodes in the network

Advantages of Star topology over Bus topology

  • Faster communication as compared to bus topology
  • Independent line of connection allows freedom of removing or adding nodes

Disadvantages of Star topology over Bus topology

  • Expensive as compared to the bus topology
  • Long cable length
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The data before encryption is known as .................................................. text.
To scramble the data, an encryption .................................................., which is a type
of .................................................., is used.
The data after encryption is known as .................................................. text.
Encryption prevents the data from being .................................................. by a hacker

The data before encryption is known as .......plain.................. text.
To scramble the data, an encryption ......................key.........................., which is a type
of ...................key............................, is used.
The data after encryption is known as ....................cipher............................. text.
Encryption prevents the data from being ......................understood...................... by a hacker

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State any four applications of electronic spreadsheets

  • Financial accounting
  • Prediction and forecasting
  • Inventory keeping
  • Budgeting
  • Keeping records
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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
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(ii) State what ROM and RAM store.

 

ROM stores BIOS / bootstrap / start-up 

RAM stores currently executing programs and data

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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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Describe a typical situation that requires the use of:

(i) a high-level language

(ii) a low-level language.


High level languages are used in situations when:

  1. Speed of execution is not a critical factor, such as in office applications.
  2. a programmer needs to use complex commands that perform complex tasks.
  3. A programmer wants to make use of standardised library / sub routines.

Low level languages are used in situations when:

  1. a program must execute quickly such as real time applications
  2. a programmer needs to write code that interacts directly with the hardware, such as device drivers
  3. a programmer needs to perform a specific command not available in a HL language.
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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

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There are security concerns associated with cloud storage.
(a) State one way in which providers of cloud storage could prevent security breaches by their own employees

 (b) Explain why data on networks is encrypted

(a) One from:

  • Background checks
  • Access control
  • Physical security
  • User policies

(b) To prevent unauthorised access (1) so that data remains confidential (1) by making it unintelligible (1) because it is scrambled (1)

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Joe plays online games using the world wide web. A sequence of processes is required to open a web page. Describe this sequence of processes

  • URL is clicked/typed into a web browser address bar. The page is requested (by the web browser) so HTML and files are fetched from a web server and the browser collates the page, which is then displayed on the monitor.
  • OR
    URL is clicked/typed into a web browser address bar (1). The browser locates the IP address either in cache or using a DNS server and the browser sends a request to the web server with that IP address web server uses HTTP to send back the requested web page and the browser displays the content of the page .
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What precaution would you take in a computer lab if humidity falls below normal for prolonged periods due to weather changes?

  1. Use a humidifier: Using a humidifier can help maintain a consistent level of humidity in the computer lab, which can prevent the negative effects of low humidity.

  2. Avoid dry air: Avoid creating a dry environment in the computer lab by opening windows or using fans to increase air circulation.

  3. Regular maintenance: Ensure that all computer components are properly maintained and cleaned to prevent damage due to static electricity.

  4. Backup data: Regularly backup all important data to avoid data loss in case of hardware failure caused by low humidity.

  5. Monitor humidity levels: Use a hygrometer to monitor the humidity levels in the computer lab and take corrective measures if the levels fall below a safe range.

  6. Use anti-static materials: Use anti-static mats or wristbands when handling computer components to prevent static electricity buildup.

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Explain why it is beneficial to get more RAM instead of relying on virtual memory.

  • More RAM will improve the performance of the computer 
  • More RAM will speed up the access to data
  • Excessive use of VM can cause disk thrashing which decreases performance
  • VM is slower to access than RAM direct (because it has to go back to RAM first)
  • Moving data between RAM and VM takes processor time
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State two benefits of using computerised traffic control systems.

  • Better/improved traffic flow control
  • reduces accidents
  • keeps delays to a minimum
  • reduces pollution
  • cars use less fuel

Give one benefit and one disadvantage of the use of wireless technology.

Advantages

  • no wires
  • fast/high-speed wireless Internet access
  • WLAN is faster than a modem or mobile
  • WLAN for working at home one day a week/teleworkers
  • see internet content away on the move
  • create and send multimedia messages to mobiles or e-mail
  • picture messaging - send photos/pictures text/sound/recorded
  • greetings from mobiles to mobiles/PCs
  • instant transmission - no busy signals/no searching for phone jacks
  • download e-mail and file attachments on mobile
  • watch live webcast on mobile/hotspot
  • listen to streaming video on mobile/hotspot
  • news/weather/sport/games while on the move
  • access information from mobile anytime
  • send/receive/delete e-mail while on the move
  • wireless Inbox on mobile - to contacts and calendar
  • view business appointments while out of the office on mobile
  • send corporate e-mail while out of the office - even behind a firewall on mobile
  • wireless internet connection from chat rooms for discussions with colleagues while on the move
  • give visual demonstrations from mobile and colleagues watch back at the office

 disadvantages e.g.

  • WLAN speeds are slower than Net access at work/narrow band width
  • any one within the WLAN nodes range with an appropriate device can use your WLAN and broad band link
  • any one who walks past your house or WLAN linked into a corporate system can access sensitive information or credit card details
  • 3G phones not compatible with 2G phones
  • Blue tooth - has limited range
  • blocked signal/distorted signal/weak signal/lag
  • health problems from microwaves
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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 three advantages of  biometric authentication

  • Protection against Password-related Vulnerabilities: Traditional password-based authentication methods are vulnerable to various risks, such as weak passwords, password sharing, or password theft.
  • Stronger Access Control: Biometric readers add an additional layer of access control to laptops. Even if someone gains physical possession of the laptop, they would still need the authorized user's biometric data to unlock it and access the data. This helps prevent unauthorized individuals from accessing sensitive information stored on the laptop,
  • Audit Trail and Accountability: Biometric authentication systems often come with built-in logging and auditing capabilities. This means that each time someone accesses the laptop using their biometric data, it can be recorded and associated with a specific user. This creates an audit trail, allowing organizations to track and monitor access to laptops and establish accountability in case of any security incidents or breaches.
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451/1

COMPUTER STUDIES

PAPER 1

THEORY

DECEMBER 2021

TIME: 2 HOURS

 

FORM TWO END OF TERM TWO 2O21 EXAM

451/1

COMPUTER STUDIES

PAPER 1

THEORY

TIME: 2½ HOURS

 

INSTRUCTIONS TO CANDIDATES:

  • Write your name and ADMISSION number in the spaces provided above.
  • Write the date of examination and sign in the spaces provided.
  • This paper consists of two sections.
  • Answer all the questions in section A.
  • Choose one topic to answer in section B
  • All answers must be written in the spaces provided in this question paper.
  1. SECTION A
  2.  Answer all questions in this section
  3. What is a computer?                                                                                                            1mks
  4. State three physical components that make up a computer                                                 3mks
  5. State the hardware technological differences between the second generation and third generation computers                                                                                                          2mks
  6. State and explain three characteristics of a computer                                                         3mks
  7. State the functions of the following special memories in a computer                                3mks
  8. Buffers
  9.  
  10. Registers
  11. Cache
  12.  
  13. Define the following as used in data representation in a computer                                  (5mks)
  14. Bit
  15.  
  16.  
  17. Byte
  18.  
  19.  
  20. Nibble
  21.  
  22.  
  23.  
  24. Word
  25.  
  26.  
  27.  
  28. Word-length
  29.  
  30.  
  31. State two reasons why a DVD is superior to a typical compact disk                               (2mks)
  32. State three advantages of flat panel monitors over cathode ray tube monitors                   3mks
  33. Explain the following terms as used in word processing                                                  3mks
  34. Section breaks
  35. Thesaurus
  36. Superscript
  37. State two advantages of  impact printers                                                                             2mks
  38. State the function of the following keys on the computer keyboard                                  3mks
  39. Enter key
  40. Insert key
  41. Delete key
  42. State the technology used by the following secondary devices to store data                      3mks
  43. Magnetic storage devices
  44. Solid state storage devices
  45. Optical storage devices
  46. State three reasons why an operating system is important in a computer                         3mks
  47. A typical computer’s main memory consists of both volatile and non-volatile memory.
  48. i)  Explain what is meant by the term volatile memory                                          (1mark)
  49. ii) What is normally stored in the non-volatile part of a computer’s main memory (1mark)
  50. Explain why having cache memory can improve the performance of the CPU         (2mks)
  51. What is a computer system?                                                                                           (1mk
  52. Give two differences between a solid state drive (SSD) and a hard disk drive (HDD)   2mks
  53. State three categories of software classified according User license agreement              (3mks)
  54. State two disadvantages of Random Access Memory                                                       (1mk)
  55.  
  56.  
  57. a) Explain the functions performed by the following components of a processor   (2 marks)
  58. Control unit
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State two advantages of electronic databases over a flat file

  • Data Integrity: they provide ways or mechanisms for enforcing data integrity constraints, such as referential integrity. If a record in the parent table is deleted, related records in the child table also get deleted. This ensures accurthe acy and consistency of data stored in the database
  • Data Security
  • Concurrency control
  • Reduces data redundancy
  • Data retrieval and querying
  • Data indexing
  • Data consistency and acid transaction
  • Data backup and recovery
  • Data sharing and collaboration
  • Convenient data maintenance
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Describe what is meant by a MAC address.

  • used to identify a device
  • it is a unique (address)
  • it is a static address // it does not change
  • it is set by the manufacturer
  • the first part is the manufacturer ID/number / identifies the manufacturer
  • the second part is the serial number / ID.

 

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