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Q&A-KCSE Computer Studies Paper 1

Describe three possible threats to the computers connected to the network and give one way each threat can be reduced or prevented

Virus / trojan / worm / malware

  • Piece of software/code/a program that replicates itself  or causes damage e.g. editing/deleting files

Prevention

  • Running anti-virus/anti-malware software 
  • don’t download from unknown sources
  • don’t click on unknown links

Spyware / malware / keylogger

  • Piece of software/code/a program that records actions/key presses and sends this data to a third party analysis

Prevention

  •  Running anti-spyware/anti-malware software/firewall

Data interception / passive

  • Data is sent to another device and is intercepted by a third party

Prevention

  • Encryption

Phishing

  • An e-mail has a link that when clicked directs the user to a fake website that collects personal data

Prevention

  • Network policy // firewall

Pharming

  • A piece of code installed that redirects user to fake website that collects personal data

Prevention

  • Anti-malware or firewall

Hacker

  • Person attempting to gain unauthorised access to the network/computers/ data/files 
  • unauthorised access and then deleting/editing data/files

Prevention

  • Firewall
  • strong password 
  • biometrics
  • penetration testing
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Using an example, explain a difference between a primary key and a foreign key in a relational database.

A primary key is a table field that uniquely identifies each record and ensures that duplicate entries are not allowed

A foreign key is primary key of a parent table placed in a child table to ensure that any record added to a child table is related to the one in parent table.


A foreign key is a field (or a set of fields) in one table that refers to the primary key of another table. It is used to establish and enforce a link between the data in the two tables, ensuring referential integrity.

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 Identify the type of software used to compress files.

Utility Software

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Suggest one disadvantage to the programmer of using a high-level language instead of a low-level language.

  • not able to directly manipulate the hardware
  • may need to wait for translation before running
  • the program may be less efficient.

 

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A web server has an internet protocol (IP) address. Give three characteristics of an IP address.

  • consists of values between 0–255 / 0–FFF
  • values are separated by full stops/colons
  • it is a unique address
  • can be static or dynamic
  • can be public or private
  • can be IPv4 / have four groups of digits
  • can be IPv6 / have eight groups of digits
  • in IPv6 :: can replace groups of zeros.
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State three types of optical disks

  • compact disks
  • DVDs
  • Blue Ray
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Distinguish between real-time and distributed operating systems (KCSE 2018)

  • Real-time OS reads information from input devices and must respond within a short duration of time to ensure correct performance
  • Distributed OS distributes computation among several physical processors which do not share memory or clock
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State the functions of the following:

  1. Hub
  2. Router
  3. Switch
  4. Bridge

Bridge: Joins together two networks that use the same base protocols.

Hub: Copies all packets of data to all devices on the network.

Router: Stores the addresses of computers on the network and transfers data between devices.

Switch : Analyses each data packet and sends it to the computer it was intended for.

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Describe how a FRID works.

RFID stands for radio frequency identification. There is an RFID reader and tag.RFID is used in contactless credit and debit cards as well as in some hotel room cards. Inside an RFID tag is a chip that contains a small amount of memory. The chip is attached to a coil of wire which acts as an antenna. When an RFID tag is scanned, the reader emits radio waves which are picked up by the tag’s antenna. The power induced in the tag’s antenna from these waves is enough to power the chip which then uses its antenna to emit its own radio wave, which contains the information held on the chip. This wave is picked up by the reader which decodes the information and returns the information to a computer.

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Explain why a developer, who is good at both low-level and high-level programming, would normally use high-level languages when writing programs                                                                                    [4 marks]

  • High-level languages have built-in functions;
  • High-level languages have built-in libraries;
  •  High-level languages have more support/help;
  • High-level languages have structures (such as selection and iteration);
  • High-level languages can be less machine-dependent/more portable;
  • It (usually) requires fewer lines of code to be written;
  • It is (usually) quicker to develop code in high-level languages;
  • It is easier to find mistakes in code;
  • The code is easier to maintain//understand;
  • • It is easier to structure code in high-level languages;
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Identify the network component that uses the IP address to send data only to its correct destination

Router

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A car park uses a number plate recognition system. Identify the reason why unsigned integers should be used to record the number of cars entering and leaving the car park, rather than signed integers

  • Unsigned integers store more positive values
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Briefly describe the following

Multitasking - the  capability of an operating system to enable users to run two or more programs at once on a single computer

Real time processing - data processing system in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

Time-sharing processing  - a processing mode in which the central processor serves two or more users with different processing requirements (tasks)

On-line processing - is that type of processing where the result of data processing transaction is available immediately

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Define disk formatting and state three reasons for formatting a disk

Definition

  • Disk formatting is the process of preparing a data storage media for initial use

Reasons:

  • To make a disk blank for reuse
  • To make it compatible with another operating system
  • to create tracks and sectors for first time use
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Give one reason why a phased implementation would be the best approach to follow in this case.

  • This approach causes minimum disruption
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Computer Studies KCSE 2006 Paper 1

SECTION A (40 MARKS)

1.What is meant by

    a)Analogue data

     b)Digital data                           (4 mks)

2. Distinguish between transcription and transposition types of errors and give an example of each  (4mks)

3. a)What are peripheral devices?  (1mk)

   b)Give two examples of peripheral devices  (1mk)

4a)What meant by the term user-friendly as used in software development? (1mk)

  b)Distinguish between the terms single-tasking and multi-user as used in operating systems  (2mks)

5.What actions should be taken in case of a fire outbreak in the computer laboratory?  (4mks)

6a) What is an Internet Service Provider?    (1mk)

  b) An employee in a business company is charged with the responsibility of putting the company advertisements on the Internet.

 i) State the professional title of the employee. (1mk)

ii) Give an example of software used by this employee to carry out the above task.    (1mk)

7.Differentiate between COM ports and LPT ports     (2mks)

8.Explain two ways in which ICT can enhance commerce.  (2mks)

9. Explain the following software terms:

    a) Portability       (1 mk)

    b) Modularity      (1 mk)

10. a) State two application areas of desktop publishing software. (2mks)

     b) Explain the following graphic terms:                                                                                     

     i) Rotate (1 mk)

    ii) Crop  (1mk)

12. a)List two arithmetic operations that can be performed on a row of numeric data in a word processing table.    (1 mk)

     b) In each case of (a) above, write the expression used.  (2mks)

13. List two methods of gathering information during the system development process   (2mks)

14.Name three types of optical disks.(3mks)

15.The diagram below shows a formatted plate surface of a storage disk.

 

 

 

            Shade and label:

            a)         one sector                                                                                ( 1mk)

            b)         One block                                                                                (1mk)

SECTION B (60 MKS)

Answer question 16 and any other three questions from this section in the  space provided

16 a) List two examples of:

       i) Third generation languages    (2mks)

       ii) Object oriented languages    (2 mks)

b) Draw a flowchart to compare three non-equal numeric values A, B, C and prints the largest of the three. (11 mks)

17 a) One of the functions of an operating system is job scheduling.  Explain what is meant by job scheduling.   (1mk)

    b)List and explain three types of user interfaces.                      (6 mks)

    c)Describe the following categories of software:

       i) Firmware                 (1mk)

       ii) Proprietary software  (1mk)

     d) a new company XYZ intends to go into the business of desktop publishing. Advise the company on three computer hardware system specification features to consider as a measure of enhancing performance. (6 mks)

18. a) distinguish between the following sets of terms as used in spreadsheets.        (2mks)

     i)Worksheet and workbook

     ii) Filtering and sorting

     b) State one way in which a user may reverse the last action taken in a spreadsheet package.        (1 mk)

     c)The following is a sample of a payroll. The worksheet row and column headings are marked  1, 2, 3, .  and A, B, C.  respectively

 

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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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What is data encryption?

  • Refers to the scrambling of data into unreadable form before transmission over a telecommunication media  OR
  • transformation of data from plaintext to ciphertext
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Give two reasons why hexadecimal is often used instead of binary in computer
science.

  • hexadecimal is easier (for humans) to read (than binary);
  • numbers are displayed in a more compact way (in hexadecimal than in binary);
  • it is quicker to type in (hexadecimal numbers than binary numbers);
  • it reduces the risk of typing errors (in hexadecimal numbers than binary numbers);
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She lost all her photographs when her computer crashed.
(i) What is meant by the term crashed?
(ii) How could she have avoided losing all her photographs?

  • the computer appears to “freeze”/”hang”
  • computer won’t respond
  • failure of hardware (stops computer normal functioning)
  • failure of software (stops computer normal functioning)
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