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Q&A-KCSE Computer Studies Paper 1

Distinguish between microwave and a radiowave transmission and a microwave transmission  (KCSE 2017 PP1)

Microwaves can cover shorter distances. On the contrary, radio waves can travel a long distance. Radio wave is usually propagated through sky mode while microwave uses the line of sight propagation. 

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Social engineering is where someone is tricked or manipulated into providing secure information or access to a secure system. Describe each of the following social engineering techniques.

Blagging

  • This is where a victim is tricked/persuaded by a fraudster to give their details or payment information for a false reason/purpose;

Phishing

  • This is where the victim receives and responds to communication that appears to be from a valid or known source but is in fact fraudulent. (It allows the fraudster to capture private information before the victim realises);

Shouldering

  • This is where someone watches and records\remembers a victim entering their pin or security information such as passwords. (They can then use this information to gain access to a system)
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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 advantages and disadvantages of video conferencing

Advantages

immediate response to questions/queries
can see each other watch body language etc.
easier to have several participants (would be difficult using instant messaging if
several people involved)

Disadvantages

need for expensive equipment/high set up costs
sometimes synchronisation problems make it difficult for delegates
need to train people to use the new technology
greater use of bandwidth

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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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Define the term multimedia

  • Is an integration of sound, text, graphics, and video to convey information
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State the functions of the following features in word processors

  • Thesaurus - Is a feature in a word processor that suggest words with the similar or opposite meaning to the one selected
  • Comments: a feature in a word processor that allows a user to attach a remark about the selection
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Identify one component common to all computers.

  • Processor
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Explain the Fetch – Execute cycle and provide an example of a Central Processing Unit (CPU) component for each stage of the cycle

The Fetch – Execute cycle is a sequence of actions, performed by the processor as it fetches
a program instruction from its memory, determines what the instruction wants to do and
carries out those actions. The stages of the cycle are provided below.

  • Fetch the instruction – the processor fetches the instruction from a memory address stored in a program counter and transfers the instruction, via a data bus, to an instruction register. At the end of the fetch operation, the counter points to the next instruction that will be read in the next cycle.
  • Decode the instruction – the processor decodes the instruction stored in the instruction register, including getting any operands required to complete the instruction.
  • Execute the instruction – the decoded instruction is executed.
  • Store the result – the result generated by the execute phase is stored in the main memory, and/or sent to an output device. The program counter is updated with feedback from the arithmetic logic unit (ALU), to a different address from which the next instruction will be fetched.
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Describe what is meant by ‘RAID 10’.

  • RAID 10 is a combination of RAID 0 (zero) and RAID 1 (one)
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Describe two features you would expect to see in the expert system’s interactive user interface.

– multiple choice/yes-no answers
– easy to understand interface e.g. use of icons/drop down menus etc.
– output shown as % probabilities of fault

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KCSE 2016 COMPUTER STUDIES PAPER 1

State the function of each of the following keys on the computer keyboard :  (2mks)

Backspace;

  • Deletes characters to the left of the cursor

Insert

  • Add characters at the cursor position
  • Toggles between overtype and insert modes

An organization intends to replace an existing system by carrying out the process in stages .

Name the implementation strategy ;  (1mk)

  • Phased change-over

Give two reasons why the  organization is opting to use the implementation strategy  in (a) above (2mks)

  • Gives employees time to learn
  • Organizations can revert to the old system in case of failure
  • Reduces resistance by the employee
  • It is easier to find system errors as you are dealing with only one part at a time
  • Accessing parts of the old system is still is possible in case of failure of the new system
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(a)State what is meant by the terms:

Parallel data transmission...................................................

Serial data transmission......................................................

(a)State what is meant by the terms:

Parallel data transmission

  • 8 bits/1 byte/multiple bits sent at a time  
  • using many/multiple/8 wires/lines

Serial data transmission

  • one bit sent at a time over a single wire
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  1. (a)State the meaning of the term disk defragmentation as used in computers  (1mk)
  • The process of rewriting parts of a file to contiguous sectors on a disk
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For your item named in (a) describe two different tasks that the microprocessor performs.

  • camera film speed, position (end of film), distance, light
  • washing machine amount of water, speed of wash/temperature/time
  • fridge temperature, display panel
  • air conditioning temperature, timing, display pane
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State and explain characteristics of an algorithm

Input : An algorithm can take 0 or more inputs well defined outputs

Finiteness: an algorithm must terminate in finite time and after finite number of steps. 

Definiteness : an algorithm must be clear and unambiguous. Each and every step of an algorithm must be clear and precise and it must have only one meaning

Feasibility: should be feasible with the available resources

 

Output : must produce at least one well defined output

Independent : should have a step-by-step directions which is independent of any programming language

Correctness: should solve the problem it is designed to solve

Efficiency: must take the shortest time possible to run and should require the least memory space. It should use a minimum number of computation steps and memory to produce the desired  output. takes little time and memory to run

Generality: should not be limited to a specific case. It should work for all the valid inputs. works for many possible inputs

Effectiveness : should statements that are relevant to the problem. Every step must be basic and essential. 

 

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What is a primary key?

  • an attribute/combination of attributes chosen to ensure that the records in a table are unique
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State three features of a typical operating system

- (provides) user interface
input/output control
security
handling interrupts
spooling
memory management
processor management
utilities (e.g. copy, save, delete, re-name, etc.)
maintain user accounts
load/run software
error reporting/handling
multiprogramming
batch processing (JCL)/real time processing
multitasking/multiuser/multi-access
file management

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Define the following modes of electronic data processing:

  1. Multitasking
  2. Real time processing
  3. Timesharing
  4. Online Processing

Multi-tasking - It is a data processing modes where a single CPU processing more than one task or program apparently at the same time

Time-sharing - a processing mode where a single CPU processes tasks from more than one user apparently at the same time

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

On-line processing - is a mode of processing where the result of data processing transaction is available immediately

Real-time processing - is a mode of data processing 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

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Mikal has been employed as a computer trainer in an organisation. State three roles that she is likely to play in the organisation

  • Developing training materials
  • Training computer users
  • Conducting ICT examinations
  • Managing the learning and examination process
  • Developing guidelines for using the computer lab
  • Planning the course content
  •  
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