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Q&A-KCSE Computer Studies Paper 1

What is a backup?

A backup is a copy of data that can be used if the original data is lost.

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Describe two benefits of using USB connections between a computer and a device.

  • devices are automatically detected and configured when initially attached
  • Impossible to connect device incorrectly/connector only fits one way
  • has become the industry standard
  • supports multiple data transmission speeds
  • lots of support base for USB software developers
  • supported by many operating systems
  • backward compatible
  • faster transmission compared to wireless
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What is an information system ?  (KCSE 2012))

Is an arrangement of people, data, processes, communication and IT that interact to support problem solving

 

Components of an information system

  • Hardware
  • Software
  • Data - information manipulated by software
  • people- all people involved
  • Processes - steps to accomplish a goal
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A company making televisions has introduced robots to replace the human work force.

(a) Describe three effects this would have on the work force

(b) Give two advantages to the company of introducing robots

(c) How could the robots be trained to assemble the televisions?

(d) A whole batch of televisions was produced with some of the parts missing. How could this error have been avoided?

(a) Describe three effects this would have on the work force

  • loss of jobs/unemployment
  • deskilling
  • need to re-train
  • different jobs available/re-skilling
  • no longer need to do hazardous/tedious jobs

(b) Give two advantages to the company of introducing robots

lower work force costs (no salaries to pay)

  • lower environmental costs (less electricity for heating/lighting)
  • higher throughput
  • more consistent product
  • robots don’t need breaks, holidays/work 24/7 etc.
  • robots don’t take industrial action

(c) How could the robots be trained to assemble the televisions?

  • tasks repeated by skilled worker and how each task is done is memorised
  • tasks programmed directly into the computer/robot memor

(d) A whole batch of televisions was produced with some of the parts missing. How could this error have been avoided?

  • if parts missing for a sequence, then a warning should be given and the assembly stopped
  • several quality control stages to spot an error early on
  • program in checks at each stage of assembly so robots can detect a fault immediately
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What is a computer keyboard?

A computer keyboard is an input device used to enter text, characters, and various commands into a computer or other digital devices.

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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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Factors to consider when choosing DTP software. (4 marks)

  1. Availability in the market
  2. Initial and maintenance cost
  3. User friendliness
  4. Compatibility
  5. User needs

One facility of a Software Development Environment is to convert source code to machine code.  Name and briefly describe four other facilities commonly found in a Software Development Environment.

  • Editor: this allows a programmer to enter and edit source code
  • Automatic formatting:  Correctly indents code
  • Automatic colour coding:  Changes key words, literals and annotation to different colours
  • Linker: this is a program which allows previously compiled code, from software libraries, to be linked together
  • Loader: this is a program which loads previously compiled code into memory.
  • Debugger: this is a program which helps locate, identify and rectify errors in a program
  • Syntax error detection:  Highlighting syntax errors before code is translated
  • Trace: this is a facility which displays the order in which the lines of a program are executed, and possibly the values of variables as the program is being run
  • Break point: this is a facility which interrupts a program on a specific line of code, allowing the programmer to compare the values of variables against expected values.  The program code can then usually be executed one line at a time.  This is called single-stepping
  • Variable watch: this is a facility which displays the current value of any variable.  The value can be 'watched' as the program code is single-stepped to see the effects of the code on the variable.  Alternatively a variable watch may be set, which will interrupt the program flow if the watched variable reaches a specified value
  • Memory inspector: this is a facility which will display the contents of a section of memory
  • Error diagnostics: these are used when a program fails to compile or to run.  Error messages are displayed to help the programmer diagnose what has gone wrong
  • Emulator: will provide and emulator to run the code/app so no physical device required
  • Context sensitive menu:  SDE suggests available options
  • Statement completion:  SDE will complete a statement such as adding an ‘end if’ to an ‘if’ statement GUI creation:  Allows programmer to create a GUI by dragging and dropping controls (buttons, etc...) onto a form.
  • Publisher: facility to package up and deploy program as an easy to install package
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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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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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List two types of network software

  • Network operating systems
  • Protocols
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State and explain four network communication devices

  • Repeaters : amplify data signal thereby extending the physical coverage of a network. It can connect two LANs locally.
  • Bridges: connect similar types of networks e.g a token ring to another token ring
  • Routers: link networks of different types
  • Gateway: allows computers in a network to connect regardless of their topology
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A company has decided to use a computer for stock control. Describe the process of systems development from the time the decision was made to proceed with computerisation until final testing.

specify output requirements
design documents/screen displays
data for input/storage
form design
storage devices
file structures/access/design
data security/back up files
systems flowchart etc.
implementation i.e. pilot/intermediate/parallel running
testing strategy
training
hardware/software
programming/algorithms
validation
user manual
technical documentation
entering data into system

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What situations are likely to call for the use of Direct Changed Over?

  • where the new system is completely different from the old one
  • if there has been extensive testing of the system and the system analyst has confidence in its functionality
  • If the system is not critical
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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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Jane has noticed the following problems with her computer  (2mks)

  • It is taking a longer time to start up;
  • It is often hanging;
  • Applications are taking longer to load.

State three possible causes of these problems and how they can be solved (3mks)

There could be several possible causes for the issues Jane is experiencing with her computer keyboard, including:

1. Software Issues
   - Cause: Outdated or corrupt system files, drivers, or operating system.
   - Solution:
     - Ensure the operating system and drivers are up-to-date.
     - Run a system file checker to repair any corrupted system files (e.g., on Windows, run "sfc /scannow" from the Command Prompt).
     - Consider reinstalling the operating system if issues persist.

2. Hardware Issues:
   - Cause: Physical damage or malfunction in the keyboard hardware.
   - Solution:
     - Check for physical damage or debris under the keys and clean the keyboard if necessary.
     - If cleaning doesn't help, consider replacing the keyboard with a new one.

3. Resource Overload:
   - Cause: The computer may be running too many background processes or lacking sufficient hardware resources.
   - Solution:
     - Close unnecessary background applications and processes to free up system resources.
     - Consider upgrading the computer's RAM, CPU, or storage if it's outdated and unable to handle current software demands.
     - Use task manager or activity monitor to identify and terminate resource-intensive processes.

4. Malware or Viruses:
   - Cause: Malicious software can slow down a computer, cause hanging, and delay startup.
   - Solution:
     - Perform a full system scan using reputable antivirus or anti-malware software to remove any threats.
     - Ensure that the operating system's security patches are up-to-date.

5. Disk Fragmentation:
   - Cause: Fragmented files can slow down the loading of applications and overall system performance.
   - Solution:
     - Run a disk defragmentation tool (e.g., Windows' built-in tool) to optimize file storage on the hard drive.
     - Consider upgrading to a solid-state drive (SSD) for faster application loading times.

6. Insufficient Storage:
   - Cause: If the hard drive is nearly full, it can cause slow performance.
   - Solution:
     - Free up space by deleting unnecessary files and programs.
     - Consider upgrading to a larger capacity hard drive or SSD if storage space remains an issue.

7. Background Processes and Startup Items:
   - Cause: Too many unnecessary programs running in the background or starting up with the computer.
   - Solution:
     - Disable or remove unnecessary startup items and background processes to improve startup time.
     - Use the Task Manager or System Preferences (on macOS) to manage startup items.

It's important to diagnose the specific cause of the issues Jane is facing by troubleshooting each potential problem one by one. In some cases, a combination of these solutions may be necessary to fully resolve the problems with her computer keyboard.

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A virus is a specific category of malware. Describe three other different categories of malware.

Trojan (horse); a program which misleads the user into thinking it is another
piece of software which, when run, executes another program;
Spyware; a program which records data such as usernames and passwords on
a host system and forwards the information to a third party;
Adware; code embedded or attached to program files which will persistently
show adverts (that attempt to generate revenue);
Worm; code which will run autonomously and replicates itself on a host system;
Ransomware; a program that encrypts a user’s data to make it unreadable until
they pay for the key;
Remote Access Tool (RAT); allows access to control and monitor a computer
from a remote network location;
Rootkit; malware that has managed to gain ‘root’ admin privileges;
Bots/Zombies; a program installed on a computer that performs a job for the
remote owner of the bot/zombie such as sending spam or sending web requests
to perform a DOS or attack a computer system;
Scareware; malware that tells you something is wrong with your system in an
attempt to get you to make a purchase;
Keylogger; a program that monitors/records a user’s keystrokes in order to steal
passwords/confidential details

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State and briefly describe three program control structures

Sequence: Sequential execution of a program one line after another

Selection:  Involve the a decision between two or more options e.g  if...then...else

Loops/Repetitions: Used for looping i.e a line of code can be made to execute a given number times before terminating.

State the types of storage devices used in a computer

  1. Primary Storage (Memory):

    • Random Access Memory (RAM): This is a volatile memory used to store data and instructions that the CPU (Central Processing Unit) can access quickly. RAM is essential for running applications and the operating system. However, its contents are lost when the computer is powered off.
    • Read-Only Memory (ROM): ROM is a non-volatile memory that stores essential firmware and instructions necessary for the computer's boot-up process. It retains its contents even when the power is turned off.
    • Cache Memory: Cache is a small and fast memory located closer to the CPU. It stores frequently accessed data to speed up the processing.
  2. Secondary Storage (Mass Storage):

    • Hard Disk Drive (HDD): HDDs use magnetic storage to store data on rotating platters. They provide relatively large storage capacities and are commonly used in computers and laptops for long-term data storage.
    • Solid-State Drive (SSD): SSDs use NAND flash memory to store data, offering faster read and write speeds than HDDs. They are more durable and consume less power, making them increasingly popular in modern computers.
    • Optical Discs: CDs, DVDs, and Blu-ray discs are examples of optical storage media. They are mainly used for distribution of software, music, movies, and archival purposes.
    • USB Flash Drives: Also known as thumb drives or pen drives, these portable storage devices use flash memory to store data and can be easily connected to a computer's USB port.
    • Memory Cards: Memory cards, such as SD cards and microSD cards, are used in various devices like cameras, smartphones, and tablets to store data, photos, videos, etc.
    • External Hard Drives: These are HDDs or SSDs contained within an external enclosure, allowing users to expand their computer's storage capacity or create backups.
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Why are CD-Rs and CD_ROMs referred to as WORM?

  • Because data is recorded to the disks once but can be accessed many times without changing the content
  • once data is written to the disk, it becomes read-only and cannot be altered or erased.
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