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Q&A-KCSE Computer Studies Paper 1

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

Describe overtype and insert modes as used in word processors

  • Overtype mode: deletes the current text at the cursor position and replaces the existing characters with new text
  • Insert Mode: pushes the existing text away as new text is inserted between the existing text

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

Explain the functions of the following parts of the CPU

Control Unit; Decodes instruction; Controls the fetching and writing of data;

Arithmetic Logic Unit/ ALU; Executes mathematical instructions;  Executes logical instructions; Compares values held in registers;

 Clock; Controls the number of instructions carried out each second;   allows the CPU to synchronize operations;

State Examples of utility programs

 

Encryption software

  • Scramble/encode/mix up data so it cannot be read/understood if intercepted/stolen

Defragmentation s/w

  • Move free space together and Move files together hence enabling Faster access to files

(Data) compression s/w

  • Reduce the file size of files or makes files smaller inorder  To use less storage space
  • enables Faster transmission
  • enables storage of more files

Anti-virus / anti-malware s/w

  • To help protect computer/data against viruses/malware
  • To scan the computer to look for/quarantine/remove viruses/malware

Disk analysis and repair s/w

  • Scan disk and look for faults
  • Prevent the loss of data due to faulty disk

Auto-update

  •  Checks Internet for new versions of software/OS
  • Downloads and installs without user interaction

Firewall

  • Examine incoming and outgoing traffic
  • To help restrict/prevent unauthorised access over a network

...over a network/external source

A supermarket uses point of sale (POS) terminals at the checkout for scanning barcodes on the products.

(a) State two items of data that are stored on the barcode.

(b) Describe how the computer system checks that the barcode has been read correctly.

(c) State the type of file access that is used to get the price from the central computer.

(d) Explain how the system updates the file when an item has been sold.

(a) State two items of data that are stored on the barcode.

  • check digit
  • product number/item number/code
  • country of origin
  • manufacturers number/code
  • weight
  • price

(b) Describe how the computer system checks that the barcode has been read correctly.

  • check digit calculation is performed on the check digit, remainder = 0 if the barcode has been read correctly
  • weights and modulus 11 and use remainder
  • or subtractions and addition and use answer


(c) State the type of file access that is used to get the price from the central computer.

  • random/direct/online

(d) Explain how the system updates the file when an item has been sold.

  • search file/master file using barcode number/product code and decrease number in stock/increase quantity sold

Explain why a software developer should be responsible for addressing ergonomic issues in software design.

Responsibilities of the software developer is to ensure that the ergonomics focuses on making software user-friendly, reduces repetitive motions or eyestrain and enables movements of users to promote comfort and efficiency.

Software can be designed with adjustable text sizes and screen brightness settings to prevent eye strain, offering users a way to customise their visual experience for better comfort during prolonged use.

Explain one drawback to a user if the program is distributed as freeware

The user is not allowed to access the source code so, they cannot tailor the software to their needs and  they cannot fix any bugs in it

The software is still covered by copyright

The user must get the owner’s permission to do anything beyond using it

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);