Computer Science

• Analogue data

  Data represented by a continuous signal
• Sampling


  • Taking measurements at regular intervals and storing the values
  • The number of samples taken per second
  • The number of bits used to store each sample
• Increasing the image resolution


  Improves the quality of a bitmap graphic
• Calculating the file size of a bitmap image

  1. Image resolution of 2048 pixels wide and 1024 pixels high

  2. Bit depth of 16 bits
• Public cloud


  Cloud storage service available to the general public
• Disadvantages of storing data on a public cloud compared to a LAN server


  • Lack of direct control over data
  • Potential security and privacy risks
• Firewall


  Security measure that controls incoming and outgoing network traffic
• Encryption


  Security measure that converts data into a coded format to protect it
• Passwords


  Security measure that restricts access to computer systems
• The database has the following structure:

  COURSE_INFORMATION(CourseID, Description, Cost)

  TUTOR(TutorID, TelephoneNumber, EmailAddress, TutorName)

  COURSE_SCHEDULE(CourseID, DateStarted, TutorID)
• The entity-relationship (E-R) diagram for the database COURSES is incomplete
• SQL script to return the total number of courses that have started after 9 September 2023

  SELECT COUNT(*) AS total_courses

  FROM COURSE_SCHEDULE

  WHERE DateStarted > '2023-09-09';
• Data verification


  Method of protecting the integrity of data by checking for errors when it is entered
• The logic expression is: Y = ((P AND Q) XOR ((NOT Q) OR R)) AND NOT P
• Truth table for the logic expression

  P | Q | R | Y

  • -+--+--+--

  0 | 0 | 0 | 0

  0 | 0 | 1 | 0

  0 | 1 | 0 | 0

  0 | 1 | 1 | 1

  1 | 0 | 0 | 0

  1 | 0 | 1 | 0

  1 | 1 | 0 | 0

  1 | 1 | 1 | 0
• Logic circuit for the logic expression: Y = ((P AND Q) XOR ((NOT Q) OR R)) AND NOT P
• Context-sensitive prompts


  IDE feature that provides relevant suggestions based on the current code context
• Single stepping


  IDE feature that allows the programmer to execute the program one line at a time
• Compressing program files


  Reduces the file size for faster downloads
• Hard disk formatter


  Tool used to prepare a new hard disk for use by creating the file system structure
• Shareware licence


  Software distribution model where the program can be tried for free but requires payment to continue using
• Reasons for a programmer to join a professional ethical body:

  • Uphold professional standards and ethics
  • Access to resources and support
  • Networking and career development opportunities
• Static RAM (SRAM)


  Type of RAM used in laptops that retains data without requiring constant refreshing
• Electrically Erasable Programmable ROM (EEPROM)


  Type of non-volatile memory that can be electrically erased and reprogrammed
• Buffer


  Temporary storage area used by the laser printer to store data before printing
• Port


  Interface on a computer used to connect external devices
• Data integrity


  Ensuring data remains complete and accurate over its entire lifecycle
• Difference and similarity between pharming and phishing

  • Difference: Pharming redirects users to a fake website, phishing uses deceptive emails or messages

  Similarity: Both aim to steal sensitive information
• Malware


  Malicious software designed to cause damage or gain unauthorized access to computer systems
• Components in the Von Neumann model (excluding registers and buses)

  • Arithmetic Logic Unit (ALU)

  2. Control Unit (CU)

  3. Memory
• Differences between special purpose and general purpose registers

  • Special purpose registers have a specific function, general purpose registers can be used for any purpose

  2. Special purpose registers cannot be freely accessed, general purpose registers can be freely accessed
• Steps of the Fetch-Execute (F-E) cycle


  Step | Description
• Software interrupt


  Interrupt caused by a software program, e.g. division by zero
• Stages when an interrupt is detected

  The device causing the interrupt transfers data to the CPU.

  4. The address of the Interrupt Service (ISR) handling routine is loaded into the Program Counter (PC).

  6. Lower priority interrupts are re-enabled.