Computer Science

• What is the Von Neumann Architecture?


  A computer architecture where data and instructions are stored in the same memory.
• What does the Fetch-Decode-Execute Cycle represent?


  It represents the continuous process of fetching instructions, decoding, and executing them by the CPU.
• What is the role of the Central Processing Unit (CPU)?


  It carries out all of the processing in a computer.
• What does the Arithmetic and Logic Unit (ALU) do?


  It performs all the arithmetic and logical operations in the CPU.
• What is the function of the Control Unit (CU)?


  It controls the flow of data within the CPU and decodes instructions.
• What is the purpose of the Accumulator (ACC)?


  It is a temporary store for the results from the ALU.
• What does the Program Counter (PC) do?


  It stores the address of the next instruction to be processed.
• What is the function of the Memory Address Register (MAR)?


  It stores the address for data to be fetched from or sent to memory.
• What does the Memory Data Register (MDR) do?


  It stores data that has been fetched from or is to be sent to memory.
• What are the steps in the Fetch-Decode-Execute Cycle?


  1. Fetch: Copy address from PC to MAR, CU fetches data to MDR, increment PC.
  2. Decode: CU decodes the instruction in the MDR.
  3. Execute: Execute the instruction (load data, move data, or perform calculations).
• What is clock speed in relation to a CPU?


  Clock speed is the number of instructions a single processor core can carry out per second.
• How is clock speed measured?

  Clock speed is measured in Gigahertz (GHz), which equals 1 billion cycles per second.
• What can happen if a CPU is overclocked?


  It can lead to overheating and cause the system to crash.
• What are the main factors affecting CPU performance?


  • Clock Speed: Higher speeds allow more instructions processed per second.
  • Cache Size: More and faster cache memory leads to quicker access to data.
  • Number of Cores: More cores enable faster processing of instructions.
• What are the levels of cache memory?


  • L1: Extremely fast but small, most expensive.
  • L2: Fairly fast and medium-sized.
  • L3: Slower than L2 but holds the most, least expensive.
• What is the role of cache memory in a CPU?


  Cache memory stores frequently used instructions and data for quick access by the CPU.
• What is a dual-core processor?


  A dual-core processor has 2 processing units within it.
• How does the number of cores affect CPU performance?


  The more cores a CPU has, the more instructions can be processed simultaneously.
• What is an embedded system?


  An embedded system is a computer system with a dedicated function as part of a larger system.
• What are examples of embedded systems?


  • Dishwasher
  • TVs
  • Microwave
  • Satellite Navigation
• What is Random Access Memory (RAM)?


  RAM is the main memory in a computer that can be written to or read from.
• What is virtual memory?


  Virtual memory is a part of the hard disk used as a temporary store for data when RAM is insufficient.
• What is the main disadvantage of using virtual memory?


  It causes a delay which slows the system down.
• What is magnetic storage?


  Magnetic storage is a common, reliable, and cost-effective storage method using rotating magnetic platters.
• What is Read Only Memory (ROM)?


  ROM is non-volatile memory that cannot be written to and contains the BIOS needed for booting up.
• What is the difference between volatile and non-volatile memory?


  Volatile memory loses all data when there is no power, while non-volatile memory retains data without power.
• What is solid-state storage?


  Solid-state storage uses flash memory and has no moving parts, making it faster than magnetic storage.
• What is optical storage?


  Optical storage uses laser light to read data from reflective disks like CDs and DVDs.
• What are the three formats of CDs and DVDs?

  • ROM (Read Only)
  • R (Write Once/Read Many)
  • RW (Rewriteable)
• What are the characteristics of different storage media?

  • HDD:
  • Capacity: 500MB – 4TB
  • Durability: Poor
  • Speed: Average
  • Flash Memory:
  • Capacity: 2 – 64GB
  • Durability: Excellent
  • Speed: Fast
  • CD/DVD/Blu-Ray:
  • Capacity: 650MB/9GB/50GB
  • Durability: Average
  • Speed: Poor
• What are the units of data in computing?

  • Bit (b): A single binary digit
  • Nibble: 4 bits
  • Byte (B): 8 bits
  • Kilobyte (kB): 1000 bytes
  • Megabyte (MB): 1000 kB
  • Gigabyte (GB): 1000 MB
  • Terabyte (TB): 1000 GB
  • Petabyte (PB): 1000 TB
• How do you convert Denary to Binary?


  Place a 1 or 0 in the table based on whether the number is higher than the binary place values.
• How do you convert Binary to Denary?


  Add together all the values of the binary digits that have a 1 underneath.
• How do you convert Hexadecimal to Binary?


  Split the hexadecimal number into parts and write them into a 4-bit binary table.
• How do you convert Hexadecimal to Denary?


  Convert the hexadecimal to binary and then convert the binary to denary.
• What are the rules for Binary Addition?


  0 + 0 = 0, 1 + 0 or 0 + 1 = 1, 1 + 1 = 10 (carry 1), 1 + 1 + 1 = 11 (carry 1).
• What is an overflow error in a CPU?


  An overflow error occurs when a calculation exceeds the maximum capacity of the CPU's bits.
• What happens during an overflow error?


  The CPU drops the overflow digit because it cannot store it anywhere.
• What is the binary representation of the decimal number 128?


  10000000
• What is the binary representation of the decimal number 64?


  01000000