Computer Science

• CPU

  CPU is the brain of the computer and its job is to take an input, process data and produce an output
• FDE cycle

  FDE cycle is the cycle that the central processing unit(CPU) runs through billions of times per second
• What is the fetch stage of the FDE cycle

  During the fetch stage of the FDE cycle the instruction or data is fetched from the Ram then to the CPU
• What is the Decode stage in the FDE cycle


  During the decode stage of the cycle the CPU works out what is required from the instruction
• What is the Execute stage in the FDE cycle

  During the execute stage of the cycle. The CPU will carry out the instruction that was fetched
• What does the ALU do and what does it stand for

  Arithmetic logic unit and it performs arithmetic and logic decision
• What doe CU stand for and what does it do

  It stands for control unit and it Co-ordinates how data is moved around and decodes the instruction fetched from the memory
• What is Cache and what does it do

  Cache is located in the CPU and stores the most frequently used data and it speeds up performance of the CPU
• Registers

  Small amount of high speed memory located in the CPU
• What does the Von Neumann Architecture consist of

  PC(program counter),MAR(memory address register), MDR(memory Data register), Accumulator(ACC)
• What does MAR stand for and what does it do

  It stands for memory address register and it holds the memory address of where data are to be fetched
• What does MDR stand for and what does it do

  It stands for Memory data register and it holds the memory address of where data or instructions which has been fetched
• Accumulator

  Stores results of any calculations that have been taken
• What is Clock speed

  Is measure the number of fetch decode execute cycles that can take place in 1 second
• Cores

  Separate processing units that can fetch decode and execute
• Embedded systems

  is a computer system with a single function inside a larger mechanical unit
• What does Volatile mean

  Maintains its data only when the device is powered
• What does non-volatile mean

  Maintains its data while powered off
• Primary storage

  Holds data and instructions that the CPU needs while turned on
• Why do you need primary storage

  It reduce the time taken to complete an FDE cycle and it has fast access times allowing primary storage to be used as short term memory and allows the CPU and Ram to run faster
• What does Ram stand for and what does it do

  Random access memory is primary storage connected to the CPU that holds the data and instructions that are currently in use
• What does ROM stand for and what does it do

  Read only memory and it holds the instruction a computer needs to start up
• Advantages of Ram

  very fast, read/write, large capacity
• Advantage of ROM

  Fast memory and read only data
• Virtual memory

  Secondary storage and is used when the Ram is nearly full and is transferred there and back when its needed
• Why is virtual memory bad

  Its slower than RAM and will negative impact to the system
• Why do we need secondary storage

  For long term storage and holds the data currently not in use
• 3 types of storage device(non volatile)

  Magnetic, Solid state, Optical
• What is magnetic storage

  Uses magnetic to stores binary 0s and 1s
• Advantage of Magnetic storage

  high storage, low cost
• What is Solid state storage

  Solid state storage uses electronic circuits to store binary 1s and 0s
• Advantage of solid state storage

  high storage, very fast, durability
• Disadvantage of Solids state storage

  Cost and reliability= limited read/write cycles
• What is Optical storage

  Optical storage uses lasers to burn the surface of a disk creating pits and land suitable for storing binary 0s and 1s
• What does HDD stand for and what kind of storage is it

  Hard disk drive an d uses magnetic storage
• What does SSD stand for and what kind of storage is it

  Solid state drive and its a solid state storage
• What storage is CD/DVD

  Optical
• How many bits in a nibble

  4 bits
• how many bits in a byte

  8
• how do you get from a byte to a kilobyte

  x1000