1.1 - Components of a computer and their uses

• Describe what is meant by the term ‘RAM'

  • Used to hold data and/or programs in use
  • Volatile/Loses its contents when power is lost.
• State one characteristic a high performance CPU might have

  • Multiple Cores
  • High/Fast Clock Speed
  • Ability to use pipelining
  • Large Cache
• State two features of the Von Neumann architecture

  • Instructions and Data stored in same area of memory
  • Single Control Unit
  • Single Arithmetic Logic Unit
• Describe one feature, not part of the standard Von Neumann Architecture, which contemporary CPUs may have in order to improve performance

  • Multiple Cores - Each core acts as a separate processing unit
  • Pipelining- whilst an instruction is being executed the next can be decoded and the subsequent one fetched
• Explain why using a RISC processor rather than a CISC processor is likely to result in increased battery life

  • RISC has a smaller instruction set (than CISC)
  • Requires fewer transistors / less complex circuitry
  • Means less power is required
• Giving an example other than DVDs, describe what is meant by the term ‘optical media’

  • read/written to, using a laser
  • data is stored using pits and lands
  • E.g. Blu-Ray/CD
• Give one advantage of films being distributed using optical media

  • Cheap to produce/buy
  • Capacity big enough to hold film
  • Portable
  • Does not need an internet connection
• Define the term ‘multicore processor’

  • more than one processing unit in a (single) processor which can independently process instructions at the same time
• State two factors that affect the performance of a CPU

  • Clock speed
  • Number of cores
  • Cache
• Explain the difference between RAM and ROM, including how these are used by the computer system

  • RAM is volatile
  • Used for storing programs/data/parts of OS currently in use
  • ROM is non volatile
  • Used for storing (e.g.) BIOS / bootstrap
• Describe one non-graphical use OCR Insurance may have for a GPU

  • Performing complex numerical calculations
  • Calculations on multiple data at the same time
• Explain what is meant by the term ‘pipelining’.

  • Concurrent processing of multiple instructions
  • One instruction can be fetched while previous is being decoded
  • And the one before is being executed.
  • In case of a branch pipeline is flushed.
  • Increases speed of execution
• State what is meant by the term ‘register’.

  • Temporary storage/memory location inside the CPU
  • Used for a single specific purpose
  • Faster access speed than RAM / secondary storage
• Describe what is meant by the term ‘Von Neumann architecture'

  • Both data and instructions share the same memory
  • Instructions and Data stored in same format
  • A single set of buses / same bus for instructions & data (to connect CPU to Memory and I/O)
  • Has a (single) control unit
  • Has an ALU.
  • Has ways to input and output.
  • Has access to storage
  • Works sequentially through instructions // follows Fetch-execute cycle (Special) registers within CPU
• Give one way that the Harvard architecture differs from the Von Neumann architecture.

  • Separate memory for data and instructions / Multiple memory units
  • Different (sets of) buses one for instructions & one for data/ instructions and data can be accessed concurrently
• Give two features of a replacement processor that would increase the typical performance of the computer

  • Higher/faster clock speed
  • More cores//dual/quad/etc core
  • More cache memory
• Explain one benefit to the charity of using a processor that allows pipelining.

  • More instructions can be carried out in a set amount of time // less time to execute the same number of instructions
  • Increasing the speed/performance/efficiency of the computer/program // quicker for the program to complete
• Describe how the accumulator is used during the Fetch-Decode-Execute cycle.

  • Holds all input/output
  • Holds results of calculations (from the ALU)
  • Checked for conditional branching (e.g. BRZ)
  • Stores data which has come from the MDR/RAM
• Describe how the program counter is used during the Fetch-Decode-Execute cycle.

  • Holds the address/location of the next instruction (to be executed/fetched)
  • Contents copied to the MAR at start of FDE
  • Incremented (by one) on every cycle
  • Can be changed by branch/jump instruction
• State the name of three other registers that are used during the Fetch-Decode-Execute Cycle

  • Memory Address Register // MAR
  • Memory Data Register // MDR
  • Current Instruction Register // CIR
  • Index Register // IR
• Explain why virtual storage is well-suited for storing backups

  • Stored away from the computer(s)/remote so in case of disaster, data is not also damaged
  • All of the data (from multiple machines) can be backed up at the same time
  • Can be accessed from elsewhere / other machines
  • Storage can be expanded as necessary//no limit on size
  • Speed of access is not a priority for a backup
  • Can make recovery from another site easier
  • No physical space needed for backup hardware
  • No on site maintenance required
  • Allows more local storage capacity for data