5. Electronic Memory

• Computer holds data and instructions using electricity. It holds data and instructions in RAM
• RAM is made of billions of memory locations

  Each memory location has an address and some data

  The address never changes
• What is RAM also known as (3)?

  Memory nit , electronic memory , primary storage
• What is this data held by?

  live electrical ciruits
• Explain volatile memory?

  Memory that uses electricity to hold data and anything held in this memory is lost if the power is turned off.

  RAM is volatile
• What is ROM?


  read only memory

  -holds the start up instructions for when the comptuer is turned on
• Compare RAM and ROM - 4 differences?

  RAM is volatile , ROM is non volatile

  RAM can change , ROM is read only and cannot change

  RAM is high capacity , ROM is low capacity

  RAM holds data and instructions , ROM holds start-up instructions
• What are registers?

  Tiny pieces of onboard memory inside the CPU each with a specific purpose
• Program counter

  What is its function?

  What does it hold?

  When is it used?

  Holds address of next line in program ; counts through program line by line

  Holds an address

  Used at the start of the cycle
• Memory Data Register

  What does it hold?

  When is it used?

  What is its function?

  Holds data

  Used during fetch and store

  During fetch part of cycle , MDR holds data tha has been fetched from memory

  During store part of cycle , it holds data ready to be saved
• Memory Address Register

  What does it hold?

  When is it used?

  What is its job?

  Holds an address

  Used during fetch and store of cycle

  During fetch part , MAR holds memory address to fetch from

  During store part , MAR holds the address to save to
• Accumulator

  What does it hold?

  When is it used?

  What is its job?

  Data

  Execute part of cycle

  Saves results of each calculation carried out by the ALU
• Explain the process of running software?


  1 - Storage : Load software and instructions sent to RAM

  2 - RAM : Run software and instructions sent to CPU

  3 - CPU : Execute and instructions carried out one by one
• What is multitasking and how does the computer multi-task?

  Using more than one application at the same time on the same computer

  Computer multi-tasks by rapidly swapping between different applications
• What is memory management?

  The process of controlling and organizing computer memory to optimize its usage.