RAM & ROM

• RAM is Random Access Memory, where programs are loaded when the user opens them. It is a volatile memory device
• ROM is Read Only Memory, a non-volatile memory device that stores the boot up scripts
• Virtual Memory is used when RAM is full, allowing a proportion of secondary storage to be used as overflow to keep programs running, albeit slower
• Primary storage includes RAM, ROM, Registers & Cache
• RAM is needed to store programs currently in use, enabling multitasking by copying data needed by programs for processing
• RAM stores data as small charges of electricity in tiny transistors etched into a circuit, needing to be refreshed every few milliseconds
• Types of RAM:

  • Dynamic RAM: 1 transistor and 1 capacitor for each bit, needs refreshing, limiting data read speed
  • Static RAM: 4-5 transistors wired together for each bit, does not lose charge, faster but more expensive
• ROM is a special memory chip that stores data even without power, used to store boot sequence instructions
• Modern ROM chips are made of flash memory, which doesn't need constant power supply to hold data
• Virtual memory is hard-drive space acting as RAM when RAM is full, operating slower than RAM
• Cache memory is a few Mb of memory inside the CPU, ensuring data access speed is equal to the CPU's speed for maintained performance
• Smaller amount of RAM leads to limited multitasking and greater need for slower virtual memory, while larger amount of RAM leads to faster performance and effective multitasking