Memory

Memory

1. RAM

   • Used as main memory in the computer
   • Volatile (Temporary data, if power is lost all data is gone)
   • slower than cache but faster than secondary storage
   • Read/ write
   • When software application and files are open they are copied from secondary storage to RAM. They stay there till the files or applications are closed.
   • Operating system is copied from secondary storage to RAM when computer is turned on

2. ROM

   • Non-volatile(If power is lost, data is not gone
   • Read Only
   • Chip built on to the motherboard
   • Contains all the instruction a computer needs to boot up. This is called the BIOS(Basic Input/ Output System)
   • Computer turns on – CPU reads instructions from the ROM – performs self checks and sets up the computer e.g. checks memory is working, what hardware devices are attached and copies the operating system to the RAM

3. Virtual Memory

   • Secondary storage used as extra RAM
   • When RAM is full it moves data that has not been recently used to secondary storage
   • Used if too many applications are open at one time
   • If the CPU wants o read data on the virtual memory it must move it back to the RAM