Memory RAM, ROM, Virtual Memory

Memory RAM, ROM, Virtual Memory

1. RAM

   • Volatile- Temporary memory. If the power is switched off, the data will be lost.
     • Uses a main memory in the computer. It stores files, data and programs when they are being used
   • Operating system is copied from secondary storage to RAM when computer is turned off
   • The RAM is slower than the cache but faster than secondary storage

2. ROM

   • Non volatile memory so it is permanent memory that stays if the computer is switched off
   • It is read only memory
   • Contains all the instructions a computer needs to boot up. This is called the BIOS
   • Computers turn on. CPU reads instructions from the ROM. It performs self cheks and sets up the computer. It checks if the memory is working and what hardware devices are attached to the RAM

3. ·

   • Virtual memory
     • An example of secondary storage. It is used as an extra RAM. When RAM is full it moves data that hasn't been used recently to secondary storage called virtual memory
       • It can be used if too many applications are open at one time
     • If the CPU wants to read data on the virtual memory it must move it back to the RAM