Memory

Memory

1. Types of memory

   • Volatile - memory is wiped when power is no longer supplied
     • e.g RAM,
   • Non -volatile - memory is saved mechanically so power can be turned off
     • e.g ROM and mechanical hard drives

2. Virtual Memory

   • If a computer runs out of RAM to use, it uses the hard disk as a 'virtual memory' to serve as extra ram.
     • The hard drive creates a temporary pagefile to save the virtual memory
     • Swapping memory between the hard drive and ram is called paging

3. RAM - used for quick reading and saving data for the CPU

   • SRAM - static ram, no refreshing, lower latency, more expensive
     • used in cache memory
   • Latency is the time it takes to read and write to ram
   • DRAM - dynamic ram, has to refresh to retain data, higher latency, cheaper
     • used in main memory
   • VOLATILE MEMORY

4. ROM - read only memory that boots to BIOS

   • NON VOLATILE
   • Built into the motherboard and not easily reprogrammed

5. Flash memory

   • Any non volatile memory that can be written to and read from
     • memory sticks
     • Solid state drives