How to understand computer memory

RAM

RAM stands for Random Access Memory. It is a TEMPORARY storage space, so when you turn off the computer everything on the RAM is lost. This means that RAM is volatile.

RAM programs instructions so the CPU can retrieve them quickly. This is because if the instructions was stored on the hard drive it would take the CPU longer to retrieve them.

This would them slow down the processing speed at which the CPU can work!

ROM, PROM and EEPROM

ROM stands for Read Only Memory. It can't be changed by the user or any programs.

Without the ROM the computer wouldn't turn on. The boot sequence is the computer's initial start-up process. After the boot, the OS controls the CPU and supplies the programs to run.

There are different types of ROM. These are PROM and EEPROM

PROM is programmable ROM. They are not rewritable so they can only be programmed once. They are programmed directly by the programmer.

EEPROM is electrically erasable programmable read-only memory. It can easily be updated from the manufacturer.

Virtual Memoey

Virtual Memory is a section of volatile memory created temporarily on the storage drive.

Virtual Memory isn't as fast as the main memory. This is because processing power is being taken up by moving data around, rather than just executing instructions.

Flash Memory