About the Main Memory

RAM and ROM

Main Memory

Main memory and backing storage are not the same. Main memory is located inside the computer system. It can either be RAM or ROM. Backing storage is outside the main processor, e.g. Hard Drives, USB Flash Memory. Main memory in today’s computers is on average around 4-6 Gb of RAM. Backing Storage is much bigger with average computers having around 500 Gb or more.

ROM (Read Only Memory)

ROM is used to store a small part of the operating system called the bootstrap loader.

Data is stored permanently in ROM. Data is not lost when the power goes off. Data in ROM cannot be changed

RAM (Random Access Memory)

This is where the operating system is stored; it also holds all programs and data. You can purchase additional RAM chips and install them in your desktop computer, which normally speeds up multi-tasking.

The processor can write to and read from RAM at high speed. Data held in RAM can be changed. All data in RAM is lost when the power is switched off.