About the Main Memory
RAM and ROM
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.