What's inside a computer?
There are two kinds of internal memory , RAM (Random Access Memory) and ROM (Read Only Memory).
RAM is a form of temporary storage for programs and data that being used at any given time. RAM is thousands of times faster than permanent storage devices like hard disks, floppy disks andCD / DVD. But information is stored only while the computer is on.
When the computer is switched off, any data that have not been stored in a permanent storage device will be lost. RAM has a capacity of hundreds of megabytes (a MB is equivalent to one million characters). ROM is a permanent storage device. ROM contents cannot be modified during machine operation. It is used to save basic computer programs (firmware).