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Memories are divided into two types:
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RAM
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Random Access Memory,
any cell can be read or written
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ROM
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Read Only Memory,
any cell can be read but not written
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RAM memories are used to store running programs and the data they work on,
while ROMs are used for special programs and unchanging data. When a
computer first starts up, a small program called a bootstrap program is
read from a ROM and executed. Since ROMs cannot be altered, this bootstrap
program cannot be deleted, erased, or harmed in any way. Once the bootstrap
starts, it turns on the other components such as the monitor, keyboard,
mouse and disk drives, and the real operating system is read from a disk
drive. ROMs are also used for many other things, such as character fonts
for printers.
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