Once data has been written onto a ROM chip, it cannot be removed and can only be
read. Unlike main memory (RAM), ROM retains its contents even when the computer is
turned off. ROM is referred to as being nonvolatile, whereas RAM is volatile.
ROM is memory that cannot be changed
by a program or user. ROM retains its
memory even after the computer is
turned off. For example, ROM stores the
instructions for the computer to start up
when it is turned on again.
RAM
RAM (pronounced ramm) is an acronym for random access memory, a type of
computer memory that can be accessed randomly; that is, any byte of memory can
be accessed without touching the preceding bytes.
RAM is a fast temporary type of memory in
which programs, applications and data are
stored. Here are some examples of what's
stored in RAM: the operating system
applications ,the graphical user interface (GUI)
.If a computer loses power, all data stored in
its RAM is lost