ROM in a computer system

The purpose of ROM in a computer system

1.2.1 Primary Storage (memory)

Primary Storage (memory) — Note 3 of 6

What you need to know

ROM stores the essential instructions needed to start (boot) the computer. Because it is non-volatile, these instructions remain even when the computer is turned off, ensuring the computer can always start up.

What to know

ROM stores firmware — the essential instructions needed to boot up the computer.
It is non-volatile, so boot-up instructions are not lost when the computer is switched off.
ROM is read-only during normal operation — its contents cannot be accidentally changed or deleted.
Without ROM, the computer would have no instructions to start the boot process.

Exam technique

Tip:If asked 'why is ROM needed?', explain that without it the computer could not boot because it would have no initial instructions to load the operating system.

Example:'State two items stored in ROM for a Follow Me car system' — (1) start-up instructions/BIOS, (2) the firmware/program to run the system. Just writing 'programs' alone is NE.

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