Read only memory (ROM)

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Quick Questions

Shade in the A or B circle for each question.

1. Which statement about ROM is correct?

A ROM is non-volatile, so its contents stay when the power is off

B ROM is volatile, so its contents are lost when the power is off

2. What is ROM mainly used to store in a computer?

A The start-up (boot) instructions

B The documents the user is currently editing

3. In normal use, what can the user do with the contents of ROM?

A Read them, but not change them

B Read them and freely overwrite them

4. A computer is switched on. Where does it first find the instructions to start up?

A RAM, because it was saved there last time

B ROM

5. Is ROM a type of primary storage?

A No, it is secondary storage like an HDD

B Yes, the CPU can access it directly

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1ROM		Apower = OFF → ROM contents = KEPT
2boot instructions		BROM is read only in normal use, so its contents are fixed and users cannot save files to it. Files are saved to secondary storage.
3ROM is non-volatile, so its contents are not lost when the power is switched off		CThe start-up program a computer runs when switched on, kept in ROM so it is always available
4ROM is also found in embedded devices, such as a washing machine, holding the fixed program that controls it		Dwashing_machine.ROM = "wash program"
5ROM is volatile, so it loses its contents when the power is off		ERead only memory: non-volatile primary storage whose contents are fixed and stay when the power is off
6The user saves their homework files into ROM		FROM is non-volatile, not volatile. It keeps its contents when the power is off. It is RAM that is volatile.

Definitions

ROM

Fill in the Blanks

Complete each line of code by filling in the missing parts.

ROM is ____________ memory: it keeps data

ROM stores the ____ instructions at start-up

ROM contents are _____ in normal use

ROM is also found in ________ devices

ROM is a type of _______ storage

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A memory ← "ROM"

B volatile ← FALSE

C holds ← "open browser tabs"

Question 2

A romVolatile ← TRUE

B powerOff ← TRUE

C IF powerOff = TRUE THEN

D OUTPUT "ROM data kept"

E ENDIF

Question 3

A device ← "washing machine"

B storedIn ← "RAM"

C OUTPUT device, storedIn

Question 4

A mode ← "normal use"

B romAccess ← "read and write"

C OUTPUT mode, romAccess

Question 5

A powerOn ← TRUE

B IF powerOn THEN

C bootCode ← READ(ROM)

D ERASE(bootCode)

E ENDIF

Answer Key

Read only memory (ROM)

Section A: Quick Questions

A — ROM is non-volatile, so its contents stay when the power is off

A — The start-up (boot) instructions

A — Read them, but not change them

B — ROM

B — Yes, the CPU can access it directly

Section B: Match the Pairs

ROM → Read only memory: non-volatile primary storage whose contents are fixed and stay when the power is off

boot instructions → The start-up program a computer runs when switched on, kept in ROM so it is always available

ROM is non-volatile, so its contents are not lost when the power is switched off → power = OFF → ROM contents = KEPT

ROM is also found in embedded devices, such as a washing machine, holding the fixed program that controls it → washing_machine.ROM = "wash program"

ROM is volatile, so it loses its contents when the power is off → ROM is non-volatile, not volatile. It keeps its contents when the power is off. It is RAM that is volatile.

The user saves their homework files into ROM → ROM is read only in normal use, so its contents are fixed and users cannot save files to it. Files are saved to secondary storage.

Section C: Definitions

ROM — Read only memory: non-volatile primary storage whose contents are fixed. It keeps the start-up (boot) instructions, so data stays when power is off. Also used in embedded devices.

Section D: Fill in the Blanks

ROM is non-volatile memory: it keeps data

ROM stores the boot instructions at start-up

ROM contents are fixed in normal use

ROM is also found in embedded devices

ROM is a type of primary storage

Section E: Spot the Error

C — ROM keeps fixed contents, mainly the start-up (boot) instructions. It does not hold open browser tabs, which live in RAM. Line 3 should be holds ← "boot instructions".

A — ROM is non-volatile, so it keeps its data when the power is off. Line 1 should set romVolatile to FALSE.

B — An embedded device such as a washing machine keeps its fixed program in ROM. RAM is volatile and would lose the program when switched off. Line 2 should be storedIn ← "ROM".

B — ROM contents are fixed and are read only in normal use. They are not freely written to like RAM. Line 2 should be romAccess ← "read only".

D — At start-up the computer reads the boot instructions from ROM and runs them. Erasing them would stop the computer starting, and ROM contents are fixed anyway. Line 4 should be RUN(bootCode).