Why a computer needs both RAM and ROM

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Date:

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Quick Questions

Shade in the A or B circle for each question.

1. Which memory holds the start-up instructions (bootstrap) that run when the computer is switched on?

A RAM

B ROM

2. Which memory holds the operating system and programs while the computer is running?

A ROM

B RAM

3. A computer has ROM but no RAM. What would happen?

A It could start up but could not run programs or hold data in use

B It would run perfectly well as ROM can store everything

4. A computer has RAM but no ROM. What would happen?

A It would not know how to start up when switched on

B It would start up normally using the RAM

5. Why can't RAM store the start-up instructions?

A RAM is volatile, so it loses its contents when the power is off

B RAM is too slow to store instructions

Match the Pairs

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

Left column		Right column
1ROM holds the bootstrap		AOnce the computer is running, the operating system, programs and data in use are loaded into RAM, where they can change quickly.
2RAM holds the OS and open programs		BPower on -> ROM bootstrap -> OS loaded into RAM
3Switch-on order: ROM runs the start-up instructions first, then the operating system is loaded into RAM		CROM only: boots, but cannot store open programs and data
4A computer with only ROM could start up but could not hold changing programs and data to run them		DThe start-up instructions are stored in ROM so they are still there when the power is switched off and the computer can start.
5A computer works with only RAM, because RAM keeps the start-up instructions when the power is off		ERAM is volatile and loses its contents when the power is off, so it cannot keep the start-up instructions. These are stored in ROM, so the computer needs ROM as well.
6The operating system and open programs run from ROM, so a computer does not need RAM		FROM holds fixed start-up instructions and is not used for the changing programs and data in use. These are held in RAM, so the computer needs RAM as well.

Definitions

RAM and ROM

Fill in the Blanks

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

POWER ON READ bootstrap FROM ___

LOAD operatingSystem INTO ___

IF power = ___ THEN RAM = EMPTY ENDIF

IF ___ = EMPTY THEN OUTPUT "Cannot start up" ENDIF

IF hasROM ___ hasRAM THEN computerWorks = TRUE ENDIF

Spot the Error

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

Question 1

A POWER ON

B ROM runs the bootloader

C bootloader loads OS into ROM

D OS starts the programs

Question 2

A ROM loses data without power

B RAM loses data without power

C So ROM holds the boot program

Question 3

A IF power is switched on THEN

B run start-up from RAM

C load the OS into RAM

D ENDIF

Question 4

A power <- ON

B CPU reads ROM

C OS copied to RAM

D CPU runs programs from ROM

Question 5

A IF computer has only ROM THEN

B it can start up

C it can hold changing data

D ENDIF

Answer Key

Why a computer needs both RAM and ROM

Section A: Quick Questions

B — ROM

B — RAM

A — It could start up but could not run programs or hold data in use

A — It would not know how to start up when switched on

A — RAM is volatile, so it loses its contents when the power is off

Section B: Match the Pairs

ROM holds the bootstrap → The start-up instructions are stored in ROM so they are still there when the power is switched off and the computer can start.

RAM holds the OS and open programs → Once the computer is running, the operating system, programs and data in use are loaded into RAM, where they can change quickly.

Switch-on order: ROM runs the start-up instructions first, then the operating system is loaded into RAM → Power on -> ROM bootstrap -> OS loaded into RAM

A computer with only ROM could start up but could not hold changing programs and data to run them → ROM only: boots, but cannot store open programs and data

A computer works with only RAM, because RAM keeps the start-up instructions when the power is off → RAM is volatile and loses its contents when the power is off, so it cannot keep the start-up instructions. These are stored in ROM, so the computer needs ROM as well.

The operating system and open programs run from ROM, so a computer does not need RAM → ROM holds fixed start-up instructions and is not used for the changing programs and data in use. These are held in RAM, so the computer needs RAM as well.

Section C: Definitions

RAM and ROM — ROM holds the start-up instructions that survive power-off. RAM holds the changing operating system, programs and data in use. A computer needs both to start up and to run.

Section D: Fill in the Blanks

POWER ON
READ bootstrap FROM ROM

LOAD operatingSystem INTO RAM

IF power = OFF THEN
  RAM = EMPTY
ENDIF

IF ROM = EMPTY THEN
  OUTPUT "Cannot start up"
ENDIF

IF hasROM AND hasRAM THEN
  computerWorks = TRUE
ENDIF

Section E: Spot the Error

C — The operating system is copied into RAM, not ROM. ROM is read-only and holds only the start-up instructions. It should say 'bootloader loads OS into RAM'.

A — ROM is non-volatile, so it keeps its contents when the power is off. That is why it can hold the start-up instructions. It should say 'ROM keeps data without power'.

B — RAM is empty when the computer is first switched on, so the start-up instructions must come from ROM. It should say 'run start-up from ROM'.

D — Once the computer is running, the OS and programs in use are held in RAM. ROM only holds the fixed start-up instructions. It should say 'CPU runs programs from RAM'.

C — ROM is read-only, so a computer with only ROM could not store changing programs and data in use. It should say 'it cannot hold changing data'.