4.1 Types of software and interrupts

Question 1

Describe the difference between system software and application software.

Give an example of each software in your answer. [4]

Answer 1

• System software provides services that the computer requires, whereas application software provides services that the user requires.

System software example: Operating system

Application software example: word processor

Question 2

State which component in the computer would store both types of software when the power is turned off.

Answer 2

Secondary storage/SSD

Question 3

State the purpose of firmware

Answer 3

Permanently stores instructions (in ROM)

Question 4

Give one example of firmware

Answer 4

BIOS

Question 5

Give two examples of system software

Answer 5

• Operating system
• Utility Software

Question 6

Describe the role and basic functions of an operating system

Answer 6

• managing files
• handling interrupts
• providing an interface
• managing peripherals and drivers

Question 7

Explain why bootloader instructions are stored in ROM and not in RAM.

Answer 7

The contents of the ROM aren’t lost when the computer is turned off.

Question 8

Understand how hardware, firmware and an
operating system are required to run applications
software

Answer 8

• Applications are run on the operating system
• The operating system is run on the firmware
• The bootloader (firmware) is run on the hardware

Question 9

What’s an interrupt?

Answer 9

• An interrupt is a signal from a software program or hardware device to the CPU.

Question 10

What’s a software interrupt, and when does it occur?

Answer 10

• A software interrupt occurs when an application program terminates or requests certain services from the OS(operating system).
• A software interrupt also occurs with 3 program errors, such as when a division by zero occurs, or when two processes try to access the same memory location

Question 11

When does a hardware interrupt occur?

Answer 11

• A hardware interrupt may occur, for example, when an I/O operation is complete or when a new USB device is plugged in and detected.
• A hardware interrupt also occurs when a key is pressed on the keyboard or the mouse is moved

Question 12

How can interrupts be triggered?

Answer 12

• Interrupts are also triggered regularly by the timer to indicate that it is the turn of the next process to have processor time.
• It is because a processor can be interrupted that multi-tasking can take place.