The operating system

Question 1

What is an operating system (OS)?

Answer 1

Software that controls hardware and software resources

Question 2

Why were operating systems developed?

Answer 2

To simplify software development by including common code needed to run computers

Question 3

What are the main functions of an OS?

Answer 3

Processor management

Question 4

What is a process?

Answer 4

A program that is currently running on a computer.

Question 5

How does the OS manage multiple processes?

Answer 5

Using a scheduler that allocates CPU time to each process based on a scheduling algorithm.

Question 6

What happens when the OS switches processes?

Answer 6

The current process is paused

Question 7

How does the OS manage processing in a multiprocessor system?

Answer 7

It distributes processes across different cores and shares processing time.

Question 8

What is a scheduling algorithm?

Answer 8

A set of rules that determines the order and time each process gets on the CPU.

Question 9

What is the role of the memory manager?

Answer 9

To track memory usage

Question 10

How does the OS keep track of memory?

Answer 10

By mapping memory to addresses and tracking which addresses are allocated to each process.

Question 11

What does the OS do with secondary storage devices?

Answer 11

Manages access to files/programs

Question 12

How does the OS support file management?

Answer 12

By offering a user-friendly system to create

Question 13

How does the OS handle I/O devices?

Answer 13

It manages requests

Question 14

What happens when an I/O device sends a critical request?

Answer 14

The OS may interrupt the current process to handle the I/O request immediately.

Question 15

How does the OS provide security?

Answer 15

By using permissions and passwords to control access to resources.

Question 16

What is the user interface provided by the OS?

Answer 16

The way users interact with the computer and receive information

Question 17

How is system software different from application software?

Answer 17

System software manages hardware and provides a platform for applications

Question 18

What are examples of system software?

Answer 18

Operating systems

Question 19

Can hardware function without software?

Answer 19

No. Hardware needs software to provide instructions and control.

Question 20

How does the OS simplify hardware-software interaction?

Answer 20

It hides hardware complexity and provides standardized access for applications.

Question 21

What determines the choice of an operating system for a task?

Answer 21

The functions that should be prioritised and the efficiency of operation for that specific task.

Question 22

What is a distributed operating system?

Answer 22

An OS that coordinates multiple networked computers (nodes) to work together as a single system.

Question 23

Why are distributed operating systems useful?

Answer 23

They are ideal for processor-intensive tasks that require more power than a single computer can provide.

Question 24

What is a multitasking operating system?

Answer 24

An OS that switches between tasks quickly

Question 25

What is a multi-user operating system?

Answer 25

An OS that allows multiple users to access the same system simultaneously while managing resources to avoid interference.

Question 26

What is a real-time operating system?

Answer 26

An OS designed to process data and respond within a guaranteed time frame

Question 27

What factors influence how processing time is allocated to tasks?

Answer 27

Time of request

Question 28

Why can't standard processing time allocation be used for all tasks?

Answer 28

Some tasks require immediate response (e.g.

Question 29

What is the role of interrupts in time-sensitive processing?

Answer 29

They allow the processor to suspend its current task and handle more urgent processes immediately.

Question 30

What is an interrupt?

Answer 30

A signal sent to the processor requesting immediate attention.

Question 31

Give examples of when an interrupt might occur.

Answer 31

- A hardware device sends data - A task is completed - A software process needs OS services - A hardware failure occurs - A timer expires

Question 32

What is an interrupt service routine (ISR)?

Answer 32

A mini-program that runs in response to a specific interrupt and processes the request.

Question 33

How does the OS handle a keypress using an ISR?

Answer 33

It detects the key via polling

Question 34

What happens to the CPU when it receives an interrupt?

Answer 34

1. Finishes current instruction 2. Saves register contents and program counter 3. Identifies and runs the appropriate ISR 4. Puts lower-priority interrupts on hold 5. Executes ISR 6. Restores saved register values 7. Resumes execution of original process

Question 35

What is the fetch-decode-execute cycle?

Answer 35

The normal cycle in which the CPU fetches

Question 36

How does an interrupt affect this cycle?

Answer 36

It temporarily halts the cycle