1.2.1 - Systems Software

Question 1

What is the primary purpose of an operating system?

Answer 1

To provide an interface between the user and computer and manage low-level tasks.

Question 2

What are the eight key features provided by an operating system?

Answer 2

Memory management, Resource management, File management, Input/Output management, Interrupt management, Utility software, Security, User interface.

Question 3

What is memory management?

Answer 3

The process of sharing main memory fairly between multiple programs and applications.

Question 4

What are the three main techniques used in memory management?

Answer 4

Paging, Segmentation, Virtual Memory.

Question 5

What is paging?

Answer 5

Splitting memory into equal-sized sections called pages that can be swapped between main memory and hard disk.

Question 6

What is segmentation?

Answer 6

Splitting memory into logical-sized divisions called segments that vary in size based on program structure.

Question 7

What is virtual memory?

Answer 7

Using a section of the hard drive to act as RAM when main memory is insufficient.

Question 8

What is disk thrashing?

Answer 8

When a computer freezes due to pages being swapped too frequently between hard disk and main memory.

Question 9

What are interrupts?

Answer 9

Signals generated by software or hardware indicating a process needs attention.

Question 10

How are interrupts stored?

Answer 10

In a priority queue within an interrupt register, ordered by priority.

Question 11

When does the processor check for interrupts?

Answer 11

At the end of each Fetch-Decode-Execute cycle.

Question 12

What is the Interrupt Service Routine (ISR)?

Answer 12

A routine that handles interrupts by saving register contents and loading the appropriate response.

Question 13

What happens after an interrupt is serviced?

Answer 13

The interrupt flag is reset, and the queue is checked for more high-priority interrupts.

Question 14

What is scheduling?

Answer 14

Ensuring all programs receive fair processing time using various algorithms.

Question 15

What are the two types of scheduling algorithms?

Answer 15

Pre-emptive and Non pre-emptive.

Question 16

What is Round Robin scheduling?

Answer 16

Each job gets equal time slices in cyclic order until completion.

Question 17

What is First Come First Served scheduling?

Answer 17

Jobs are processed in the order they entered the queue.

Question 18

What is Shortest Job First scheduling?

Answer 18

Jobs are ordered by completion time, with shortest jobs first.

Question 19

What is Shortest Remaining Time scheduling?

Answer 19

Jobs are ordered by time left for completion, with least time first.

Question 20

What is Multilevel Feedback Queues?

Answer 20

Using multiple queues with different priorities for job scheduling.

Question 21

What is processor starvation?

Answer 21

When a process isn’t given adequate processor time to complete.

Question 22

What is a distributed operating system?

Answer 22

Runs across multiple devices to spread processing load.

Question 23

What is an embedded operating system?

Answer 23

Built for specific devices with limited functionality and low power consumption.

Question 24

What is a multi-tasking operating system?

Answer 24

Allows seemingly simultaneous task execution using time slicing.

Question 25

What is a multi-user operating system?

Answer 25

Allows multiple users to share one computer, typically a supercomputer.

Question 26

What is a real-time operating system?

Answer 26

Designed to perform tasks within guaranteed time frames for time-critical systems.

Question 27

What is BIOS?

Answer 27

Basic Input Output System - the first program that runs when a computer is switched on.

Question 28

What does BIOS do?

Answer 28

Runs hardware tests (POST), checks CPU clock, memory, processor, and detects external devices.

Question 29

What are device drivers?

Answer 29

Programs that allow the operating system to interact with hardware.

Question 30

Why are device drivers specific?

Answer 30

They are specific to both computer architecture and operating system.

Question 31

What is a virtual machine?

Answer 31

A software implementation of a computer system that runs intermediate code.

Question 32

What is intermediate code?

Answer 32

Code halfway between machine code and object code, independent of processor architecture.

Question 33

What are advantages of virtual machines?

Answer 33

Malware protection, running incompatible software, saving time and money on hardware.

Question 34

What is a disadvantage of virtual machines?

Answer 34

Running intermediate code can be slower than native low-level code execution.