System software 1.2.1

Question 1

What is meant by an Operating system(OS)?

Answer 1

Software that manages computers, and allows humans to use them.

Question 2

Describe the features of Operating system.

Answer 2

Held in permanent memory
Loaded by the Basic Input Output System (BIOS)
Manages the computer’s hardware.

Question 3

What are the five roles of an operating system?

Answer 3

Memory management
Interrupt service routines
Processor scheduling
Backing store management
Input / Output management

Question 4

What is meant by backing store management?

Answer 4

Allocating addresses in secondary memory.
Modifying and deleting data in secondary memory.

Question 5

Describe the function of a driver?

Answer 5

Allow a computer system to interface with new hardware.

Question 6

What is meant by memory management?

Answer 6

Allocating, tracking, and deleting data on primary memory.

Question 7

What is physical location?

Answer 7

A register on a hardware device.

Question 8

What is logical location?

Answer 8

A position in an algorithm or process.

Question 9

Describe the functions of paging?

Answer 9

Memory is divided into 4Kb sections.
Processes can be stored across several pages.
Pages can be loaded / dumped as needed.

Question 10

What is meant by segmentation?

Answer 10

Dividing memory logically according to program needs.

Question 11

Describe the functions of segmentation?

Answer 11

Memory is divided into sections of variable length.
Sections can be loaded individually.

Question 12

What is meant by an interrupt?

Answer 12

A signal to the CPU to change the process it is completing.

Question 13

Describe the process of interrupt?

Answer 13

Interrupt signal received.
Stores values of registers for current task.
Completes interrupt service routine.
Restores previous task.

Question 14

Examples of interrupts?

Answer 14

Power failure
Clock (scheduled) interrupt
Input / Output requests

Question 15

Define Processor scheduling?

Answer 15

Assigning different tasks to a CPU at different times to give the appearance of multi-tasking.

Question 16

What are the 5 examples of processor scheduling?

Answer 16

First come First Served
Shortest Remaining Time
Shortest Job First
Round robin
Multi-level feedback queues

Question 17

What is the basic input output system(BIOS)?

Answer 17

Initialises system hardware and loads the operating system.
Communicates hardware errors

Question 18

Describe the functions of a Multi Tasking System?

Answer 18

Runs on a standalone computer. Performs multiple tasks at the same time. e.g. Windows 10

Question 19

Describe the functions of a multi-user multi tasking system?

Answer 19

A single powerful computer connected to multiple terminals. Each user gets a slice of CPU time.

Question 20

Describe the functions of a distributed operating system?

Answer 20

A parallel processing system that performs tasks across multiple computers and servers, but appears to the user as a single interface.
e.g. The school network
It allows each device to do what it does best.

Question 21

Describe the function of a real-time operating system?

Answer 21

An OS that responds very quickly to inputs. Deals with many inputs simultaneously. Incorporates redundancy.
It must not stop even if there’s an error.

Question 22

What is meant by an Embedded Operating Systems?

Answer 22

An OS built into another device.

Question 23

What are the features of an Embedded Operating Systems?

Answer 23

Usually very simple.
Limited RAM, little if any secondary storage.
Few inputs / outputs.

Question 24

What is meant by a virtual machine?

Answer 24

Software that imitates an operating system on another machine.

Question 25

State the uses of virtual machine.

Answer 25

Use a portion of the real operating system’s resources.
Test suspicious software / files.
Test software in specific environments.