6.2 Functions of an Operating System

Question 1

What are the four main roles an Operating System does?

Answer 1

Device Configuration
Files Management
Memory Management
Interface Platform

Question 2

What does Device Configuration mean?

Answer 2

Controls Peripheral devices connected to the computer

Question 3

What does File Management mean? [4]

Answer 3

Transfers files between main memory and secondary storage.
Manages file folders.
Allocates secondary storage space
File protection and recovery.

Question 4

What does memory management entail?

Answer 4

Allocates the use of RAM to requesting processes.

Question 5

What is the interface platform?

Answer 5

Allows the computer to run other applications.

Question 6

How does the OS achieve its roles? [6]

Answer 6

It controls peripheral devices
Manages Primary and Secondary Memory
Controls Virtual Memory
Provides an Interface
Time Slicing
Interrupt Handling

Question 7

How does the OS control peripheral devices?

Answer 7

Through drivers, which allows translation programs to translate the input/output information from the peripherals.

Question 8

How does the OS manage primary Memory?

Answer 8

The OS ensures each program runs in its allocated memory space.

Question 9

What problems could occur if the programs are not allocated primary memory space?

Answer 9

corruption and security issues

Question 10

What is the role of Virtual Memory for the OS?

Answer 10

Virtual Memory compensates for shortages in physical memory by temporarily transferring data from RAM to disk storage.

Question 11

How does the OS manage secondary Memory?

Answer 11

The OS provides structure to secondary storage called folder-structure

Question 12

What is the folder-structure?

Answer 12

it is a file system that allows the OS to store data in organised positions, and that they are secure.

Question 13

What does the User interface allow?

Answer 13

User interface allows the user to interact with the system.

User sends input/output data through the interface which sent to the correct memory address to be processed.

Question 14

What is time-slicing?

Answer 14

A time slice in a multi-user system is the set amount of processing time each user gets.

In a single-user system, a time slice is the set amount of processing time each program gets.

Question 15

Why does an OS time-slice?

Answer 15

The slices are alternately processed to give the illusion of many tasks happening at once.

Question 16

What is an interrupt?

Answer 16

a high quality task that needs the current code to stop to complete.

Question 17

What is interrupt handling?

Answer 17

The interrupt handler in the OS causes the program to stop.

Question 18

What techniques does the OS use to manage resources? [6]

Answer 18

Scheduling
Polices
Multi-tasking
Paging
Interrupt
Polling

Question 19

What is scheduling?

Answer 19

The process of assigning resources to complete the work.

Question 20

What are policies?

Answer 20

The policies is the OS telling what is to be done, and how long you have to do it.

Question 21

What are mechanisms?

Answer 21

The OS mechanism tells it how it is to be done.

Question 22

Why are policies and mechanisms separated in the OS?

Answer 22

The separation of mechanism and policy allows flexibility for the system.

Question 23

What is paging?

Answer 23

Paging is the process of moving RAM to disk storage.

Paging is carried out by the MMU (memory manager unit)

Question 24

What does interrupt allow?

Answer 24

To help prioritise important instructions.

Question 25

What is polling and why does an OS do it?

Answer 25

Polling is when the OS waits for an external device to check whether it is ready.

This allows a resource not to become overloaded

Question 26

Which is more efficient polling or interrupts?

Answer 26

Interrupts is more efficient than polling because it reduces processor usage and/or bandwidth consumption.

Question 27

What are the advantages of a dedicated OS? [3]

Answer 27

Security
Customisability
Modify Procedures

Question 28

How does a Dedicated OS make the system more secure?

Answer 28

Specific security measures for specific problems

Question 29

How does a dedicated OS allow for customisability?

Answer 29

Because it can be specifically designed for a specific purpose.

Question 30

How does a dedicated OS allow for the modifying of priorities?

Answer 30

By eliminating aspects of the OS that aren’t required. Reducing secondary storage and RAM being used.

Question 31

How does an OS hide complexity? [3]

Answer 31

Abstraction
Drive Letters
Java Virtual Machine

Question 32

How does abstraction help hide complexity?

Answer 32

Users see the hardware through the OS

This allows the user to not see certain hardware details (abstraction)

Users can’t see changes in hardware, and allow similar things to appear the same.

Question 33

What are drive letters and how do they hide complexity?

Answer 33

A ‘drive letter’ is a single alphabetical character that has been assigned to a drive or drive partition in the computer.

This allows the user to differentiate between them.

Question 34

What is a Java Virtual Machine and how does it hide complexity?

Answer 34

A JVM interprets complied binary code for a computer processor so that it can perform java instructions.

Each platform gets its own JVM so that the Java Code can run on any platform.