Revision Lecture

Question 1

What is the need for an OS?

Answer 1

1. Controls Hardware.
2. Isolates users from the details.
3. Provides a User Interface (UI) - Including a way to navigate file systems.
4. Runs Software - Including a File System.

Question 2

What are the four OS types?

Answer 2

1. Desktop OS - Windows
2. Server OS - FreeBSD
3. Mobile OS - Android
4. Real-time OS

Question 3

What is the function of the Kernel?

Answer 3

Offers core services accessing the hardware.

Question 4

What functions are provided through the Kernel?

Answer 4

1. User Interface
2. OS Apps
3. 3rd party apps
4. CPU
5. Memory
6. Drivers - Input and Output devices

Question 5

How does the OS manage Peripherals?

Answer 5

Uses drivers to abstract details of how hardware works.

Question 6

How does the OS manage Multitasking?

Answer 6

Manages the processor to work on multiple tasks at the same time.

Question 7

How does the OS manage Security?

Answer 7

File Security, Permissions, quotas

Question 8

What is the System Call Interface in the OS?

Answer 8

A library/API to access the OS functions controlling hardware (Including network hardware)

Question 9

What OS has a massive market share in Sever OS?

Answer 9

Linux.

Question 10

What Kernel does Android use?

Answer 10

Kernel is Linux but then everything else is not. Android is Linux-based but not considered Linux.

Question 11

What Language are apps made when using Android?

Answer 11

Java

Question 12

What Kernel does iOS use?

Answer 12

Kernel is Darwin (BSD) but the OS is closed-source.

Question 13

What Language are apps made with using iOS?

Answer 13

Objective-C or Swift.

Question 14

What are the three terms associated to Multi-tasking?

Answer 14

1. Time-Slice
2. Time-Sharing
3. Modern Multitasking

Question 15

What are the features of Time-Slice when multitasking?

Answer 15

1. The amount of time a task gets to execute.

2. Typically 10-100ms

Question 16

What is the feature of Time-sharing when multitasking?

Answer 16

Old style multitasking - processes take turns to run.

Question 17

What is a file?

Answer 17

Files are abstraction mechanisms of data in disks.

Question 18

What operations can a file be manipulated with?

Answer 18

CREATE, DELETE, OPEN, CLOSE, READ, WRITE, APPEND, SEEK

Question 19

How are files organised?

Answer 19

Directories

Question 20

What is a File System?

Answer 20

A File System (FS) is a mechanism organising files in hierarchical folders (directories)

Question 21

Name 3 File Systems OS support

Answer 21

1. FAT
2. NTFS
3. Ext2fs

Question 22

What is the need for Memory Management?

Answer 22

1. Allow access to memory for individual apps.
2. Extend memory - Using Virtual memory
3. Manage the operations needed for the above.