Systems software

Question 1

What is paging?

Answer 1

Paging is when memory is split up into equal sized sections known as pages.

Question 2

What is segmentation?

Answer 2

Splitting up memory into logical sized divisions known as segments, which vary in size.

Question 3

What is virtual memory?

Answer 3

Virtual memory is when there isn’t enough RAM left so part of the hard drive is used to act like RAM

Question 4

What is the interrupt service routine?

Answer 4

The processor checks the contents of the interrupt register at the end of every Fetch Execute Decode cycle. If there is a high enough priority interrupt the interrupt is scheduled.

Question 5

How does the Round Robin scheduling algorithm work?

Answer 5

Each job is given an equal section of processor time to execute, even if the job is not finished it will still move to the next job at the end of the time slice.

Question 6

How does first come first serve scheduling work?

Answer 6

Jobs are processed in the order that they come in at, they are completed in full.

Question 7

How do multilevel feedback scheduling queues work?

Answer 7

Jobs are given a priority level and are executed in the order of priority.

Question 8

How does shortest job first scheduling work?

Answer 8

The shortest task is done first until completion.

Question 9

How does shortest time remaining scheduling work?

Answer 9

The shortest job is done first, if a shorter tasks joins the queue then that will be take priority and be completed.

Question 10

What are the different types of operating system?

Answer 10

Distributed, embedded, multitasking, multiuser, real-time.

Question 11

What is a distributed OS?

Answer 11

A type of operating system that runs across multiple devices allowing the load to be separated across multiple computers processors

Question 12

What is an embedded OS?

Answer 12

An embedded OS has a small range of specific tasks that can be completed, with the OS being catered towards a specific device.

Question 12

What is an embedded OS?

Answer 12

An embedded OS has a small range of specific tasks that can be completed, with the OS being catered towards a specific device.

Question 13

What is a multitasking OS?

Answer 13

A multitasking OS enables the user to carry out tasks seemingly simultaneously. It uses time slicing to switch between programs and applications in memory.

Question 14

What is a multiuser OS?

Answer 14

When more than one user can use one computer, (a scheduling algorithm is used so every user gets fair time)

Question 15

What is a real time OS?

Answer 15

A real time OS completes tasks in a guaranteed timeframe

Question 16

What is applications software?

Answer 16

A software designed to be used by the end user to perform one specific task.

Question 17

What is systems software?

Answer 17

Low level software that is responsible for running the computer system smoothly

Question 18

What does a translator do?

Answer 18

A translator converts high level source code into low level object code which is ready to be executed by a computer. There are 3 different translators all of which slightly different.

Question 19

What is a compiler?

Answer 19

Compilers translate high level language into machine code all at once.

Question 20

What is an interpreter?

Answer 20

Interpreters translates and executes code line by line.

Question 21

What is an assembler?

Answer 21

An assembler translates assembly code into machine code.

Question 22

What different stages are used when translating code into machine code?

Answer 22

Lexical analysis, syntax analysis, code generation, optimisation.

Question 23

What happens in lexical analysis?

Answer 23

Whitespace and comments are removed from code.
Keywords and variables are replaced with a token.

Question 24

What happens in syntax analysis?

Answer 24

Tokens are analysed against the grammar and rules of the programming language. Any tokens that break the syntax rules are flagged as syntax errors.

Question 25

What happens in code generation?

Answer 25

The machine code is created.

Question 26

What happens in the optimisation stage?

Answer 26

The code is checked to see if there are any areas that could be made more efficient.

Question 27

What stages are there in the waterfall lifecycle?

Answer 27

ADIEM:
Analysis
Design
Implementation
Evaluation
Maintenance

Question 28

What are the benefits and drawbacks of the waterfall lifecycle? When will it be used?

Answer 28

Advantages:
Straightforward to manage
Clearly documented
Disadvantages:
Lack of flexibility
No risk analysis
Limited user involvement
When to be used:
Static, low risk projects which require little user involvement

Question 29

What are the stages in the agile methodology?

Answer 29

ADIF
Analysis
Design
Implementation
Feedback

Question 30

What are benefits and drawbacks of the agile methodology?
When will it be used?

Answer 30

Advantages:
Produces high quality code
Flexible to change user requirements
Regular user input

Question 31

What are the stages of the spiral model?

Answer 31

ADIE
Analysis
Design
Implementation
Evaluation

Question 32

What are the benefits and drawbacks of the spiral model?
When will it be used?

Answer 32

Advantages:
Thorough risk analysis and mitigation.
Caters to changing user needs
Produces prototypes throughout
Disadvantages:
Expensive to hire risk assessors
Lack of focus on code efficiency
High costs due to constant prototyping
Where will it be used:
Large, risk intensive projects with a high budget.

Question 33

What is Rapid application development?

Answer 33

RAD is an interactive methodology which uses partially functioning prototypes which are constantly reviewed and built upon.

Question 34

What are the benefits and drawbacks of RAD?
When will it be used?

Answer 34

Advantages:
Caters to changing user requirements
Highly useable finished product
Focus on core features, reducing development time.
Disadvantages:
Poorer quality documentation
Fast pace may reduce code quality
When will it be used:
Small to medium, low budget projects with short time frames.