Assessment 4

Question 1

List three functions other than memory management, of an operating system

Answer 1

Provides a user interface

Provides security

Manages hardware/peripherals

Question 2

What is the name of the memory management technique in which the operating system divides the memory into equally sized chunks?

Answer 2

Pagination

Question 3

Describe how the operating system would use virtual memory to load a program there is not enough space for

Answer 3

The operating system uses an area of secondary storage as virtual memory

And moves unused pages of programs currently in memory to virtual memory

Then loads the program there wasn’t enough space for into physical memory

Question 4

Explain what happens when a search engine indexes a page

Answer 4

A program called a crawler traverses the web and takes each word in the document

It adds an entry for the page under the word in the index, alongside the word’s position on the page

Question 5

Explain why using a RISC processor rather than a CISC one is likely to result in increased battery life

Answer 5

RISC has a smaller instruction set than CISC and as such requires fewer transistors. This means less power is required.

Question 6

Give two reasons why an operating system may be stored in ROM

Answer 6

It cannot be accidentally overwritten or deleted

It will not be lost when the device is switched off

Question 7

Describe one advantage to a company of using a RISC processor in a product rather than a CISC processor

Answer 7

Costs less to produce because there are fewer transistors

Question 8

Describe what is meant by a peer to peer network

Answer 8

Devices on the network have equal status and share data

Question 9

Give one disadvantage of using cloud storage to store photos

Answer 9

Potentially vulnerable to hacking

Question 10

What are secondary keys used for?

Answer 10

To search for information

Question 11

What is First Normal Form?

Answer 11

When a database has:

No repeating fields/data

Data is atomic

Data has a primary key

Question 12

What is Second Normal Form?

Answer 12

When a database is:

In First Normal Form

And where every field is dependent on the primary key

Question 13

What is Third Normal Form

Answer 13

When there are no transitive relationships

Question 14

What is a primary key

Answer 14

A unique identifier

Question 15

What is a hash?

Answer 15

A result generated by applying an algorithmic process to a value

Question 16

What is are advantages of storing passwords as hashes?

Answer 16

Hash functions are one way

If someone gains access to a database of password they cannot access users’ passwords

Question 17

What are SQL SELECT related keywords?

Answer 17

SELECT

UPDATE

SET

WHERE

FROM

AND

Question 18

What is referential integrity?

Answer 18

Ensuring changes are consistent across a database

If a record is removed all references to it are also removed

Question 19

What is a server?

Answer 19

A device which provides a central point of control

Question 20

Why is it important for transactions to be checked server-side?

Answer 20

Client side processing can be modified

To prevent malicious code such as SQL injection

Question 21

Why is it important for transactions to be checked server-side?

Answer 21

Client side processing can be modified

To prevent malicious code such as SQL injection

Question 22

What is meant by the term ‘Atomic’ in the context of ACID transactions?

Answer 22

A transaction cannot partially complete

Question 23

What do the letters in ACID stand for

Answer 23

Atomic

Consistency

Isolation

Durability

Question 24

Give an advantage and disadvantage of changing character sets from ASCII to Unicode UTF-32

Answer 24

Advantage: More characters can be represented

Disadvantage: Text takes up more storage

Question 25

What is a WAN?

Answer 25

A Wide Area Network - a network between two different geographical locations in which devices are connected to share data

Question 26

Why are protocols important on a network?

Answer 26

Protocols control the rules of a network

Protocols allow devices to communicate by ensuring all devices follow the same rules

Question 27

State the name of the four layers of the TCP/IP stack

Answer 27

Application

Transport

Internet

Network Interface

Question 28

What is the TCP/IP stack?

Answer 28

Stands for Transmission Control Protocol/Internet Protocol

Protocols are a set of rules for communicating across a network

Question 29

Give one disadvantage of using ASCII rather than Unicode

Answer 29

Characters from different languages can’t be represented

Question 30

What is compression?

Answer 30

The process of making a file snaller

Question 31

The following sequence has been compressed using Run Length Encoding:

3C3M4C

Show the result of decompressing the sequence

Answer 31

CCCMMMCCCC

Question 32

Show the result of using Run Length Encoding to compress the sequence CCCCOLLLCCCCCMOCCCCC

Answer 32

4C1O3L5C1N1O5C