cs m1

How is colour represented in bitmap?

All colours are combinations of RGB

Each colour is 8 bits

Why is encryption used?

To prevent unauthorised reading of personal data

Why should devices be connected to networks?

To provide access to the internet

Share data

Communicate

Deploy/update applications

Why is wireless connectivity better?

May not have space for cables to be installed

Employees and visitors can move around the building without disconnecting

Adding new users just means giving SSiD and password

Why is data loss acceptable when using lossy compression?

Most people do not notice

People have a limited hearing range

People's brains fill in the blanks

Why is RLE not a good choice for encrypting a text file?

May increase the file size

Characters may be distributed randomly

How does the operating system use scheduling to allocate processor time?

All processes are held in a queue

Some are prioritised

Processes are switched on each clock cycle

What is the function of utility software?

Converting files

Why is the improper disposal of devices harmful to human health?

Disposal in landfill can cause harmful chemicals to leak into drinking water

If batteries are not removed they can catch fire and cause burns

What is penetration testing?

Networks are put under deliberate attack in order to identify weaknesses so they can be fixed

What checks are carried out during a code review?

Bad programming practice

Logic errors

Inefficient code

Security vulnerabilities

How does a router direct data on the internet?

Reads the data to find the recipient's adress

Has physical connections to 2 or more different networks

Holds a routing table

Stores information about IP adresses

Forwards data

Chooses the most efficient path to the next node

What is the best case for a binary search algorithm?

It is in the middle of the list

What is the worst case for a binary search algorithm?

The item is not on the list

Cloud storage

What is a mesh network topology?

Each node is connected to every other node, decentralised, self configuring

How is data stored on solid state devices?

If transistors conduct this represents 1

If they do not it represents 0

Arranged in a grid

At intersections, two transistors create a cell

By applying voltage to control gate transistors, electrons flow onto the floating gate

Creates a net positive charge that interrupts current flow

Why is a higher bit depth better for audio?

The original sound can be represented more accurately

Why is hexadecimal used?

As a short hand for binary so humans find it easier to read

How does the operating system use virtual memory?

The OS uses part of the secondary storage to act as main memory

The OS moves programs that are not needed out of main memory and stores them in secondary storage using paging

Active programs are swapped into main memory

Why is it important to review network and user policies?

Changes in technology mean that security can be improved or changes in law mean that technology must change

What is image resolution?

The number of pixels in an image per cm^2

What effect would more bits to represent an image have?