Availability

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Which statement best describes availability?

A Authorised users can reach data and systems when they need them

B Only the data owner can ever open a file

2. A school network is down during a Year 10 exam and students cannot log in. Which part of security is affected?

A Confidentiality

B Availability

3. Which event can reduce availability?

A A hard drive failure that takes a file server offline

B Locking a classroom door at night

4. A denial of service attack floods a school website with traffic. What does it mainly target?

A Authentication, so the attacker can guess passwords

B Availability, so real users cannot reach the site

5. True or false: A system that is secure but offline all day still has good availability.

A False

B True

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Availability		AThis describes confidentiality, not availability. Availability is about authorised users being able to reach data and systems when needed.
2Uptime: 99.9%		BAuthorised users can reach data and systems when they need them
3A school network goes down during a lesson, so students cannot open their work		CAttack: DoS -> Availability reduced
4A denial of service attack floods a server so real users cannot get in		DHardware failure can reduce availability. If a server or disk breaks, users may not be able to reach the system or data.
5Availability = keeping data secret from outsiders		EAvailability lost: network offline
6Hardware failure cannot affect availability		FThe system is working and reachable almost all of the time, which shows high availability

Definitions

Availability

Fill in the Blanks

Complete each line of code by filling in the missing parts.

uptime ← 9900 total ← 10000 availability ← uptime _ total * 100

IF serverStatus = "down" THEN _______ "Network is down" ENDIF

__ diskFailed THEN useBackup() ENDIF

IF requests _ 100 THEN blockTraffic() ENDIF

IF isAuthorised ___ systemUp THEN grantAccess() ENDIF

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A server_up = True

B if server_up = True:

C print('Log in OK')

D else:

E print('Network down')

Question 2

A uptime = 99

B target = 95

C if uptime <= target:

D print('Available')

Question 3

A disks = 2

B failed = 1

C working = disks - failed

D if working > 0

E print('Data reachable')

Question 4

A requests = 5000

B limit = 1000

C overloaded = requests < limit

D print(overloaded)

Question 5

A servers = ['A', 'B']

B for s in servers:

C print('Check', server)

D print('Backup ready')

Answer Key

Availability

Section A: Quick Questions

A — Authorised users can reach data and systems when they need them

B — Availability

A — A hard drive failure that takes a file server offline

B — Availability, so real users cannot reach the site

A — False

Section B: Match the Pairs

Availability → Authorised users can reach data and systems when they need them

Uptime: 99.9% → The system is working and reachable almost all of the time, which shows high availability

A school network goes down during a lesson, so students cannot open their work → Availability lost: network offline

A denial of service attack floods a server so real users cannot get in → Attack: DoS -> Availability reduced

Availability = keeping data secret from outsiders → This describes confidentiality, not availability. Availability is about authorised users being able to reach data and systems when needed.

Hardware failure cannot affect availability → Hardware failure can reduce availability. If a server or disk breaks, users may not be able to reach the system or data.

Section C: Definitions

Availability — Authorised users can reach data and systems when they need them, such as a school network that stays up. Attacks and hardware failure can reduce it.

Section D: Fill in the Blanks

uptime ← 9900
total ← 10000
availability ← uptime / total * 100

IF serverStatus = "down" THEN
  DISPLAY "Network is down"
ENDIF

IF diskFailed THEN
  useBackup()
ENDIF

IF requests > 100 THEN
  blockTraffic()
ENDIF

IF isAuthorised AND systemUp THEN
  grantAccess()
ENDIF

Section E: Spot the Error

B — A single = assigns a value. An if statement needs == to compare. It should be if server_up == True:

C — The system meets its availability goal when uptime is at least the target, so the operator should be >=, not <=.

D — An if statement must end with a colon. It should be if working > 0: so the data stays reachable on the working disk.

C — A denial of service flood overloads a server when requests are greater than its limit, so the operator should be >.

C — The loop variable is s, so server is not defined and causes an error. It should be print('Check', s).