1. Which protects confidentiality when data is intercepted?
- A larger monitor
- Appropriate encryption
- Sorting records
Check the answer and reasoning
Appropriate encryption
Encryption can make intercepted content unreadable without the required key.
CS / AS level
System software and security
Operating systems schedule work, manage memory and files, and coordinate devices. Interrupts allow a processor to respond to events without continually checking every device.
Learning objectives
- Explain system software and security using a concrete example.
- Apply the worked method and justify each step.
- Recognise the limitation described in the final check.
The big idea
Operating systems schedule work, manage memory and files, and coordinate devices. Interrupts allow a processor to respond to events without continually checking every device.
Security, privacy and data integrity overlap but are not identical. Access controls, encryption, verification and backups answer distinct questions and need consistent operational policies.
Worked example
What does an interrupt usually cause the processor to do?
Follow the solution
The system preserves a return context before servicing the event according to its interrupt mechanism.
Investigate and explain
Predict the worked result before calculating. Change one input, record the new result, and explain which assumptions still hold.
Use the prediction activity below; a local model appears only where it supports this topic.
Check your understanding
2. What does an interrupt usually cause the processor to do?
- Erase RAM
- Recompile every program
- Save relevant state and run a handler
Check the answer and reasoning
Save relevant state and run a handler
The system preserves a return context before servicing the event according to its interrupt mechanism.
3. Does an encrypted backup automatically guarantee availability?
- No
- Yes
- Only for text
Check the answer and reasoning
No
Availability also requires accessible copies, keys, tested recovery and resilient storage.