IB Computer Science HL · Year 2 · Lesson 34
Polling/interrupts, multitasking and resource allocation
Operating systems coordinate resources and processes; control systems sense, decide and act in the physical world.
Paper 150 minutesA1.3.4 · A1.3.5
Use Next or the arrow keys.
Today’s targets
What you need to be able to do
2 / 7
- EvaluateThe use of polling and interrupt handling
- ExplainThe role of the operating system in managing multitasking and resource allocation
A1.3.4A1.3.5
Paper 1 lensMatch the depth of every response to the command term. Previously learned content can move quickly, but retrieval must still be accurate.
Page 2 of 7
Retrieve
Rapid Recall Deck
3 / 7
Say the answer aloud before flipping. Mark secure knowledge quickly and spend time on the gaps.
- What is polling?: The CPU or controller repeatedly checks a device or condition to see whether an event has occurred.
- What is interrupt handling?: A device or event signals the CPU when attention is needed, causing the CPU to pause normal execution and run an interrupt-handling routine.
- Which factors influence a polling-versus-interrupt decision?: Event frequency, CPU overhead, power source, predictability, latency requirements, and security concerns.
- What is resource contention?: Two or more tasks compete for the same limited resource, such as CPU time, memory, a file, or a device.
- What is deadlock?: A situation where tasks wait indefinitely for resources held by one another, so none can proceed.
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A1.3.4 + A1.3.5 · Learn
Core knowledge and application
4 / 7
A1.3.4Evaluate
The use of polling and interrupt handling
Operating systems coordinate resources and processes; control systems sense, decide and act in the physical world.
Exam moveWeigh strengths and limitations in context, then reach a supported judgement.
Required detail 1Event frequency, CPU processing overheads, power source (battery or mains), event predictability, controlled latency, security concerns
Required detail 2Apply to keyboard and mouse inputs, network communications, disk input/ output operations, embedded systems, real-time systems
Explain it without notes
Evaluate: The use of polling and interrupt handling in the context of a computer running many tasks while controlling a smart device.
- Event frequency, CPU processing overheads, power source (battery or mains), event predictability, controlled latency, security concerns
- Apply to keyboard and mouse inputs, network communications, disk input/ output operations, embedded systems, real-time systems
A1.3.5Explain
The role of the operating system in managing multitasking and resource allocation
Operating systems coordinate resources and processes; control systems sense, decide and act in the physical world.
Exam moveGive the mechanism or relationship and make the reasons/causes explicit.
Required detail 1The challenges of multitasking and resource allocation, including task scheduling, resource contention and deadlock
Explain it without notes
Explain: The role of the operating system in managing multitasking and resource allocation in the context of a computer running many tasks while controlling a smart device.
- The challenges of multitasking and resource allocation, including task scheduling, resource contention and deadlock
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Apply
Transfer to a new scenario
5 / 7
ScenarioA computer running many tasks while controlling a smart device needs a design or technical decision related to today’s topic. Explain what matters and why.
- Event frequency, CPU processing overheads, power source (battery or mains), event predictability, controlled latency, security concerns
- Apply to keyboard and mouse inputs, network communications, disk input/ output operations, embedded systems, real-time systems
- The challenges of multitasking and resource allocation, including task scheduling, resource contention and deadlock
Page 5 of 7
Exam lens
Paper 1 practice
6 / 7
Build the response before checking notesUse precise terminology and match the required depth.
- Evaluate: The use of polling and interrupt handling in the context of a computer running many tasks while controlling a smart device.
- Explain: The role of the operating system in managing multitasking and resource allocation in the context of a computer running many tasks while controlling a smart device.
Self-checkAnswer the exact command term. For explain, include mechanism/reason; for compare, pair criteria; for discuss/evaluate/justify, build supported reasoning and a conclusion.
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Homework
Finish the learning cycle
7 / 7
IA — main task
Finish Criterion D evidence: development documentation, testing evidence, video planning/recording and full source-code appendix.
Syllabus — short
Complete a short Paper 1 retrieval set based on today’s topic.
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End of Lesson 34.