A Level · Topics 14–15
Compare protocols and processor designs
Connect switching, parallel execution, virtualization, and Boolean simplification.
Lessons distinguish AS topics 1–12 from A Level topics 13–20. Examples include Cambridge pseudocode and Python.
Explain the communication tradeoff
Circuit switching reserves a path for a communication session. Packet switching shares links among packets and may use different routes. Compare setup needs, capacity use, and delay variability for the scenario instead of treating one method as universally superior.
A protocol defines messages and behavior, not merely a port number. Explain how naming, addressing, delivery, and application protocols cooperate when a user accesses a service. Secure transport adds protection but does not repair an application's incorrect permissions.
Reason about execution resources
Parallel processing divides suitable work across execution resources, but dependencies and communication limit speedup. A virtual machine provides an execution environment separated from the underlying physical details, with a cost in management and resource use.
For a logic expression, simplify using Boolean identities and confirm equivalence with a truth table. De Morgan's law changes both the operator and the negation: NOT(A AND B) equals NOT A OR NOT B. Test all input combinations, not only one convenient case.
Check yourself
Why does doubling the number of processors not guarantee half the execution time?Show answer
Sequential dependencies, communication, synchronization, and overhead can limit parallel work.
References used to build these lessons
We used these official documents as references when building this course's lessons. They are the sources for the syllabus structure and course requirements.
Cambridge International · 9618 · Exams 2027–2029