A Level · Topics 16–17
Manage memory and establish trust
Explain scheduling, memory management, translation, and cryptographic trust.
Lessons distinguish AS topics 1–12 from A Level topics 13–20. Examples include Cambridge pseudocode and Python.
Share processor and memory fairly
A scheduler decides which ready process runs next. Different policies balance response time, throughput, and fairness. A time slice lets a process run for a bounded interval, but switching processes also costs time.
Virtual memory separates a process's address space from physical memory. Paging moves fixed-size units between memory and storage as needed. Excessive page faults can make a system spend more time moving pages than doing useful work.
Check identity as well as secrecy
Symmetric encryption uses a shared secret; asymmetric cryptography uses related public and private keys. A digital certificate associates an identity with a public key through a signature that must be verified against a trusted issuer.
Encrypting a connection to an impostor does not establish that the impostor is the intended service. Explain certificate validation, key protection, and the purpose of the protocol in the attack scenario. Translation and operating-system controls remain separate parts of the system.
Check yourself
What can cause virtual memory to reduce performance sharply?Show answer
Frequent page faults and repeated transfer of pages between storage and main memory can dominate execution time.
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