Systems Software and Operating Systems
Explaining how operating systems, utilities and firmware manage hardware resources, processes, memory, files, devices, users and services.
How to study A-level Computer Science
Define the problem and representation, trace the state change, justify the algorithm or architecture, then test the result against requirements, evidence and constraints.
Core concepts
Concept 1
An operating system abstracts hardware while allocating processor time, memory, devices and persistent storage.
Exam cue: Name the resource being managed and the conflict or abstraction the service resolves.
Concept 2
Process scheduling, memory management and file systems coordinate competing activities and protect state.
Exam cue: Distinguish a running process from a stored program.
Concept 3
Utilities, drivers, firmware and virtualisation support operation, maintenance and controlled access to resources.
Exam cue: Evaluate policies by responsiveness, throughput, fairness, isolation and overhead.
Risk pitfalls and guardrails
Describing an operating system only as a user interface.
Guardrail: Do not substitute a memorised definition or generic advantage until you have identified the input, state, stakeholder and constraint in the task.
Confusing multitasking with multiple processor cores.
Guardrail: Do not substitute a memorised definition or generic advantage until you have identified the input, state, stakeholder and constraint in the task.
Assuming virtual memory is simply additional physical RAM.
Guardrail: Do not substitute a memorised definition or generic advantage until you have identified the input, state, stakeholder and constraint in the task.
Memory anchors
Operating System
An operating system manages resources and provides services to programs and users.
Process
A process is a program in execution with its own state and resources.
Scheduler
A scheduler decides which ready process receives processor time.
Virtual Memory
Virtual memory uses secondary storage and address translation to extend or isolate address spaces.
Device Driver
A device driver lets the operating system control a particular class of hardware.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
What is a core purpose of an operating system?
Several ready processes compete for one processor core. What decision is made by the operating-system scheduler?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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