Process
Eduqas A-Level Computer Science A500QS
Data Structures: Arrays, Records and Hash Tables
Stacks, Queues, Linked Lists and Trees
Boolean Logic and Simplification
Algorithms, Pseudo-Code and Programming Constructs
Variables, Scope, Parameters and Identifiers
Recursion and Modular Programming
Sorting Algorithms
Searching and Shortest-Path Algorithms
Big O Notation and Algorithm Efficiency
Validation, Verification and Testing
Data Compression
Programming Paradigms and Computer Languages
Topic overviewProgramming paradigms and where each is usedProcedural programmingEvent-driven and visual programmingMark-up languagesObject-oriented programming: objects, classes and methodsAmbiguity in natural language and the standardisation of languagesBackus-Naur form and syntax diagramsHigh-level and low-level languages, and choosing one
Systems Analysis, Maintenance and Documentation
Topic overviewWaterfall, Agile and approaches to systems developmentThe feasibility study, budgets and time scalesMethods of investigationAbstraction, decomposition and data flow diagramsSelecting suitable hardware and softwareAcceptance testing and methods of changeoverPerfective, adaptive and corrective maintenanceBackup and recovery proceduresUser and maintenance documentation
System Design and Human-Computer Interaction
Software Engineering Tools and Translators
Topic overviewSoftware tools for the software engineering processSoftware packages in analysis, specification, design and testingIntegrated development environmentsDebugging toolsProgram version managementCompilers, interpreters and assemblersThe stages of compilationTranslation errors and execution errors
Computing, Society and the Law
Computer Architecture, the Processor and Assembly Language
Topic overviewHardware elements and how they are connectedVon Neumann architecture and the stored program conceptThe processor: control unit, ALU and registersTypes of memory: RAM, ROM and virtual memoryCache memory and locality of referenceThe fetch-execute cycle and its registersParallel processing and the limits to parallelisationAssembly language and executing a program
Input, Output and Secondary Storage
Topic overviewInput devices and how data is capturedOutput devices and how results are presentedChoosing input and output devices for a situationVoice input, dictation and voice print recognitionMagnetic, optical and solid state storageComparing secondary storage for a purposeDisc organisation, fragmentation and defragmentation
Networks, Protocols and the Internet
Topic overviewNetworks, LANs and WANsNetwork topologies and connection hardwareNetworking standards and the layered modelIP addressing, TCP and UDPApplication protocols: HTTP, FTP, SMTP, IMAP and DHCPHandshaking and establishing a connectionWireless hardware and wireless technologiesThe internet and connected mobile devices
Data Transmission and Network Performance
Topic overviewSerial and parallel transmissionSimplex, half duplex and full duplexMultiplexing and sharing a channelCircuit, message and packet switchingPackets, headers and packet contentsNetwork collisions and collision detectionRouting traffic on a networkCalculating transfer rates and lowest cost routes
Number Systems and Binary Arithmetic
Data Types, Characters and Floating Point
Topic overviewPrimitive data typesStorage requirements for each data typeASCII and standardised character setsUnicode and multilingual encodingFloating point form: mantissa and exponentConverting between real numbers and floating pointInteger and floating point comparedTruncation, rounding and accuracy
Files, Records and File Organisation
Topic overviewThe purpose of files in data processingFiles, records and fieldsFixed and variable length fields and recordsMaster files and transaction filesSerial and sequential file accessIndexed sequential access and multi-level indexesDirect access and hashing algorithmsOverflow handling and file reorganisationFile security, backups, generations and archiving
Databases, Normalisation and Entity Modelling
SQL, Big Data and Distributed Systems
Topic overviewQuery languages and the purpose of SQLCreating tables: CREATE TABLE, data types and keysRetrieving data with SELECT, FROM and WHEREComparison operators, IN, AND, OR and sub-queriesSorting, grouping and aggregate functionsInserting, updating, deleting and joining dataThe DBMS, the data dictionary and distributed databasesBig Data, data warehousing, data mining and predictive analytics
The Operating System and Its Modes
Topic overviewThe need for an operating system and the role of the kernelManaging peripherals, processes and memory protectionThe user interface and the layers between user and hardwareDirectory structures and file attributesUtility softwareBatch processing, real time control and real time transaction systemsTypes of operating system: single-user, multi-user, multi-tasking and multi-programmingDesigning an interface for different users and environments
Interrupts, Memory Management and Scheduling
Topic overviewWhat causes an interruptInterrupt handling and the interrupt service routineInterrupt priorities and how they are allocatedPartitioning main memoryMethods of data transfer between processor and devicesBuffers and double bufferingHigh level scheduling, processor and device allocationProcess states, time-slicing, polling and threading
Types of Software System
Data Security, Cryptography and Attack
Topic overviewOnline updating and the integrity of shared filesDangers of holding personal dataClerical procedures, access levels, passwords and write protectionCryptography: its purpose, and symmetric and asymmetric keysHashing, digital signatures and certificatesCaesar and Vernam ciphers and comparing cipher strengthBiometric technologies and their limitationsThreats, damage and contingency planningMalicious software, hacking and penetration testing
Interrupts, Memory Management and Scheduling
- 8 subtopics
- 24 things to know
- Component 2
What Interrupts, Memory Management and Scheduling covers
Interrupts, Memory Management and Scheduling is examined in Component 2, Computer Architecture, Data, Communication and Applications. It covers what causes an interrupt, interrupt handling and the interrupt service routine, interrupt priorities and how they are allocated, partitioning main memory, methods of data transfer between processor and devices, buffers and double buffering, high level scheduling, processor and device allocation and process states, time-slicing, polling and threading.
Where it is assessed
Component 2
Computer Architecture, Data, Communication and Applications.
Check the Eduqas specification ↗The 8 subtopics
Each one has its own page.
- What causes an interruptFour broad categories of interrupt, hardware failure interrupt and interrupt does a user pressing a key generate.Open →
- Interrupt handling and the interrupt service routineWhat happens immediately after the processor accepts an interrupt, interrupt service routine and interrupt vector.Open →
- Interrupt priorities and how they are allocatedThree factors that decide the priority given to an interrupt, non-maskable interrupt and danger of giving every interrupt the same priority.Open →
- Partitioning main memoryPartitioning main memory, difference between fixed and variable partitioning and internal fragmentation in a partitioned main memory.Open →
- Methods of data transfer between processor and devicesProgrammed input and output, interrupt-driven data transfer and direct memory access.Open →
- Buffers and double bufferingHow a buffer is used when reading from a disc, double buffering and buffer underrun.Open →
- High level scheduling, processor and device allocationHigh level scheduling, three aims of a scheduler and job priority.Open →
- Process states, time-slicing, polling and threadingRunning, ready and blocked, what moves a process between them, and how time-slicing, polling and threads share one processor between many processes.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
What puts a process into the blocked state, and what does the scheduler then do?
Key term
What is an interrupt?
Process
When in the fetch-execute cycle does the processor test for an interrupt?
Key term
Why do interrupts need priorities?
Key term
What is meant by partitioning main memory?
Key term
What is a buffer?
Key term
What is scheduling?
Key term
Name the four broad categories of interrupt.
Key term
Why is the current instruction completed before an interrupt is serviced?
Key term
Which kind of interrupt is normally given the highest priority?
Key term
Give two reasons main memory is partitioned.
Process
Why is data transfer between processor and peripheral a problem?
Process
Why is a buffer needed between a processor and a printer?
Key term
What is high level scheduling?
Process
Name the three basic states of a process.
Key term
Give two examples of a hardware failure interrupt.
Process
Describe what happens immediately after the processor accepts an interrupt.
Key term
State three factors that decide the priority given to an interrupt.
Key term
Explain the difference between fixed and variable partitioning.
Key term
What is programmed input and output?
Key term
Where is a printer buffer usually located?
Key term
State three aims of a scheduler.
Process
What does it mean for a process to be running?
Take Interrupts, Memory Management and Scheduling further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Buffer vs Cache
Buffer: holding data in transit between devices of different speed. Cache: holding copies of data likely to be needed again.
Time-slicing vs Priority scheduling
Time-slicing: sharing the processor by the clock. Priority scheduling: choosing by importance, and most systems combine the two.
Masking vs Priority
Masking: disabling an interrupt entirely for a time. Priority: only deciding the order in which pending interrupts are served.
Questions from this topic
Each one with the model answer underneath.
- 1
What is an interrupt?
Model answer
An interrupt is a signal sent to the processor asking it to suspend its current work. The processor deals with the event and then resumes what it was doing.
- 2
Name the four broad categories of interrupt.
Model answer
The four categories are hardware failure, program error, input or output, and timer interrupts. Each category names the source of the signal rather than its urgency.
- 3
Give two examples of a hardware failure interrupt.
Model answer
A failure of the power supply raises a hardware interrupt. A memory parity error raises a second kind.
- 4
Give two events that generate an input or output interrupt.
Model answer
A printer signalling that it has run out of paper generates an input or output interrupt. A disc drive reporting a completed transfer does the same.
- 5
What is a timer interrupt used for?
Model answer
A timer interrupt is generated at fixed intervals by a hardware clock. The operating system uses it to end the time slice of the running process.
- 6
Give three program errors that raise an interrupt.
Model answer
An attempt to divide by zero raises an interrupt. An illegal instruction and an address outside the process's own memory do the same.
What is inside Levo
Six ways to work the same material.
Interrupts, Memory Management and Scheduling revision questions
- What does Interrupts, Memory Management and Scheduling cover in Eduqas A-Level Computer Science?
- 8 subtopics: what causes an interrupt, interrupt handling and the interrupt service routine, interrupt priorities and how they are allocated, partitioning main memory, methods of data transfer between processor and devices, buffers and double buffering, high level scheduling, processor and device allocation and process states, time-slicing, polling and threading. Each one has its own page with questions and model answers.
- How is Interrupts, Memory Management and Scheduling organised?
- By the Eduqas A500QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Interrupts, Memory Management and Scheduling, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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