Key term
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
Boolean Logic and Simplification
- 7 subtopics
- 21 things to know
- Component 1
What Boolean Logic and Simplification covers
Boolean Logic and Simplification is examined in Component 1, Programming and System Development. It covers AND, OR and NOT truth tables, XOR, NAND and NOR truth tables, truth tables for combined Boolean expressions, boolean identities and rules, de Morgan's laws, simplifying Boolean expressions and logical operators in programs, masking and encryption.
The 7 subtopics
Each one has its own page.
- AND, OR and NOT truth tablesTruth table, output of an AND operation and output of an OR operation.Open →
- XOR, NAND and NOR truth tablesOutput of an XOR operation, output of a NAND operation and output of a NOR operation.Open →
- Truth tables for combined Boolean expressionsBuilding the table for an expression with several operators: 2ⁿ rows for n inputs, listed in binary counting order, with an intermediate column for each part of the expression.Open →
- Boolean identities and rulesIdempotent laws, complement laws and double negation law.Open →
- De Morgan's lawsDe Morgan's first law, de Morgan's second law and procedure for applying De Morgan's laws.Open →
- Simplifying Boolean expressionsGeneral strategy for simplifying a Boolean expression and redundant term in a Boolean expression.Open →
- Logical operators in programs, masking and encryptionBit mask and how XOR provides a simple form of encryption.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
How are OR and NOT written in Boolean algebra?
Key term
Describe the output of an XOR operation.
Key term
How is a truth table built for a compound expression?
Key term
State the identity law for OR with 0.
Key term
State De Morgan's first law.
Key term
Why is a Boolean expression simplified?
Key term
How is AND used in a program condition?
Key term
Describe the output of a NAND operation.
Numbers
How many rows are needed for a truth table with four inputs?
Key term
State the identity law for AND with 1.
Key term
State De Morgan's second law.
Key term
Simplify A.B + A.NOT B.
Key term
How is OR used in a program condition?
Key term
What is a truth table?
Key term
Describe the output of a NOR operation.
Key term
Why are intermediate columns useful in a truth table?
Key term
State the null law for AND with 0.
Process
Describe the procedure for applying De Morgan's laws.
Key term
Simplify A + A.B.
Key term
How is NOT used in a program condition?
Take Boolean Logic and Simplification further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
NAND vs AND
NAND: true except when both inputs are true. AND: true only when both inputs are true.
AND masking vs OR masking
AND masking: clearing the chosen bits by combining them with 0. OR masking: setting the chosen bits by combining them with 1.
Logical addition vs Arithmetic addition
Logical addition: an operation in which 1 combined with 1 gives 1. Arithmetic addition: an operation in which 1 combined with 1 gives 10.
Questions from this topic
Each one with the model answer underneath.
- 1
What is a truth table?
Model answer
A truth table lists every possible combination of input values together with the resulting output. The table defines a logical operation completely.
- 2
How many rows does a truth table with three inputs need?
Model answer
A truth table with three inputs needs 8 rows. The number of rows is 2ⁿ for n inputs.
- 3
Describe the output of an AND operation.
Model answer
An AND operation gives 1 only when both inputs are 1. Every other combination of inputs gives 0.
- 4
Describe the output of an OR operation.
Model answer
An OR operation gives 1 when at least one input is 1. Only two zero inputs give an output of 0.
- 5
Describe the output of a NOT operation.
Model answer
A NOT operation inverts its single input. An input of 1 gives 0 and an input of 0 gives 1.
- 6
Give the AND truth table in words.
Model answer
The AND outputs are 0, 0, 0 and 1 for the input pairs 00, 01, 10 and 11. Only the last row gives an output of 1.
What is inside Levo
Six ways to work the same material.
Boolean Logic and Simplification revision questions
- What does Boolean Logic and Simplification cover in Eduqas A-Level Computer Science?
- 7 subtopics: and, or and not truth tables, xor, nand and nor truth tables, truth tables for combined boolean expressions, boolean identities and rules, de morgan's laws, simplifying boolean expressions and logical operators in programs, masking and encryption. Each one has its own page with questions and model answers.
- How is Boolean Logic and Simplification organised?
- By the Eduqas A500QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Boolean Logic and Simplification, on a schedule.
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