Learning Zone ✕

Theory Concepts

Cryptography Computer Hardware Computer Networks Algorithms OOP Programming Binary Data Boolean Logic Database Concepts

Interactive Quizzes

View All Quizzes

GCSE Computer Science (UK)

1.1 System Architecture 1.2 Memory and Storage 1.3 Computer networks 1.4 Network security 1.5 – Systems software 1.6 – Impacts of digital technology
2.1 – Algorithms 2.2 – Programming fundamentals 2.3 – Producing robust programs 2.4 – Boolean logic 2.5 – Programming languages and IDEs

A-Level Computer Science (UK)

1.1 Contemporary processors, input, output and storage devices 1.2 Software and software development 1.3 Exchanging data 1.4 Data types, data structures and algorithms 1.5 Legal, moral, cultural and ethical issues
2.1 Elements of computational thinking 2.2 Problem solving and programming 2.3 Algorithms

Coding Challenges ✕

Python Challenges

Python Challenges - All Levels Python Challenges - Beginner Level Python Challenges - Intermediate Level Python Challenges - Advanced Level Python Turtle Challenges Solved Challenges

HTML / CSS & JavaScript

HTML / CSS & JavaScript

LMC

LMC Challenges LMC Simulator

SQL

SQL Challenges

Block Programming

BBC micro:bit Challenges Scratch Challenges

Interactive Coding Puzzles

Pirate Island Space Explorer Interactive Coding Quizzes

Online Interactive Tools ✕

Coding Tools

Online Python IDE LMC Simulator Flowchart Sudio Trace Table 101 Dashboard Difference Engine Emulator Analytical Engine Emulator

Design Tools

Network Designer Database ERD Designer

Logic Gates Circuits

Logic Gates Circuits Simulator Logic Gates Diagrams Binary Activities Karnaugh Maps

Cryptography Corner

Enigma Simulator Enigma Mission X Turing-Welchman Bombe Simulator Frequency Analysis Cipher Wheel Visual Cryptography Pigpen Cipher Encoder MRX20 Mission to Mars Cryptography Challenges

More results...

Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
post
page
◑ Python IDE Dashboard

Member's Area ✕

Register/Sign Up

Become a Member Login Your Account Solved Challenges Membership FAQ Logout

Get In Touch

About Us Contact Us Follow Us

Books Corner

101 Python Challenges 101 Extra Python Challenges

OCR H446/02 – 2.3 Algorithms

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
2.3 Algorithms - Overview / Checklist
2.3.1 Algorithms
(a) Analysis and design of algorithms for a given situation.
(b) The suitability of different algorithms for a given task and data set, in terms of execution time and space.
(c) Measures and methods to determine the efficiency of different algorithms, Big O notation (constant, linear, polynomial, exponential and logarithmic complexity).
(d) Comparison of the complexity of algorithms.
(e) Algorithms for the main data structures, (stacks, queues, trees, linked lists, depth-first (post-order) and breadth-first traversal of trees).
(f) Standard algorithms (bubble sort, insertion sort, merge sort, quick sort, Dijkstra’s shortest path algorithm, A* algorithm, binary search and linear search).

Recommended Resources

2.3.1 Algorithms
Searching & Sorting Algorithms
Bubble Sort Algorithm – Visualisation Merge Sort Algorithm – Visualisation Quick Sort Algorithm Sorting Algorithms – Visualisation Searching & Sorting Algorithms – Practice Linear Search Functions Binary Search: Guess The Number Linear vs Binary Search: Domain Name Server Challenge Bubble Sort Algorithm – Visualisation Insertion Sort Algorithm – Visualisation Sorting Algorithms – Python Code Shuffling Algorithm (Python Challenge)

Algorithms & Data Structures
– Binary Trees
Breadth-First Traversal of a Binary Tree Binary Search Tree Implementation Prime Factor Tree Algorithm Morse Code using a Binary Tree Huffman Coding Algorithm – Graphs
Air-Flight Route Planner The Social Network Food Chain and Food Web London Underground Journey Planner

– Hash Tables
Airport Lookup Check Chemical Elements Quiz

– 2D and 3D Arrays
Cinema Booking Challenge Laser Maze Game My Weekly Timetable Four in a row Challenge Noughts & Crosses Challenge Battleship Challenge Drone Display Space Invaders 2D/3D Pixel Art

– Stack & Queues
Stacks and Queues using Python The Ice Cream Stack Bracket Validator (using a Stack) Reverse Polish Notation (using a Stack)

Big O Notation

Big O Notation

The question we will try to answer in this blog post is as follows: How can we measure the effectiveness/performance of an algorithm? First let’s consider this quote from Bill Gates (Founder of Microsoft): “Measuring programming progress by lines of … Continue reading


Big O Notation – Quiz

Before completing this quiz, we invite you to revisit the main Big O Notations used to describe the time complexity and space complexity of an algorithm.. The main Big O Notations this quiz will focus on are: Take the Quiz! … Continue reading

Short Path Algorithms

Dijkstra’s Shortest Path Algorithm

Dijkstra’s Shortest Path Algorithm is an algorithm used to find the shortest path between two nodes of a weighted graph. Before investigating this algorithm make sure you are familiar with the terminology used when describing Graphs in Computer Science. Let’s … Continue reading


A* Search Algorithm

The A* Search algorithm (pronounced “A star”) is an alternative to the Dijkstra’s Shortest Path algorithm. It is used to find the shortest path between two nodes of a weighted graph. The A* Search algorithm performs better than the Dijkstra’s … Continue reading


Short Path Algorithm Practice

Before completing this task, you will need to familiarise yourself with the following 2 algorithms used to find the shortest path between two nodes of a weighted graph: Dijkstra’s Short Path Algorithm A* Algorithm Dijkstra’s Short Path Algorithm For each … Continue reading


Air Flight Route Planner London Underground Journey Planner The Social Network

OCR H446/01 – 2.2 Problem solving and programming

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
2.2 Problem solving and programming - Overview / Checklist
2.2.1 Programming techniques
(a) Programming constructs: sequence, iteration, branching.
(b) Recursion, how it can be used and compares to an iterative approach.
(c) Global and local variables.
(d) Modularity, functions and procedures, parameter passing by value and by reference.
(e) Use of an IDE to develop/debug a program.
(f) Use of object oriented techniques.
2.2.2 Computational methods
(a) Features that make a problem solvable by computational methods.
(b) Problem recognition.
(c) Problem decomposition.
(d) Use of divide and conquer.
(e) Use of abstraction.
(f) Learners should apply their knowledge of:

    backtracking
    data mining
    heuristics
    performance modelling
    pipelining
    visualisation to solve problems.

Recommended Resources

2.2.1 Programming techniques
View All Our Python Challenges View All Our Programming Quizzes

Procedural Programming
Procedural Programming Drag and Drop Sequencing, Selection and Iteration Quiz Procedural Programming Crossword Procedural Programming – Code Spotlight Parameter Passing & Scope of a Variable – Quiz Procedural Programming Concepts – Q&A Procedural Programming Terminology

Object Oriented Programming
OOP Concepts Classes & Objects OOP Quiz! OOP Terminology OOP Crossword Inheritance Q&A Encapsulation Q&A Multimedia Library (OOP) My MP3 Playlist (OOP) Shopping Basket Class

Recursive Algorithms/Challenges
Recursive vs Iterative Q&A Factorial Challenge The Climbing Stairs Puzzle Recursive vs Iterative Palindrome Checker Recursive Tree Challenge The Moroccan Spices Box Set Puzzle (using Recursion) Poem Decoding Challenge (using Recursion)

2.2.2 Computational methods
Backtracking Maze Path Finder Backtracking Magic Square Solver Backtracking Sudoku Solver Backtracking Sudoku Generator Algorithm Frog Puzzle Backtracking Algorithm Noah’s Ark Backtracking Algorithm Heuristics Approaches to Problem Solving Connect Flow Backtracking Algorithm (+ heuristics) Rush Hour Backtracking Algorithm (+ heuristics) Data Visualisation Algorithms Data Visualisation Q&A

OCR H446/02 – 2.1 Elements of computational thinking

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
2.1 Elements of computational thinking - Overview / Checklist
2.1.1 Thinking abstractly
(a) The nature of abstraction.
(b) The need for abstraction.
(c) The differences between an abstraction and reality.
(d) Devise an abstract model for a variety of situations.
2.1.2 Thinking ahead
(a) Identify the inputs and outputs for a given situation.
(b) Determine the preconditions for devising a solution to a problem.
(c) The nature, benefits and drawbacks of caching.
(d) The need for reusable program components.
2.1.3 Thinking procedurally
(a) Identify the components of a problem.
(b) Identify the components of a solution to a problem.
(c) Determine the order of the steps needed to solve a problem.
(d) Identify sub-procedures necessary to solve a problem.
2.1.4 Thinking logically
(a) Identify the points in a solution where a decision has to be taken.
(b) Determine the logical conditions that affect the outcome of a decision.
(c) Determine how decisions affect flow through a program.
2.1.5 Thinking concurrently
(a) Determine the parts of a problem that can be tackled at the same time.
(b) Outline the benefits and trade offs that might result from concurrent processing in a particular situation.

Recommended Resources

2.1.1 Thinking abstractly
Understanding Abstraction

Abstraction, Decomposition and Structure Diagrams

Any software developer, working on a new project will need to take time to step back and think before going straight into programming mode and writing their first line of code! Their first step will be to consider their new … Continue reading


Structure Diagram for an online-shop

An online-shop or e-commerce website is a complex web-based system that includes many functionalities. In order to design such a complex system. it is essential to think think abstractly to simplify the system we want to create and to break … Continue reading


2.1.2 Thinking ahead
Battle of the Knights Laser Maze Game in Python
2.1.3 Thinking procedurally
My Conversion Library Triangle Geometry Functions Circle Geometry Functions Brunel’s Engineering Algorithms Eureka! King Hiero’s Crown
2.1.4 Thinking logically

Computational Features of Video Games

If you are confident enough with your Python skills, you might feel ready to move on to the next stage and start creating your own arcade video game. To do so you will have to research and investigate existing video … Continue reading


2.1.5 Thinking concurrently

Multi-threading in Python

In this blog post we will investigate how to implement concurrent processing in a Python program to allow multiple processes to be executed concurrently. To do so will create and run multiple threads in our program and will need to … Continue reading


OCR H446/01 – 1.5 Legal, moral, cultural and ethical issues

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
1.5 Legal, moral, cultural and ethical issues - Overview / Checklist
1.5.1 Computing related legislation
(a) The Data Protection Act 1998.
(b) The Computer Misuse Act 1990.
(c) The Copyright Design and Patents Act 1988.
(d) The Regulation of Investigatory Powers Act 2000.
1.5.2 Moral and ethical Issues
The individual moral, social, ethical and cultural
opportunities and risks of digital technology:

    Computers in the workforce.
    Automated decision making.
    Artificial intelligence.
    Environmental effects.
    Censorship and the Internet.
    Monitor behaviour.
    Analyse personal information.
    Piracy and offensive communications.
    Layout, colour paradigms and character sets.

Recommended Resources

1.5.1 Computing related legislation

UK Legislation relevant to Computer Science

As a computer scientist, you need to be aware of the legislation that is relevant to the use of Computer Science related technologies. Whether you are designing a new website, creating a computer program or system or just using a … Continue reading


The Apple–FBI Encryption Dispute

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


Unveiling the World of Ethical Hacking

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


The MafiaBoy dDoS attack

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


The Hyperlink Patent Case and the Copyright, Designs and Patents Act

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


Mickey Mouse Enters the Public Domain

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


The Cadbury Ruling: Can Colours be Trademarks in the UK?

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


The Salami Hack & the Computer Misuse Act Legislation

This post is part of series of blog posts investigating different impacts of UK legislation relevant to Computer Science with a particular focus on: Data Protection Legislation Intellectual Property Protection (incl. Copyright and Trade Marks legislation) Computer Misuse Act (1990)


1.5.2 Moral and ethical Issues

The Environmental Impacts of Computer Science

This post is part of series of blog posts investigating different ethical, environmental and legal impacts of Computer Science in today’s world.


OCR H446/01 – 1.4 Data types, data structures and algorithms

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
1.4 Data types, data structures and algorithms - Overview / Checklist
1.4.1 Data Types
(a) Primitive data types, integer, real/floating point, character, string and Boolean.
(b) Represent positive integers in binary.
(c) Use of sign and magnitude and two’s complement to represent negative numbers in binary.
(d) Addition and subtraction of binary integers.
(e) Represent positive integers in hexadecimal.
(f) Convert positive integers between binary hexadecimal and denary.
(g) Representation and normalisation of floating point numbers in binary.
(h) Floating point arithmetic, positive and negative numbers, addition and subtraction.
(i) Bitwise manipulation and masks: shifts, combining with AND, OR, and XOR.
(j) How character sets (ASCII and UNICODE) are used to represent text
1.4.2 Data Structures
(a) Arrays (of up to 3 dimensions), records, lists, tuples.
(b) The following structures to store data: linked-list, graph (directed and undirected), stack, queue, tree, binary search tree, hash table.
(c) How to create, traverse, add data to and remove data from the data structures mentioned above. (NB this can be either using arrays and procedural programming or an object-oriented approach).
1.4.3 Boolean Algebra
(a) Define problems using Boolean logic.
(b) Manipulate Boolean expressions, including the use of Karnaugh maps to simplify Boolean expressions.
(c) Use the following rules to derive or simplify statements in Boolean algebra: De Morgan’s Laws, distribution, association, commutation, double negation.
(d) Using logic gate diagrams and truth tables.
(e) The logic associated with D type flip flops, half and full adders.

Recommended Resources

1.4.1 Data Types

Data Types Quiz

When using variables and constants in your programs it is important to use the correct data types. The main data types are: Integer: for whole numbers only such as 7, Float/Real: for numbers with decimals only such as 9.81, String: … Continue reading


Epoch/Unix Timestamp Converter

The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight GMT). This explains how date & time values are actually stored on computers: using an … Continue reading


Binary Logic Activities

Access a range of activities about binary logic, logic gates, truth tables and Karnaugh maps: Did you like this challenge? Click on a star to rate it! Submit Rating Average rating 4.5 / 5. Vote count: 158 No votes so … Continue reading


Access Rights using Binary Masks

Imagine a building with 8 rooms. Each room is fitted with a card reader used to give access or not to different members of staff. Each member of staff has a card giving them access to some of the rooms. … Continue reading


XOR Encryption Algorithm

The XOR Encryption algorithm is a very effective yet easy to implement method of symmetric encryption. Due to its effectiveness and simplicity, the XOR Encryption is an extremely common component used in more complex encryption algorithms used nowadays. The XOR … Continue reading


1.4.2 Data Structures
Linked Lists
Linked Lists

Binary Trees
Binary Trees Linked Lists Traversal of a Binary Tree Breadth-First Traversal of a Binary Tree Binary Expression Trees Binary Search Tree Implementation Prime Factor Tree Algorithm Morse Code using a Binary Tree Huffman Coding Algorithm Graphs
Graph Terminology Air-Flight Route Planner The Social Network Food Chain and Food Web London Underground Journey Planner

Hash Tables
Airport Lookup Check Chemical Elements Quiz

2D and 3D Arrays
Cinema Booking Challenge Laser Maze Game My Weekly Timetable Four in a row Challenge Noughts & Crosses Challenge Battleship Challenge Drone Display Space Invaders 2D/3D Pixel Art

Stack & Queues
Stacks and Queues using Python The Ice Cream Stack Bracket Validator (using a Stack) Reverse Polish Notation (using a Stack)

1.4.3 Boolean Algebra
Half Adders and Full Adders D-Type Flip Flop Circuits 4 bit Counter using Logic Gates Boolean Algebra Boolean Algebra using Logic Gates Using Karnaugh Maps to Simplify a Boolean Expresssion Karnaugh Map LED Dice using Logic Gates BCD to 7 Segment Display using Logic Gates

Further Reading…

Extra Resources
Investigate Key elements of the CPU using Logic Gates Circuits:
Logic Gates Tester Kit Creating Logic Gates using Transistors Fetching Data using Logic Gates Binary Decoder using Logic Gates 8-bit ALU using Logic Gates Binary Additions Using Logic Gates Comparison Operators using Logic Gates Digital Padlock Logic Gates Binary Subtractions Using Logic Gates Binary Shifters using Logic Gates Traffic Lights Controller using Logic Gates

OCR H446/01 – 1.3 Exchanging data

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
1.3 Exchanging data - Overview / Checklist
1.3.1 Compression, Encryption and Hashing
(a) Lossy vs Lossless compression.
(b) Run length encoding and dictionary coding for lossless compression.
(c) Symmetric and asymmetric encryption.
(d) Different uses of hashing
1.3.2 Databases
(a) Relational database, flat file, primary key, foreign key, secondary key, entity relationship modelling, normalisation and indexing.
(b) Methods of capturing, selecting, managing and exchanging data.
(c) Normalisation to 3NF.
(d) SQL – Interpret and modify.
(e) Referential integrity.
(f) Transaction processing, ACID (Atomicity, Consistency, Isolation, Durability), record locking and redundancy.
1.3.3 Networks
(a) Characteristics of networks and the importance of protocols and standards.
(b) The internet structure:

    The TCP/IP Stack.
    DNS
    Protocol layering.
    LANs and WANs.
    Packet and circuit switching.

(c) Network security and threats, use of firewalls, proxies and encryption.
(d) Network hardware.
(e) Client-server and peer to peer.

1.3.4 Web Technologies
(a) HTML, CSS and JavaScript.
(b) Search engine indexing.
(c) PageRank algorithm.
(d) Server and client side processing.

Recommended Resources

1.3.1 Compression, Encryption and Hashing
Symmetric and asymmetric encryption

Symmetric vs. Asymmetric Encryption

Cryptography is the art of encoding and decoding secret messages. Cryptographic techniques have been used for thousands of years, well before the introduction of computers, and the techniques have evolved since. (e.g. See how the Caesar Cipher was used by … Continue reading


Cryptography Challenges

Hashing Algorithms

Hashing Algorithms for Integrity Validation

Imagine working for the British Secret Services during World War 2 or during the cold war. As part of your role, you would be expected to exchange secret messages with your allies. Your messages would most likely be encrypted using … Continue reading


Hashing Algorithms for Storing Sensitive Data

More and more online systems such as e-commerce websites, online banking apps, or social networks need to access some sensitive data about you including your password, your credit card details and more recently, some biometric data (e.g. for fingerprint authentication … Continue reading


Hashing Algorithms for Memory Addressing

In this blog post, we will investigate the use of hashing algorithms to quickly locate a record in a large database. Let’s consider the database of members of a social network such as Instagram, Twitter or Facebook. Every time the … Continue reading


Luhn Algorithm UPC Barcode Check Digit Algorithm

Lossy and Lossless Compress

Lossless Compression: Huffman Coding Algorithm

The Huffman Coding algorithm is used to implement lossless compression. For the purpose of this blog post, we will investigate how this algorithm can be implemented to encode/compress textual information. The principle of this algorithm is to replace each character … Continue reading

Lossless Compression Algorithms

In this blog post, we will focus on two fundamental lossless compression techniques: dictionary encoding and run-length encoding. By implementing these methods in Python … Continue reading

Lossless Compression Poem Decoding Challenge
1.3.2 Databases
Relational Databases

Relational Databases

Tables, Records & Fields A table is a collection of records. Each record is made of fields. Each field has a data type such as String/Text, Integer, Float/Real, Boolean, Date & Time, etc. Primary Keys, Foreign Keys & Relationships The … Continue reading


Learn SQL

SQL is a language used to query a database. In other words SQL is used to filter, sort and manipulate data stored in relational databases. By completing the following activities you will learn more about the syntax of SQL and … Continue reading


Relation Databases Crossword Relational Databases – Question Time The Stolen Gemstones (SQL Task) The Bike Shop (SQL Task) The Computer Shop (SQL Task) Driving School (ERD Task) Rent-A-Bike (ERD Task) Hair & Beauty Salon (ERD Task) French Cuisine (ERD Task) web2.0 (ERD Task) EasyFlights Database (ERD Task)

Exchanging data (JSON, XML) using an API
Real Time ISS Tracker Weather Forecast API What-3-Words Localisation API Real-time Asteroid Watch Currency Converter using an API

1.3.3 Networks

Network Design

In this post we will investigate the different components needed to set up a network. We will investigate their purpose and how all the devices are connected together to create a basic network diagram/design. Your task will then to design … Continue reading


Network Design Tasks

In this post we will investigate the different components needed to set up a network. We will investigate specific customer requirements to create suitable network designs. You will use our online network design tool to create these designs using the … Continue reading


Small Office Network (Network Design Task) The Retro-Gaming Internet Café (Network Design Task) TCP/IP Protocols and Packet Switching The TCP/IP Stack: Layers & Protocols Daily Protocolometer IP Addresses (IPv4, IPv6), MAC addresses and URLs Network Design – Drag and Drop Computer Networks – Quiz Computer Networks – Terminology Computer Networks – Crossword Network Design – Quiz Computer Networks – Acronyms Computer Networks – Noughts and Crosses The Mesh Network Puzzle Wired and Wireless Connection Methods

1.3.4 Web Technologies

Client-Server Technologies in a Web-Based Application

If you are learning to build websites you will most likely have started learning about HTML, eventually CSS and JavaScript. These three languages are client-side languages which run on your computer through the web-browser. A website that only relies on … Continue reading


Search Engine Indexing and Page Rank Algorithm

Search Engines Indexing Search engines like Google maintain huge databases called “indexes” of all the keywords and the web addresses of pages where these keywords appear. When a web designer creates a new website they can contact the search engine … Continue reading


Page Rank Algorithm – Take the Quiz!

HTML, CSS and JavaScript

HTML and CSS Quizzes

Do you know your HTML tags used to create a webpage? Do you know how to use CSS to customise the look and feel of all the elements of this page? See how many HTML tags and how many CSS … Continue reading


CSS Noughts and Crosses Quiz Build your own website from scratch using HTML and CSS Extra HTML, CSS and JavaScript Challenges

OCR H446/01 – 1.2 Software and software development

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
1.2 Software and software development - Overview / Checklist
1.2.1 Systems Software
(a) The need for, function and purpose of operating systems.
(b) Memory Management (paging, segmentation and virtual memory).
(c) Interrupts, the role of interrupts and Interrupt Service Routines (ISR), role within the Fetch-Decode-Execute Cycle.
(d) Scheduling: round robin, first come first served, multi-level feedback queues, shortest job first and shortest remaining time.
(e) Distributed, embedded, multi-tasking, multi-user and Real Time operating systems.
(f) BIOS.
(g) Device drivers.
(h) Virtual machines, any instance where software is used to take on the function of a machine, including executing intermediate code or running an operating system within another.
1.2.2 Applications Generation
(a) The nature of applications, justifying suitable applications for a specific purpose.
(b) Utilities.
(c) Open source vs closed source.
(d) Translators: Interpreters, compilers and assemblers.
(e) Stages of compilation (lexical analysis, syntax analysis, code generation and optimisation).
(f) Linkers and loaders and use of libraries.
1.2.3 Software Development
(a) Understand the waterfall lifecycle, agile methodologies, extreme programming, the spiral model and rapid application development.
(b) The relative merits and drawbacks of different methodologies and when they might be used.
(c) Writing and following algorithms.
1.2.4 Types of Programming Language
(a) Need for and characteristics of a variety of programming paradigms.
(b) Procedural languages.
(c) Assembly language (including following and writing simple programs with the Little Man Computer instruction set).
(d) Modes of addressing memory (immediate, direct, indirect and indexed).
(e) Object-oriented languages with an understanding of classes, objects, methods, attributes, inheritance, encapsulation and polymorphism.

Recommended Resources

1.2.1 Systems Software

Types of Software

A computer system is made of both hardware and software. The hardware components of a computer systems are the physical components of the system and include the motherboard, the CPU, RAM and ROM and all input, output and output devices. … Continue reading


Job Scheduling Algorithms – Q&A

One of the main purpose of the Operating System is to control the hardware and more specifically the CPU. The CPU performs all the jobs/processes requested by the different applications. A scheduler is a program of the … Continue reading


Scheduling Algorithms – Python Challenge

A scheduler is part of the Operating system. It would most likely have been programmed using low-level (assembly) language. However for the purpose of this task, we are going to use a Python program to create a high-level… Continue reading


1.2.2 Applications Generation

The 4 Stages of the Compilation Process

Can you identify and describe the 4 stages of the compilation process? Task 1: Drag and Drop Complete the fill in the gaps activity below to label the 4 stages of the compilation process with for each stage their input … Continue reading


Abstract Syntax Tree Generator

In computer science, an abstract syntax tree (AST), or just syntax tree, is a tree representation of the high level source code. The compilation process consists of translating the high level source code (e.g. Java, Python, C++, FORTRAN, etc.) into … Continue reading


Reserved Keywords of the Python Language

If you have reached this page, you have probably already started to learn to code using a high-level programming language such as Python, JavaScript, C, php or Ruby. But what does “learning a new programming language” involve? Learning a programming … Continue reading


1.2.3 Software Development

Software Development Methodologies

Software development methodologies are structured approaches to the process of creating software. They provide a framework that guides business analysts, system designers, software developers, system testers and project managers through the various stages of software development, from initial concept to final product. … Continue reading

Python Challenges
1.2.4 Types of Programming Language

Assembly Language

Assembly language is a low-level programming language. Each assembly language is specific to a particular computer architecture. Assembly language uses mnemonics to represent low-level machine instructions or opcodes. Many operations require one or more operands in order to form a … Continue reading


Understanding Memory Address Modes

There are many ways to locate data and instructions in primary memory and these methods are called “memory address modes”. Memory address modes determine the method used within the program to access data either from the Cache or the RAM. … Continue reading


Object-Oriented Programming Concepts

Object-Oriented Programming (OOP) is a programming approach based on objects and classes. The object-oriented paradigm allows us to organise software as a collection of objects that consist of both data/attributes and behaviours. This programming concept appeared in the 1980s and … Continue reading

LMC Challenges
LMC Simulator LMC Mini Challenges LMC Burglar Alarm LMC 5-4-3-2-1 LMC Max Function LMC Countdown Timer LMC Higher or Lower Game LMC Finding the factors of… LMC Step Count Algorithm LMC Fibonacci Sequence LMC Triangular Numbers LMC Trace Table LMC Multiplication LMC Factorial

Procedural Programming
Procedural Programming Drag and Drop Sequencing, Selection and Iteration Quiz Procedural Programming Crossword Procedural Programming – Code Spotlight Procedural Programming Concepts – Q&A Procedural Programming Terminology

Prolog Challenges
Solving a Murder Mystery Using Prolog Sorting Hat Challenge (Prolog) Family Tree Challenge (Prolog) Food Web Challenge (Prolog)

OOP Challenges
OOP Quiz! OOP Terminology OOP Crossword Inheritance Q&A Encapsulation Q&A Classes & Objects Multimedia Library (OOP) My MP3 Playlist (OOP) Shopping Basket Class

Further Reading…

Extra Resources
UML Diagrams Solving a Zebra Puzzle using Prolog
Bubble Sort Algorithm in LMC Memory Filler in LMC Self-Modifying Code in LMC Stacks and Queues in LMC

OCR H446/01 – 1.1 The characteristics of contemporary processors, input, output and storage devices

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
1.1 The characteristics of contemporary processors, input, output and storage devices - Overview / Checklist
1.1.1 Structure and function of the processor
(a) The Arithmetic and Logic Unit; ALU, Control Unit and Registers (Program Counter; PC, Accumulator; ACC, Memory Address Register; MAR, Memory Data Register; MDR, Current Instruction Register; CIR). Buses: data, address and control: how this relates to assembly language programs.
(b) The Fetch-Decode-Execute Cycle; including its effects on registers.
(c) The factors affecting the performance of the CPU: clock speed, number of cores, cache.
(d) The use of pipelining in a processor to improve efficiency.
(e) Von Neumann, Harvard and contemporary processor architecture
1.1.2 Types of processor
(a) The differences between and uses of CISC and RISC processors.
(b) GPUs and their uses (including those not related to graphics).
(c) Multicore and Parallel systems.
1.1.3 Input, output and storage
(a) How different input, output and storage devices can be applied to the solution of different problems.
(b) The uses of magnetic, flash and optical storage devices.
(c) RAM and ROM.
(d) Virtual storage.

Recommended Resources

1.1.1 Structure and function of the processor

From transistors to micro-processors

Vacuum Tubes and Transistors: Many consider the transistor to be one of the most important inventions of all time. Though the precursors of the transistor were invented in 1907 (at the time they were not transistors yet, they were vacuum … Continue reading


The Von Neumann Processor Architecture

John Von Neumann (1903-1957) was a Hungarian-American mathematician, physicist and computer scientist and a founding figure in computer science, with significant contributions to computing hardware design. The Von Neumann architecture refers to a processor architecture which has access to a … Continue reading


The FDE Cycle… In your own words

Before completing this task, you will need to revisit the main characteristics of the Von Neumann Processor Architecture. You task is to write a description in your books or on the space provided below to describe, in your own words, … Continue reading


LMC Simulator

LMC simulators are based on the Little Man Computer (LMC) model of a computer, created by Dr. Stuart Madnick in 1965. The LMC simulator is generally used to for educational purposes, because it models a simple Von Neumann architecture computer … Continue reading


CPU Design using Logic Gates

Let’s embark on an exciting journey to dissect and understand a small, fully functional CPU made entirely of logic gates. This design serves as a proof of concept, illustrating how the main components of a CPU work together to execute a program stored in memory using the Fetch-Decode-Execute cycle. … Continue reading


1.1.2 Types of processor

RISC and CISC Processors

RISC and CISC are two computers architectures that are used by CPUs. Complete this drag and drop activity to highlight the characteristics of RISC & CISC processors. instructions several Complex Reduced Software circuitry 1 Desktop simpler Embedded devices Many clock … Continue reading


The Uses and Characteristics of Graphics Processing Units (GPUs)

A Graphics Processing Unit (GPU) is a specialised electronic circuit designed to rapidly manipulate and alter memory to perform complex calculations on large data sets and/or to accelerate the creation of images in a frame buffer intended for output to a display device. … Continue reading


1.1.3 Input, output and storage

Hardware Contest

In this hardware contest, you will be presented with two computers at a time (desktops or laptops). Your task is to compare the technical specifications of both computers and discuss and justify which computer seems to have the highest specifications. … Continue reading


Disk Scheduling Algorithms

A hard drive is a magnetic storage device consisting of several disks (a.k.a. platters) where data is stored. Each disk is divided into many concentric circular tracks. Each track contains several sectors where data is stored. When the Operating System … Continue reading


Further Reading…

Extra Resources
Input / Storage / Output Devices – Quiz Computer Hardware Crosswords Computer Hardware Acronyms Hardware Contest Embedded Systems in a smart world Wired and wireless connection methods – Quiz!

Investigate Key elements of the CPU using Logic Gates Circuits:
Logic Gates Tester Kit Creating Logic Gates using Transistors 4-Bit Program Counter using Logic Gates Fetching Data using Logic Gates Binary Decoder using Logic Gates 8-bit ALU using Logic Gates Binary Additions Using Logic Gates Binary Subtractions Using Logic Gates Binary Shifters using Logic Gates Comparison Operators using Logic Gates

UK Legislation relevant to Computer Science

Posted on by Administrator Posted in A Level Concepts, A Level Quiz, Computer Science, GCSE Concepts, GCSE Quiz, J277 - Computer Science GCSE (OCR), Quizzes, UK Legislation

As a computer scientist, you need to be aware of the legislation that is relevant to the use of Computer Science related technologies.

Whether you are designing a new website, creating a computer program or system or just using a computer in your work, you have to make sure you are always acting lawfully.

In the UK, there are three main acts that are very relevant to the use of computer science technologies:

  1. The Copyright, Designs & Patents Act
  2. The Data Protection Act
  3. The Computer Misuse Act

Let’s find out more about this legislation.

The Copyright, Designs & Patents ActThe Data Protection ActThe Computer Misuse Act

The Copyright, Designs & Patents Act

This act provides a legal means of ensuring that content creators can protect the work they have produced.

When anyone creates something, they automatically own it. This could include:

  • a picture, drawing or photograph
  • an animation, a film or a video clip
  • a sound file, podcast or music
  • a piece of text incl. an article, news report, blog post or a book
  • a video game or a computer program (e.g. source code)

When using copyrighted material, it is illegal to…

  • Make copies
  • Publish
  • Distribute
  • Sell copies

…unless you have been given permission by the copyright owner.

The Data Protection Act

The purpose of this act is to ensure our personal data is being used and dealt with sensibly.

Example of personal data:

  • Name and address
  • Date of birth
  • Employment records
  • Medical records
  • Religion/faith

This act stipulates that personal information stored on a computer system must be kept securely.

Personal data shall be processed fairly and lawfully in accordance with the rights of data subjects.

When an organisation stores personal data about individuals on a computer system, they must only store data that is relevant/necessary, accurate and up-to-date.

Personal data kept by an organisation on a computer system shall not be kept for longer than is necessary and should be deleted if it is no longer needed.

When personal data is shared with a third party, it has to be done fairly and lawfully, securely and with the permission of the data subject.

The Computer Misuse Act

The purpose of this act is to discourage people from accessing computer systems without permission (hacking) whether to intend to commit further illegal activities or not.

This acts make it illegal to access data on a computer when that material will be used to commit further illegal activity, such as fraud or blackmail.

It is also illegal to access and change the contents of someone’s files without their permission. It is therefore illegal to install a virus or other malware on someone’s computer as this is done without their consent.

UK Legislation: Drag and Drop Task

Complete the following activity to test your understanding of the three main UK legislation relevant to Computer Science.
UK Legislation – Drag and DropOpen in New Window

Types of Software

Posted on by Administrator Posted in Computer Science, Computing Concepts, GCSE Concepts, GCSE Quiz, J277 - Computer Science GCSE (OCR), Quizzes

A computer system is made of both hardware and software.

The hardware components of a computer systems are the physical components of the system and include the motherboard, the CPU, RAM and ROM and all input, output and output devices.

Software consists of the computer programs that run on hardware. They fall into three main categories:

Operating Systems


The Operating System is an essential software needed to operate a computer. The Operating System is responsible for:

  • Process Management & Multitasking: The operating system allocates CPU time to the different jobs being processed by the CPU and may allow for multitasking, enabling the end-user to work on different applications at the same time.
  • Memory Management: The Operating System allows the user to load files and applications into the primary memory (RAM) and to remove these from RAM when they are no longer needed.
  • File Management: The Operating System lets the user organise their files in a folder structure. Users can create, rename, delete or move folders, subfolders and files that will be stored by the Operating System on the secondary storage devices.
  • Providing a User Interface to allow the user to interact with the computer. On a laptop or desktop computer most Operating systems (e.g. Windows, MacOs, Linux etc.) provide a Graphical User Interface (GUI) enabling the user to open apps in separate windows, use the mouse pointer to click on menus and icons. Similar Graphical User Interfaces are also available on smartphones running an iOS or Android Operating Systems.
  • User Management: Maintaining User Accounts and Access Levels: The operating system enables users to authenticate themselves often using a username or password or, on more recent smartphones, a fingerprint scanner or facial recognition software. Once logged in, the identified user will be given access to their own files, folders and settings based on their access-level
  • Peripheral Management: Managing the hardware including input, output and storage devices: The Operating System is the only software that will communicate with the different hardware components to decide what to display on screen, where to save or retrieve a file on secondary storage, what information to send to the printer, etc…

Drivers

To enable the Operating System to communicate with a wide range of hardware peripherals from many different manufacturers it is sometimes required to install drivers which are used to teach the OS how to communicate with a specific peripheral. (e.g. When connecting a new printer or game controller, you may have to install the required driver first).

Utility Software

Utility software is specific software that performs tasks to help with maintaining the computer system, to optimise the resources and keep the system secure.

There is a wide range of utility software including:

  • File Management software to help you organise your files using folders and sub-folders, move, rename or delete files and folders.
  • Disk cleanup software to help you free up space on your hard disk, and hence improve system performance. Disk cleanup software scans your disk to locate temporary files, Internet cache files, and other unnecessary program files that you can safely delete to free up space.
  • Defragmentation software is used to reorganise/optimise how files are stored on a hard-disk drive resulting in reduced read/write time when accessing files.
  • Backup software can be used to perform regular automated backup of all your files. Taking a backup of your files can be useful in case you have lost a file or your files are corrupted.
  • File compression software is used to create compressed files or group of files to save space on your secondary storage or to save time when transferring these files across the Internet.
  • Anti-virus and Anti-malware software that scan the content of your hard-disk drive to identify and quarantine potentially infected files and other malware such as trojan horses, worms, spyware or ransomware.
  • Firewall Software can be used to scan all incoming and outgoing traffic from/to your computer and block malicious requests and potential hacking attempts.
  • Encryption software is used to encrypt sensitive information before either storing it (e.g. Password Management Software) or before sending it across the network/ the Internet

Application Software

Application software is the main software that you will want to use when on your computer, tablet or smart phone. It incudes software such as:

  • Word Processing Software,
  • Spreadsheet Software,
  • Presentation Software,
  • Graphic & Photo Editing Software,
  • Video Editing Software,
  • Web Browsers.

Most of the Apps you use on your smartphone are also examples of application software.


Types of Software – Drag and DropOpen in New Window