Learn about HTML, CSS, JavaScript, search engine indexing, the PageRank algorithm and client-side and server-side processing. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 3.4 - Web Technologies Specification: Computer Science H446 Watch on YouTube : HTML CSS JavaScript Search engine indexing PageRank algorithm Server-Side & Client-Side Processing This topic looks at the languages that web pages are comprised of (HTML , CSS and JavaScript ) as well as search engines and network processing (client-side and server-side ). HTML HTML ( HyperText Markup Language ) is the standard language used to create and structure web pages . It uses tags enclosed in angle brackets to define elements on a page . A web page begins with , which contains a section for metadata , links and the

Learn about programming paradigms such as procedural language (e.g. Python), assembly language (including Little Man Computer) and object-oriented programming (OOP) language (e.g. Java). Methods of memory addressing (immediate, direct, indirect and indexed) are also covered. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 2.4 - Types of Programming Language Specification: Computer Science H446 Watch on YouTube : Programming Paradigms Procedural Language Little Man Computer Addressing Modes Object-Oriented Language Programming paradigms are different approaches to writing and structuring code to solve problems . The procedural paradigm focuses on step-by-step instructions and the use of functions to organise tasks . The assembly paradigm operates at a low level , giving direct control over hardware through processor-specific instructions . The object-oriented paradigm models programs around objects that combine data ( attributes ) and behaviour ( methods ), promoting modular and reusable design . Procedural Language A procedural programming language organises code into reusable blocks ( procedures or functions ), which perform specific tasks in a step-by-step manner . It focuses on a clear sequence of instructions that operate on data, often using variables , loops and conditionals . Examples include Python , C , Pascal and BASIC . These languages are commonly used for software development , data processing and teaching programming fundamentals as they emphasise logical structure and modular design . Assembly Language / Little Man Computer Assembly language is a low-level programming language that uses short , readable codes called mnemonics to represent machine-level instructions executed by the CPU . Each command in assembly corresponds closely to a specific hardware operation , making it highly efficient but difficult to write and maintain . It is mainly used for embedded systems , device drivers and performance-critical tasks where direct control of hardware is required . For the OCR A-Level course , you must understand and be able to write code using the 11 mnemonics of Little Man Computer ( LMC ), which is an educational form of assembly language . Modes of Addressing Memory An addressing mode in assembly language defines how the CPU should locate the data (operand ) needed for an instruction (opcode ). It tells the processor whether the data is stored directly in the instruction , in memory , or needs to be calculated using an address or register . There are four main types : Immediate addressing : The operand contains the actual data to be used , rather than a memory address. Direct addressing : The operand contains the memory address where the required data is stored . Indirect addressing : The operand contains an address that points to another memory location holding the actual data . Indexed addressing : The operand provides a base address that is adjusted by the value in an index register to find the final memory address of the data . Object-Oriented Language An object-oriented programming ( OOP ) language organises code around objects , which combine data ( attributes ) and behaviour ( methods ) into reusable units . Key features of OOP : Classes are templates from which objects are created . Classes define both attributes (data ) and methods (functions or behaviours ). Encapsulation allows data to be protected by making attributes private and providing controlled access through public methods . Inheritance enables a class to reuse or extend the attributes and methods of a parent class , promoting the reuse of code . Polymorphism allows methods or attributes to behave differently depending on the object or class that uses them . Examples of OOP languages include Java , Python , C++ and C# . These languages are widely used for large-scale software development , game development and graphical user interfaces , where modularity and code reuse are crucial . Programming Paradigms Q uesto's K ey T erms Programming Paradigms: procedural language, assembly language, object-oriented language Procedural Language: input, output, comments, variables, casting, count-controlled iteration, condition-controlled iteration, logical operators, selection, string handling, subroutines, arrays, files Assembly Language: Little Man Computer, INP, OUT, LDA, STA, ADD, SUB, HLT, DAT, BRA, BRP, BRZ Modes of Addressing Memory: immediate, direct, indirect, indexed, index register, opcode, operand Object-Oriented Language: class, method, attribute, encapsulation, inheritance, polymorphism, instantiation, constructor method, get method, set method D id Y ou K now? Python was named after the 1970s British comedy group ' Monty Python ', not the snake . Guido van Rossum created Python in the late 1980s during his Christmas holidays as a ' hobby project '. 2.3 - Software Development A-Level Topics 3.1 - Compression & Encryption

Learn how to create print statements in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 1a - Printing Printing in Python To output a message onto the screen, use the print command. Then place your message within brackets and speech marks . For example: print ( "Welcome to Python!" ) When you run the program, the text will print to the Python console: Welcome to Python! Printing Task 1 (Full Name & To Your Left) On the first line, print your first name and surname. On the next line, write another print statement to print t he name of the person (or thing) to your left. Example solution: Elsie Parker pencil case Printing over Several Lines One way of writing across multiple lines is to write several print commands like this: print ( "Welcome to...." ) print ( "Computer Science " ) print ( "Newbies!!! " ) = Welcome to .... Computer Science Newbies!!! However, when we program, we always want to make our code the most efficient it can be by using as few lines as possible . Therefore you can write \n within a printed statement to move it to the next line. Make sure you use \ and not / otherwise it will print the slash and not make a new line! print ( "Welcome to....\n Computer Science\n Newbies!!! " ) = Welcome to .... Computer Science Newbies!!! Both pieces of code display the same thing, but the second one is more efficient because it only uses one line. Printing Task 2 (Name, Colour, Movie) Use \n to write your name, favourite colour and favourite movie in only one line of code. Example solution: Matthew yellow Interstellar ⬅ Setting Up Python 1b - Comments ➡

Learn about the six programming errors - syntax, runtime (execution), linking, logical, rounding and truncation. Based on the 2020 Eduqas (WJEC) GCSE specification. 10.3: Programming Errors Exam Board: Eduqas Specification: 2020 Syntax Error A syntax error is a mistake in the grammar or spelling of the program. A syntax error will prevent the program from being compiled . Examples: Incorrect Spelling: pront ( "hello" ) Incorrect punctuation: print ( "hello" ( Execution (Runtime) Error An execution error is when the program unexpectedly stops as a result of an operation during execution . Examples: Dividing by zero: 400 / 0 Reading too far in a file: #There are 50 lines in the file line = file.readlines( ) print ( line [100] ) Logical Error Linking Error A logical error is a mistake made by the programmer - the program still works but displays the wrong output . Examples: Truncation Error Rounding Error A linking error occurs when a compiler can’t find a sub procedure (e.g. the random library in Python) that has been used. The programmer might have declared it incorrectly or forgotten to link (import) it . Examples: Spelling an import command incorrectly: import ramdon number = random.randint(1,10) Requesting a function without linking: number = random.randint(1,10) Incorrect calculation: total = num1 - num2 print (total) Incorrect variable printed: age = 16 name = "Steve" print ( "Nice to meet you" , age) A rounding error is when the program rounds a real number to a fixed number of decimal places. This results in losing some value as the number becomes less accurate . Examples: Rounding up: 80.87 = 80.9 (Inaccurate by 0.03) Rounding down: 63.4 = 63 (Inaccurate by 0.4) A truncation error is when the program truncates a real number to a fixed number of decimal places . This results in losing some value as the number becomes less accurate . Examples: Truncation to 2 decimal places: 92.13787 = 92.13 (Inaccurate by 0.00787) Truncation to 1 decimal place: 25.199876 = 25.1 (Inaccurate by 0.099876) Q uesto's Q uestions 10.3 - Programming Errors: 1. Describe and give an example of each type of error: a. Syntax Error [ 3 ] b. Execution (Runtime) Error [ 3 ] c. Logical Error [ 3 ] d. Linking Error [ 3 ] e. Rounding Error [ 3 ] f. Truncation Error [ 3 ] 2. State the error that will occur for each scenario: [1 each ] a. A command word (such as for or print) has been misspelt. b. The average speed is 120.3856 but only 120.3 is displayed. c. The cost of a meal is £47 but £40 is displayed. d. A program uses a subroutine that has not been imported. e. The height of a dog is 33.38cm but 33.4cm is displayed. f. The user wants to read line 9 of a file that only has 6 lines. g. The user's age is printed instead of their name. h. The programmer has typed print("hello"( i. A number is divided by 0. j. The program is asked to generate a random number but 'import random' has not be written. 10.2 - Stages of Compilation Theory Topics 11.1 - Impacts of Technology

Navigate between all Unit F161 (Developing Application Software) topics in the OCR Cambridge Advanced National in Computing (AAQ) specification. Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F161: Developing Application Software Certificate: Computing: Application Development (H029 / H129) Unit F161: Developing Application Software These pages are based on content from the OCR Cambridge Advanced National in Computing (AAQ) specification . Unit F161 YouTube Playlist Topic 1: Application Software Considerations 1.1 - Application Platforms 1.2 - Devices 1.3 - Storage Locations Topic 2: Data & Flow in Application Software 2.1 - Data Formats & Types 2.2 - Data Flow 2.3 - Data States Topic 3: API & Protocols 3.1 - Application Programming Interfaces (API) 3.2 - Protocols Topic 4: Application Software Security 4.1 - Security Considerations Topic 5: Operational Considerations 5.1 - Testing 5.2 - Types of Application Software Installation 5.3 - Policies Topic 6: Legal Considerations 6.1 - Legal Considerations

A complete list of tags required for students to know how to use in the 2016 Eduqas GCSE specification. Follow the links on each tag to see how to use them. Here you can find a list of tags. Click a tag to see how to use it. Tags for Eduqas GCSE:

Learn about the three elements of computational thinking - abstraction, decomposition and algorithmic thinking. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 1.1: Computational Thinking Exam Board: OCR Specification: J277 There are three key components to computational thinking (smart problem solving): Abstraction is when you ignore unnecessary information and focus only on the important facts . Abstraction is used because it simplifies a problem to make it less complex . This makes it more straightforward to understand the problem and create a solution . Decomposition is when you break a problem down into smaller tasks so that it is easier to solve . Each individual problem can be separately tested and solved . Decomposition also enables different people to work on the different parts of a larger problem that can later be recombined to produce a full solution . Algorithmic thinking is the final stage as logical steps are followed to solve the problem . The problem is broken down using decomposition into smaller problems . The required data and relevant data structures are considered using abstraction . Watch on YouTube : Abstraction Decomposition Algorithmic Thinking Q uesto's Q uestions 1.1 - Computational Thinking: 1. What does the term 'abstraction ' mean? Why is it important ? [2 ] 2. What is meant by ' decomposition '? Why is it important ? [ 2 ] 3. What is algorithmic thinking ? What does it involve? [3 ] Theory Topics 1.2 - Designing Algorithms

Learn how to split, edit and removes lines using files in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. Python 10c - REMOVE & Edit LINES Splitting a File The split command is used to split up a line of a file into different parts . The character or string in brackets after the split command is the value that will denote each split . In the example below I have split the file at each comma . Remember that Python numbering starts at 0 so the first section is 0, not 1. 0 1 2 3 The program below splits each line of the file at each forward-slash ( / ). The printed statement is the employee's first name, surname and job position. 0 1 2 3 4 Practice Task 1 Create a file (new txt document in Notepad) called movies. Type in the movie name, main actor, genre (e.g. horror), year it was released and your rating out of 10. Print just the movie name and year it released. Example solution: Deleting Lines in a File Exact Line Name The code below shows how to remove a line from a file using the exact name of the line , which will only work for short or simple files . First open the file in read move to save each line in a variable I've named lines. Then ask the user to input the exact line they want to remove (e.g. 'plum' in my example). Then open the file in write mode and use a for loop to read each line and only write it back into the file if it isn't equal to the line the user entered - such as 'plum'. The line.rstrip() command is important as it removes any spaces or empty lines that may interfere with matching the line to the input. Deleting Lines in a File Word in the Line The code below shows how to remove a line from a file if a certain word appears in that line , although this could be dangerous with large files. In my example I have written apple which has also removed pineapple! The difference from the previous program is to change the for loop so that it checks if the inputted word appears in the line . If it does appear then nothing happens (except a print statement to acknowledge it's been found). If the word doesn't appear then that line can be safely rewritten to the file . Practice Task 2 Download the trees text file. Give the user a choice of removing a specific tree or a type of tree. If they choose a specific tree then remove the line if it is an exact match (e.g. Field Maple). If they choose to remove a type of tree remove all lines that contain the name of that tree (e.g. willow) Make sure you actually check the file to see if the lines have been removed correctly! Example solution: Download the trees file: Sorting a File Sorting a file into alphabetical (or numerical ) order is a simple process. Open the file in read mode and save the lines into a list . The sort c ommand will automatically order the list of lines. If necessary, in the brackets type reverse = True to sort the list in reverse. Practice Task 3 Expand on your tree program from the previous practice task. As well as SPECIFIC or TYPE, allow the user to enter SORT to sort the tree file either in alphabetical order or reverse alphabetical order. Check the text file to see if it has been sorted correctly. You may make this a separate program from task 2 if you wish. Example solution: Editing Lines in a File Overwriting data in a file is a tricky process. The program below uses the same Employees.txt file as above but allows the user to change the address of an employee . A temporary file is created to store the lines of the employee file, but the line with the changes is replaced specifically with the new address. I have explained each line of the program to the right: When I executed the program below I entered Thomas Wynne's details and changed his address. When I opened the employees file the address had been updated : 1: Importing os allows me to rename and remove files later in the program. 3: Opens the employee file in read mode . 5 - 8: Input lines allow the user to enter the first name, surname and the person's new address. 10: A found flag is set up and set to False . 12: The for loop cycles through each line in the file. 13: Each line is split into separate parts from each / . 15: An if statement checks if the first name and surname match an employee in the file. 16: A replacement line is created by putting the original line together but with the new address. 18: The found flag is changed to True because the employee first name and surname matched . 19: A temporary file is created and opened in write mode . 20: The seek command restarts the file at line 0 . 22: The for loop cycles through each line of the employee file from the beginning. If the first name and surname match it will write the new line to the file, otherwise it will rewrite the original line . 28 & 29: Both files are closed . 31 & 32: If the names didn't match , an appropriate message is printed. 34 - 37: If the address was changed, the original file is renamed and deleted and the temp file is renamed as the original file. Practice Task 4 Use the movie file you created for practice task 1. Ask the user to enter the name of a movie. Ask them to enter an updated rating out of 10. Update the file to change the rating to the new value. Example solution: ⬅ 10b - Read & Search Files Section 10 Practice Tasks ➡

Learn about the purpose, characteristics, advantages, disadvantages, examples and client requirements of application software categories including open, closed, shareware, freeware and embedded software. Resources based on Unit F160 (Fundamentals of Application Development) for the OCR Cambridge Advanced National in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) 1.3.2 - Application Software Categories Watch on YouTube : Open Software Closed Software Shareware Freeware Embedded Software There are five application software categories you need to know : Open Closed Shareware Freeware Embedded For each software category you need to know : Its purpose and common characteristics . The types of devices the software may be used on. The advantages and disadvantages of using the software. How client requirements affect the selection of that software. Application Categories Open Software Closed Software Open (usually known as open-source ) software is developed to be freely accessible and allow users to view , modify and distribute the source code . Its purpose is to promote collaboration and customisation when developing software . Closed (or closed-source or proprietary ) software is developed and distributed by a company or individual who owns the source code . The purpose is to maintain control , generate profit and ensure a consistent user experience . Shareware Shareware is closed software that is distributed for free on a trial basis , often with limited features or time restrictions . The purpose is to let users try before they buy , encouraging them to later purchase the full version . Freeware Freeware is closed software that is completely free to use , usually without restrictions like time limits or limited features , but still owned by a developer or company . The purpose is to provide software for free while retaining control over its code and distribution . Embedded Software Embedded software is designed to run on specific hardware and perform dedicated tasks . It is usually built into devices that are not traditional computers (like washing machines or microwaves ), allowing those devices to function efficiently and potentially automatically . Q uesto's Q uestions 1.3.2 - Application Software Categories: 1. Summarise the five categories of application software in two sentences each . [5 ] 2. An independent video game company has made a short game with just three levels. Justify which application software category they should use and why . [4 ] 3. Describe the advantages and disadvantages of using embedded software . [ 4 ] WinRAR is a shareware compression tool with a 40-day free trial , but it never actually locks users out. Since 1995 , WinRAR has been downloaded an estimated 500 million times . D id Y ou K now? 1.3.1 - Application Types Topic List 1.3.3 - Application Software Types

Learn about the purpose of Green IT, the benefits for an organisation following its practice and methods of use. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 4.3 - Green IT Exam Board: OCR Specification: 2016 - Unit 2 What is 'Green IT'? ‘Green IT ’ is to use computers and IT resources in an efficient and environmentally responsible way to reduce an organisation’s carbon footprint . To 'reduce carbon footprint ' means to decrease the amount of pollution (such as CO2 ) produced by an organisation and to engage in more eco-friendly practice. Examples of Green IT Practice Global Requirements of Green IT United Nations Climate Change conferences occur every year and are attended by leaders of each country in the United Nations. The conferences establish obligations for countries to work towards reducing their carbon footprints and emissions of greenhouse gases . Whilst Green IT is not specifically mentioned in these talks, IT is a hugely important sector with large annual emissions that need to be reduced to meet the climate change limitations, such as the Paris Agreement. In the UK, the Greening Government ICT Strategy (running between 2011 and 2015) was an annual report that investigated how IT use could become 'greener' within the government . Positive consequences of this strategy included: Using more cloud storage technology , enabling fewer individual storage devices to be purchased, reducing emissions . Using social media more widely to contact voters - saving money by posting fewer letters and leaflets. Increasing the use of teleconferencing and video calls - reducing the need for unnecessary travel to meetings and avoiding the generation of heavy pollution. Q uesto's Q uestions 4.3 - Green IT: 1. What is meant by the term 'Green IT '. [3 ] 2a. Explain four ways that an organisation can follow good green IT practice . [4 ] 2b. Describe two reasons why it is beneficial to a company of following Green IT . [4 ] 3a. Why are the United Nations Climate Change conferences important ? [2 ] 3b. Describe two ways that the UK government have used Green IT . [4 ] Turn off computers , monitors and other connected devices when not in use . Adjust power options to help minimise power consumption. Use cloud storage or virtualisation to reduce the number of physical devices being bought, powered and maintained. Repair older devices rather than throwing them away. Consider if it is necessary to print a document before doing so and print only what is required . Recycle ink cartridges and paper . Donate older equipment to charities or schools for reuse . Why use Green IT? It is in an organisation's best interests to use Green IT practices for the following reasons: To become more sustainable by reducing the company's carbon footprint and positively impacting the environment . Reducing energy costs (e.g. by turning equipment off when not in use) and saving money . Improving the public image of the organisation as people are increasingly environmentally conscious and will prefer to do business with a company that follows environmentally-friendly policies. 4.2 - Global Legislation Topic List 5.1 - Data Types & Sources

Learn about different types of operating systems and the various roles that they manage, including memory, security and processing. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 2.4: Operating Systems Exam Board: OCR Specification: 2016 - Unit 1 An operating system (OS) is software that manages the resources of a computer system . The operating system is loaded by the BIOS (Basic Input / Output System). Types of Operating System Single user operating systems are found on most desktop computers, laptops and tablets where only one person will use the device at a single time. Multi-user operating systems allow more than one user to access the processor simultaneously , such as a server that users, with correct permissions , can access remotely . However, one user should not be negatively impacted by another user on the same operating system and security must be managed carefully as data may be visible to other users . Single Processor operating systems have only a single processor (CPU), which is shared between users by dividing the CPU time into time-slices and allocating one of these to each user in turn. The time-slices are very short, giving each user the impression that their programs are running continuously. Multiple Processor operating systems have more than one processor (CPU). Users still have to share processors and it is a more complicated system but performance is improved as there are fewer users per processor. Some supercomputers have thousands of processors running in parallel. Operating systems can also be off-the-shelf , open-source or bespoke . See 2.1 . What are the roles of an Operating System? Manage Input / Output Devices Receives data from input devices (e.g. a keyboard). Sends data to output devices (e.g. a monitor) in the correct format . Manage Printing Checks the printer is free then uses spooling (storing data in a queue ) to print documents in order. Manage Backing (Secondary) Storage Ensures data is stored correctly and can be retrieved from secondary storage devices (e.g. hard drive / SSD ). Organises files in a hierarchical structure. Manage Memory (RAM) Ensures that programs / data do not corrupt each other and are stored in correct memory locations . Manage Processes Ensures different processes can utilise the CPU and do not interfere with each other or crash. On most OS the tasks appear to run simultaneously . Manage Security Allows users to create, manage and delete user accounts with different permissions. Allows users to logon and change passwords . User Interface The final function of an operating system is to provide a user interface . This includes: A folder and file system is displayed and manipulated allowing for copying , searching , sorting and deleting data. Icons are displayed to represent shortcuts to applications and files. Multiple windows can be opened at the same time and switched between. The interface can be customised , such as changing font sizes and the desktop background . System settings can be accessed such as network and hardware options . Q uesto's Q uestions 2.4 - Operating Systems: 1. Describe five different roles of the operating system. Include the importance of the operating system in performing each role. [ 5 ] 2. What is the difference between single user and multi-user operating systems? [2 ] 3. What is the difference between single processing and multi-processing operating systems? [2 ] 4. Using your knowledge from 2.1 Software Types, explain two advantages and one disadvantage to a company if they decided to use a closed source operating system. [6 ] 2.3 Utility Software Topic List 2.5 Communication Methods

A key term generator to display randomised or sequential terms from the OCR GCSE Computer Science (J277) course. Filter terms by topics and 'favourite' tricky terms to focus on later. Perfect for students learning GCSE Computer Science in UK schools. GCSE Key Terms Generator If you see this message, your school may be using a strict network filter which has blocked it. The tool uses basic JavaScript and should work fine on a home network. Use this tool to check your understanding of the OCR GCSE J277 specification's key terms . OCR GCSE Homepage