Frequently asked questions about CSNewbs including content, the creator and contact. Frequently Asked Questions about Computer Science Newbies What is CSNewbs? CSNewbs (standing for Computer Science Newbies ) is an educational website and YouTube channel that contains information about a range of computing topics . It is primarily aimed at British GCSE and A-Level specifications , but is also relevant for all years and locations . It covers all necessary content from relevant specifications , but breaks it down so it is easier to understand and gets straight to the point . It is made by just one person , but updates are frequent . Which courses does CSNewbs cover? The ' Year 10 & 11 ' section follows the OCR J277 specification and Eduqas specification ( 2020 edition ) . The ' Year 12 & 13 ' section follows the OCR A-Level H446 specification and OCR Cambridge Advanced Nationals in Computing specification for Application Development . There is also content for the now-finished Cambridge Technicals IT course. The ' Programming ' section contains material for Python , HTML , Greenfoot and others. The ' Year 7, 8 & 9 ' section covers basic Computer Science topics including computer components and cybersecurity. Is the site linked to any exam boards? CSNewbs is not affiliated with any exam board , financially or in any other way . The content on this site has been independently created by closely manually analysing (no AI ) the publicly released specifications by exam boards such as Eduqas and OCR and their previous exams and mark schemes. How was this website made? CSNewbs.com was created and is maintained using Wix . What's the deal with copyright? CSNewbs is protected by copyright , and some copy / paste features have been disabled on the site. All images have either been self-created or used from Wix's copyright-free vector gallery / their stock image library / or with a licence from Noun Project . Embedded videos are linked to content from the CSNewbs YouTube page. Will other exam boards be added? The site continues to expand over time with new content . The eventual aim is to cover every exam board for GCSE and A-Level Computer Science but that will take a lot of time! Why is something on the site not working at my school? Your school's IT administrators may have blocked some elements such as JavaScript or embedded YouTube videos . The videos can be watched directly on YouTube (if not blocked on your school network). Who is the robot? The robot is called Questo . It's the site logo and appears on some pages to ask questions about the content (' Questo's Questions ') or to display key terms . What else? If you work for an exam board or educational resource organisation , and your organisation has opportunities available , please send me an email. I have previously done work for Educake . How can I contact the creator of CSNewbs? The contact email is: Privacy Policy

Learn about data structures including arrays, records, lists, tuples, linked-lists, graphs, stacks, queues, trees, binary search trees and hash tables. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 4.2 - Data Structures Specification: Computer Science H446 Watch on YouTube : Arrays Records Lists & tuples Stacks Queues Linked lists Trees Graphs Hash tables Data structures are used to organise and store data so it can be accessed and processed efficiently , often through the use of an index or reference . They can be static , meaning their size is fixed during program execution , or dynamic , allowing them to grow or shrink as data changes . Arrays An array is a data structure that stores a collection of items of the same data type , with each item accessed using an index . A one-dimensional (1D ) array is a simple sequence of values , such as test scores for a single person : scores = [12, 15, 18, 20] . A two-dimensional (2D ) array is like a table or grid , made up of rows and columns - for example, storing a timetable or test scores for a class . A three-dimensional (3D ) array stores data in multiple layers , like a series of 2D grids . For example, test scores for a class across multiple subjects . This page is under active development. Check here for the latest progress update. YouTube video uploading soon Records A record groups together related but different types of data under one name . Each individual piece of data within a record is called a field and each field can have a different data type (e.g. string , integer , Boolean ). For example, a student record might include fields such as Name (string ), Age (integer ) and Enrolled (Boolean ). Records are often used in databases or programming to represent real-world entities where multiple attributes need to be stored together . YouTube video uploading soon Lists & Tuples A list stores an ordered collection of items , which can be changed (mutable ) after creation. Items in a list can be added , removed or modified , and they can be of different data types . For example, in Python : myList = [10, "apple", True] . A tuple is similar to a list but is immutable , meaning its contents cannot be changed once created . Tuples are often used for fixed sets of data that should not be altered , such as coordinates or dates . For example: myTuple = (3, 5, 7) . YouTube video uploading soon Stacks A stack stores data in a last in , first out (LIFO ) order, meaning the most recently added item is the first one to be removed . It works much like a stack of plates - you can only add or remove from the top . Two integral functions are push and pop . The push operation adds (or “pushes”) a new item onto the top of the stack . The pop operation removes (or “pops”) the item from the top of the stack . Stacks are commonly used in undo features , function calls and expression evaluation , where tracking the most recent item first is important . YouTube video uploading soon Queues A queue stores items in a first in , first out (FIFO ) order, meaning the first item added is the first one removed . New items are added at the rear of the queue using an enqueue operation, and items are removed from the front using a dequeue operation. Queues are often used in task scheduling , print spooling and data buffering , where operations must occur in the same order they were requested . YouTube video uploading soon Linked Lists A linked list is a dynamic data structure made up of a series of elements called nodes , where each node contains data and a pointer to the next node in the sequence . Unlike arrays, linked lists do not store elements in contiguous memory locations , making it easy to insert or delete items without having to shift other elements . The head is the first node in the list , and the last node usually points to null , indicating the end of the list . YouTube video uploading soon Trees A tree is a hierarchical data structure made up of nodes connected by branches , starting from a single root node . Each node can have child nodes , and nodes without children are called leaf nodes . Trees are useful for representing data with natural hierarchies , such as file systems or organisational charts . A binary search tree is a special type of tree where each node has at most two children - a left and a right . All values in the left subtree are smaller than the parent node , and all values in the right subtree are larger . This structure allows for efficient searching , insertion and deletion of data , often much faster than in lists or arrays . YouTube video uploading soon Graphs A graph is made up of nodes (also called vertices ) connected by edges and is used to represent relationships between items. Graphs can be directed , where edges have a specific (one-way) direction , or undirected , where connections go both ways . They can also be weighted , where edges have values such as distance or cost , or unweighted , where all connections are equal . Graphs are widely used in computing, for example, in social networks (users and friendships ), maps (locations and routes ) and network routing algorithms . YouTube video uploading soon Hash Tables A hash table stores key–value pairs and allows for very fast data access . It uses a hash function to convert a key (such as a name or ID ) into an index (hash value ), which determines where the associated data (value ) is stored in memory . When retrieving data , the same hash function is applied to the key to find the value’s location instantly , making lookups close to constant time complexity on average . If two keys produce the same hash (a collision ), techniques such as chaining or linear probing are used to handle it . Hash tables are commonly used in databases , caches and programming languages for tasks like fast searching and indexing . YouTube video uploading soon Q uesto's K ey T erms Arrays: array, 1-dimensional, 2-dimensional, 3-dimensional, static Records: record, field, data type, primary key Lists and Tuples: list, tuple, mutable, immutable, dynamic Stacks and Queues: stack, queue, last in first out (LIFO), first in first out (FIFO), push, pop, enqueue, dequeue, pointer Linked Lists: linked list, null Trees & Graphs: tree, binary tree, binary search tree, root node, branch, graph, weights, directions Hash Table: hash table, key, value, collision, linear probing, chaining D id Y ou K now? Trees are used for dialogue options in narrative video games , displaying possible paths based on the player’s previous choices . The final ' suicide mission ' of Mass Effect 2 has hundreds of possible variations depending on ship upgrades , squad member loyalty , and assigned roles during the last mission . 4.1 - Data Types A-Level Topics 4.3 - Boolean Algebra

Learn about the motherboard, graphics processing unit (GPU), sound card, embedded systems and input / output systems. Based on the 2020 Eduqas (WJEC) GCSE specification. 1.6: Additional Hardware Exam Board: Eduqas Specification: 2020 1.6a - Internal Hardware Motherboard The motherboard is the main circuit board of a computer , unique for each device. It holds and connects the different components together , allowing data to be transferred between them. Components such as the CPU and ROM are directly attached to the motherboard. The motherboard has expansion slots for additional cards (i.e. sound cards) and ports (i.e. USB). Graphics Processing Unit (GPU) Sound Card A GPU is a microprocessor that performs complex calculations to generate graphical images to be displayed on a monitor . There are two types of GPU, integrated GPUs within the motherboard circuitry or dedicated GPUs on an additional card (known as a 'graphics card'). An integrated GPU is cheaper and generates less power because it uses the RAM of the computer . Integrated GPUs are used in tablets and laptops as they generate less heat and are optimal for general computing uses (e.g. web browsing or watching movies). A dedicated GPU is more expensive and generates more heat, often requiring a fan because it contains its own memory . Dedicated cards are used by animation professionals and professional gamers who require the best graphics. Sound cards convert analogue sound waves into digital data (binary) when inputting audio through a microphone. 0010 1011 0101 0101 0110 0111 0101 0001 0101 0010 1011 0101 0101 0110 0111 0101 0001 0101 Sound cards also convert digital data (binary) into analogue sound waves to output audio through speakers or headphones. 1.6b - Embedded Systems Example: A washing machine has a control chip that manages the different program cycles. An embedded system is a computer system built into a larger machine to provide a means of control . Embedded systems perform a specific pre-programmed task which is stored in ROM . An embedded system uses a combination of hardware and software . Example: A traffic light has a control chip that determines when to change to a green or red light. 1.6c - Input & Output Devices Input devices are used by humans to interact with a computer system , through methods such as text , voice or touch . Output devices show the result of computer processing , such as sound , printed text or a visual display on a monitor. Storage devices , such as a USB stick or an external hard drive, are neither input nor output devices - see 1.4 . Input Devices These are just some of the more common input devices . A mouse and a keyboard have been described in further detail. Are there any devices below you haven't heard of before? Mouse Benefits: Easy to navigate a graphical user interface. A wireless mouse takes up less space . Faster to select options (e.g. in a video game). Drawbacks: Difficult to use for people with restricted hand movement . Difficult to use on some surfaces . Other input devices: Scanner Controller Microphone Webcam Chip Reader OCR Scanner OMR Scanner Barcode Scanner Graphics Tablet Sensors (e.g. light or temperature) Touch Screen Remote Control Biometric Scanner (e.g. fingerprint or iris) Concept Keyboard Sip / Puff Switch Keyboard Benefits: Quick to input text . Easy to use with a familiar layout on most keyboards. Keys can be customised and shortcuts can be used . Drawbacks: Takes up a large amount of space on a desk. Difficult for people to use with restricted hand movement or poor eyesight . Output Devices Monitor These are just some of the more common output devices . A monitor and a printer have been described in further detail. Are there any devices below you haven't heard of before? Other output devices: Plotter Speakers Projector Alarm Light Headphones Touch Screen Braille Terminal What is it? A monitor is required to see the result of human input and computer processing . Monitors can be bought in different sizes and resolutions for a range of purposes such as video editing or playing games . Monitors settings can be changed to alter the brightness or contrast . Printer What is it? A printer uses ink or toner to print a document (such as text or images) onto paper . Inkjet printers use ink cartridges , are generally slower and print in a lower quality . Laser printers use toner cartridges and are generally quicker and print to a higher quality . Q uesto's Q uestions 1.6 - Additional Hardware: 1.6a - Internal Hardware 1. What is the purpose of the motherboard ? [2 ] 2a. What is the purpose of the GPU ? [ 2 ] 2b. Describe two differences between integrated and dedicated expansion cards . [ 4 ] 3. Explain how a sound card works. [ 4 ] 1.6b - Embedded Systems 1. What is an embedded system ? [3 ] 2a. Give two examples of an embedded system. [ 2 ] 2b. Research and describe another example of an embedded system. [ 2 ] 1.6c - Input & Out[ut Devices 1. Choose four input devices and describe at least two benefits and two drawbacks of using each one. [ 8 ] 2. Describe three output devices . [ 3 ] 3. Justify which input and output devices would be most suitable in the following scenarios: a. A teacher needs to take the class register . [ 4 ] b. A family want to communicate with their cousins in Australia. [ 4 ] c. The school movie club wants to play Star Wars in the assembly hall. [ 4 ] d. An e-sports player is taking part in an online multiplayer tournament . [ 4 ] e. A laboratory needs security so that only registered scientists can enter. [ 4 ] 1.5 - Performance 2.1 - Logical Operators Theory Topics

Homepage for learning about computer science in school. Discover topics across GCSE and Level 3 IT subjects, plus programming languages including Python, HTML and Greenfoot. C omputer S cience P ros Official 2026 CSPros: Henry C Rohan Finlay Adam Chantel Olivia Jessie Kelvin Lucas Gajanan Danny Marcus José Claudia Charlie Ryan Harry Ethan Henry P Yash Marcus Thomas Walter Folu Asher Pippa Zach Leighton Jess James Holly Zac Ryan 2025 CSPros: Jack Harry Aarav Trisha Mario Hiba Rory Clark Lucy Divya Luke Callum James Zoya Timucin Matthew 2024 CSPros: 2023 CSPros: Henry Zain Iman Alex I-C Alex B Tomos Aidan Rahul Hussain Diyar Sam Harry Will Alex H 2022 CSPros: Logan Eleanor Mark Edward Alfie Henry Enzo Sam George Harry Ella Kav

Navigate between all topics in the OCR A-Level Computer Science H446 specification. Includes all topics from Component 1 (Computer Systems) and Component 2 (Algorithms and Programming). OCR Computer Science A-Level These pages are based on content from the OCR H446 Computer Science specification . This website is in no way affiliated with OCR . Component 1: Computer Systems Paper 1 Playlist on YouTube This content is under active development. Check here for the latest progress update. OCR A-Level Key Term Generator 1. Hardware 1.1 - Structure & Function of the Processor (The CPU) 1.2 - Types of Processor 1.3 - Input, Output & Storage 2. Software 2.1 - Systems Software 2.2 - Applications Generation 2.3 - Software Development 2.4 - Types of Programming Language 3. Networks & Databases 3.1 - Compression, Encryption & Hashing 3.2 - Databases 3.3 - Networks 3.4 - Web Technologies 4. Data & Logic 4.1 - Data Types 4.2 - Data Structures 4.3 - Boolean Algebra 5. Laws 5.1 - Computing-Related Legislation 5.2 - Moral & Ethical Issues Component 2: Algorithms & Programming 1. Computational Thinking 1.1 - 1.5 - Computational Thinking 2. Problem Solving & Programming 2.1 - Programming Techniques 2.2 - Computational Methods 3. Algorithms 3.1a - 3.1d - Algorithm Complexity 3.1e - Data Structure Algorithms 3.1f - Standard Algorithms

Learn about the denary, binary and hexadecimal number systems and how to convert between them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.8 & 1.9 - Number Systems & Conversion Exam Board: OCR Specification: 2016 - Unit 1 What is binary? What is denary? Denary (also known as decimal ) is the number system that you've been using since primary school. Denary is a base 10 number system. This means that it has 10 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 . How to convert from binary to denary: How to convert from denary to binary: What is hexadecimal? Hexadecimal is a base 16 number system. This means that it has 16 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F . Hexadecimal is used as a shorthand for binary because it uses fewer characters to write the same value . This makes hexadecimal less prone to errors when reading or writing it , compared to binary. For example, 100111101011 is 9EB. Hexadecimal only uses single-character values. Double-digit numbers are converted into letters - use the table on the right to help you understand. How to convert from binary to hexadecimal: How to convert from hexadecimal to binary: Converting from denary to hexadecimal / hexadecimal to denary To convert from denary to hexadecimal or the other way round you must convert to binary first . Denary > Binary > Hexadecimal Hexadecimal > Binary > Denary Use the videos on this page if you need help converting to or from binary. The most common number systems question in exams are from denary to hexadecimal or from hexadecimal to denary so make sure that you practice these conversions. Q uesto's Q uestions 1.8 & 1.9 - Number Systems: 1. Explain why hexadecimal numbers are used as an alternative to binary . [ 2 ] 2. Convert the following values from binary to denary : a. 00101010 b. 11011011 c. 01011101 d. 11101110 e. 01011111 [1 each ] 3. Convert the following values from denary to binary : a. 35 b. 79 c. 101 d. 203 e. 250 [1 each ] 4. Convert the following values from binary to hexadecimal : a. 11110101 b. 01100111 c. 10111010 d. 10010000 e. 11101001 [1 each ] 5. Convert the following values from hexadecimal to binary : a. C2 b. 8A c. DE d. 54 e. F7 [1 each ] 6. Convert the following values from denary to hexadecimal : a. 134 b. 201 c. 57 d. 224 e. 101 [1 each ] 7. Convert the following values from hexadecimal to denary : a. 32 b. A5 c. 88 d. C0 e. BE [1 each ] Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube By now you should know that computer systems process data and communicate entirely in binary . Section 1.7 explained different binary storage units such as bits (a single 0 or 1), nibbles (4 bits) and bytes (8 bits). Binary is a base 2 number system. This means that it only has 2 possible values - 0 or 1 . Click the banners above to try self-marking quizzes (Google Form) on these topics. Denary to Binary: Binary to Denary: Binary to Hexadecimal: Hexadecimal to Binary: 1.7 - Units of Measurement Topic List 2.1 Software Types

Learn about the elements of a data flow diagram and factors that may disrupt them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 5.2 - Data Flow Diagrams Exam Board: OCR Specification: 2016 - Unit 2 A data flow diagram is a visual representation of how data is transferred within a system or organisation . Data flow diagrams are often abbreviated to just 'DFD '. You will need to recognise the symbols , understand the diagrams and explain how data flow can be affected . Data Flow Diagram Symbols The common symbols used in a DFD are shown below: External Entity (e.g. Employee, Customer) Alternative DFD symbols you may see on the exam paper (both sets of symbols have been accepted in previous exam papers): Process (e.g. Calculate Pay, Review Application) Data Store (e.g. Staff Database, Customer Database) External Entity Process Data Store Data Flow Level 0 data flow diagrams show the transfer of data in a simple manner . Processes may be generalised and not shown separately , for a more basic overview . Below is an example of a Level 0 DFD to show the process of an employee submitting an application to be promoted : Level 1 data flow diagrams show the transfer of data in a more detailed manner . Processes are shown separately , for a more complex and realistic overview . Below is an example of a Level 1 DFD to show the process of an employee submitting an application to be promoted . The individual processes have been expanded from the Level 0 DFD above to show how the application must first be signed off by an administrator before it is reviewed by management: Rules for Drawing a Level 1 DFD Data flows only in one direction . Every data flow is labelled (with the data itself , not the action). Every data flow connects to at least one process . At least one input or output for each external entity . Impacts Affecting the Flow of Information There are several reasons why the flow of information within an organisation may be delayed or inefficient , such as: Information characteristics e.g. information is entered incorrectly, causing delays. Human error e.g. information is lost or staff don't follow protocol. Hardware failure e.g. network connection breaking or system failure. Communication breakdown e.g. meetings postponed or emails unread. Q uesto's Q uestions 5.2 - Data Flow Diagrams: 1. Draw the symbols for the four parts of a data flow diagram . [4 ] 2. Look at the image of the Level 1 DFD . State one example of: An external entity A process A data flow A data store [1 each ] 3. Give one difference between a Level 0 and Level 1 DFD . [2 ] 4. State three rules for drawing a correct data flow diagram . [3 ] 5. After heavy snow, a school has decided to shut for the next two days. Many parents were not informed of this decision and are angry that they brought their children in. Give three reasons why the transfer of data (the data being a message about school closure) might not have flowed efficiently in this example. [6 ] 1 Level 0 Data Flow Diagram Level 1 Data Flow Diagram 5.1 - Data Types & Sources Topic List 6.1 - Security Principles

Learn about different forms of cyber attacks online including malware, SQL injection, DoS attacks and social engineering. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 4.1: Security Threats Exam Board: OCR Specification: J277 Watch on YouTube : Malware Social Engineering, Brute-Force & DoS Interception & SQL Injection Types of Malware Malware is any type of harmful program that seeks to damage or gain unauthorised access to your computer system. Virus A virus can replicate itself and spread from system to system by attaching itself to infected files . A virus is only activated when opened by a human . Once activated, a virus can change data or corrupt a system so that it stops working . Worm A worm can replicate itself and spread from system to system by finding weaknesses in software . A worm does not need an infected file or human interaction to spread. A worm can spread very quickly across a network once it has infiltrated it. Trojan A trojan is a harmful program that looks like legitimate software so users are tricked into installing it . A trojan secretly gives the attacker backdoor access to the system . Trojans do not self replicate or infect other files. Spyware Spyware secretly records the activities of a user on a computer. The main aim of spyware is to record usernames, passwords and credit card information . All recorded information is secretly passed back to the attacker to use. Keylogger A keylogger secretly records the key presses of a user on a computer. Data is stored or sent back to the attacker. The main aim of a keylogger is to record usernames, passwords and credit card information . Keyloggers can be downloaded or plugged into the USB port . Ransomware Ransomware locks files on a computer system using encryption so that a user can no longer access them. The attacker demands money from the victim to decrypt (unlock) the data . ? ? ? ? Attackers usually use digital currencies like bitcoin which makes it hard to trace them. SQL Injection SQL ( Structured Query Language ) is a programming language used for manipulating data in databases . A SQL injection is when a malicious SQL query (command) is entered into a data input box on a website. If the website is insecure then the SQL query can trick the website into giving unauthorised access to the website’s database . An SQL injection can be used to view and edit the contents of a database or even gain administrator privileges . DoS Attack A DoS (Denial of Service ) attack is when a computer repeatedly sends requests to a server to overload the system . A server overload will slow the system and may take websites offline temporarily. A DDoS (Distributed Denial of Service ) attack is a coordinated attack using a botnet of infected systems to overload a server with requests . A botnet is a large group of devices controlled and used maliciously by an attacker. Brute-Force Attack Every possible combination is tested in order from start to finish . This is not a quick method but it should break the password eventually and can be sped up if multiple computer systems are used at the same time. Social Engineering Social engineering means to trick others into revealing their personal data by posing as a trusted source . For example, impersonating an IT technician of a school via email and asking for a student's username and password . Data Interception This is when data packets on a network are intercepted by a third party (e.g. a hacker) and copied to a different location than the intended destination. Software called packet sniffers are used to intercept and analyse data packets. Q uesto's Q uestions 4.1 - Security Threats: 1. What is malware ? [ 2 ] 2a. Describe three characteristics of a virus . [3 ] 2b. Describe three characteristics of a worm . [3 ] 2c. What is a trojan ? [ 3 ] 2d. Describe how spyware and keyloggers work. [ 4 ] 2e. Explain how ransomware works and why it is difficult to trace attackers . [ 3 ] 2f. In your opinion, which malware do you think is the most dangerous and why ? [ 2 ] 3. Describe what an SQL injection is and how an attacker would use it. [ 3 ] 4a. Describe what a DoS attack is and its impact . [2 ] 4b. Describe how a DDoS attack is different to a DoS attack . [2 ] 5a. Describe a brute-force attack. [ 2 ] 5b. Describe social engineering and give an example of when it might be used . [2 ] 5c. Describe interception . [2 ] 3.2b - Protocols & Layers Theory Topics 4.2 - Preventing Vulnerabilities

Learn about required internal hardware including the CPU, motherboard and PSU. Find out about ports and expansion cards. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.2 Computer Components Exam Board: OCR Specification: 2016 - Unit 1 This page describe the various components inside of computer systems . The first three are necessary in every type of computer: Processor Motherboard Power Supply Unit The main role of a processor is to manage the functions of a computer system by processing data and instructions . The primary processor of each computer system is the Central Processing Unit ( CPU ). A processor is attached to the motherboard using a connection point called a CPU socket . The motherboard is the main circuit board of a computer on which components such as the CPU and ROM are connected . The motherboard contains PCI slots for expansion cards and ports for external devices to be connected . The power supply unit (PSU ) converts electricity from AC (Alternating Current) from the mains power supply to DC (Direct Current) which the computer system can use . The PSU of desktop computers is internal whereas portable devices require an external 'charger '. Memory Computer memory is split into two types - volatile and non-volatile . Volatile storage is temporary (data is lost whenever the power is turned off ). Non-volatile storage saves the data even when not being powered , so it can be accessed when the computer is next on and can be stored long-term . Random Access Memory (RAM) Read-Only Memory (ROM) Cache Memory RAM is volatile (temporary) storage that stores all programs that are currently running . RAM also stores parts of the operating system to be accessed by the CPU. RAM is made up of a large number of storage locations, each can be identified by a unique address . ROM is non-volatile storage that cannot be changed . ROM stores the boot program / BIOS for when the computer is switched on. The BIOS then loads up the operating system to take over managing the computer. Cache memory is volatile (temporary) storage that stores frequently accessed data . It is very quick to access and faster than other types of memory like RAM because it is stored on the processor itself. RAM ( R andom A ccess M emory) ROM ( R ead O nly M emory) Cache Memory Secondary Storage Magnetic Storage Optical Storage Optical Storage Characteristics: X - Low CAPACITY : 700 MB (CD ), 4.7 GB (DVD ), 25 GB (Blu-ray ). X - Not DURABLE because discs are very fragile and can break or scratch easily. ✓ - Discs are thin and very PORTABLE . X - Optical discs have the Slowest ACCESS SPEED . Magnetic Disks are spelled with a k and Optical Discs have a c. Magnetic Storage Characteristics: ✓ - Large CAPACITY and cheaper per gigabyte than solid state . X - Not DURABLE and not very PORTABLE when powered on because moving it can damage the device. ✓ - Relatively quick ACCESS SPEED but slower than Solid State . Optical storage uses a laser to project beams of light onto a spinning disc, allowing it to read data from a CD , DVD or Blu-Ray . This makes optical storage the slowest of the four types of secondary storage. Disc drives are traditionally internal but external disc drives can be bought for devices like laptops. A magnetic hard disk drive (HDD ) is a common form of secondary storage within desktop computers. A read/write head moves nanometres above the disk platter and uses the magnetic field of the platter to read or edit data. Hard disk drives can also be external and connected through a USB port . An obsolete (no longer used) type of magnetic storage is a floppy disk but these have been replaced by solid state devices such as USB sticks which are much faster and have a much higher capacity. Another type of magnetic storage that is still used is magnetic tape . Magnetic tape has a high storage capacity but data has to be accessed in order (serial access ) so it is generally only used by companies to back up or archive large amounts of data . Solid State Storage Cloud Storage When you store data in 'the cloud ', using services such as Google Drive, your data is stored on large servers owned by the hosting company . The hosting company (such as Google) is responsible for keeping the servers running and making your data accessible on the internet . Cloud storage is typically free for a certain amount of storage and users can buy more storage space when they need it - the scalable nature of this storage type makes it very flexible for businesses. Cloud storage is very convenient as it allows people to work on a file at the same time and it can be accessed from different devices . However, if the internet connection fails , or the servers are attacked then the data could become inaccessible . Cloud storage is also known as 'virtual storage ' because the data is saved remotely , freeing up physical storage space for users on their own devices . There are no moving parts in solid state storage . SSD s (Solid State Drives ) are replacing magnetic HDDs (Hard DIsk Drives) in modern computers and video game consoles because they are generally quieter , faster and use less power . A USB flash drive ( USB stick ) is another type of solid state storage that is used to transport files easily because of its small size. Memory cards , like the SD card in a digital camera or a Micro SD card in a smartphone , are another example of solid state storage. Solid State Characteristics: X - High CAPACITY but more expensive per gigabyte than magnetic . ✓ - Usually DURABLE but cheap USB sticks can snap or break . ✓ - The small size of USB sticks and memory cards mean they are very PORTABLE and can fit easily in a bag or pocket. ✓ - Solid State storage has the fastest ACCESS SPEED because they contain no moving parts . Cloud Storage Characteristics: ✓ - Huge CAPACITY and you can upgrade your subscription if you need more storage. ✓ / X - Cloud storage is difficult to rank in terms of PORTABILITY , DURABILITY and ACCESS SPEED because it depends on your internet connection. A fast connection would mean that cloud storage is very portable (can be accessed on a smartphone or tablet) but a poor connection would make access difficult . Storage Protocols SCSI ( Small Computer System Interface ) is a protocol (set of rules) for attaching external devices to a computer system, such as a printer, storage drive or scanner. SAS ( Serial Attached SCSI ) is an improved version of SCSI that enables many more external devices (up to 128) to be connected at the same time to a computer system. Expansion Cards Expansion cards are dedicated circuit boards with a specific purpose that are attached to the motherboard . Most of the following expansion cards can also exist as integrated components on the motherboard, rather than a separate card. Graphics Card Sound Card Processes graphical data (e.g. videos or animations) and converts it into a displayable output on a monitor . Network Interface Card (NIC) 0010 1011 0101 0101 0110 0111 0101 0001 0101 Sound cards convert analogue sound waves into digital data (binary) when inputting audio through a microphone. Sound cards also convert digital data (binary) into analogue sound waves to output audio through speakers or headphones. 0010 1011 0101 0101 0110 0111 0101 0001 0101 Allows computers to connect to networks (such as the Internet ) and enables them to transfer data to other computers. Transfers data between servers across a network. Fibre channel allows for quick transfer speeds and is primarily used to connect data storage to servers in large data centres. Fibre Channel Card Storage Controller Card Required for the computer to manage and use any attached storage devices . Ports A port is the interface between external devices and the computer . Ports allow data to be transferred from and to these devices. USB Port Connects storage devices such as USB sticks or external hard drives . Connects input devices such as a keyboard or mouse, as well as other devices for data transfer such as a camera or smartphone. Ethernet Port Connects computers to network devices such as a modem or router, allowing access to the internet . FireWire Port Developed for Apple products, FireWire transfers data at a high speed from devices such as camcorders and external hard drives . FireWire supports isochronous devices , meaning data is sent in a steady , continuous stream . SATA Port Allows fast data transfer to external HDD , SSD or optical drives . SD Port Enables data from an SD card to be transferred from a device like a camera to the computer. Micro SD Port Allows data from a micro SD card to be transferred from devices such as smartphones , tablets and handheld games consoles to a computer. Q uesto's Q uestions 1.2 - Computer Components: Vital Components: 1. Describe the purpose of the following components : a. The CPU (Central Processing Unit ) [2 ] b. The motherboard [2 ] c. The PSU (Power Supply Unit ) [2 ] Primary Memory: 2a. What is the difference between primary and secondary memory ? [2 ] 2b. What is the difference between volatile and non-volatile storage ? [2 ] 2c. For each of the three types of primary memory , describe its role and give an example of what it can store. [6 ] Secondary Storage: 3a. For magnetic , optical and solid-state storage rank these three secondary storage mediums in terms of capacity , durability , portability and speed . [9 ] 3b. For the following scenarios justify which secondary storage medium should be used and why it is the most appropriate : Sending videos and pictures to family in Australia through the post. [3 ] Storing a presentation to take into work. [3 ] Storing project files with other members of a group to work on together. [3 ] Backing up an old computer with thousands of file to a storage device. [3 ] Additional Components: 4a. State the purpose of five different expansion cards . [5 ] 4b. What is the purpose of the motherboard ? [2 ] Ports: 5a. Describe the six different ports . [6 ] 5b. What is the difference between SCSI and SAS ? [2 ] 1.1 - Computer Hardware Topic List 1.3 - Computer System Types

Learn about different types of utility software including firewall, anti-virus, defragmenter, compressor and backup software. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 2.3: Utility Software Exam Board: OCR Specification: 2016 - Unit 1 What is utility software? Utility software are dedicated programs used for the maintenance and organisation of a computer system. Antivirus Software Antivirus software is used to locate and delete viruses on a computer system. The antivirus scans each file on the computer and compares it against a database of known viruses . Files with similar features to viruses in the database are identified and deleted . There are thousands of known viruses but new ones are created each day by attackers so antivirus software must be regularly updated to keep systems secure. Other roles of an antivirus: Checking all incoming and outgoing emails and their attachments . Checking files as they are downloaded . Scanning the hard drive for viruses and deleting them . Firewall A firewall manages incoming and outgoing network traffic . Each data packet is processed to check whether it should be given access to the network by examining the source and destination address . Unexpected data packets will be filtered out and not accepted to the network. Defragmentation As files are edited over time they will become fragmented - this is when the file is split into parts that are stored in different locations on the hard disk drive . Files that are fragmented take longer to load and read because of the distance between the fragments of the file. Defragmentation software is used to rearrange the file on the hard disk drive so that all parts are together again in order. Defragmentation improves the speed of accessing data on the hard disk drive. Compression Compression is used to decrease the size of a file . This is beneficial as more files can be stored on a storage device if the size has been reduced. Compressed files can be transferred faster across a network because they are smaller in size . Monitors, Managers & Cleaners Other roles of a firewall include: Blocking access to insecure / malicious web sites . Blocking certain programs from accessing the internet . Blocking unexpected / unauthorised downloads . Preventing specific users on a network accessing certain files . Monitoring network ports . System monitors check the resources of a computer and display how much CPU time and memory current applications are using. Task managers allow a user to close processes and applications if they have stopped responding or if one is using too many resources. Press Ctrl + Alt + Delete on any Windows computer to open Windows Task Manager which is a system monitor and task manager tool. A disk cleaner is used to scan a hard disk drive and remove unused files . This is used to free up space on the hard drive. A disk scanner will scan a hard disc for any errors and attempt to repair them . Backing Up Data A backup is a copy of data that can be used if the original data is corrupted or lost . Backups of all data should be made regularly and stored in an alternative location . Alternatively, imaging (also known as disk cloning ) creates an identical image of a storage drive to be stored in a different location . Q uesto's Q uestions 2.3 - Utility Software: 1. What is the purpose of utility software ? [1 ] 2a. Describe how antivirus software works. [ 2 ] 2b. Describe 3 further roles of antivirus software . [ 3 ] 3a. What is the purpose of a firewall ? [ 2 ] 3b. Describe 3 further roles of a firewall . [ 3 ] 4a. Describe what is meant by defragmentation . [ 2 ] 4b. Explain why defragmentation software is used . [ 2 ] 5. Describe 2 benefits of using compression . [ 2 ] 6a. Explain why system monitor / task management software could be used . [ 2 ] 6b. Explain the purpose of disk cleaners and disk scanners . [ 2 ] 7a. Explain what a backup is and why they are are important. [ 2 ] 7b. Describe what imaging is. [ 2 ] 2.2 - Applications Software Topic List 2.4 - Operating Systems

Test your understanding of imported commands in Python including random and time. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python - Section 5 Practice Tasks Task One: Random Numbers Ask the user to input 4 different numbers . Put the four variables in a list with square brackets and use the choice command from section 5a to randomly select one. Example solutions: Enter number 1: 10 Enter number 2: 20 Enter number 3: 30 Enter number 4: 40 The computer has selected 30 Enter number 1: 2023 Enter number 2: 2024 Enter number 3: 2025 Enter number 4: 2026 The computer has selected 2026 Task Two: Logging In You will make a program for logging into a system. Print a greeting then ask the user for their name . Wait 2 seconds then print a simple login message with the user’s name . Then print the current time (current hour and minute ). Example solutions: Welcome to Missleton Bank Please enter your name: Steve Steveson Logging you in Steve Steveson The time is 08:02 Welcome to Missleton Bank Please enter your name: Gracie Jones Logging you in Gracie Jones The time is 15:53 Task Three: Random Wait Generate a random number between 3 and 10 to represent seconds . Print this number then print the current hour, minute and second . Wait for the random number of seconds then print the current time again. Example solutions: The random wait will be 6 seconds. The time is 08:17:57 The time is 08:18:03 The random wait will be 3 seconds. The time is 08:21:39 The time is 08:21:42 Task Four: Independence Checker Create a program that displays how many days three specific countries have been independent for. The user will choose either Fiji , Samoa or Australia and the difference between today's date and the day they become independent will be displayed. Fiji became independent on 10th October 1970 . Samoa became independent on 13th December 1962 . Australia became independent on 1st January 1901 . Use the 'Today's Date ' and 'Between Dates ' parts of Section 5c to help you get today's date , make the other three dates and find the difference . Making Samoa's independence date would be samoadate = date(1962,12,13) for example. Example solutions: Enter FIJI, SAMOA or AUSTRALIA to check how long it has been independent for: AUSTRALIA Australia has been independent for 44822 days. Enter FIJI, SAMOA or AUSTRALIA to check how long it has been independent for: FIJI Fiji has been independent for 19338 days. Task Five: Square Root Create a program that asks the user to enter a whole number . Calculate the square root of the number. Round the answer down to the nearest whole number using the floor command. Example solutions: Enter a number: 156 The rounded down square root is 12 Enter a number: 156 The rounded down square root is 12 ⬅ 5e - More Librarie s 6a - For Loops ➡

Learn about the different types of LAN, MAN and WAN networks and how to draw network diagrams. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 3.4 - Connection Methods Exam Board: OCR Specification: 2016 - Unit 1 Local Area Network (LAN) A Local Area Network (LAN ) is a network in which the computer systems are all located geographically close to each other , for example, in the same building or on the same site , like a school or office . A type of LAN is a Wired Ethernet LAN ( technically Ethernet is a protocol that controls how data is transmitted over a LAN). Wired Ethernet LANs have a high bandwidth so data can be transferred quickly and because it uses cables the data is harder to intercept than a wireless network. Metropolitan Area Network (MAN) A Metropolitan Area Network (MAN ) connects several LANs together to cover the range of a town or city , for example a university campus network. MANs are usually very efficient at providing fast communication for cities , with high connection speeds through the use of fibre optic cables. Wide Area Network (WAN) A Wide Area Network (WAN ) is a network spanning a large geographical area , such as multiple cities or countries . The internet is the ultimate example of a WAN as it stretches across the entire world. Different types of WAN rules and standards are used: ADSL ADSL ( Asymmetric Digital Subscriber Line ) is a method of transferring data across copper wire telephone lines . ADSL is contended, which means that connection speeds are affected and slowed down by more systems that use the network at the same time . The old copper wires also affect data transfer over long distances and can cause data packet loss . Security is also an issue, as the line is shared with others, making data interception more likely . To improve security, a firewall and/or VPN (Virtual Private Network) may be used. Because ADSL uses the telephone system, a modem is require d at both the sending and receiving ends of the connection. A microfilter is also required to allow internet and telephone access at the same time . ADSL is contended - shared between sites. Internet Service Provider ADSL requires a modem Leased Line Leased Line is a method of providing an uncontended , fixed-bandwidth data connection . The user maintains a dedicated connection that is more secure and, because it is uncontended , will have the same speed all of the time , regardless of how busy the network is . Bandwidth is high , security is better , the connection speed is constant and the network is full-duplex (allowing for data transmission both ways simultaneously). These advantages come at a high cost - possibly hundreds of pounds per month - as well as an expensive installation that can take time to be put in place . As it is a complex configuration , a CSU/DSU (Channel Service Unit/Data Service Unit) device is required to properly terminate the leased line . Internet Service Provider Leased Line is dedicated. C A CSU/DSU is required for a leased line. ISDN ISDN (Integrated Services Digital Network ) transmits video and voice data simultaneously over traditional copper telephone wires . This method uses a circuit-switched network where all data packets take the same route between computer systems. Voice Networks Voice networks primarily transfer audio data using phones and telephone lines . PSTN PSTN (Public Switched Telephone Network ) is the global collection of wired public telephone networks that are used to transmit data over a long distance. PSTN is fixed into position using underground cables and therefore the connection quality is much more consistent than other voice networks. Using a wired connection like a PSTN is more reliable and communication will be clearer than alternatives such as cellular or satellite methods. Cellular Cellular networks require a cell tower (also called a transmitting tower ) to be in close proximity to the communication device. Cellular networks have a greater range than PSTN, but buildings and poor weather can disrupt this point-to-point communication method (where line of sight is necessary ). Each cell tower is also connected to the PSTN . Satellite Satellite networks use point-to-multipoint communication by using satellites above the Earth's atmosphere that receive a transmission and rebroadcast them back to Earth. Because of the distance between the communication device and the satellite (potentially thousands of miles ), there is a delay between data transmission and it being received . Satellite networks are beneficial in remote locations , such as natural disaster zones , where the cell tower may not be present or may be damaged. Transmitting large files using satellites may take longer , and it is not recommended for low-latency needs such as video gaming. There are different types of satellites used in communication and networking : Geostationary satellites are used for consistent communication over a specific region , such as TV broadcasts and weather monitoring . They can also be used to transfer data between remote locations . Low-Earth orbiting satellites are closer to the ground so they enable fast communication for internet services . Medium-Earth orbiting satellites are often used for GPS (Global Positioning System ) and other navigation systems . A global positioning satellite is an example of this type of satellite that provides time and geolocation data to GPS receivers back on Earth. Diagrammatical Representation In an exam, you may be asked to draw a diagram representing how networks are connected . This is different from drawing a network topology (e.g. ring or mesh) and refers to: Connection type (e.g. ADSL / Leased Line). Devices (e.g. router / modem), Security methods (e.g. firewall / VPN) Two LANs connected using a Leased line Two LANs connected using an ADSL line Rules for drawing a network diagram: Label each device and label your LANs . Use appropriate symbols and be neat . There are no set symbols, just be consistent (e.g. both modems are the same shape). ADSL must have a modem and VPN router + Firewall . (ADSL is not very secure so it needs to be protected with the VPN router and firewall. It also uses the telephone line across the internet so it requires a modem at both ends). Leased Line must have a router , a direct connection and CSU/DSU . (Leased line is a secure and direct connection - so it doesn’t need a firewall or VPN router and should be direct (not across the internet )). Q uesto's Q uestions 3.4 - Connection Methods: 1a. What is the definition of a LAN ? [ 2 ] 1b. Describe two benefits of using a wired Ethernet LAN . [ 4 ] 2. What is the definition of a MAN ? [ 2 ] 3a. What is the definition of a WAN ? [ 2 ] 3b. What is the difference between a contended and an uncontended network? [ 2 ] 3 c. Describe the differences between a leased line and ADSL . You should discuss security , connection speed and contention ( contended or uncontended ) . [6 ] 3d. Describe the use of any two network devices required for either a leased line and/or for ADSL . [ 4 ] 3e. Describe the purpose of ISDN . [ 2 ] 4a. Compare the use of PSTN and Cellular methods to make telephone calls . [ 4 ] 4b. Explain 1 way that a satellite network should be used and 1 way it shouldn't be used . [ 4 ] 5. Draw a diagram to show how a leased line or ADSL network can be set up between two existing LANs. [6 ] 3.3 - Network Characteristics Topic List 3.5 - Business Systems