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Learn about network devices such as a switch, router, modem and NIC. Also learn about internet terms and services including DNS and the Cloud. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.1b: Network Hardware + The Internet Exam Board: OCR Specification: J277 Watch on YouTube : The Internet Network Hardware DNS Servers The Cloud Network Devices When sending data across a network, files are broken down into smaller parts called data packets . Whole files are too large to transfer as one unit so data packets allow data to be transferred across a network quickly . Each packet of data is redirected by routers across networks until it arrives at its destination. Data packets may split up and use alternative routes to reach the destination address. When all the packets have arrived at the destination address the data is reassembled back into the original file. Wireless Access Point A Wireless Access Point provides a link between wireless and wired networks . It creates a wireless local area network that allows WiFi-enabled devices to connect to a wired network. Examples of a wireless access point in a public space could be a WiFi or Bluetooth hotspot , for example a WiFi hotspot in a coffee shop or airport to provide access to the internet. A wireless access point may be a separate device or built into another device such as a router. Router Routers are used to transfer data packets between networks . Routers receive data packets and use the IP address in the packet header to determine the best route to transmit the data. Data is transferred from router to router across the internet towards the destination. A router stores the IP address of each computer connected to it on the network and uses a list called a routing table to calculate the quickest and shortest route to transfer data. Switch A switch is used to connect devices together on a LAN . It receives data packets from a connected node, reads the destination address in the packet header and forwards the data directly to its destination. A switch will generate a list of the MAC addresses of all devices connected to it when it receives data , and must scan for a matching destination address before sending. An alternative to a switch is a hub but a hub is slower and less secure as it forwards a copy of received data to all connected nodes . Network Interface Controller / Card A Network Interface Controller (NIC ) commonly also known as a Network Interface Card is an internal piece of hardware that is required for the computer to connect to a network . The card includes a MAC address which is used when sending data across a LAN . An ethernet cable is plugged into the network card to allow data to be exchanged between the device and a network. A NIC used to be a separate expansion card but is now typically embedded on the motherboar d . Transmission Media Although not technically a device, the communication channel along which data is transferred will affect performance . Three common types of transmission media include: Ethernet cables - used typically on a LAN to transfer data between nodes and hardware such as switches. Examples include Cat5e and Cat6. Fibre Optic cables - very fast but more expensive and fragile cables typically used to send data quickly along a WAN . Data is sent as pulses of light . Coaxial cables - older , slower , copper cables that are not used as much in modern times as they can be affected by electromagnetic interference . The Internet The internet is a global network of interconnected networks . The world wide web (WWW ) is not the same as the internet. It is a way of accessing information , using protocols such as HTTPS to view web pages . Servers provide services on the internet , such as a web server which responds to the web browser (client) request to display a web page . The web server processes the client request to prepare the web page and return it so the web browser can display it to the user . A website must be hosted (stored) on a web server so that it can be accessed by others using the internet . A unique domain name (e.g. csnewbs.com) must be registered with a domain registrar – this is a company that checks the name is valid and not already taken . What is the Internet? DNS Servers A DNS ( Domain Name System ) server stores a list of domain names and a list of corresponding IP addresses where the website is stored. The first thing to understand is that every web page has a domain name that is easy for humans to remember and type in (such as www.csnewbs.com ) as well as a related IP address (such as 65.14.202.32) which is a unique address for the device that the web page is stored on. The steps taken to display a web page: 1. A domain name is typed into the address bar of a browser . 2. A query is sent to the local DNS server for the corresponding IP address of the domain name . www.facebook.com 3. The local DNS server will check if it holds an IP address corresponding to that domain name. If it does it passes the IP address to your browser . 66.220.144.0 4. The browser then connects to the IP address of the server and accesses the web site . If the local DNS server does not hold the IP address then the query is passed to another DNS server at a higher level until the IP address is resolved. If the IP address is found, the address is passed on to DNS servers lower in the hierarchy until it is passed to your local DNS server and then to your browser. Cloud Storage The cloud refers to networks of servers accessed on the internet . Cloud computing is an example of remote service provision . Cloud servers can have different purposes such as running applications , remote processing and storing data . When you store data in 'the cloud', using services such as Google Drive or Dropbox, 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 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 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 . ✓ - Cloud storage is typically free for a certain amount of storage. Users can then buy a subscription to cover their needs - Dropbox allows 2 GB for free or 2 TB for £9.99 a month. Q uesto's Q uestions 3.1b - Network Hardware & Internet: 1a. Explain how a switch works. [ 2 ] 1b. Describe the purpose of a router . [ 2 ] 1c. State what WAP stands for and why it is used . [ 2 ] 1d. State what NIC stands for and why it is required . [ 2 ] 1e. State the differences between the three main types of transmission media . [ 3 ] 2a. State what the internet is and how it is different to the world wide web . [ 2 ] 2b. What is web hosting ? [ 2 ] 3a. What is a DNS server ? [ 2 ] 3b. Describe, using a mix of text and icons / images , how a DNS server is used to display a web page . [5 ] 3c. Describe how a DNS server searches for an IP address if it is not found on the local DNS server . [ 2 ] 4a. Describe what cloud computing is. [ 2 ] 4b. State two advantages and two disadvantages of the cloud . [ 4 ] 3.1a - Network Types & Performance Theory Topics 3.2a - Wired & Wireless Networks

Learn about troubleshooting tests and information to record when a hardware error occurs. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.6 - Hardware Troubleshooting Exam Board: OCR Specification: 2016 - Unit 1 What is troubleshooting? Troubleshooting means to analyse and solve a problem with a computer system. Hardware troubleshooting refers to fixing an issue with the physical parts of the computer or any connected devices. Hardware issues might occur as a result of damage (intentional or accidental), power surges or malware . Steps to Take When an Error Occurs Try to identify the problem by looking for the simplest explanation first (e.g. checking the power supply) and ask the user questions about the issue. Create a theory about what the cause of the problem could be and prepare to test the theory using a series of troubleshooting tests . Create a troubleshooting plan and record the steps that are taken before moving on to the next test. Check the system works after each stage of the plan. Create a findings document that explains if and how the problem was fixed, for future reference if the problem occurs again. Documentation Technicians and help desk (see 3.5 ) staff should document , on a fault sheet , the following information regarding the issue: The fault itself (such as 'system not turning on'). The system in question. The user logged in at the time. Exact date & time the problem occurred. Symptoms of the issue (such as 'slow load times' or 'beeping'). Problem history - checking if it has happened to this system before. Back up documentation - Whether the data been backed up recently. Troubleshooting Tools The following tools can be used to identify an error so a technician has a greater understanding of the problem. Event Viewer Event Viewer is a type of utility software that lists detailed information about an error when one occurs. It can be used to work out how to fix the issue and will display both minor and major faults. Power On Self Test (POST) On start-up, a power on self test (POST) checks memory, power, hardware and cooling systems are all working properly. Beep codes signal if an error has been detected; 1 beep will sound for no error but if multiple beeps are heard then an error has been discovered. Ping Test This is a connectivity test between two computers. A message is sent to the destination computer and waits for a return message named the echo reply . This procedure can be repeated with other systems until the source of the problem is identified from a computer that does not reply . Q uesto's Q uestions 1.6 - Hardware Troubleshooting: 1. Summarise the 'Steps to Take when an Error Occurs ' section into your own top three tips for what to do when a hardware error happens . [3 ] 2. List 6 pieces of information that an IT technician should record when a hardware error has occurred . [6 ] 3. Briefly explain the purpose of three troubleshooting tools . [6 ] 1.5 - Communication Hardware 1.7 - Units of Measurement Topic List

The fourth part of a quick guide to the basics of Python aimed at Key Stage 3 students. Learn about calculations and simple mathematical operators. Python - #4 - Calculations 1. Creating Calculations To add in Python use + To subtract in Python use - To multiply in Python use * To divide in Python use / Task 1 - Create a new Python program and save the file as 4-Calculations.py Print 4 different calculations - use each operator once.(add/subtract/multiply/divide) Python is very clever, so don't be afraid to make your own calculations using larger numbers and more than one operator . 2. Using Inputs and Calculations You can ask the user to enter numbers by writing input lines. Python can then perform calculations using the numbers that the user has entered. Don't forget to add int ( and double close brackets when using numbers ! Task 2 - Copy the new code from the picture. Change the text and num1 so you are dividing by 5 not 3. Don't delete your earlier code , just add this underneath. I have cropped the images to make the new code clearer. 3. Using Calculations in a Sentence When we have printed the calculations so far, they have not been very informative! You can print calculations together with sentences so that they mean more. Use a comma ( , ) between calculations and sentences . Task 3 - Use the pictures to help you add commas and sentences to your program to be more informative. Challenge Programs Use everything that you have learned on this page to help you create these programs... Challenge Task 1 - Multiplication Create a new Python program. Save it as ' 4 -Multiplication.py ' Add a comment at the top with your name and the date. Write an input line ( don't forget int ! ) that asks the user to enter number 1. Write an input line ( don't forget int ! ) that asks the user to enter number 2. Multiply number 1 and number 2 together and print the answer. BONUS : Try to show number 1 and number 2 in the print statement (see practice task 3 to help you). Remember: Break up variables in a print line by using commas. When you run it, it could look something like this: Challenge Task 2 - Retirement Create a new Python program. Save is as ' 4-Retirement.py ' Add a comment at the top with your name and the date. Write an input line ( don't forget int ! ) that asks the user to enter their age. Print the year that they will turn 65. (This is slightly tricky. Hint : You need to know their age, and you need to know the current year. You need to subtract something, and you need to add something. Try using scrap paper to help you figure it out.) BONUS : Use only one print line. BONUS : Try to use only two lines in total . Remember: Break up variables in a print line by using commas. When you run it, it could look something like this: <<< #3 Inputs #5 Selection >>>

Learn how to read and search through files in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. Python 10b - Read & Search Files Reading from a File To read and print from a file you must open it in read mode by typing "r" instead of "a". If you are writing and reading in the same program, make sure you close the file in append mode before you open it in read mode . The program below uses the Customers.txt file from the last section. A simple for loop can be used to print each line of the file. The end = "" code just prevents a space between each line. Practice Task 1 Open one of the files that you used in Section 10a and print each line. Example solution: Reading Specific Lines from a File Sometimes it is necessary only to print certain lines. The following example uses a file where I have written a sentence of advice on each line. The user is asked to enter a number between 1 and 6. If they enter 1, the first line of the file is printed. If they enter 2, the second line of the file is printed etc. Remember Python starts counting everything at 0 so each line is a digit less than you would expect . Square brackets must be used to denote the line to print: [1] not (1). The end = "" code is not necessary but removes space after the line. Practice Task 2 Create a text file (saved in the same folder as your Python file) with a list of video games. Ask the user to enter a number between 1 and 10. Print the line for the number that they input. Example solution: Print a Random Line The randint command can be imported and used to print a random line from a file . The example below prints one of the 12 months . The file is opened in read mode and the readlines() command extracts each line , placing them in a list . A random number is then generated between 0 and one less than the total number of lines . This random number is then used to print a line from the extracted list of lines . Python code from random import randint file = open ( "months.txt" , "r" ) lines = file.readlines() random = randint(0,11) print (lines[random]) months.txt January February March April May June July August September October November December potential outputs March December April July If the length of the file is not fixed (e.g. new lines are being added or lines removed ) then the random number generation line can be adapted to use the len command to calculate the current number of lines . This is required to know the upper limit of the random number . random = randint(0,len(lines)-1) Searching Through Files A for loop is used to search through a file , line by line . First, an input line is used to allow the user to enter their search term . If the term that is being searched for is found, then the whole line is printed. The example below uses a variable named found to state if there is a match when the file is searched. If the search term is found, then the found variable is changed to true . If the search term is not found , the found variable remains as false, so the 'no customers found' statement is printed . Practice Task 3 You should have completed Practice Task 2 from Section 10a (the A Level task). Add extra code to that program so that you can search for specific students. Example solution: ⬅ 10a - Open & Write Files 10c - Remove & Edit Lines ➡

Learn about utility software including antivirus, firewall, compression, disk partitioners, defragmenters, backup and file managers. Based on the 2020 Eduqas (WJEC) GCSE specification. 6.2: Utility Software Exam Board: Eduqas / WJEC Specification: 2020 + What is utility software? Utility software are dedicated programs used for the maintenance and organisation of a computer system. Antivirus 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 . 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. Disk Defragmenter 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. Backup Software System backup copies data onto a separate storage device in case the original information is lost or corrupted . Backups should be saved regularly and stored in a different location to the rest of the data. Magnetic tape is a common backup medium. A typical backup policy is one known as 'grandfather - father - son' which uses three different backups at a time. Disk Compression Compression is the process of decreasing the size of a file . Disk compression is a utility tool that automatically compresses files when saved so that more data can be stored on the hard disk drive. When a file is to be opened, the program is automatically decompressed . Disk compression increases the amount of space on a hard disk drive but it takes longer to open and close files . Disk Checker This utility is used to scan a hard drive for any corrupted data . The corrupted data is deleted to speed up reading from and writing to the hard drive. More advanced disk checkers are used to scan for bad sectors . A bad sector is a permanently damaged section of the hard drive which can no longer be used and must be skipped over. Disk Formatter Disk Partition Editor This utility tool prepares a storage device such as the hard disk drive to be used by removing the current data and creating a file system . A file system manages how data is stored and accessed . Other devices like a USB stick may need to be formatted before they can be used for the first time . Within memory, partitions are segments of data that have been grouped together logically on the hard disk drive . A disk partition editor allows a user to view and modify these memory partitions . Options include creating, editing and deleting partitions. Clipboard Manager The clipboard is a temporary storage space for copied data. For example, a large amount of text can be copied and stored on the clipboard to be pasted into another document, even when the original file has been closed . The clipboard manager adds more functionality to the clipboard to allow multiple pieces of data to be copied, cut and pasted . System Profiles A system profiler displays detailed information about the applications on a computer system, as well as data about any attached hardware devices . Information is provided and updated in real-time about the performance of software and internal components such as the CPU . Data Recovery Data recovery tools allow deleted, corrupted or otherwise inaccessible data to be returned to a usable state . The data loss may have been caused by physical damage to a drive, corrupt memory partitions or accidental deletion . Most data is not permanently removed when it is deleted so data recovery software can often be used to reaccess files . Revision Control Revision control software manages previous versions of an application so that if an error occurs the program can be returned to a previous state . This is also called version control software and can be used to manage and monitor changes made to files over time. Archiver Archiving is the process of storing important data that is not currently required . It must not be deleted but it shouldn't take up valuable storage space either. An archiver compresses multiple files using lossless compression into one folder . This archived folder can be stored on a computer system or transferred to a storage device and won't take up much space . Cryptographic Utilities A cryptographic utility is used to encrypt data so that it cannot be understood if intercepted . Encryption is commonly for data in transit - being sent between devices . Cryptographic software can also encrypt data at rest - when stored on a hard disk drive for example - so that hackers would be unable to use the data . File Manager This utility tool provides an interface to the user for accessing, editing and moving files and folders on the system. Programs will be displayed in a hierarchical ( ordered ) structure with icons representing the application logo or file type. Files can be ordered in alphabetical, chronological or other orders and the manager provides an abstracted visualisation of where the data is stored. Q uesto's Q uestions 6.2 - Utility Software: 1. What is meant by utility software ? [1 ] 2. Describe each type of utility software : a. Antivirus b . Firewall c . Disk Defragmenter d . Backup Software e . Disk Compression f . Disk Checker g . Disk Formatter h . Disk Partition Editor i . Clipboard Manager j . System Profiles k . Data Recovery l . Revision Control m . Archiver n . Cryptographic Utilities o . File Manager [2 ] 6.1 - Operating Systems Theory Topics 7.1 - Language Levels

Learn about visual design elements of human-computer interfaces such as colours, interaction, location hierarchy, messages (help, error) and typography (style, size). 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) 5.2 - Human Computer Interface Visual Design Considerations Watch on YouTube : Visual design considerations When creating a human-computer interface , there are several visual design considerations that the development team must take into account, such as the use of colour and the style of typography . You need to know how each visual design consideration is used when designing human-computer interfaces and how these interfaces can be improved to be more effective . As with most topics, it is also vital to consider how client requirements may impact changes related to visual design , for example, using larger text for users with visual impairments . Visual Design Considerations Visual Design Considerations Colours are used to define the visual appearance of the interface . This includes background colours , button colours , icons and text . Interaction refers to how users control or respond to the system through input methods like clicking , tapping , swiping , typing or speaking . Location hierarchy is about the placement and organisation of interface elements based on importance . Messages are displayed to provide feedback , guidance or explanations - such as confirming actions , explaining errors or offering help . Typography includes the choice of font types and the size , spacing , weight (boldness) and alignment of text . Q uesto's Q uestions 5.2 - Human-Computer Interface Visual Design Considerations: 1. Explain how colours can be used effectively in human-computer interfaces . [4 ] 2. Describe what is meant by location hierarchy and why it is important to consider . [4 ] 3. Suggest specific visual design considerations an application developer should consider when making software for a primary school in Dubai . [ 5 ] Approximately 1 in 12 men and 1 in 200 women are colour-blind , meaning good designers should include text or icons rather than relying on just colour to convey meaning . D id Y ou K now? 5.1.2 - Types of Devices Topic List 5.3 - HCI Designs & Diagrams

Learn about the different data types used in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 3a - Data Types Data Types in Python If you are a Computer Science student you need to know about the different data types that are used in programming. String – A sequence of alphanumeric characters (e.g. “Hello!” or “Toy Story 4” or “Boeing 747” ) Integer – A whole number (e.g. 1470 or 0 or -34) Float (also called Real ) – A decimal number (e.g. -32.12 or 3.14) Boolean – A logical operation (True or False) Character – A single alphanumeric character (e.g. “a” or “6” or “?”) [ Not used in Python as it would just be a string with a length of 1] Converting to Another Data Type Converting a variable from one data type to another is called casting . Casting Commands str (variable_name) converts a variable to a string . int (variable_name) converts a variable to a integer . float (variable_name) converts a variable to a float (decimal number). An integer (or float ) value may be cast into a string so that it can be used with + as part of a sentence to avoid spaces . total = 45 print ( "You owe £" , total , "in total." ) print ( "You owe £" + str (total) , "in total." ) = You owe £ 45 in total. You owe £45 in total. When dividing an integer the answer is automatically given as a decimal number (float ), even if it is .0 (e.g. 10 / 2 would give 5.0). Casting a float (also known as real) number into an integer using int() will remove the decimal . total = 100/10 print ( "The answer is" , total ) print ( "The answer is" , int(total) ) The answer is 10.0 The answer is 10 = Data Types Task 1 ( Time) Write an input line with int to ask the current hour . Write another input line with int to ask the current minute . Write a print line with str() that outputs this as a clock time. Example solution: What is the hour? 12 What is the minute? 44 The time is 12:44 Data Types Task 2 ( Decimal ) Write an input line with int to ask for any number . Use float() in a print line to output number as a decimal. Example solution: Enter any number: 456 456.0 ⬅ Section 2 Practice Tasks 3b - Simple Calculations ➡

A simple Little Man Computer (LMC) editor. Perfect for students learning A-Level Computer Science in UK schools. Little Man Computer (LMC) Editor You can use this simple Little Man Computer ( LMC ) editor below to check any LMC code you have written to ensure it outputs correctly . Use the reminders on the right for the 11 commands needed in the OCR A-Level specification . LMC is a simplified form of assembly language . This page is under active development. INP is used without a label to input a number . The number is temporarily stored in the accumulator. Example: INP OUT will output the current value of the accumulator. Example: OUT STA stores the value that is currently in the accumulator into a named memory location. Example: STA num1 ADD is used to add the value of a named memory location to the value currently stored in the accumulator. Example: ADD num1 SUB takes away the value of a named memory location from the value currently stored in the accumulator. Example: SUB num1 LDA is used to load the value of a stored variable into the accumulator. Example: LDA num1 BRZ is used to branch to a labelled line of code if the value in the accumulator is exactly 0 . Example: BRZ ifzero BRP is used to branch if the value in the accumulator is currently positive (including 0). Example: BRP repeat BRA is used to branch regardless of the accumulator's current value . Example: BRA loop HLT will stop the program. Example: HLT DAT defines and stores data in memory. It creates a variable or memory location that can hold a specific value. It is written after the final HLT command. Example: fifty DAT 50

Learn database topics including entity relationships, keys, normalisation, capturing and exchanging data, SQL, referential integrity, transaction processing and ACID (atomicity, consistency, isolation, durability). Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 3.2 - Databases Specification: Computer Science H446 Watch on YouTube : Database Keys & Relationships Flat File & Relational Databases Capturing & Managing Data SQL Normalisation Referential Integrity & ACID Database Keys & Relationships A database is an organised collection of data stored in tables , where each table represents an entity such as a customer or product . Each table is made up of records ( rows ), which store information about individual instances of that entity , and fields ( columns ), which hold specific attributes like names or prices . A primary key uniquely identifies each record , while a foreign key links records between tables to create relationships . Secondary keys use indexing to speed up searches and data retrieval . Relationships between entities are shown using an Entity–Relationship ( ER ) diagram , which illustrates one-to-one , one-to-many and many-to-many connections between tables . YouTube video uploading soon Flat File & Relational Databases A flat file database stores all data in a single table or file , often in a simple format such as a spreadsheet or text file . It is easy to create and manage , making it suitable for small-scale applications . However, it can lead to data duplication and inconsistency because the same data may be repeated in multiple records . A relational database stores data in multiple related tables , linked together using primary and foreign keys . This design reduces data redundancy and improves data integrity by storing each piece of information only once . The main disadvantage is that relational databases are more complex to design and maintain , requiring more processing power and knowledge to manage effectively . YouTube video uploading soon Capturing & Managing Data Data can be captured from sources such as forms , Optical Character Recognition (OCR ), Optical Mark Recognition (OMR ) and sensors . These methods allow information to be collected automatically or manually and entered into a computer system for processing . Data can be selected and filtered using tools like Query By Example (QBE ) or SQL commands . This allows users to retrieve only the specific records that meet certain criteria from a database . Data management involves manipulating stored information , such as performing arithmetic functions or adding , editing and deleting records . This ensures that the data remains accurate , up to date and useful for decision-making . Data can be exchanged (shared ) between systems using common file formats such as CSV and JSON . These formats make it easier to transfer data between different software applications or platforms while maintaining structure and meaning . YouTube video uploading soon Database Normalisation Database normalisation is the process of organising data in a database to reduce redundancy and improve data integrity . It ensures that each piece of data is stored only once , making updates and maintenance more efficient and reducing the risk of inconsistent data . Normalisation is measured in 'forms ': First Normal Form (1NF ): Ensures that all fields contain atomic (indivisible ) values and that there are no repeating groups in a table. Each table must have a primary key . Second Normal Form (2NF ): Builds on 1NF by ensuring that all non-key attributes depend on the entire primary key , removing partial dependencies . Third Normal Form (3NF ): Builds on 2NF by removing transitive dependencies , meaning non-key attributes depend only on the primary key and not on other non-key attributes . YouTube video uploading soon Structured Query Language (SQL) SQL ( Structured Query Language ) is used to create , manage and manipulate data in databases . It allows users to retrieve specific data using commands such as SELECT , FROM and WHERE , often combined with logical operators like AND and OR to filter results . The LIKE command and wildcards such as * and % are used to search for patterns within text data . SQL also supports data modification through commands like INSERT (to add data ), DELETE (to remove data ) and DROP (to delete entire tables ). More advanced queries can use nested SELECT statements or JOIN commands to combine data from multiple tables for more complex analysis . YouTube video uploading soon Referential Integrity & ACID Referential integrity ensures that relationships between tables in a relational database remain consistent . It means that a foreign key in one table must always refer to a valid primary key in another table . Transaction processing refers to the handling of a sequence of database operations (a transaction ) that must be completed fully or not at all . It ensures that databases remain accurate and consistent even if errors or system failures occur during the process . The ACID rules define the key properties of reliable transactions : Atomicity : The transaction is all or nothing - it either completes fully or not at all . Consistency : The database must remain valid before and after the transaction . Isolation : Transactions are independent , so one cannot interfere with another . Durability : Once completed , a transaction’s changes are permanent , even if the system crashes . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Database Keys & Relationships: field, record, table, primary key, secondary key, indexing, foreign key, entity relation (ER) diagram, one-to-one, one-to-many, many-to-many, flat file database, relational database Capturing & Managing Data: form, OCR, OMR, sensor, query by example, SQL, CSV, JSON, electronic and non-electronic data transfer SQL: SELECT, nested SELECT, FROM, WHERE, LIKE, AND, OR, DELETE, INSERT, DROP, JOIN, wildcards (* and %) Normalisation: first normal form (1NF), second normal form (2NF), third normal form ( 3NF), partial dependency, non-key dependency Referential Integrity & ACID: referential integrity, ransaction processing, ACID (atomicity, consistency, isolation, durability), record locking, redunancy D id Y ou K now? In 2013 the web portal / search engine company Yahoo! was hacked , with all 3 billion user accounts in their database compromised - the largest hack in history . Personal details such as names , email addresses and hashed passwords were taken , causing major reputational and financial damage to the company . 3.1 - Compression & Encryption A-Level Topics 3.3 - Networks

Learn about things to consider when trying to make a good impression at work, including written, verbal and physical considerations. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 4.1 - Communication Skills Exam Board: OCR Specification: 2016 - Unit 1 Communication skills are vital for anybody working within the IT industry. Employees will need to communicate with other members of their team and with those who encounter issues with their computer systems. Interpersonal Skills Communication is not just through speaking to another person, behaviour is also important. Employees should sit up straight in their chairs to show interest and eye contact should be maintained when speaking to another person or listening in a meeting. It is important to speak clearly so that others can understand what you are trying to say. Verbal Communication Employees should know when to use informal and formal language appropriately. For example, formal language should be used in meetings as it is a work environment . Employees should think carefully about when to use technical terms . Technical terminology should be used when discussing issues with technicians but simplified explanations should be given to customers who may be inexperienced with their systems. Questioning Techniques Questioning is used to uncover problems in order to solve them . Closed questions will be direct and prompt a short, often one-word answer, such as "How many times have you tried to log in?". Open questions don't have an obvious answer and may elicit an opinion , such as "Why are you using Internet Explorer instead of Google Chrome?". Avoid leading questions - where you expect a certain response from the answerer, such as "Is the system always this slow?" Written Communication Again this form of communication can be formal - such as a letter to apply for a job - or informal - like sending a text or instant message to a team member. There are a number of considerations to take before deciding whether communication should be formal or informal. For example, if the communication is between peers or external agencies (such as other companies or customers), any policies the organisation has in place and whether the communication will be legally recorded (such as saving all email correspondence). Barriers to Communication There are several reasons why communication between people may be received or understood incorrectly . For example, noise in the room , language (this could be different spoken languages or the use of difficult technical terms ) and impairments (such as a hearing or visual impairment ). Another barrier is distraction - an email may be delayed because an employee is distracted by social media or other co-workers. Phones should also be turned off or silent during meetings. Q uesto's Q uestions 4.1 - Communication Skills: 1. Describe 3 interpersonal actions that an employee should follow when speaking or listening to other team members. [ 3 ] 2. Explain when an employee should use technical terms and when they should simplify their explanations . [ 4 ] 3. Describe the difference between closed , open and leading questions , giving an example of each. [6 ] 4. Describe 3 things that should be considered when deciding between formal or informal written communication . [3 ] 5. Describe 3 different barriers to successful communication . [3 ] 3.5 - Business Systems Topic List 4.2 - Communication Technology

Learn about the four logical operators - NOT, AND, OR and XOR - and truth tables. Based on the 2020 Eduqas (WJEC) GCSE specification. 2.1: Logical Operators & Truth Tables Exam Board: Eduqas / WJEC Specification: 2020 + What is a logical operator? Inside of each computer system are millions of transistors . These are tiny switches that can either be turned on (represented in binary by the number 1 ) or turned off (represented by 0 ). Logical operators are symbols used to represent circuits of transistors within a computer. The four most common operators are: NOT AND OR XOR What is a truth table? A truth table is a visual way of displaying all possible outcomes of a logical operator. The input and output values in a truth table must be a Boolean value - usually 0 or 1 but occasionally True or False. NOT A NOT logical operator will produce an output which is the opposite of the input . NOT is represented by a horizontal line . Boolean Algebra Notation written as NOT A A Truth Table AND An AND logical operator will output 1 only if both inputs are also 1 . AND is represented by a full stop. Boolean Algebra Notation written as A AND B A.B Truth Table OR An OR logical operator will output 1 if either input is 1 . OR is represented by a plus. Boolean Algebra Notation written as A OR B A+B Truth Table XOR An XOR (exclusive OR) logical operator will output 1 if the inputs are different and output 0 if the inputs are the same . XOR is represented by a circled plus. Boolean Algebra Notation written as A XOR B A B Truth Table Multiple Operations Exam questions will ask you complete truth tables that use more than one logical operator . Work out each column in turn from left to right and look carefully at which column you need to use. Simplification You may be asked to use a truth table to simplify an expression . This is actually really easy. Once you've completed the truth table see if any columns match the final expression . A+B and A+(A+B) both result in the same values , therefore: A+(A+B) can be simplified as just A+B. Q uesto's Q uestions 2.1 - Logical Operators: 1. Copy and complete the following truth tables: 1b. Simplify the expression in the second truth table. 2a. A cinema uses a computer system to monitor how many seats have been allocated for upcoming movies. If both the premium seats and the standard seats are sold out then the system will display a message. State the type of logical operator in this example. 2b. For the more popular movies, the cinema's computer system will also display a message if either the premium seats or the standard seats have exclusively been sold out. However, it will not output a message when both have been sold out. State the type of logical operator in this example. 1.6 - Additional Hardware 2.2 - Boolean Algebra Theory Topics

Learn about internet topics including web browsers, URL structure and DNS servers. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.7: The Internet Exam Board: Eduqas / WJEC Specification: 2020 + What is the internet? The internet is a global network of interconnected networks . The world wide web (WWW ) is not the same as the internet. It is a way of accessing information , using protocols such as HTTPS to view web pages . What is a web browser? A web browser is software that uses the HTTP or HTTPS protocol to access and display web pages . Popular web browsers include Google Chrome , Mozilla Firefox and Microsoft Edge . What is a URL? URL stands for Uniform Resource Locator . Web pages are accessed by typing a URL (a web address) into the address bar of a web browser . The URL is the complete address that matches an IP address where the website is stored. We use URLs because they are easier to remember than IP addresses, for example, 'twitter.com' is simpler than '199.59.149.165'. What is the structure of a URL? A URL is structured into different segments: What is a DNS Server? A DNS ( Domain Name System ) server stores a list of domain names and a list of corresponding IP addresses where the website is stored. The first thing to understand is that every web page has a domain name that is easy for humans to remember and type in (such as www.csnewbs.com ) as well as a related IP address (such as 65.14.202.32) which is a unique address for the device that the web page is stored on. The steps taken to display a web page: 1. A domain name is typed into the address bar of a browser . 2. The browser checks a local (cached) host file to check if it already holds the IP address, but if it doesn't... 3. A query is sent to the local DNS server for the corresponding IP address of the domain name . www.facebook.com 4. The local DNS server will check if it holds an IP address corresponding to that domain name. If it does it passes the IP address to your browser . 66.220.144.0 5. The browser then connects to the IP address of the server and accesses the web site . If the local DNS server does not hold the IP address then the query is passed to another DNS server at a higher level until the IP address is resolved. If the IP address is found, the address is passed on to DNS servers lower in the hierarchy until it is passed to your local DNS server and then to your browser. Q uesto's Q uestions 3.7 - The Internet: 1a. Describe the difference between the internet and the world wide web ( WWW ). [ 2 ] 1b. What is the purpose of a web browser ? [ 2 ] 1c. Why do humans use URLs instead of IP addresses? [ 1 ] 1d. Write out the following URL and label each section: https://www.skynews.co.uk/worldnews/ukstockmarket [ 6 ] 2a. What is a DNS server ? [ 2 ] 2b. Describe, using a mix of text and icons / images , how a DNS server is used to display a web page . [5 ] 2c. Describe how a DNS server searches for an IP address if it is not found on the local DNS server . [ 2 ] 3.6 - 7-Layer OSI Model Theory Topics 3.8 - Cyber Threats