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  • 2.2.1a - Recursion & Variables | OCR A-Level | CSNewbs

    Exam Board: OCR 2.1a - Recursion & Variables Specification: A-Level 2015 An instruction set is a list of all the instructions that a CPU can process as part of the FDE cycle . ​ CPUs can have different sets of instructions that they can perform based on their function. The two most common instruction sets are the simpler RISC (Reduced Instruction Set Computer ) and more complicated CISC (Complex Instruction Set Computer ). Instruction Sets This page is still being updated. Graphical Processing Unit What is cache memory? ​ Cache memory is temporary storage for frequently accessed data . ​ Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Multicore & Parallel Systems What is cache memory? ​ Cache memory is temporary storage for frequently accessed data . ​ Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Multicore & Parallel Systems What is cache memory? ​ Cache memory is temporary storage for frequently accessed data . ​ Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . Q uesto's Q uestions 2.1a - Recursion & Variables: ​ 1. What is cache memory ? [ 2 ] ​ 1.1 - Computational Thinking Theory Topics 2.1b - Modularity & IDE

  • Python | 4b - Mathematical Operators | CSNewbs

    top Python 4b - Mathematical Operators Modulo Division The modulo operator - the percentage symbol % - will work out the remainder left over when one value is divided by another. print (30 % 6) = 0 30 ÷ 6 = 5, which is a whole number, so there is no remainder and 0 is output . print (30 % 7) = 2 30 ÷ 7 = 4 remainder 2 ; so the remainder is output . You can use modulo with variables too: num1 = 33 num2 = 4 print ( "The remainder is" , num1 % num2) The remainder is 1 = A common use of modulo is to check if a number is odd or even . If a number has no remainder when divided by 2 then it is even . = num = int ( input ( "Enter a number: " )) if num % 2 == 0: print (num, "is even." ) else : print (num , "is odd." ) Enter a number: 400 400 is even. Enter a number: 191 191 is odd. = Modulo Div i sion Task 1 ( Remainder) Ask the user to input a whole number . ​ Use the modulo operator ( % ) to check if there is a remainder when the user's number is divided by 5 . Print the re mainder. Example solution: Enter a number: 123 The remainder when divided by 5 is 3 Modulo Div i sion Task 2 ( Rollercoaster) Use the odd/even program above to help solve this problem: ​ A rollercoaster only lets people on in groups of 4 . ​ Ask the user to input a number for how many people are in their group. Check if that number is directly divisible by 4 using modulo division ( % ). If it is then print “Perfect groups of four!” Else print “You will be split up” . Example solutions: Welcome to the Hyper Coaster! How many in your group? 6 You will be split up! Welcome to the Hyper Coaster! How many in your group? 12 Perfect groups of four! Integer Division Integer division removes any decimal numbers when performing division , leaving just the integer (whole number ). ​ In Python integer division is performed using // . print (20 / 3) print (20 // 3) = 6.666666666666667 6 Integer Div i sion Task 1 ( Integer Division by 5 ) Use an input line with int to ask the user to enter a number . ​ Use integer division ( // ) to divide the number by 5 without keeping any decimal values . ​ Challenge: Improve your solution by altering the print line to be more user friendly . Example solutions: Enter a number: 27 5 Enter a number: 27 5 goes into 27 5 times. Integer Div i sion Task 2 ( Plane Rows) A large plane has 6 seats in row. ​ Input the number of passengers on the plane and use integer division to work out how many full rows will be filled. Example solution: How many passengers are there in total? 174 There will be 29 full rows on the plane. Exponent (Powers) An exponent is the number of times a value is multiplied by itself , for example 2 = 2 x 2 x 2 = 8 . The symbol to represent an exponent in Python is ** . For example: 4**2 represents 4 which is also 4 x 4 . 3 2 print (4**4) = 256 base = 5 exponent = 4 print (base**exponent) 625 = Exponent Task 1 ( Square Number) Use an input line with int to ask the user to enter a number . ​ Output the square of this number. Example solution: Enter a number: 12 12 squared is 144 Exponent Task 2 ( Custom Exponent) Use an input line with int to ask the user to enter a number, this will be the base . Make another input line with int to ask for the exponent . ​ Use ** between the base and the exponent and print it. ​ Challenge: Make your solution better by including the base and exponent in the print line. Example solutions: Enter the base: 7 Enter the exponent: 3 343 Enter the base: 7 Enter the exponent: 3 7 to the power of 3 is 343 ⬅ 4a - If Statements 4 c - Log ical Operators ➡

  • OCR CTech IT | Unit 1 | 4.5 - Job Roles | CSNewbs

    4.5 - Job Roles Exam Board: OCR Specification: 2016 - Unit 1 There are several different IT-related roles within most companies. Each role requires specific skills and attributes to be performed successfully. ​ Try to apply the most suitable personal attributes that were described in 4.3 , as well as any other important skills relevant to the role , such as programming. Self-motivation Leadership Respect Dependability Punctuality Problem Solving Determination Independence Time Management Team Working Numerical Skills Verbal Skills Planning & Organisation Network Manager A network manager must control a group of employees with strong leadership to clearly set out their vision for the team. They must be able to motivate and encourage the team members to meet objectives . Because a network manager is high-ranking, there may not be many senior staff above them so they must be self-motivated and able to complete tasks independently , without being monitored . Network managers must be dependable and decisive , able to weigh up the consequences of a decision and make tough calls whilst under pressure . Time management is an important attribute for a network manager, they must be able to prioritise tasks and ensure deadlines are kept to . IT Technician IT technicians must have good interpersonal skills so that they can communicate clearly with other employees or customers. They should be able to use simplified terminology to help another person with their problem. ​ They must be able to use questioning effectively to work out what the issue is to begin to solve it. ​ IT technicians should have plenty of experience with hardware and software troubleshooting and be able to use a range of troubleshooting tools to solve a problem. ​ They need to be respectful to customers and employees when solving a problem and show determination , as well as self-motivation , to fix issues within acceptable time limits . Programmer A programmer needs to be competent in specific programming languages that the company use. It would be beneficial to have knowledge of more than one programming language so they can be more versatile and approach a problem in different ways . Programmers need to have a logical mind so that they are able to creatively solve problems. Using computational thinking is an important set of skills that programmers should have - for example, by using decomposition to break a large problem into smaller, more manageable chunks. They must have good planning and organisational skills so that they can stay on top of the numerous tasks that need to be done. They need good time management skills to prioritise the more important tasks and stick to a deadline . Programmers must be patient individuals, all programs will contain errors that must be debugged and rewritten numerous times. Good interpersonal skills are necessary so programmers can work efficiently in teams - often multiple programmers will work on subsections of the same program that fit together later. Web Designer & Animator Web designers create , plan and code web pages to fit specific requirements made by their customers. ​ They must create both the technical and graphical aspects of the web page, editing both how it looks and how it works. ​ Web designers could also be responsible for maintaining a site that currently exists. An animator may use a mixture of digital and hand-drawn images or even puppets and models. ​ The main skill of animation is still artistic ability , but there is an ever-increasing need for animators to be experienced with technical computer software . ​ Animators usually work as part of a team with strict deadlines . Q uesto's Q uestions 4.5 - Job Roles: ​ 1. Describe the key skills and personal attributes that a new programmer should have. [10 ] ​ 2. A brief job description of a web designer and an animator are shown above on this page. ​ Use the descriptions of what makes a suitable network manager, IT technician and programmer to help you explain which personal attributes and skills are required for:​ a) A web designer b) An animator [8 each ] 4.4 - Ready for Work Topic List 4.6 & 4.7 - Bodies & Certification

  • 2.1 - Programming Fundamentals - OCR GCSE (2020 Spec) | CSNewbs

    2.1: Programming Fundamentals Exam Board: OCR Specification: 2020 Programming Constructs There are three constructs ( ideas of programming ) that are used to control the flow of a program : Sequence Structuring code into a logical, sequential order . Selection Decision making using if statements . Iteration Repeating code using for or while loops . Variables Variables are used to store data in programs. They can be changed as the program runs . A variable has two parts - the data value such as "Emily" and an identifier such as First_Name . ​ An efficient program will use variables with sensible identifiers that immediately state their purpose in the program. ​ Using variable names like 'TotalNum' and 'Profit' rather than 'num1' and 'num2' mean that other programmers will be able to work out the purpose of the code without the need for extensive comments. Local & Global Variables Large programs are often modular - split into subroutines with each subroutine having a dedicated purpose. Local variables are declared within a specific subroutine and can only be used within that subroutine . ​ Global variables can be used at any point within the whole program . ​ Local variable advantages Saves memory - only uses memory when that local variable is needed - global variables use memory whether they are used or not. Easier to debug local variables as they can only be changed within one subroutine. You can reuse subroutines with local variables in other programs. ​ Global variable advantages Variables can be used anywhere in the whole program (and in multiple subroutines). Makes maintenance easier as they are only declared once. Can be used for constants - values that remain the same. Constants π As specified before, a variable is data that can change in value as a program is being run. ​ A constant is data that does not change in value as the program is run - it is fixed and remains the same. ​ An example of a constant in maths programs is pi - it will constantly remain at 3.14159 and never change. Operators Comparison Operators Comparison operators are used to compare two data values . A table of common comparison operators used in programs are below: Arithmetic Operators Arithmetic operators are used to mathematically manipulate values . The most common arithmetic operators are add (+ ), subtract (- ), multiply (* ) and divide (/ ). ​ Further arithmetic operators are shown below: Modulo division (also known as modulus ) reveals the remainder from the last whole number . For example: ​ 9 % 4 = 1 (4 goes into 9 twice (8) with a remainder of 1) Integer division (also known as quotient ) reveals the ‘whole number of times ’ a number can be divided into another number : ​ 9 // 4 = 2 (4 goes into 9 fully, twice) The symbol ^ represents exponentiation . For example '2^3 = 8' as it means '2³ = 8'. Logical Operators Logical operators typically use TRUE and FALSE values which is known as Boolean . You can find more information about Boolean values in section 4.1 . Q uesto's Q uestions 2.1 - Programming Fundamentals: Programming Constructs ​ 1. Describe and draw a diagram for the 3 programming constructs . [6 ] ​ Variables 1. What is the difference between local and global variables ? [4 ] 2. Describe two advantages of using local variables . [2 ] 3. Describe two advantages of using global variables . [2 ] 4. What is a constant ? Give an example . [2 ] 1.3 - Searching & Sorting Theory Topics 2.2 - Data Types

  • Greenfoot | CSNewbs

    Links: Installing Greenfoot Greenfoot Game Tutorial Glossary of Key Code Help with Errors I'm Greta the Gecko and I'm here to teach you Greenfoot.

  • 3.1b - Hardware & Internet - OCR GCSE (2020 Spec) | CSNewbs

    3.1b: Network Hardware & Internet Exam Board: OCR Specification: 2020 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. 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 ) as well as a related IP address (such as 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 . 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 . 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

  • 4.3 - Green IT | Unit 2 | OCR Cambridge Technicals | CSNewbs

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

  • 4.6 - Graphical Representation - Eduqas GCSE (2020 Spec) | CSNewbs

    4.6: Graphical Representation Exam Board: Eduqas / WJEC Specification: 2020 + There are two main types of graphics used in computer systems: raster (also known as bitmap ) and vector graphics. Raster (Bitmap) Graphics Vector Graphics Raster graphics are made up of a grid of pixels . Vector graphics use objects (lines and curves ) to mathematically form shapes. If scaled to a larger size, a vector graphic does not lose any image quality . If scaled to a larger size, a raster graphic loses image quality . Raster graphics are generally larger in file size because data is stored for each pixel . Vector graphics are generally smaller in file size . Examples of raster images include photographs and screenshots. Examples of vector graphics include logos and cartoons. How to Calculate File Size File Size = Resolution x Colour Depth The resolution of an image is the width in pixels multiplied by the height in pixels. x The colour depth (also known as bit depth ) is the number of bits that are used to represent each pixel's colour . 1 bit represents 2 colours (0 or 1 / black or white). 2 bits will allow for 4 colours, 3 bits for 8 colours, 4 for 16 etc. A colour depth of 1 byte (8 bits ) allows for 256 different colours . ​ Remember you must multiply the colour depth , not the number of available colours (e.g. 8 not 256). ​ The RGB (Red , Green , Blue ) colour model uses 3 bytes (a byte of 256 red shades , a byte of 256 green shades and a byte of 256 blue shades ) that together can represent 16.7 million different colours. Example Height = 6 bits ​ Resolution = height x width Resolution = 8 x 6 = 48 bits -------------------------- Colour Depth = 1 bit (only 2 colours) -------------------------- File Size = Resolution x Colour Depth File Size = 48 x 1 = 48 bits ​ File Size in bytes = 48 ÷ 8 = 6 bytes File Size in kilobytes = 6 ÷ 1000 = 0.00 6 kilobytes Width = 8 bits Look carefully at the exam question to see if the examiner is expecting the answer in bits, bytes or kilobytes . ​ Always calculate the file size in bits first then: Divide the file size in bits by 8 to convert to bytes . Divide the file size in bytes by 1000 to convert to kilobytes . Metadata for Graphics Metadata is additional data about a file . Common image metadata includes: ​ Dimensions Colour depth Make Model Orientation Exposure time Metadata is important, For example, the dimensions must be known so the image can be displayed correctly . Metadata for a smartphone-taken picture: width in pixels, e.g. 720 height in pixels, e.g. 480 Q uesto's Q uestions 4.6 - Graphical Representation: 1. Describe three differences between raster (bitmap) and vector images . [ 6 ] ​ 2. How many colours can be represented with a colour depth of... a. 1 bit [ 1 ] b . 5 bits [ 1 ] c. 1 byte [ 1 ] ​ 3. How is the file size of an image calculated? [2 ] ​ 4a. An image file has a width of 10 pixels , a height of 8 pixels and a colour depth of 2 . What is the file size in bytes ? [3 ] ​ 4b. An image file has a width of 120 pixels , a height of 120 pixels and a colour depth of 1 . What is the file size in kilobytes ? [3 ] ​ 4c. An image file has a width of 32 pixels , a height of 21 pixels and a colour depth of 1 . What is the file size in bytes ? [3 ] ​ 5. State what is meant by metadata and give three examples of metadata for a graphics file. [ 3 ] 4.5 Character Sets & Data Types Theory Topics 4.7 - Sound Representation

  • OCR CTech IT | Unit 1 | 1.5 - Communication Hardware | CSNewbs

    1.5: Communication Hardware Exam Board: OCR Specification: 2016 - Unit 1 The devices on this page are used to create or link together networks , allowing data to be sent between computer systems . Hub A hub receives data packets from a connected device and transfers a copy to all connected nodes . Switch A switch receives data packets , processes them and transfers them on to the device s pecifically listed in the destination address of the packet. Modem Modems are used to send data across the telephone network . The telephone lines can only transfer analog signals so a modem is used to convert a computer's digital data into an analog signal . Another modem converts the signal back to a digital format at the receiving end. Router Routers are used to transfer data packets between networks . Data is sent from network to network on the internet towards the destination address listed in the data packet. A router stores the address of each computer on the network and uses routing tables to calculate the quickest and shortest path . Wireless Access Point (WAP) 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. Combined Device Also known as a hybrid device , this provides the functionality of multiple communication devices (e.g modem, router, switch and/or wireless access point) in a single device . They can be more expensive than a single device but are more adaptable - if the routing part of the device fails it might still be able to function as a switch / wireless access point etc. ​ However, you will see an increased performance from a standalone device rather than a combined one as standalone devices have more complex features (e.g. VPN support). Network Interface Card (Network Adapter) A Network Interface Card (often shorted to NIC ) is an internal piece of hardware that is required for the computer to connect to a network . It used to be a separate expansion card but now it is commonly built directly into the motherboard (and known as a network adapter ). Wireless network interface cards allow wireless network connection. Q uesto's Q uestions 1.5 - Communication Hardware: 1. What is the difference between a hub and a switch ? [2 ] 2. Explain how a modem works. [3 ] 3. Explain the purpose of a router . [2 ] 4. What is a Wireless Access Point (WAP )? [2 ] 5. Describe what is meant by a 'combined device '. Give one advantage and one disadvantage of using a combined device. [3 ] 1.4 - Connectivity 1.6 - Hardware Troubleshooting Topic List

  • 7.1 - Language Levels - Eduqas GCSE (2020 Spec) | CSNewbs

    7.1: Language Levels Exam Board: Eduqas / WJEC Specification: 2020 + There are two types of programming languages used within computer systems: High-Level Languages Why do programmers use high-level languages? ​ H igh-level programming languages use code written in a way that is similar to a natural human language , such as English, making it easier to understand and use the language. ​ Using high-level languages leads to fewer errors and allows for more powerful and complex commands compared to low-level languages. ​ However, a high-level language must be translated into machine code (binary) before it can be run, as high-level languages cannot be executed directly by the CPU . Popular high-level languages: PYT HON C++ Ja v a Visual Basic Low-Level Languages Low-level languages do not closely resemble a natural human language , making it harder for humans to understand and write in. ​ Low-level languages are used when a program must be executed quickly or when programmers need to write code that interacts directly with the hardware , such as device drivers. ​ There are two types of low-level language : Machine Code ​ This is the pure binary code that computers can directly process and execute . ​ It is extremely tedious and difficult for humans to understand and write machine code. ​ However, machine code can be used when a programmer needs to perform a very specific command that can't be done in a high-level language. ​ Machine code will be executed faster than high-level programs because it is already in a format the CPU can execute and does not need to be translated . 0010 1011 0101 0101 0110 0111 0101 0001 0101 0101 0101 0100 1010 1010 1010 1010 1111 1110 0010 1001 0100 1001 0010 0111 0111 0101 0011 1010 1000 0101 0110 0111 0000 1010 1010 0011 1101 1001 0010 1101 0010 0100 1001 0011 1010 1001 0101 0101 0010 0101 0111 0101 0101 1000 1011 0111 Assembly Language ​ Assembly language uses specialised command mnemonics to perform actions . See the Assembly Language section in the programming tab for a list of mnemonics such as INP , OUT and HLT . ​ Assembly language is preferred by many programmers over machine code because it is easier to understand and spot errors . ​ It is faster to execute than high-level languages and, like machine code, can be used to directly control the CPU . Q uesto's Q uestions 7.1 - Language Levels: ​ 1a. Describe three reasons why programmers use high-level languages . [ 3 ] 1b. Explain one limitation of using high-level languages . [2 ] ​ 2a. Describe a key difference between low-level languages and high-level languages . [ 2 ] 2b. Describe when a low-level language would be used instead of a high-level language . [2 ] 2c. Describe an advantage and a disadvantage of writing directly in machine code . [2 ] 2d. Describe what assembly language is. Give one benefit to using assembly language instead of machine code and one benefit to using it instead of a high-level language . [3 ] ​ 3. Compare high-level and low-level languages by stating which is: a. Easier to understand [ 1 ] b. Requiring translation [ 1 ] c. Quicker to execute [ 1 ] INP STA Number1 OUT HLT Number1 DAT 6.2 - Utility Software Theory Topics 8.1 - Programming Principles

  • 3.2b - Protocols & Layers - OCR GCSE (2020 Spec) | CSNewbs

    3.2b: Protocols & Layers Exam Board: OCR Specification: 2020 Protocols A protocol is a set of rules that allow devices on a network to communicate with each other . TCP / IP (Transmission Control Protocol / Internet Protocol) TCP / IP is actually two separate protocols that combine together. ​​TCP is a protocol that allows packets to be sent and received between computer systems. It breaks the data into packets and reassembles them back into the original data at the destination. IP is a protocol in charge of routing and addressing data packets . This ensures data packets are sent across networks to the correct destination . It is also an addressing system - every device on a network is given a unique IP address so data packets can be sent to the correct computer system. HTTP is used to transfer web pages over the Internet so that users can view them in a web browser . All URLs start with either HTTP or HTTPS (e.g. HTTPS is a more secure version of HTTP that works with another protocol called SSL ( Secure Sockets Layer ) to transfer encrypted data . You should see a padlock symbol in the URL bar if your connection to that website is secure. HTTP/HTTPS (Hypertext Transfer Protocol) Transfer Protocols FTP ( File Transfer Protocol ) is used to transfer files across a network. It is commonly used to upload or download files to/from a web server . SMTP ( Simple Mail Transfer Protocol ) is a protocol used to send emails to a mail server and between mail servers . POP ( Post Office Protocol ) and IMAP (Internet Message Access Protocol ) are both protocols for receiving and storing emails from a mail server. POP will delete an email once it has been downloaded to a device . Pop! IMAP syncs the message with an email server so it can be accessed by different devices . IP vs MAC Address There are two versions of IP addressing currently used - IPv4 and IPv6 . IPv4 uses a 32-bit address that allows for over 4 billion unique addresses . IPv4 uses a numeric dot-decimal notation like this: 4 billion unique addresses may sound like a lot but there are nearly 8 billion people in the world. Therefore a newer version - IPv6 - was developed with a 128-bit address , represented in hexadecimal that allows for a mind-boggling number of unique addresses. A MAC address is a unique hexadecimal number assigned to each network interface card inside a networked device e.g. a router or a laptop . While an IP address may change , the MAC address can’t be changed . Networking Standards Networking standards are rules that allow computer systems to communicate across networks . Standards have been created to ensure devices can exchange data and work together . 4-Layer TCP/IP Model The TCP/IP model is split into 4 layers . The model is used to visualise the different parts of a network as each of the four layers has a specific role . ​ Splitting a network design into layers is beneficial to programmers as it simplifies design , making it easier to modify and use . ​ Each layer has a certain purpose and is associated with different protocols . ​ The four layers are explained below: 4 Allows humans and software applications to use the network e.g. browsers (HTTP /HTTPS ) and email (SMTP ) and file transfer (FTP ). 3 TCP breaks the data down into data packets . This layer makes sure the data is sent and received in the correct order and reassembled at the destination without errors. 2 IP is responsible for addressing and routing data packets . The optimal route for the data to take is calculated in this layer. Also known as the 'Internet Layer '. 1 Ethernet sets out the format of data packets . This layer handles transmission errors and passes data to the physical layer . Q uesto's Q uestions 3.2b - Protocols & Layers: 1. Describe each of the following protocols . It might be helpful to also draw an icon or small diagram for each one: a. TCP [ 2 ] b. IP [ 2 ] c. HTTP & HTTPS [ 3 ] d. FTP [ 2 ] e. SMTP [ 2 ] f. POP3 & IMAP [ 2 ] ​ 2. State which protocol would be used in the following scenarios : a. Transferring a music file to a friend over the internet. [ 1 ] b. Sending an email to a family member in America. [ 1 ] c. Using a webpage to enter a password securely. [ 1 ] d. Receiving an email from a bank. [ 1 ] ​ ​ 3a. What are networking standards ? [ 2 ] 3b. Describe why network designs are split into layers . [ 2 ] ​ 4. Create a diagram similar to the one above and describe each layer of the TCP/IP Model. [ 8 ] ​ 5. Look at the statements below and name the layer that is being described: a. This layer ensures data packets are sent and received correctly. b. This layer checks for errors in transmission and sets out the data packet format. c. This layer allows software like web browsers to interact with the network. d. This layer uses addresses to ensure data packets take the correct route. [ 7 ] 3.2a - Wired & Wireless Networks Theory Topics 4.1 - Security Threats

  • 1.5 - Performance - Eduqas GCSE (2020 spec) | CSNewbs

    1.5: Performance Exam Board: Eduqas / WJEC Specification: 2020 + The performance of a computer system is affected by three main factors: Cache Memory: Size & Levels What is cache memory? ​ Cache memory is temporary storage for frequently accessed data . ​ Cache memory is very quick to access because it is closer to the CPU than other types of memory like RAM . What are the 3 levels of cache memory? Level 1 cache is the smallest level but it is also the fastest . Level 2 cache is larger than level 1 but slightly slower. Level 3 cache is located outside of the CPU core which makes it slower than the first two levels but it is much larger . How does cache memory work? ​ When the CPU searches for data , it looks first in level 1 cache, then level 2 and then level 3 . If the data has been found , this is called a 'cache hit '. If the data is not found then the CPU searches in RAM instead which takes more time - this is called a 'cache miss '. How does cache memory improve performance? Cache memory is closer to the CPU than RAM , meaning that it can provide data and instructions to the CPU at a faster rate . ​ A computer with more cache memory (e.g. 8MB instead of 4MB) should have a higher performance because repeatedly used instructions can be stored and accessed faster . ​ Larger level 1 and level 2 cache sizes will improve a computer's performance as data can be accessed extremely quickly . What is the limitation of cache memory? Cache memory is costly, so most computers only have a small amount . ​ Multiple cache misses will result in data latency (delay) as information is accessed from RAM which is further away from the CPU. Clock Speed What is clock speed? Clock speed is the measure of how quickly a CPU can process instructions . ​ Clock speed is measured in Gigahertz (GHz) . A typical desktop computer might have a clock speed of 3.5 GHz . This means it can perform 3.5 billion cycles a second . How does clock speed improve performance? ​ The faster the clock speed, the faster the computer can perform the FDE cycle resulting in better performance because more instructions can be processed each second . How does overclocking and underclocking affect performance? Typical clock speed: 3.5 GHz Underclocking Overclocking 3.9 GHz 3.1 GHz Overclocking is when the computer's clock speed is increased higher than the recommended rate. ​ This will make the computer perform faster, but it can lead to overheating and could damage the machine . Underclocking is when the computer's clock speed is decreased lower than the recommended rate. ​ This will make the computer perform slower but will increase the lifespan of the machine . Number of Cores What is a core? ​ A core is a complete set of CPU components (control unit, ALU and registers). Each core is able to perform its own FDE cycle . ​ A multi-core CPU has more than one set of components within the same CPU. How does the number of cores improve performance? ​ In theory, a single-core processor can execute one instruction at a time , a dual-core processor can execute two instructions, and a quad-core can execute four instructions simultaneously . ​ Therefore, a computer with more cores will have a higher performance because it can process more instructions at once . What are the limitations of having more cores? ​ If one core is waiting for another core to finish processing, performance may not increase at all. ​ Some software is not written to make use of multiple cores , so it will not run any quicker on a multi-core computer. Q uesto's Q uestions 1.5 - Performance: ​ Cache Size & Levels 1a. What is cache memory ? [ 2 ] 1b. Describe the three levels of cache memory . [ 3 ] 1c. Describe what is meant by a ' cache hit ' and a ' cache miss '. [ 2 ] 1d. Describe two ways that more c ache memory will mean performance is higher . [ 4 ] 1e. Explain why most computers only have a small amount of cache memory. [ 1 ] Clock Speed 2a. What is clock speed ? What is it measured in? [ 2 ] 2b. Explain how a higher clock speed improves performance . [ 2 ] 2c. Explain the terms 'overclocking ' and 'underclocking ' and explain the effects of both on the performance of a computer. [ 4 ] ​ Number of Cores 3a. What is a core ? [ 2 ] 3b. Explain why a quad-core processor should have a higher performance than a dual-core processor . [ 3 ] 3c. Explain two reasons why having more cores doesn't necessarily mean the performance will be better . [ 2 ] 1.4 - Secondary Storage 1.6 - Additional Hardware Theory Topics

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