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C omputer S cience Newb ie s CSNewbs is aimed at GCSE Computer Science and OCR Cambridge Technicals IT students . ​ The site is viewed in the UK and internationally by thousands of users each week . ​ Click here for frequently asked questions and information about CSNewbs . ​ TEACHER RESOURCES ! Take a free sneak peek at the Eduqas GCSE resources coming soon ! Quick links to popular topics on CSNewbs: What's New on CSNewbs? Python OCR Cambridge Technicals Level 3 IT You are viewing the mobile version of CSNewbs. The site may appear better on a desktop or laptop . WJEC / Eduqas GCSE Topics Greenfoot Brand new Greenfoot topic section ​ Updated Greenfoot Glossary of key code ​ New Greenfoot tutorials on YouTube ​ New HTML tutorials on YouTube ​ Improved 6.6 Logical Protection (OCR Unit 2) ​ Improved 4.1 UK Legislation (OCR Unit 2) CSNewbs last updated: Tuesday, 30th March 2021 You are viewing the desktop version of CSNewbs. Have you tried it on mobile ? Keep updated on social media:

4.5: Sound Representation Exam Board: Eduqas / WJEC Specification: 2016 + To on a computer must be store sound analog sound waves converted in to digital data ( binary ). The sound is sampled using an ADC (Analog to Digital and (such as 01010011) called Convertor) stored as a binary value a . sample 0010 1011 0101 0101 Analog sound wave ADC (Analog to Digital Converter) Binary sample Sampling an Analog Sound Wave Digital sampling is and not continuous like analog waves. discrete (separate) To get the sound, highest quality many samples are taken to recreate the analog wave as . closely as possible Sample Rate The is the . sample rate number of samples taken per second It is measured in (kHz), for example CD quality is 44.1kHz (44,100 kilohertz samples per second). The , the as the digital data more . higher the sample rate better the audio quality closely resembles an analog wave ​ However, because for each individual sample. higher sample rates result in larger file sizes more data is stored A will result in a because the . low sample rate low-quality sound digital data does not closely resemble the original analog wave A will result in a because the . higher sample rate higher-quality sound digital data more closely resembles the original analog wave Improving Audio Quality Bit Depth Bit Rate The is defined as the . It is measured in ( ). bit rate amount of audio data processed per second kilobytes per second kbps The bit rate is calculated by . multiplying the sample rate and bit depth ​ Because the bit rate is the measure of the sample rate and bit depth multiplied together, the . the higher the bit rate higher the quality of the sound The is the number of bits . For example, a sample with a bit depth of 4 could be 0101 or 0111 or 1010. A sample with a bit depth of 8 could be 01010110 or 1010110 or 11001111. A common bit depth is . bit depth available to represent each sample 16 bits The higher the bit depth , the to be used for each sample. Therefore the . more bits are available quality is often higher as the wave more closely resembles an analog wave ​ The if the bit depth is higher, as . file size will also be larger each sample stores additional bits A short audio sample has a and a samples . The clip is . Example: bit depth of 4 sample rate of 10 per second 15 seconds long ​ by : 4 bits x 10 = . Calculate the bit rate multiplying the sample rate and bit depth 40 bits Now that is the correct data for Multiply the by the in the file: 40 x 15 = . one second. bit rate number of seconds 600 bits ​ To convert the answer from , . bits to bytes divide by 8 ​ 600 bits ÷ 8 = . 75 bytes Calculating File Size Metadata for Sound Files ​ Music libraries such as Apple Music or Spotify store a huge amount of on each song. Metadata is such as: metadata additional data about a file Artist Title / Track Title Product / Album Title Track Number Date Created / Year Genre Comments Copyright Software Type Duration File size Bit rate Sampling rate Channels Volume uesto's uestions Q Q 4.7 - Sound Representation: ​ 1. Explain how an analog sound wave is converted into a binary sample . [ 2 ] ​ [ 2a. What is a sample rate ? 1 ] [ 2b. Explain two ways an audio file will be affected if the sample rate is increased . 4 ] [ 3a. What is bit depth ? 2 ] [ 3b. two ways Explain an audio file will be affected if the bit depth is increased . 4 ] 3c. Explain what the bit rate is. [ 2 ] ​ . An audio sample has a , a and it is . What is the file size in ? 4 bit depth of 8 sample rate of 10 12 seconds long bytes [ 2 ] ​ 5a. What is metadata ? [ 2 ] 5b. State four different types of metadata for audio files . [ 4 ] low bit rate = lower quality high bit rate = higher quality Converting Analog Sound to Binary 1 4.4 Graphical Representation Theory Topics 4.6 - Compression

9.5: Data Management Exam Board: Eduqas / WJEC Specification: 2016 + Why is data management important? Managing data is important to is . ensure that sensitive information not accessed by unauthorised users such as hacking could lead to , , , and for both organisations and individuals. Data loss legal trouble identity theft privacy invasion fraud financial losses User Access Levels are used to particular files. Access levels only allow certain users to access and edit ' Read-Only ' access is when a user can only view a file and is not allowed to change any data . ​ For example, a teacher might set homework instructions as for students to view. read-only ' Read and Write ' access allows a user to read and edit the data in a file. ​ For example, a teacher might set an online workbook as access for students to fill in. read and write so that can view and change data. The more users who have access to a file, the more likely it is to be compromised. Certain users may also have to a file - when they can't view or edit it. It is important to set access levels only authorised users no access Suitable Passwords are required to the of and to from . Strong passwords minimise likelihood being broken prevent attackers accessing private information ​ Rules for creating a strong password include: Aa Bb Cc Dd Ee ********* Passwords should be more than at least 8 characters long. Passwords should use uppercase and lowercase letters . Passwords should not use common words found in a dictionary . Passwords should use numbers and punctuation marks . You should use a different password for each account that you have. Encryption is the process of into an so that it during transmission. Encryption scrambling data unreadable format attackers cannot understand if intercepted ​ The (known as ) is using an . Only at the correct destination will the be used to back into to be understood by the receiving computer. original data plain text converted to scrambled cypher text encryption key encryption key convert the cypher text plain text ​ A very simple method of encryption is to use the . is used on the to . Using on the will reverse the encryption to . XOR logical operator XOR plain text and key together create the cypher text XOR again cypher text and key reveal the plain text Encryption using XOR = 00110100 Plain text = Key 10100110 XOR = 10010010 Cypher text Decryption using XOR ​ = 10010010 Cypher text = / Key 10100110 XOR = 00110100 Plain text Data Policies are that clearly in an organisation. It is important that all employees stick to these policies and requirements so that data is kept safe and can be replaced if lost or corrupted. The following methods are examples of common data policies. Data policies written documents define how data should be managed Acceptable Use Policy (AUP) Workplaces and schools often require people to sign an being allowed to use the network. It is a and that when using the computer systems. acceptable use policy (AUP) before list of rules expected behaviour users must follow Typical rules include: (such as social media or gambling sites), Which websites are off-limits (such as who can download and install software) Download permissions (such as appropriate language). Email communication if rules of the AUP are broken. Punishments ​ The AUP is sometimes known as a . This is an example of a , with . An would , such as (e.g. email layout or desk organisation). Code of Conduct formal code of practice written rules and clear expectations informal code of practice not be officially written down personal habits and preferences Disaster Recovery With important data often stored on a computer network, it is absolutely vital that a detailed and effective is in place in the event of data being lost due to an unexpected disaster. disaster recovery policy ​ Disasters include (e.g. fire, flood, lightning), (e.g. power supply unit failing), (e.g. virus damage) and (e.g. hacking). natural disasters hardware failure software failure malicious damage ​ ​ ​ There are three clear parts to a disaster recovery policy:​​ Before the disaster: All of the to spot if there are any weaknesses in preparation. possible risks should be analysed should be taken after the analysis, such as making rooms or storing important data at a . Preventative measures flood-proof different location should take place to inform employees what should happen in the event of a disaster. Staff training During the disaster: The is very important – employees should and ensure that data is protected and appropriate measures are put in place. staff response follow their training should be implemented while the disaster is taking place, such as or in a safe room and until the disaster is over. Contingency plans uploading recent data to cloud storage securing backups using alternative equipment After the disaster: should be followed, such as using backups to repopulate computer systems. Recovery measures needs to be purchased for equipment that is corrupted or destroyed. Replacement hardware on the new hardware. Software needs to be reinstalled Disaster recovery policies should also be . updated and improved Backup System backup in case the . copies data onto a separate storage device original information is lost or corrupted ​ Backups should be and to the rest of the data. is a common backup medium. saved regularly stored in a different location Magnetic tape ​ A typical backup policy is one known as ' which uses at a time. grandfather - father - son' three different backups (e.g. every month) Grandfather backup (e.g. every week) Father backup (e.g. every day) Son backup Archiving When data is , but is , it is . no longer needed regularly still important archived ​ This means it is . Data can be archived on or and stored in a secure room or archived on . stored in a secure location to be retrieved if needed external hard disk drives magnetic tape cloud storage Data may be archived for: (such as ex-students data in a school). Historical reasons (such as CCTV tapes for previous months). Security (such as laws requiring police data to be kept for a certain amount of time). Legal reasons - there is little use in storing a large amount of data that is infrequently accessed and slows down access speed for other files. Data is archived so that space is freed up on the computer system or network An will set out should be archived and it needs to be kept for. archival policy what data how long Cookies A when you visit them. They and are often used to , such as: cookie is a small piece of data that is stored by websites allow the website to identify the user speed up processes (by saving account details) Automatic login (such as pizza delivery sites) Save items into a basket . Display adverts related to your previous search terms Although they can be used to save time, some argue that cookies can be and store too much information. intrusive uesto's uestions Q Q 9.5 - Data Management: ​ 1. Why is data management important? [ 2 ] ​ [ 2a. Why are user access levels important? 1 ] 2b. Explain the two main types of access level and give an example . [ 4 ] ​ 3. State 5 tips for choosing a strong password . [ 5 ] ​ 4a. Describe what encryption is. Use keywords such as plain text , encryption key and cypher text . [ 4 ] 4b. Using an example , explain how XOR can be used to encrypt data . [ 3 ] ​ 5a. What is the purpose of an acceptable use policy ( AUP )? [ 2 ] 5b. State 4 things that may be included in an AUP . [ 4 ] 5c. Describe the difference between formal and informal codes of practice , using examples . [ 4 ] ​ 6a. State 3 different events / scenarios that count as a disaster . [ 3 ] 6b. Describe the steps an organisation should take during each stage of a disaster recovery plan : Before i. During ii. After [ iii. 3 each ] ​ 7a. What is a backup and why should they be regularly made ? [ 2 ] 7b. State and briefly describe a common backup policy . [ 2 ] ​ 8a. What is archiving ? [ 2 ] 8b. What types of data are archived ? [ 3 ] 8c. Why is archiving performed? [ 2 ] ​ 9. Describe what a cookie is and give 3 ways in which they can be used . [ 4 ] 9.4 Identifying Vulnerabilities Theory Topics 10.1 - Ethical Issues

about Frequently Asked Questions Computer Science Newbies Who made CSNewbs? My name is Mr Pulsford . I am a Computer Science teacher from London and I currently teach at a secondary school in Birmingham , England . ​ When and why did you make this? I wanted to make a resource that my . I was working on a paid summer project at in London in students could access outside of the classroom G o o g l e 2016 when I was inspired to start the site. I've been updating it ever since as much as I can, outside of lessons and life. I made CSNewbs to support students in lessons and at home because Computer Science can be a tricky subject and many websites are too technical or peripheral . Which courses does CSNewbs cover? The ' GCSE ' section follows the Eduqas specification ( both 2016 and 2020 ). The ' CTech ' section follows the OCR Cambridge Technicals Level 3 IT 2016 specification for Unit 1 (Fundamentals of IT) and Unit 2 (Global Information). The ' Programming ' section contains material for Python , HTML , Greenfoot and others. The ' KS3 ' section covers basic Computer Science topics aimed at Year 7 - 9 students . ​ Do the exam boards pay you money for this? CSNewbs is , . The content on this site has been by closely following the publicly released specifications by Eduqas and OCR. not affiliated with any exam board financially or otherwise independently created ​ Can I get a level 9 / distinction just from CSNewbs? The content on this website is of and should be used to of the course's content. Like all resources , it should be and . CSNewbs makes no miraculous claims linking content use and final exam results.​ high-quality guide students towards a better understanding however supported with a range of appropriate material sound classroom teaching How did you make this website? CSNewbs.com was created and is maintained using . Wix ​ What's the deal with copyright? CSNewbs is , and copy / paste features have been disabled on the site. All images have either been or used from . Embedded videos are linked to content from the page. If you think any content on this site , please email me, and I will make . protected by copyright created by myself Wix's copyright-free vector gallery / their stock image library CSNewbs YouTube infringes a copyright-protected work immediate changes ​ I don't see any adverts, how are you making money? You're right, there are and I intend to keep it that way. including but the . no adverts CSNewbs teacher resources are currently in development lesson slides , worksheets and revision activity sheets content on the site will always stay free and available ​ Can you add Unit 3 / OCR A-Level / something else? The site continues to . The eventual aim is to cover every exam board for GCSE Computer Science but that will take a lot of time! expand over time with new content Who is the robot? The robot is called Questo . It's the site mascot and it appears on most pages to ask you questions about the content (' Questo's Questions '). It used to have a body but since 2020 it's just a head. ​ I can't believe one person made this whole site while teaching and the rest, what are your long-term plans? If you work for an exam board or educational resource organisation , and your organisation has opportunities available , please send me an email. How can I contact the creator of CSNewbs? The contact email is: You can stay updated on CSNewbs additions and improvements by following our social media pages : Privacy Policy

3.1: Network Characteristics Exam Board: Eduqas / WJEC Specification: 2020 + What is a network? A network is allowing for and . more than one computer system connected together communication sharing of resources There are many benefits but also some drawbacks to using a network compared to having an unconnected ( ) computer: 'standalone' Advantages of Networks Easily , and between computers. share files software hardware Disadvantages of Networks Larger companies will need to buy and . There is an because like routers are . initial cost network devices required maintain a server and and files. Log in from any connected computer access your data A network manager / administrator might need to be employed to maintain the network . An administrator can monitor network activity and control security settings. Data from computers on the network can be automatically backed up on central storage. and , such as worms, can across the network. Security breaches are more likely malware spread quickly If the web server fails , all connected computers won't be able to access files or log on . Network Types Networks can be split into , usually categorised by their apart and the that they serve. different types geographical distance area Local Area Network A ( ) has computer systems situated , usually within the , like a . local area network LAN geographically close together same building or small site school or office Wide Area Network A ( ) has computer systems situated to each other, possibly or even . The that spans the globe. wide area network WAN geographically distant across a country across the world internet is an example of a WAN Personal Area Network A PAN is a personal network for an individual , such as a photographer connecting a smartphone, desktop computer and printer together. Metropolitan Area Network A is larger than a LAN but smaller than a WAN and typically covers a relatively large area like a . MAN university campus, town or city Virtual Private Network A allows for a like the internet. It is often used to an individual's by concealing their real location. VPN secure and encrypted connection to a public network protect privacy Wired & Wireless Networks Wired Connections Wireless Connections Wireless connections, such as or , use but require a ( ). WiFi Bluetooth no cables wireless network interface card WNIC Wireless connections generally have a and can be the computer's from the wireless router as well as like walls or bad weather. slower speed affected by distance obstacles Wired connections use , such as , and require a ( ) to connect to a network. physical cables copper or fibre optic wires network interface card NIC These wired connections use a wired connection protocol - most commonly . Ethernet Restricted Movement Faster More Secure NIC Required Freedom of Movement Slower Less Secure WNIC Required uesto's uestions Q Q 3.1 - Network Characteristics: ​ A retirement home for the elderly is considering installing a , give and they might find . [ ] 1. LAN 3 benefits 3 drawbacks of using a network 6 ​ Describe the between a and . [ ] 2a. difference LAN WAN 2 Give an example of how a and a could each . [ 2b. LAN WAN be used 2 ] ​ 3 differences between a , and . [ . Explain the PAN MAN VPN 3 ] ​ For each of the below, state which would be : 4. scenarios network type most suitable The IT rooms of a secondary . [ a. school 1 ] A study in a with a desktop and printer. [ b. house 1 ] Using online banking when abroad on a holiday to stay . c. secure [ 1 ] A large technology company with offices across . d. Europe [ 1 ] Council offices with several locations across . e. Manchester [ 1 ] ​ Briefly and . 5. compare wired wireless networks [ 8 ] 2.2 - Boolean Algebra 3.2 - Data Packets & Switching Theory Topics

4.6 & 4.7 - Bodies & Certification Exam Board: OCR Specification: 2016 - Unit 1 What is a professional body? A is an organisation that seeks to in a certain profession. professional body develop and support workers ​ Professional bodies will , help people and support any . share best practice starting in the profession role-related learning ​ In the UK a popular professional body is the - also known as the Chartered Institute for IT - with over 65,000 members. British Computer Society (BCS) What is industry certification? exist to provide trainees with . Professional bodies industry certification Industry certifications are in different areas of expertise so applicants are . qualifications trained with up-to-date knowledge and skills ​ Two popular organisations that administer industry certifications in America are and . Cisco's website claims that they provide "certifications for covering topics in , , , and more. Cisco's certification program can meet you where you are on your learning journey and take you to where you want to go." Cisco CompTia all experience levels networking security collaboration Advantages of Industry Certification Disadvantages of Industry Certification Develop IT skills: Trainees develop and ​ experience competency in areas relevant to actual jobs. Access resources: Trainees are part of a of like-minded professionals with access to from . network help experts P rofessional development opportunities: ​ Trainees are invited to special and seminars to ensure . events skills remain up-to-date Cost: Training for industry certification can cost or even thousands of pounds and is often . ​ hundreds self-funded No guarantees: ​ Earning a certificate or more money. doesn't guarantee you a better job Time and dedication: Like other qualifications, or must be completed. must be passed at the end of the course. ​​ classroom activities online learning Exams Many organisations now to have . require IT employees earned relevant industry certifications​ This is so that the that the and will have at the for the certification. The employee should be able to as a result of gaining the certification. organisation can be confident employee has been appropriately trained gained experience required level demonstrate technical knowledge uesto's uestions Q Q 4.6 & 4.7 - Bodies & Certification: ​ What is a ? [ ] 1a. professional body 1 State 3 roles of a . [ ] 1b. professional body 3 ​ What are ? [ ] 2. industry certifications 2 ​ Describe and of an IT worker . [ ] 3. 3 advantages 3 disadvantages earning industry certifications 2 each ​ Why do many IT organisations to have ? [ ] 4. require its employees earned industry certifications 4 4.5 - Job Roles Topic List 5.1 - Ethical Issues

Python 1a - Printing Printing in Python To onto the screen, use the command. output a message print Then place your message and . For example: within brackets speech marks When you press (or click the ‘ ’ tab then ‘ ’), the text will print to the Python shell: F5 Run Run Module Practice Task 1 1 . Print your full name to the screen. ​ he name of the person (or thing) to your left. 2. On the next line, write another print statement to print t Example solution: Printing over Several Lines One way of writing across multiple lines is to write several print commands like this: = However, when we program, we always want to make our code the by . most efficient it can be using as few lines as possible ​ Therefore you can write within a printed statement to transfer it to the next line. \n = Both pieces of code display the same thing, but the second one is more because it only uses one line. efficient Practice Task 2 1. O n line 1 print your first name to the screen. 2. On line 2 print your favourite colour. 3. On line 3 print your favourite movie. 4. Run the program. he same output but using only line of code (Hint: use ) 5. Now re-write your program to print t \n Example solution: Setting up Python 1b - Commenting

Python - Section 5 Practice Tasks Task One Ask the user to enter 4 different numbers. Then select one of those numbers and print it. randomly Example solution: Task Two You will make a program for logging into a system. Print a greeting then ask the user for their name. then print “logging in” and the user’s name. Wait 2 seconds Then print the (current hour and minute). current time Example solution: Task Three Generate a between 3 and 10. random number Print this number then print the . current minute and current second for the random number you generated then print the current minute and current second again. Wait Example solution: 5c - Date & Time 6a - For Loops

Python 7a - Procedures Subroutines A is a in the same program. subroutine section of code that can be re-used several times It is from the main code and has to be upon. separate ‘called’ Subroutines are designed to be repeated, and they have three key benefits: ​ Subroutines make programs . easier to read They . reduce the duplication of code are into . Complex problems broken down smaller chunks ​ There are of subroutines: and . two types procedures functions ​ A just , such as printing something a certain number of times. procedure executes commands A produces information by receiving data from the main program and to the main program. function returning a value For example, a function could take the radius of a sphere from the main program, calculate a sphere’s area and return the value of the area to the main program. A function generally requires to work – these are the values to be transferred from the main program to the subroutine. parameters Procedures A s a type of that . procedure i subroutine runs independently of the main program ​ A subroutine before the main code by typing and the . must be defined at the top of the program def name of the subroutine ​ In the example below I have created a procedure to calculate the multiplication of two numbers and a separate procedure for the division. The starts , against the left side of the editor. main program beneath the subroutines ​ I have created a that asks the user if they want to multiply, divide or stop the program. while true loop ​ If they choose to multiply, the is . This initiates that subroutine then when it is complete. multiply subroutine called returns to the main program ​ If they choose to divide, the is instead. Typing stop will (end) the loop. divide subroutine called break Here you can see the two parts of the program put together. ​ , with the rest of the program underneath. Subroutines must be written first . Below I have run the program and divided then multiplied before breaking the loop: Subroutines can be called in any order Practice Tasks 1 Create a procedure called hello that just prints “Hello there ”. 1. ! ​ In the main program create a for loop that calls the procedure 10 times. ​ You must use a procedure. Create a program with two procedures. The addition procedure allows the user to add two numbers together. The subtraction procedure allows the user to take a number away from another. Use a while true loop in the main program and a break to stop the loop. 2. Example solution for #1: Local & Global Variables Programming languages use and . local variables global variables ​ A can be . global variable used anywhere in the program ​ A can . local variable only be used in the subroutine it is created in ​ I have adapted the multiply / divide program below to use global variables by stating the command and the in each subroutine. This allows me to ask the user to enter numbers in the main program. global name of the variables Practice Tasks 2 1. Adapt your addition / subtraction program from the first practice task section to use global variables. ​ Create a program that asks the user to enter their name in the main program. Call a subroutine that greets the user using the name variables. 2. You must use a procedure and a global variable . Example solution for #2: Section 6 Practice Tasks 7b - Functions

Python 10c - Split & Edit Files Splitting a File The command is used to into . split split up a line of a file different parts ​ The or string after the split command is the that will . character in brackets value denote each split ​ In the example below I have . Remember that Python numbering so the first section is 0, not 1. split the file at each comma starts at 0 0 1 2 3 The program below each line of the file at each forward-slash ( ). splits / ​ The printed statement is the employee's first name, surname and job position. 0 1 2 3 4 Practice Task 1 Create a file (new txt document in Notepad) called movies. ​ Type in the movie name, main actor, genre (e.g. horror), year it was released and your rating out of 10. ​ Print just the movie name and year it released. Example solution: Editing a File in a file is a tricky process. Overwriting data ​ The program below uses the same Employees.txt file as above but allows the user to . change the address of an employee ​ A is created to store the lines of the employee file, but the line with the changes is specifically with the new address. temporary file replaced I have of the program to the right: explained each line When I executed the program below I entered Thomas Wynne's details and changed his address. ​ When I opened the employees file the address had been updated : 1: Importing os allows me to rename and remove files later in the program. ​ 3: Opens the employee file in read mode . ​ 5 - 8: Input lines allow the user to enter the first name, surname and the person's new address. ​ 10: A found flag is set up and set to False . ​ 12: The for loop cycles through each line in the file. ​ 13: Each line is split into separate parts from each / . ​ 15: An if statement checks if the first name and surname match an employee in the file. ​ 16: A replacement line is created by putting the original line together but with the new address. ​ 18: The found flag is changed to True because the employee first name and surname matched . ​ 19: A temporary file is created and opened in write mode . ​ 20: The seek command restarts the file at line 0 . ​ 22: The for loop cycles through each line of the employee file from the beginning. If the first name and surname match it will write the new line to the file, otherwise it will rewrite the original line . ​ 28 & 29: Both files are closed . ​ 31 & 32: If the names didn't match , an appropriate message is printed. ​ 34 - 37: If the address was changed, the original file is renamed and deleted and the temp file is renamed as the original file. Practice Task 2 Use the movie file you created for practice task 1. ​ Ask the user to enter the name of a movie. Ask them to enter an updated rating out of 10. ​ Update the file to change the rating to the new value. Example solution: 10a - Read & Search Files Section 10 Practice Tasks