OCR GCSE Computing Learning Grids H/W

COMPUTING GCSE OCR J275 OCR GCSE Computing Learning Grids H/W Unit A451: Computer Systems and Programming This learning grid H/W belongs to: Name: Form: Mr. Ahmed

A451 - ATTENTION! Please read! These learning grids cover the key theory content of the OCR GCSE Computing specification. Learn them and you will pass the exam! The grids closely follow the content and order of unit A451: Computer Systems and Programming. Complete each section for homework once they are covered in your lessons! All sections must be fully completed! Once you have completed a section hand it in to your teacher. To help you find the information you need, the grids contain page references to the corresponding sections of GCSE computing book: HODDER OCR Computing for GCSE published by Hodder Education (ISBN: 978-14441-7779-4).

Contents Blank Grids... Error! Bookmark not defined. 1 Fundamentals of Computer Systems... 2 2 Computing Hardware... 4 3 Software... 9 4 Representation of Data in Computer Systems... 11 5 Databases... 17 6 Computer Communications and Networking... 20 7 Programming... 26 Talk to Us! Love it as it is? Let the author and other teachers know what you think Got a suggestion? If your improvement leads to an update we will send you a new copy for free Found a problem? We will fix it and send you a free updated copy OCR GCSE Computing Learning Grids Page 1 of 28

L 1 Fund ament als of Comput er Syst ems 1 FUNDAMENTALS OF COMPUTER SYSTEMS HODDER: 7-16 COMPUTER SYSTEMS What is a computer system? What is the name for the interconnections between systems? What are the three main stages in any system? 3. What is a system boundary? Why can they be difficult to define? What is the difference between generalpurpose and dedicated systems? Give an example of each. Difference: Examples: What is an embedded system? Explain what is meant by the kernel in operating systems. Why is reliability important in computer systems? Give an example of a situation in which reliability is essential. OCR GCSE Computing Learning Grids Page 2 of 28

1 Fundamentals of Computer Systems COMPUTER SYSTEMS (CONTINUED) How can the reliability of a system be assessed? Why is it useful to develop systems to standards? Explain the difference between proprietary and open standards. What name is given to a standard which develops simply through common usage? Give an example of a computing industry standard. What is meant by ethics in regard to computer use? How has the Internet affected people's right to privacy? Describe two ways in which the use and disposal of computer systems can have a negative effect on the environment. State two UK legal acts relating to computer use, and explain the purpose of each. OCR GCSE Computing Learning Grids Page 3 of 28

L 2 Co mputing H ardwar e 2 COMPUTING HARDWARE HODDER: 18-45 CENTRAL PROCESSING UNIT (CPU) HODDER: 19-23 What is the purpose of the CPU? What are the two main components of the CPU? What cycle does the CPU carry out continuously to process instructions? What is meant by clock speed? What component controls the clock speed? Who is credited with the idea of storing data and programs in the same place in the computer architecture? What is a dual-core CPU? In computing, what is a bus? MEMORY HODDER: 25-30 What does the ROM usually store? What is virtual memory, and why is it used? What is a disadvantage of having to use virtual memory? OCR GCSE Computing Learning Grids Page 4 of 28

2 Computing Hardware MEMORY (CONTINUED) What is flash memory? Using an example for each, explain the difference between primary and secondary storage. What is the purpose of cache memory? What it the purpose of RAM? How could the addition of extra RAM speed up a computer? Why might this not always be effective? BINARY LOGIC HODDER: 31-35 ZIGZAG: 13-15 Why do computers operate in binary? What is a logic gate? Name three types of logic gate. What are truth tables used for? What logic gate does this symbol represent? OCR GCSE Computing Learning Grids Page 5 of 28

2 Computing Hardware BINARY LOGIC (CONTINUED) What logic gate does this symbol represent? What logic gate does this symbol represent? Draw a truth table for the following circuit. A B R=A OR B P What name is given to the branch of algebra used in logic circuits? INPUT AND OUTPUT DEVICES HODDER: 36-41 Name three input devices. 3. Name three output devices. 3. Give an example of a device which has both input and output functionality. State a common application of the device given in the previous question. OCR GCSE Computing Learning Grids Page 6 of 28

2 Computing Hardware INPUT AND OUTPUT DEVICES (CONTINUED) State and describe a suitable input device for a user with a visual impairment. State and describe a suitable input device for a user with severely limited physical mobility. Device: Description: Device: Description: What is a sensor? What is an actuator? Name two input devices typically found on a smartphone. Name two output devices typically found on a smartphone. State and describe a suitable output device for a user with a visual impairment. Device: Description: State and describe a suitable output device for a user who is unable to communicate verbally. Device: Description: State three applications of RFID tags. 3. Describe two types of printer and suggest what applications they might have. OCR GCSE Computing Learning Grids Page 7 of 28

2 Computing Hardware SECONDARY STORAGE HODDER: 42-45 Why is secondary storage necessary? Name the three main categories of secondary storage device. State three common secondary storage devices and describe a purpose for which each might be used. 3. 3. Briefly describe how data is physically written to a hard-disk. Briefly describe how data is physically written to a CD or DVD. Name the five factors that are necessary to consider when choosing an appropriate secondary storage device. What is the most common secondary storage device used as the main storage for desktops and laptops? 3. 4. 5. OCR GCSE Computing Learning Grids Page 8 of 28

L 3 Softwar e 3 SOFTWARE HODDER: 47-67 SOFTWARE HODDER: 47-67 Define the term software. What is a user interface? Describe two different types of user interface that could be used to operate a computer. Explain the difference between system software and application software. How can an operating system multitask? What is meant by memory and peripheral management? Give three examples of common security features in operating systems. 3. What is meant by utility software? OCR GCSE Computing Learning Grids Page 9 of 28

3 Software SOFTWARE (CONTINUED) Name and describe two types of disk organisation utility. Name and describe two types of system maintenance utility. Name and describe two types of security utility. Explain the difference between customwritten and off-the-shelf software. Describe one advantage to a business of using custom-written software. Describe one disadvantage to a business of using custom-written software. Explain the difference between proprietary and open-source software. Describe one advantage of using open-source software. Describe one disadvantage of using open-source software. OCR GCSE Computing Learning Grids Page 10 of 28

L 4 R epresent ation of Dat a in Computer Syst ems 4 REPRESENTATION OF DATA IN COMPUTER SYSTEMS UNITS HODDER: 70 What name is given for the number system in base 10 that humans use? What name is given to the number system in base 2 that computers must use to store and process data? HODDER: 69-88 Why must all data be converted into this form before it can be processed by the computer? Fill in the gaps in the sequence to order the binary units from smallest (top) to largest (bottom). bit byte kilobyte gigabyte How many bits are there in a byte? How many bytes are there in a kilobyte? How many bits are there in a kilobyte? What name is given to the unit made up of approximately a billion bytes? What name is given to the unit made up of 1,024 gigabytes? Consider a five-digit binary number. What is the highest number that can be stored? OCR GCSE Computing Learning Grids Page 11 of 28

4 Representation of Data in Computer Systems NUMBERS HODDER: 70-76 Convert these binary numbers into denary. 010 10101 1110 0011 Convert these denary numbers into binary. 34 53 Convert these hexadecimal numbers into denary. 37 C4 Convert these hexadecimal numbers into binary. Hint: convert each hex digit into four binary digits and concatenate. 41 5D Why is hexadecimal number representation often used in computing? Add these two binary numbers together. 101 1101 + 001 1010 Explain a problem that can arise when adding two 8-bit binary integers to get an 8-bit answer. OCR GCSE Computing Learning Grids Page 12 of 28

4 Representation of Data in Computer Systems CHARACTERS HODDER: 78-79 How are individual characters represented by a computer? What is meant by the term character set? What does ASCII stand for? How many different characters can the ASCII set represent? How many bits does this use per character? Explain the limitations of using ASCII for global communication. Suggest a different character set that would be more useful for global communication. How many bits does this character set use per character? Explain one possible disadvantage to using this character set instead of ASCII. Do you think that this is a significant problem or not? OCR GCSE Computing Learning Grids Page 13 of 28

4 Representation of Data in Computer Systems IMAGES HODDER: 80-83 What is a pixel? Describe how a simple black and white bitmap image can be stored by the computer. The binary numbers below represent a simple black and white bitmap image. On the 8 8 grid, fill in the appropriate spaces to create the image. A 1 represents black and a 0 represents white. Fill in each 8-bit string of digits in regular reading order. 1111 1111 1000 0001 1000 0001 1000 0001 1000 0001 1111 1111 0001 1000 0111 1110 How is the storage of a colour images different from that of black and white images? What is colour depth? What is metadata? What information might typically be stored in image metadata? OCR GCSE Computing Learning Grids Page 14 of 28

4 Representation of Data in Computer Systems IMAGES (CONTINUED) What is resolution? What are the effects of colour depth and resolution on the file size of the image? How do vector graphics differ from bitmap images? What is a possible advantage of using vector graphics instead of bitmaps? SOUND HODDER: 84-86 Explain the difference between analogue and digital signals. Describe the process of converting an analogue sound signal to digital. What is meant by the sample rate of an audio recording? What effect does the bit rate have on the audio quality? What effect do the bit rate and sample rate have on the file size of the recording? OCR GCSE Computing Learning Grids Page 15 of 28

4 Representation of Data in Computer Systems INSTRUCTIONS HODDER: 87-88 Explain how the CPU distinguishes between instructions and data. What are the two parts of each program instruction called? What are registers? What is the name of the register which keeps the address of the next instruction to be processed? What is the name of the register that stores data currently in use? What is an address? OCR GCSE Computing Learning Grids Page 16 of 28

L 5 D atabases 5 DATABASES HODDER: 90-110 THE DATABASE CONCEPT HODDER: 90-96 Define database. Explain the difference between a serial file and a sequential file. What is an indexed sequential file? What is a flat file database made up of? How many tables does a flat file database have? What is meant by data redundancy? Why is this undesirable? Explain the difference between data validation and data verification. State three types of data validation check. 3. DATA MODELS HODDER: 96-98 What is a relational database? State two other database models. What name is given to a subject about which data is stored? What is a meant by a one-to-many relationship? OCR GCSE Computing Learning Grids Page 17 of 28

5 Databases DATA MODELS (CONTINUED) Draw a diagram which represents a one-to-many relationship, using an example of your choice. What are attributes? How are attributes stored in a data table? What are records? How are records stored in a data table? DATABASE DESIGN HODDER: 98-100 What a schema? What data structure stores schemata? What are primary keys used for? What quality must primary keys have to make them useful? What is meant by mission critical databases? State four decisions which must be made about each field in the database. 3. 4. What is a foreign key? OCR GCSE Computing Learning Grids Page 18 of 28

5 Databases DATABASE MANAGEMENT SYSTEMS (DBMS) HODDER: 100-109 What is a DBMS? What is the purpose of using a DBMS? Give three examples of ways in which the DBMS enables protection and security. Name and describe three different ways in which a database can be viewed. 3. 3. How does the DBMS deal with concurrency problems? What does the acronym ACID stand for? A: C: I: D: What is the purpose of ACID? What is a query and what are they used for? What does SQL stand for? Explain what is meant by the term data mining. Suggest one reason why many highstreet chains of shops issue electronic loyalty/reward cards to customers. OCR GCSE Computing Learning Grids Page 19 of 28

L 6 Co mputer Communic ations and Networ king 6 COMPUTER COMMUNICATIONS AND NETWORKING NETWORKS HODDER: 112-136 What is a network? Describe three ways in which computer networks have improved productivity in the workplace. HODDER: 112-147 3. Describe two potential issues that can arise from the use of networks. What is the function of the network interface card? Where can network interface cards usually be found in the computer? What device can be used to prevent signal bouncing in bus networks? What name is given to the process of signals losing integrity as they travel through a network medium? What device can be used to counter the above issue? How does it work? Explain the purpose of a hub. Why may using several hubs potentially slow down a network? What device can be used to connect different network media and segments? OCR GCSE Computing Learning Grids Page 20 of 28

6 Computer Communications and Networking NETWORKS (CONTINUED) What is a switch? Why are switches able to operate at such high speeds? Explain the difference between a level 2 and a level 3 switch? What is the purpose of a router? Describe the features of a peer-topeer network. Explain the workings of the client server network model. Give two advantages of using client server networks over peer-to-peer. Give two disadvantages of using client server networks over peer-to-peer. Outline the main features of the bus, ring and star network topologies. Bus: Ring: Star: OCR GCSE Computing Learning Grids Page 21 of 28

6 Computer Communications and Networking NETWORKS (CONTINUED) Draw a simple diagram to represent each network topology. Bus: Ring: Star: What do the acronyms LAN and WAN stand for? Explain the primary difference between a LAN and a WAN. What is the function of a metropolitan area network (MAN)? What is a VPN? LAN: WAN: Describe one reason why an organisation might use a VPN. State three mediums for transmitting data over a network. For each medium above, state one potential advantage and disadvantage of using that medium. Medium Advantage Disadvantage OCR GCSE Computing Learning Grids Page 22 of 28

6 Computer Communications and Networking NETWORKS (CONTINUED) What is a protocol? Name and describe three common network protocols. What is a MAC address? 3. What is an IP address? Explain how IP addresses can be static or dynamic. Describe how the process of packet switching is used to carry data across a network. What is meant by bandwidth? There are likely to be several network policies in place on your school network. Can you identify three of these? What is meant by acceptable use? 3. Explain the difference between back-up and archiving. Explain what is meant by a network disaster recovery policy. OCR GCSE Computing Learning Grids Page 23 of 28

6 Computer Communications and Networking THE INTERNET HODDER: 138-146 Fundamentally, what is the Internet? State two of items of hardware that are required to connect to the Internet. Describe, in simple terms, the function of each of these hardware items. What is the difference between the World Wide Web and the Internet? What is a hyperlink? Explain the role of DNS servers and how this relates to IP addresses. What standard language is used to write web pages? Describe two other standards which can be applied to web pages. State a common Internet file standard for images. State a common Internet file standard for sound files. OCR GCSE Computing Learning Grids Page 24 of 28

6 Computer Communications and Networking THE INTERNET (CONTINUED) State a common Internet file standard for storing documents. What is compression? Why is it important when sending files over the Internet? Explain the difference between lossy and lossless compression. Surely lossless compression always a better choice than lossy compression? Justify your answer. Give an example of a type of file for which lossy compression should not be used. OCR GCSE Computing Learning Grids Page 25 of 28

L 7 Progr amming 7 PROGRAMMING HODDER: 149-183 ALGORITHMS HODDER: 150-156 What is an algorithm? Who is regarded as the first ever computer programmer? What was the name of the first ever general-purpose, high-level programming language? State and describe two different ways in which an algorithm can be represented. What shape on a flow chart is used to represent a selection (decision or choice)? What shape on a flow chart is used to represent an input or output? What does this flow chart symbol represent? What is meant by tracing an algorithm? OCR GCSE Computing Learning Grids Page 26 of 28 ZigZag Education, 2014

7 Programming ALGORITHMS (CONTINUED) Draw a flow chart for an algorithm to represent the following situation: A boy leaves his house in the morning to travel to school. He checks the time on his watch when he sets off. If the time is before 8am, he decides to walk to school. However, if the time is 8am or later he decides to take the bus. He always follows this rule, and either way he will reach school on time. Ensure that you use the correct symbols for each stage of the algorithm. Write an equivalent algorithm in pseudocode for the same process. OCR GCSE Computing Learning Grids Page 27 of 28

7 Programming PROGRAMMING LANGUAGES HODDER: 156-162 What is machine code? What is assembly language? How did it evolve from machine code? What defines high-level languages? Describe the function of translator software. Describe each of the following translators: Assembler: Interpreter: Compiler: What is an IDE? Describe each of the following tools that might be provided by an IDE. Code editor: Error diagnostics: Run-time environment: Auto-documentation: OCR GCSE Computing Learning Grids Page 28 of 28

7 Programming CONTROL FLOW IN IMPERATIVE LANGUAGES HODDER: 163-167 What is meant by sequence in programming? What is meant by selection? Give two examples of programming constructs which use selection. What is meant by iteration? Give two examples of programming constructs which use iteration. Read the following pseudocode example. Identify an instance of sequence, selection and iteration. 1 START program 2 INPUT A 3 INPUT B 4 FOR j = 1 to 10 5 C = (A +B)/2 6 IF A=B-4 7 A = 6 8 B = 13 9 END IF 10 NEXT j 11 OUTPUT C 12 END program Sequence: Selection: Iteration: HANDLING DATA IN ALGORITHMS HODDER: 168-175 Explain what is stored by each of the following data types: Integer: Real/float: Boolean: Character: String: OCR GCSE Computing Learning Grids Page 29 of 28

7 Programming HANDLING DATA IN ALGORITHMS (CONTINUED) Suggest an appropriate data type to store each of the following data items. The quick brown fox jumps over the lazy dog A 8715 54 TRUE Explain the difference between variables and constants. Explain the difference between declaration and assignment. TESTING HODDER: 176-183 What is an array used for? What is meant by the dimension of an array? Why is it important that programs are tested? What is a syntax error? Give an example of a common cause of syntax error. What is a logic error? Give an example of a common logic error. OCR GCSE Computing Learning Grids Page 30 of 28

Fundament als of Comput er System 7 Programming TESTING (CONTINUED) Explain the difference between valid extreme and invalid extreme test data. If working correctly, how should a program deal with erroneous test data? What name is given to test data which is out of range and should be rejected by the program, but is the correct type of input? What name is given to acceptable test data which is in the correct range? Consider a very simple program which outputs whether an inputted integer between -100 and 100 is positive, negative or zero. For each of the different types of test data, name the type and give two appropriate examples of data to test this program with. Type Example Test Data OCR GCSE Computing Learning Grids Page 31 of 28