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2012-2013 Computing

2012-2013 Computing. Higher. Computing – Higher Section I. 1. Write the ten digit binary number 1101101110 as a positive integer. 2. A register can be used to store an instruction . State two other types of item that can be stored in a register. 878 - 1 mark Data - 1 mark

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2012-2013 Computing

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  1. 2012-2013 Computing Higher

  2. Computing – Higher Section I 1. Write the ten digit binary number 1101101110 as a positive integer. 2.A register can be used to store an instruction. State two other types of item that can be stored in a register. 878 - 1 mark Data - 1 mark Address/memory location - 1 mark Max 2 marks

  3. Computing – Higher Section I 3. (a) State the type of virus that infects data files in application software. (b) Name two other types of malicious programs which may affect a computer. Macro – 1 mark Worm Trojan Hourse 1 mark each bullet, max 2Section I marks

  4. Computing – Higher Section I 4. A switch and a hub can both be used to connect devices on a network. Explain why aswitch is now more often used than a hub. A switch routes traffic towards the correct destination (1 mark) A hub repeats the traffic to all connected nodes (1 mark) Max 2 marks

  5. Computing – Higher Section I 5. Brian uses his operating system to load a program from hard disk (a) State two tasks carried out by the memorymanagement part of the operating system during this operation. Identify space in memory to load program to Protect other processes from being overwritten Manage caching to disk of memory pages Ensure only valid processes have permission to access memory space. Other valid 1 mark each bullet, max 2 marks

  6. Computing – Higher Section I (b) State one task carried out by the input/output part of the operating system during this operation. Copy blocks of program from disk to memory Manage error messages during transfer Accept user command to load program (mouse click, keyboard input) Other valid 1 mark each bullet, max 1 mark

  7. Computing – Higher Section I 6. Two functions of an interface are voltage conversion and protocol conversion. State two other functions of an interface. Buffering Data format conversion/serial to parallel/analogue to digital Managing/Handling status signals (do not accept status signals on its own) 1 mark each bullet, max 2 marks

  8. Computing – Higher Section I 7. Hamish has created a poster using vector graphic software. Describe how a vector graphic is stored. Vector graphic is stored as a number of objects (1 mark) and their associated attributes (1 mark).

  9. Computing – Higher Section I 8. Explain why the software development process is often an iterative process. The software development process is iterative because we often have to return to earlier stages (1 mark) as the result of new information (1 mark) – accept a description, Max 2 marks

  10. Computing – Higher Section I 9. Pseudocode is a commonly used design notation. (a) Data flow is often included when pseudocode is written. State the purpose of data flow. To identify the data/variables used at each step of the design To show what data is passed to/from/in/out of procedures Identify which variables will be passed as parameters Identify mechanism of parameter passing (IN, OUT, IN/OUT) Other valid 1 mark for any bullet

  11. Computing – Higher Section I (b) State two other advantages of using pseudocode to design a program. 10. Name one graphic design notation. Direct one to one link with program code Suitable design tool for any programming language Supports a logical breakdown of program in a top-down fashion Other valid 1 mark each bullet, 2 marks Structure diagram (1 mark) Flow chart (1 mark) Max 2 marks

  12. Computing – Higher Section I 11. A compiler may be used in the software development process. (a) State one stage of the software development process where a compiler may be used. (b) Explain how the compiler would be used in the stage named in part (a). Implementation Maintenance 1 mark for any one of the above Implementation – compiling code as it is developed. Maintenance – used to compiler the adapted code as a result of maintenance 1 mark for any one bullet, max 1 mark

  13. Computing – Higher Section I 12. Procedures and functions are types of subprograms which can be used to create software. (a) State how the use of subprograms can improve the efficiency of a program. (b) Other than the use of subprograms, state two characteristics of programming code that improve maintainability. Subprograms can be reused therefore not requiring code to be repeated / duplicated 1 mark Use of white space Use of meaningful variables Internal commentary 1 mark each bullet, max 2 marks

  14. Computing – Higher Section I (c) Explain one difference between a procedure and a function. A procedure can return multiple values (1 mark), a function can return a single value (1 mark) OR A procedure cannot be used in an assignment statement (1 mark)but a function can be used in an assignment. (1 mark) Max 2 marks

  15. Computing – Higher Section I 13. Describe one difference between a declarative language and an event-driven language.  14. Top-down design is a technique for software development. Explain the process of top-down design. Declarative language stores program as facts and rules (1 mark) but an event driven language stores program responses to specific known events (1 mark) Max 2 marks Develop the solution to a problem by breaking it down into smaller sections which are easier to solve. (1 mark)

  16. Computing – Higher Section II 15. Andrew buys a new laptop computer with the following specification. Ultrabook 2013 8 Gigabytes Main Memory 4.8 GHz 4-Core processor 16 Megabyte Cache Memory Includes ChromeWin OS and Utility Software 1 Year of Super Anti-virus 2013 

  17. (a) The computer has a maximum addressable memory of 32 Gigabytes. It has an address bus width of 32 bits (i) Explain why the manufacturer may not normally supply the laptop with the maximum possible memory. Maximum memory not required for typical processing. Maximum memory would add additional to manufacture. Other valid 1 mark any bullet

  18. Computing – Higher Section II (ii) Calculate the width of the data bus. Show all your working. Number of addresses is 232 =4294967296 (1 mark) Number of bits in 32Gb = 32 * 1024 = 32768 Mb = 32768 * 1024 = 33554432 kb = 33554432 * 1024 = 34359738368 bytes = 34359738368 * 8 = 274877906944 bits (1 mark) With of memory = 274877906944 / 4294967296 = 64 bits (1 mark) Max 3 marks

  19. Computing – Higher Section II (b) The laptop has 16 megabytes of cache memory. Describe how the use of cache memory may improve system performance. (c) Describe the function of the address bus, database and control lines during a memory write operation. Cache is used to preload instructions and data (1 mark) to make them available in a space which can be accessed by the processor faster than main memory (1 mark) Max 2 marks Address bus is set up the address in memory to be written to (1 mark) Databus is set up with the data to be written to memory (1 mark) The write line on the control bus is set (1 mark) and the data travels to the selected memory location along the databus.

  20. Computing – Higher Section II (d) Andrew tests the laptop using software which produces the following output. (i) Which of the measures of performance is the most accurate indicator of actual computer performance? (ii) Explain why your answer to (i) above is the most accurate measure. Application based testing (1 mark) Application based tests are carried out using real applications and tools so that the results of the test reflect actual tasks rather than test numbers. ( 1 mark)

  21. Computing – Higher Section II (iii) Andrew is confused that the MIPs for the “Weston 982 Ultra” is much higher than the MIPs for his new computer but his MegaFLOPs is higher.   Explain why this result is possible. The Weston 982 Ultra may have a processor which uses less-complex instructions (1 mark) hence a greater number executed per second. (1 mark) Max 2 marks

  22. Computing – Higher Section II (e) Andrew’s laptop has developed a problem and is refusing to load the operating system when it starts up. Explain how a disc editor could be used to fix the problem. A disc editor allows Andrew to edit the binary data on the disc (1 mark) so he may be able to find the data error on this disc preventing the OS from load and correct it (1 mark) Max 2 marks

  23. Computing – Higher Section II (f) A virus infected Andrew’s laptop but the Anti-virus software did not detect it because Andrew had failed to update the virus signatures. (i) Name and describe one anti-virus software detection technique other than the use of virus signatures.  (ii) Andrew only discovered the virus when it had executed a delivery action. Explain what delivery means as a virus code action. Heuristic detection – monitoring system for virus like behaviour. Checksum – validating files against calculated checksums, if the calculation shows the filesize has change then the file may be infected. 1 mark for the name, 1 mark for the description, max 2 marks Delivery is when a virus delivers its payload such as destroying files or displaying a message.(1 mark)

  24. Computing – Higher Section II (iii) Name one other virus code action and explain how it may be triggered. Replication (1 mark) may be triggered when the program containing the virus is run (1 mark). Watching (1 mark) – this behaviour happens once the first has been loaded to memory (1 mark). Other valid with explanation. 2 marks

  25. Computing – Higher Section II 16. A system called DataDigger gathers data for the government from web sites, social media and mobile communications. The system is operated from terminals which are connected to a mainframe. (a) Explain the difference between processing data with a mainframe and terminals and processing data with a network of computers. Mainframe data is processed centrally by mainframe as terminals have no processing power (1 mark) In network of computers, each computer is responsible for its own processing (1mark)

  26. Computing – Higher Section II (b) A number of network topologies where considered when the means of connecting the terminals to the mainframe was designed. (i) A ring topology was ruled out as unsuitable.Draw a labelled diagram of a ring topology network. (ii) State a more suitable topology and describe one advantage it has over a ring topology for this purpose. 1 mark for diagram,1 mark for labels A star topology (1 mark) would provide a channel from each terminal to the mainframe therefore any failure of a channel would only affect a single node.(1 mark)

  27. Computing – Higher Section II (c) The DataDigger system captures the username and domain from email addresses as shown in the variables below. (see paper) (i) Name the data type used to store the “Emailaddress”. String (1 mark)

  28. Computing – Higher Section II (ii) Name the operation used to extract both the “Username” and “Domain” details. (iii) The contents of “Username” are stored in memory in UNICODE format. Calculate the minimum amount of memory required to store the contents of this variable in bytes. Substring (1 mark) kenneth.muir is username 12 characters Unicode is 16 bit code 12 x 16 = 192 bits (1 mark) 192 bits / 8 = 24 bytes (1 mark)

  29. Computing – Higher Section II (d) The DataDigger system looks for email addresses that are on a “watch” list of thousands of email addresses which are used by possible terrorists. (see paper) Using pseudocode, design an algorithm to find and display a result if an “emailaddress” matches one on the “watch list” or a shows a “not found” message if the “emailaddress” is not present in the list.

  30. Computing – Higher Section II 1 mark for FOR with termination 1 mark for IF inside loop with termination 1 mark for Condition in IF 1 mark for both assignments correct (found = false, found= true) - no half marks 1 mark for display alert 1 mark for second IF statement with correct condition and display details. Total 6 marks Found = false FOR each item on watch list IF watchlist(item) = emailaddress THEN Display alert Found = true ENDIF NEXT item on watch list If found=false Then Display “not found” ENDIF

  31. Computing – Higher Section II (e) A decision has been made to change the use of the watch list so that it counts the number of times an email address appears in the watch list. Changes need to be made to the pseudocode you wrote in part (d). (i) State one change that you would make to your pseudocode for part (d). Initialise a counter (counter = 0 ) before entering the loop. Add counter = counter + 1 inside the first IF statement. Remove the found variable as it can be replaced with counter=0 Change the last IF so the the “not found” is displayed on counter zero and the total occurrences is displayed otherwise. 1 mark for any 1 bullet, max 1 mark

  32. Computing – Higher Section II (ii) Explain why this change is necessary. To start the count at zero for the occurrences of username 1 mark for any 1 bullet, max 1 mark

  33. Computing – Higher Section II (f) Programs, such as DataDigger, make use of conditional statements. State the part of the processor which is responsible for evaluating conditional statements. ALU (1 mark)

  34. Computing – Higher Section II 17. A football club has written a program to check-in the 11 players and 3 substitutes in their squad. The football squad always contains the same number of players. Part of the pseudocode that was written for the software is shown below. player number = 1 do while player number < 15 if player number is 1 then issue goalkeeping football kit else issue standard kit with player number end if player number = player number + 1 loop

  35. Computing – Higher Section II (a) Explain why this pseudocode may not represent the most efficient method of carrying out his task. The number of players is fixed therefore would be more efficient as a fixed loop (1 mark) Because the while loop adds an additional comparison that which makes additional demands on the processor (1 mark).

  36. Computing – Higher Section II (b) Show how these lines could be rewritten in a more efficient way. For player number = 1 to 15 …. Next Player 1 mark for For..Next Loop 1 mark for correct range Max 2 marks

  37. Computing – Higher Section II (c) Another program used by the club records details of the goals scored in a game. Some data from this program is shown below. (see paper) Name the data structure and data type used to store “Goals For” and “Goals Against” above. An array (1 mark) of Integers (1 mark) Max 2 marks

  38. Computing – Higher Section II (d) The football club software makes use of parameter passing. (i) State the purposeof an in parameter. (ii) State the purposeof an out parameter. Current value (of variable) passed into a subprogram for use To allow data to be passed by value Protect (original value of) variable from change by subprogram 1 mark for any bullet Data/variables (created within procedure and only) passed out of a subprogram. A new variable is passed out of subprogram 1 mark for any bullet

  39. Computing – Higher Section II 18. MediaForYou are a publishing company and have employed a project manager and a systemsanalyst to create a mobile version of a news web site that they operate. (a) (i) Explain why the systems analyst interviews the client during the analysis stage. (ii) State two other techniques that a systems analyst could use during the analysis stage. To gather the exact details of what is required by the client. To establish good and bad points of current systems. Other valid point 1 mark for any bullet Use of questionnaires Observe workers/current practice/ Examine documentation/information about current system. 1 mark each bullet, max 2 marks

  40. Computing – Higher Section II (b) The systems analyst creates the software specification at the end of the analysis stage. This document is shared with the client and the project manager. (i) State two reasons why the client has to agree to the software specification before it is finalised. (ii) State two elements of the software specification which are particularly important for the project manager. It sets out exactly what will be delivered as part of the project. It is a formal contract/legal agreement with the client. The client ensures that all items are included in the project as others added later will incur additional cost. 1 mark each bullet, max 2 marks The timescale/delivery data (1 mark) The total budget for the project (1 mark)

  41. Computing – Higher Section II (c) Explain how producing a design that supports modularity can assist the project manager during the implementation stage. (d) During implementation a global variable is introduced into the program. (i) State the meaning of the term “global variable”. A modular design will allow the project manager to allocate modules to different programmers (1 mark) so that multiple parts of the project can be developed at the same time (1 mark). A variable that can be used/accessed/updated anywhere in a program (1 mark).

  42. Computing – Higher Section II (ii) Explain why programmers normally try to avoid the use of global variables when programming.  [END OF SECTION II] Data flow becomes unclear (1 mark) which reduces readability (1 mark). Global variable may be inadvertently changed (1 mark) by interacting with variables of same name in subprograms (1 mark) Memory assigned to local variables is only retained for the duration of the subprogram (1 mark) but global variables memory reserved for duration of program run (1 mark). Other valid Max 2 marks

  43. Computing – Higher Section III – Part A – Artificial Intelligence 19. The SmartTab XL is a tablet computer that runs the ioDroid Operating System. One of the features of the ioDroid Operating Systems is natural language processing. Many app developers for the ioDroid Operating System are using the NLP functionality in their apps. (a) State two possible applications of NLP that might be used for on the SmartTab XL. Any 2 from: Speech driven / recognition in software Natural Language search engine Translation software Natural Language database interface 1 mark per bullet. Max 2 marks.

  44. Computing – Higher Section III – Part A – Artificial Intelligence (b) One problem the developers of apps that use the Natural Language Processing, is that of ambiguity. A developer has created an app that classifies news items from the web based on the headline. Explain why the ambiguity in the following news headlines may be difficult for the app to classify correctly. “Giant hold up at bank” “Lady hits man with umbrella” “hold up” can refer to a robbery or delay unclear whether lady hits a man with an umbrella or if the lady hita man who had an umbrella 1 mark per bullet. Max 2 marks

  45. Computing – Higher Section III – Part A – Artificial Intelligence (c) Identify the stage of the NLP process that will attempt to resolve ambiguities. Natural Language Understand (do not accpet NLU) 1 mark

  46. Computing – Higher Section III – Part A – Artificial Intelligence 20. Computer games like checkers and chess have been used to further the research of Artificial Intelligence. (a) State two reasons why these types of games were seen as suitable for Artificial Intelligence research. Well defined and restricted rule set / domain Able to represent problem as facts and rules Requires problem solving skills to play Other appropriate answer 1 mark per bullet. Max 2 marks

  47. Computing – Higher Section III – Part A – Artificial Intelligence (b) (i) Identify one development in hardware that has improved the response time of AI chess games. (ii) Explain how this development has improved response times. One from: parallel processing, increased memory 1 mark Parallel processing – able to evaluate multiple next moves / states at on time leading to a faster output Increased memory – able to store more rules in memory at a time instead of slower virtual memory/backing storage, therefore speeding up the time it takes to evaluate possible moves 1 mark for appropriate answer based on part I

  48. Computing – Higher Section III – Part A – Artificial Intelligence (c) Many people argue that chess programs are not intelligent. Explain why this statement might be true. Answer should be in context of chess, eg: Problem solving in chess is only one aspect of intelligence. Chess programs do not display other aspects of intelligence such as creativity. Chess has a limited domain of knowledge unlike human players. 1 mark.

  49. Computing – Higher Section III – Part A – Artificial Intelligence (d) Other research into AI involved the development of programs that could hold a conversation. One of these programs was called Eliza (i) Identify the test for intelligence that can be carried out to determine if a conversational program is intelligent. (ii) Describe how this test is carried out Turing Test 1 mark Tester sits at a terminal and has a conversation with either another person at another terminal or a computer program (1) The tester is not told which one they are talking to and must decide at the end of the conversation if they were speaking to a human or a program(1) Max 2 marks

  50. Computing – Higher Section III – Part A – Artificial Intelligence 21. A computer vision system has been developed to aid structural engineers identify faults in buildings. For example, the vision system will compare photographs of a structure taken over a period of time to try and identify if there has been any structural movement. (a) During the computer vision process, an image of a structure needs to be captured. This image is then compared to an earlier image of the same structure. Later on in the process, the program outputs the results of the comparison. Identify the stage of the vision process that is responsible for capturing the image. Image Acquisition 1 mark

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