1. Virtual University - Human Computer Interaction 1 © Imran Hussain | UMT Imran Hussain University of Management and Technology (UMT) Lecture 36 Behavior & Form – Part IV Virtual University Human-Computer Interaction

2. Virtual University - Human Computer Interaction 2 © Imran Hussain | UMT In Last Lecture … Evaluation –Conceptual framework for developing an interactive product –How we can use this framework to identify certain usability problems –Tactical vs. strategic usability

3. Virtual University - Human Computer Interaction 3 © Imran Hussain | UMT Usability can be tactical as well as strategic

4. Virtual University - Human Computer Interaction 4 © Imran Hussain | UMT In Today’s Lecture … Undo functionality Files and Save functionality

5. Virtual University - Human Computer Interaction 5 © Imran Hussain | UMT Understanding Undo

6. Virtual University - Human Computer Interaction 6 © Imran Hussain | UMT Users and Undo Reverses previous action

7. Virtual University - Human Computer Interaction 7 © Imran Hussain | UMT User Mental Models of Mistakes Humans make mistakes Programmers should not think of human mistakes as errors Programmers follow implementation model Human being do not like to be told that they have make an error so the software should not contradict users

8. Virtual University - Human Computer Interaction 8 © Imran Hussain | UMT Undo Enables Exploration Users are like explorers using a tool They like experiment to see what they can achieve with computer Undo reassures user if they are in trouble then this function helps them to reverse any action

9. Virtual University - Human Computer Interaction 9 © Imran Hussain | UMT

10. Virtual University - Human Computer Interaction 10 © Imran Hussain | UMT Designing an Undo Facility Undo not directly related to goal of user Users have different models of undo –Novice: help –Intermediate: deleted data –Expert: stack of procedures that can be undone Undo should be designed to support exploration and not for reversing errors Undo should be global-wide function

11. Virtual University - Human Computer Interaction 11 © Imran Hussain | UMT Types of Undo Incremental and Procedural Actions Blind and Explanatory Undo Single and Multiple Undo Redo

12. Virtual University - Human Computer Interaction 12 © Imran Hussain | UMT Incremental and Procedural Actions Procedural component What the user did? Data component What information was affected? Incremental actions there is both procedural component and data component Procedural actions do not have data component –These operations act on data but do not add or delete the data

13. Virtual University - Human Computer Interaction 13 © Imran Hussain | UMT Blind and Explanatory Undo Blind Undo –There is no indication what the operation is Explanatory Undo –There is some textual and visual information of the particular operation

14. Virtual University - Human Computer Interaction 14 © Imran Hussain | UMT Single Undo Most common form of undo It reverses the effects of the most recent user’s action

15. Virtual University - Human Computer Interaction 15 © Imran Hussain | UMT

16. Virtual University - Human Computer Interaction 16 © Imran Hussain | UMT Other Models for Undo-like Behavior Comparison Category-specific undo Deleted data buffers Milestoning and reversion Freezing

17. Virtual University - Human Computer Interaction 17 © Imran Hussain | UMT Other Models for Undo-like Behavior Comparison Category-specific undo Deleted data buffers –Saves the user having to remember exact undo operations and their sequence Milestoning and reversion –For significant changes make a milestone copy, use revert option to access it Freezing –Lock the document so certain aspects cannot be changed

18. Virtual University - Human Computer Interaction 18 © Imran Hussain | UMT What’s wrong with saving changes to files …

19. Virtual University - Human Computer Interaction 19 © Imran Hussain | UMT Saving Changes to Files Programs and data files exist in 2 places at the same time Data and program managed by file system –Explorer (Windows) –Finder (Mac) The file system and the disk storage facility it manages is the primary cause of disaffection in computer users

20. Virtual University - Human Computer Interaction 20 © Imran Hussain | UMT

21. Virtual University - Human Computer Interaction 21 © Imran Hussain | UMT

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24. Virtual University - Human Computer Interaction 24 © Imran Hussain | UMT Let’s consider the ‘save as’ dialog box …

25. Virtual University - Human Computer Interaction 25 © Imran Hussain | UMT

26. Virtual University - Human Computer Interaction 26 © Imran Hussain | UMT what’s the point in having a redundant dialog box that users always click yes? …

27. Virtual University - Human Computer Interaction 27 © Imran Hussain | UMT what’s the point in a function that will confuse new users and they might click ‘no’?

28. Virtual University - Human Computer Interaction 28 © Imran Hussain | UMT.. confuses possibility with probability (poor assumption)

29. Virtual University - Human Computer Interaction 29 © Imran Hussain | UMT … why would someone close the document if they didn’t want the changes

30. Virtual University - Human Computer Interaction 30 © Imran Hussain | UMT … why does it ask for saving changes when you are done and not when making them?

31. Virtual University - Human Computer Interaction 31 © Imran Hussain | UMT saving changes -------- closing doc (compare with writing in a notebook) when user closes doc, this is the time the differences between the memory and disk need to be reconciled no obvious connection, e.g. - erasing notes when closing book - discarding changes when we leave room

32. Virtual University - Human Computer Interaction 32 © Imran Hussain | UMT Reason? implementation model is rendered as interface for users

33. Virtual University - Human Computer Interaction 33 © Imran Hussain | UMT Problems with implementation model …

34. Virtual University - Human Computer Interaction 34 © Imran Hussain | UMT What happens when I try to rename a file …

35. Virtual University - Human Computer Interaction 35 © Imran Hussain | UMT

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37. Virtual University - Human Computer Interaction 37 © Imran Hussain | UMT Q: What’s the function of the ‘save as’ window? Ans: placing and naming a file

38. Virtual University - Human Computer Interaction 38 © Imran Hussain | UMT I close the ‘save as’ dialog box, go to ‘explorer’, and try renaming again …

39. Virtual University - Human Computer Interaction 39 © Imran Hussain | UMT

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41. Virtual University - Human Computer Interaction 41 © Imran Hussain | UMT Another example: What happens when I then open the document make some changes that don’t make difference to the contents of the file …

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44. Virtual University - Human Computer Interaction 44 © Imran Hussain | UMT

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46. Virtual University - Human Computer Interaction 46 © Imran Hussain | UMT So why do we have these problems …

47. Virtual University - Human Computer Interaction 47 © Imran Hussain | UMT The Computer’s File System Data and program managed by file system –Explorer (Windows) –Finder (Mac) File system is an internal facility and shouldn’t affect the user Software applications (you) treat file system (a car) just like the OS (a mechanic) does

48. Virtual University - Human Computer Interaction 48 © Imran Hussain | UMT Let’s say you want to create a copy for archive … [no explicit function for creating copy have to use ‘save as’]

49. Virtual University - Human Computer Interaction 49 © Imran Hussain | UMT

50. Virtual University - Human Computer Interaction 50 © Imran Hussain | UMT

51. Virtual University - Human Computer Interaction 51 © Imran Hussain | UMT

52. Virtual University - Human Computer Interaction 52 © Imran Hussain | UMT … have to close ‘hci2.doc’, go to explorer, and then reopen original file

53. Virtual University - Human Computer Interaction 53 © Imran Hussain | UMT And now a perfectly reasonable scenario: have made changes to doc (without saving) and now want to create a copy and keep on working …

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55. Virtual University - Human Computer Interaction 55 © Imran Hussain | UMT

56. Virtual University - Human Computer Interaction 56 © Imran Hussain | UMT … invoke ‘save as’.. … new file ‘hci2.doc’ contains changes, not ‘hci.doc’

57. Virtual University - Human Computer Interaction 57 © Imran Hussain | UMT

58. Virtual University - Human Computer Interaction 58 © Imran Hussain | UMT I work on new file and delete those recent changes..

59. Virtual University - Human Computer Interaction 59 © Imran Hussain | UMT

60. Virtual University - Human Computer Interaction 60 © Imran Hussain | UMT … now I reopen the original file …

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63. Virtual University - Human Computer Interaction 63 © Imran Hussain | UMT … changes lost forever!

64. Virtual University - Human Computer Interaction 64 © Imran Hussain | UMT Implementation Model vs. Mental Model Users view electronic documents just like printed documents