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When IT Goes Bad From Software to Society

INFO100 and CSE100. Fluency with Information Technology. When IT Goes Bad From Software to Society. Katherine Deibel. Errors and IT. Basic fact: Technology can go bad At least two sources of fault How the technology operates How people use the technology At least two forms of correction

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When IT Goes Bad From Software to Society

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  1. INFO100 and CSE100 Fluency with Information Technology When IT Goes BadFrom Software to Society Katherine Deibel Katherine Deibel, Fluency in Information Technology

  2. Errors and IT • Basic fact: Technology can go bad • At least two sources of fault • How the technology operates • How people use the technology • At least two forms of correction • Debugging • IT Fluency Katherine Deibel, Fluency in Information Technology

  3. Understanding Errors Ooops… Katherine Deibel, Fluency in Information Technology

  4. The Infamous Bug • While working on the Mark II, Grace Hopper discovered a moth stuck in a relaythat had caused an electric short • Originated the term “debugging” Katherine Deibel, Fluency in Information Technology

  5. Replicating Errors • By replicating, you can • Learn factors that led to the error • Eliminate erroneous correlations • Some errors you do not want to replicate/cannot replicate • Install corruptions • Hard drive crashes • Explosions Katherine Deibel, Fluency in Information Technology

  6. Some Errors are Random • Cosmic "rays" • Energetic charged particles from space • Usually blocked by the Earth's magnetic field and atmosphere • More prevalent during solar storms and/or at higher altitudes • When they collide with electronics • Can cause bit flips (01 or 10) • Lead to essentially random errors • Rare but not unknown Katherine Deibel, Fluency in Information Technology

  7. Some Errors are Chaotic • Chaos ≠ Random • Chaos means that the patterns are very complex and difficult to pin down • Therac-25 errors were fairly chaotic • Some errors only occur when specific factors are in play • Problems with copy/paste in Excel if I have macros enabled plus the Chrome browser is running Katherine Deibel, Fluency in Information Technology

  8. Some Errors are Annoying • Some errors disappear when you try to investigate them • Called 'Heisenbugs' after the Heisenberg Uncertainty Principle • By observing what is going on on your computer, you change some factors • Those factors are what were causing the bug • Typically, these are the rarest and hardest bugs to address Katherine Deibel, Fluency in Information Technology

  9. Implications • Some errors are only one-time events • Difficult to replicate • Due to randomness, chaos, or a heisenbug • When an error occurs • Step back and observe what happened • Recall what you were doing • Recall what the computer was doing (beyond just the active window) Katherine Deibel, Fluency in Information Technology

  10. Error-Correction • Computers can be designed to correct specific errors • Parity checks for flipped bits due to cosmic rays • Browsers render invalid XHTML • Computers only detect errors that they are told to look out for • The computer's correction may not be what you want it • Remember: Garbage In  Garbage Out Katherine Deibel, Fluency in Information Technology

  11. Debugging THE ANTS… THEY'RE IN MY PANTS!!! Katherine Deibel, Fluency in Information Technology

  12. General Principles of Debugging • Do not panic (unless something is on fire) • Observe what happened, what did not • Note any error messages • Work from the most likely causes down to the least likely causes • When in doubt, seek help Katherine Deibel, Fluency in Information Technology

  13. Many Types of Debugging • Programming Debugging • Writing HTML, CSS, Javascript, etc. • Software Malfunction • Program crashes, feature doesn't work as expected, etc. • Hardware Debugging • Printer will not print • Wireless will not connect Katherine Deibel, Fluency in Information Technology

  14. Your Role as the Debugger • Programming Debugging • You are the chief mechanic • Software and Hardware Mechanic • Your role is much more limited Historically, it was much, much easier for people without technical degrees to perform repairs on home electronics: televisions, radios, etc. Katherine Deibel, Fluency in Information Technology

  15. Programming Debugging • Ignore the number of errors • Remember, errors propagate errors • Start with the error that first occurs • Again, errors propagate errors • If there is error feedback, read it! • Make a fix and then check • Do NOT fix repeated errors unless you are certain that you know the cause Katherine Deibel, Fluency in Information Technology

  16. Example: XHTML Validation • We attempt to validate a page • We get 24 errors and warnings.. EEK! • What do we do? Katherine Deibel, Fluency in Information Technology

  17. Example: XHTML Validation • We attempt to validate a page • We get 24 errors and warnings.. EEK! Ignore the number of errors Katherine Deibel, Fluency in Information Technology

  18. Example: XHTML Validation • First error reported is an <h1> tag <h1 class="banner>…</h1> • We put in the missing quote Start with the first occurring error Katherine Deibel, Fluency in Information Technology

  19. Example: XHTML Validation • We save and revalidate • Only 4 errors and warnings now Make a fix and then check Katherine Deibel, Fluency in Information Technology

  20. Example: XHTML Validation • All of our errors now look like this • We need to put <img> inside <p>…</p> • We can do this for all four Line 11, Column 25: document type does not allow element "img" here; missin one of "p", "h1", "h2", "h3", "h4", "h5", h6", "div", "pre", "address", "fieldset", "ins", "del" start-tag ... <imgsrc="photo.png" alt="a cute calico cat" /> Only fix multiple errors if certain of cause Katherine Deibel, Fluency in Information Technology

  21. Software/Hardware Debugging • Much more difficult • If possible, first save and backup your work • Look around and see what you know • Read the screen • Write down any error messages to look up online • Is there a pointer/link that offers help • When in doubt, restart Katherine Deibel, Fluency in Information Technology

  22. The Levels of Restart • Close and restart the program • Might need to close in Task Manager (Windows) • Log out and log back in • Restart the machine (hot reboot) • Shutdown the machine, wait a few minutes, then restart (cold reboot) Katherine Deibel, Fluency in Information Technology

  23. Why Restarting Helps • Think mental exhaustion • When programs run • Memory gets allocated and deallocated (available for others to use) • Memory is not cleared when deallocated • Legacies of past calculations build up • Minor things begin to snowball • Entropy ensues Katherine Deibel, Fluency in Information Technology

  24. Why Restarting Helps • Helps flush away the clutter, clears the board, etc. • Power down causes most volatile memory to "zero" out • Basically gives programs a do-over, mulligan, fresh start, etc. Katherine Deibel, Fluency in Information Technology

  25. Seeking Out Help ● ● ● − − − ● ● ● Katherine Deibel, Fluency in Information Technology

  26. Finding Answers on the Web • If you have an error message, use that text plus the program name:excel 2010 vba error 1045 • Otherwise, try to describe the error and search with the program name or computer type:thinkpad t410 keyboard "poiurewq" Katherine Deibel, Fluency in Information Technology

  27. Find Specific Forums • Many computer and software companies have support sites • FAQs for searching • Message boards • Online support chat • Updates (software, drivers, etc.) Katherine Deibel, Fluency in Information Technology

  28. Ask a Computer Buddy • Two minds are better than one • Does not necessarily mean you need to find an 'expert' • Experience is often better than a degree • Peers are often trying to do similar tasks Katherine Deibel, Fluency in Information Technology

  29. But I must whine… Why bugs will always occur Katherine Deibel, Fluency in Information Technology

  30. IT Cannot Be Perfect • Bugs, errors, etc. cannot be avoided beyond very simple situations • Proven to be mathematically impossible • Unless you invoke a god-like being • But you cannot prove the god-like being will always work • Unless you invoke a god-like, god-like being… • Etc. Katherine Deibel, Fluency in Information Technology

  31. We Do Our Best • Software engineering • Testing before products hit market • Upgrades and fixes • Risk assessments and failure cost analyses Debugging will always be necessary Katherine Deibel, Fluency in Information Technology

  32. Summary • IT can and does go wrong at times. • Debugging can help you fix the problems • You just need to observe and think Katherine Deibel, Fluency in Information Technology

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