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• Will fixed-point arithmetic be worth my trouble?

  - by Thomas

  I'm working on a fluid dynamics Navier-Stokes solver that should run in real time. Hence, performance is important. Right now, I'm looking at a number of tight loops that each account for a significant fraction of the execution time: there is no single bottleneck. Most of these loops do some floating-point arithmetic, but there's a lot of branching in between. The floating-point operations are mostly limited to additions, subtractions, multiplications, divisions and comparisons. All this is done using 32-bit floats. My target platform is x86 with at least SSE1 instructions. (I've verified in the assembler output that the compiler indeed generates SSE instructions.) Most of the floating-point values that I'm working with have a reasonably small upper bound, and precision for near-zero values isn't very important. So the thought occurred to me: maybe switching to fixed-point arithmetic could speed things up? I know the only way to be really sure is to measure it, that might take days, so I'd like to know the odds of success beforehand. Fixed-point was all the rage back in the days of Doom, but I'm not sure where it stands anno 2010. Considering how much silicon is nowadays pumped into floating-point performance, is there a chance that fixed-point arithmetic will still give me a significant speed boost? Does anyone have any real-world experience that may apply to my situation?

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• hover effect jQuery

  - by Ori Cohen

  I have a bunch of li elements that I want to alternate in color using odds and evens, and then highlight based on mouse hover. In order to un-highlight I need to keep track of what the color used to be, odd or even. To do this when I apply the highlight color, I first set an arbitrary attribute to it. Are there any downsides to doing it this way? Is there a better way? Here's the code: <script type="text/javascript"> var init = function(event){ $("li:odd").css({'background-color' : '#eeeeee', 'font-weight' : 'bold'}); $("li:even").css('background-color', '#cccccc'); //initial colors setup $("li").hover( function () //hover over { var current = $(this); current.attr('old-background', current.css('background-color')); current.css('background-color', '#ffee99'); } , function() //hover out { var current = $(this); current.css('background-color', current.attr('old-background')); }) } $(document).ready(init); </script> So is there a better way to do this?

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• Why is an Add method required for { } initialization?

  - by Dan Tao

  To use initialization syntax like this: var contacts = new ContactList { { "Dan", "[email protected]" }, { "Eric", "[email protected]" } }; ...my understanding is that my ContactList type would need to define an Add method that takes two string parameters: public void Add(string name, string email); What's a bit confusing to me about this is that the { } initializer syntax seems most useful when creating read-only or fixed-size collections. After all it is meant to mimic the initialization syntax for an array, right? (OK, so arrays are not read-only; but they are fixed size.) And naturally it can only be used when the collection's contents are known (at least the number of elements) at compile-time. So it would almost seem that the main requirement for using this collection initializer syntax (having an Add method and therefore a mutable collection) is at odds with the typical case in which it would be most useful. I'm sure I haven't put as much thought into this matter as the C# design team; it just seems that there could have been different rules for this syntax that would have meshed better with its typical usage scenarios. Am I way off base here? Is the desire to use the { } syntax to initialize fixed-size collections not as common as I think? What other factors might have influenced the formulation of the requirements for this syntax that I'm simply not thinking of?

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• javascript scope problem when lambda function refers to a variable in enclosing loop

  - by Stefan Blixt

  First question on stackoverflow :) Hope I won't embarrass myself... I have a javascript function that loads a list of albums and then it creates a list item for each album. The list item should be clickable, so I call jQuery's click() with a function that does stuff. I do this in a loop. My problem is that all items seem to get the same click function, even though I try to make a new one that does different stuff in each iteration. Another possibility is that the iteration variable is global somehow, and the function refers to it. Code below. debug() is just an encapsulation of Firebug's console.debug(). function processAlbumList(data, c) { for (var album in data) { var newAlbum = $('<li class="albumLoader">' + data[album].title + '</li>').clone(); var clickAlbum = function() { debug("contents: " + album); }; debug("Album: " + album + "/" + data[album].title); $('.albumlist').append(newAlbum); $(newAlbum).click(clickAlbum); } } Here is a transcript of what it prints when the above function runs, after that are some debug lines caused by me clicking on different items. It always prints "10", which is the last value that the album variable takes (there are 10 albums). Album: 0/Live on radio.electro-music.com Album: 1/Doodles Album: 2/Misc Stuff Album: 3/Drawer Collection Album: 4/Misc Electronic Stuff Album: 5/Odds & Ends Album: 6/Tumbler Album: 7/Bakelit 32 Album: 8/Film Album: 9/Bakelit Album: 10/Slow Zoom/Atomic Heart contents: 10 contents: 10 contents: 10 contents: 10 contents: 10 Any ideas? Driving me up the wall, this is. :) /Stefan

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• Handling close-to-impossible collisions on should-be-unique values

  - by balpha

  There are many systems that depend on the uniqueness of some particular value. Anything that uses GUIDs comes to mind (eg. the Windows registry or other databases), but also things that create a hash from an object to identify it and thus need this hash to be unique. A hash table usually doesn't mind if two objects have the same hash because the hashing is just used to break down the objects into categories, so that on lookup, not all objects in the table, but only those objects in the same category (bucket) have to be compared for identity to the searched object. Other implementations however (seem to) depend on the uniqueness. My example (that's what lead me to asking this) is Mercurial's revision IDs. An entry on the Mercurial mailing list correctly states The odds of the changeset hash colliding by accident in your first billion commits is basically zero. But we will notice if it happens. And you'll get to be famous as the guy who broke SHA1 by accident. But even the tiniest probability doesn't mean impossible. Now, I don't want an explanation of why it's totally okay to rely on the uniqueness (this has been discussed here for example). This is very clear to me. Rather, I'd like to know (maybe by means of examples from your own work): Are there any best practices as to covering these improbable cases anyway? Should they be ignored, because it's more likely that particularly strong solar winds lead to faulty hard disk reads? Should they at least be tested for, if only to fail with a "I give up, you have done the impossible" message to the user? Or should even these cases get handled gracefully? For me, especially the following are interesting, although they are somewhat touchy-feely: If you don't handle these cases, what do you do against gut feelings that don't listen to probabilities? If you do handle them, how do you justify this work (to yourself and others), considering there are more probable cases you don't handle, like a supernonva?

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• How to avoid concurrent execution of a time-consuming task without blocking?

  - by Diego V

  I want to efficiently avoid concurrent execution of a time-consuming task in a heavily multi-threaded environment without making threads wait for a lock when another thread is already running the task. Instead, in that scenario, I want them to gracefully fail (i.e. skip its attempt to execute the task) as fast as possible. To illustrate the idea considerer this unsafe (has race condition!) code: private static boolean running = false; public void launchExpensiveTask() { if (running) return; // Do nothing running = true; try { runExpensiveTask(); } finally { running = false; } } I though about using a variation of Double-Checked Locking (consider that running is a primitive 32-bit field, hence atomic, it could work fine even for Java below 5 without the need of volatile). It could look like this: private static boolean running = false; public void launchExpensiveTask() { if (running) return; // Do nothing synchronized (ThisClass.class) { if (running) return; running = true; try { runExpensiveTask(); } finally { running = false; } } } Maybe I should also use a local copy of the field as well (not sure now, please tell me). But then I realized that anyway I will end with an inner synchronization block, that still could hold a thread with the right timing at monitor entrance until the original executor leaves the critical section (I know the odds usually are minimal but in this case we are thinking in several threads competing for this long-running resource). So, could you think in a better approach?

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• What is a more "ruby way" to write this code?

  - by steadfastbuck

  This was a homework assignment for my students (I am a teaching assistant) in c and I am trying to learn Ruby, so I thought I would code it up. The goal is to read integers from a redirected file and print some simple information. The first line in the file is the number of elements, and then each integer resides on its own line. This code works (although perhaps inefficiently), but how can I make the code more Ruby-like? #!/usr/bin/ruby -w # first line is number of inputs (Don't need it) num_inputs = STDIN.gets.to_i # read inputs as ints h = Hash.new STDIN.each do |n| n = n.to_i h[n] = 1 unless h[n] and h[n] += 1 end # find smallest mode h.sort.each do |k,v| break puts "Mode is: #{k}", "\n" if v == h.values.max end # mode unique? v = h.values.sort print "Mode is unique: " puts v.pop == v.pop, "\n" # print number of singleton odds, # odd elems repeated odd number times in desc order # even singletons in desc order odd_once = 0 odd = Array.new even = Array.new h.each_pair do |k, v| odd_once += 1 if v == 1 and k.odd? odd << k if v.odd? even << k if v == 1 and k.even? end puts "Number of elements with an odd value that appear only once: #{odd_once}", "\n" puts "Elements repeated an odd number of times:" puts odd.sort.reverse, "\n" puts "Elements with an even value that appear exactly once:" puts even.sort.reverse, "\n" # print fib numbers in the hash class Fixnum def is_fib? l, h = 0, 1 while h <= self return true if h == self l, h = h, l+h end end end puts "Fibonacci numbers:" h.keys.sort.each do |n| puts n if n.is_fib? end

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• Codeigniter xss_clean dilemma

  - by Henson

  I know this question has been asked over and over again, but I still haven't found the perfect answer for my liking, so here it goes again... I've been reading lots and lots polarizing comments about CI's xss_filter. Basically majority says that it's bad. Can someone elaborate how it's bad, or at least give 1 most probable scenario where it can be exploited? I've looked at the security class in CI 2.1 and I think it's pretty good as it doesn't allow malicious strings like document.cookie, document.write, etc. If the site has basically non-html presentation, is it safe to use global xss_filter (or if it's REALLY affecting performance that much, use it on per form post basis) before inserting to database ? I've been reading about pros and cons about whether to escape on input/output with majority says that we should escape on output only. But then again, why allow strings like <a href="javascript:stealCookie()">Click Me</a> to be saved in the database at all? The one thing I don't like is javascript: and such will be converted to [removed]. Can I extend the CI's security core $_never_allowed_str arrays so that the never allowed strings return empty rather than [removed]. The best reasonable wrongdoing example of this I've read is if a user has password of javascript:123 it will be cleaned into [removed]123 which means string like this document.write123 will also pass as the user's password. Then again, what is the odds of that to happen and even if it happens, I can't think of any real harm that can do to the site. Thanks

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• Laptop LCD sometimes stops working on reboot. Please help.

  - by J Ringle

  I have a Gateway P-6831FX Laptop with Vista Ultimate. The Laptop LCD will sometimes not come on after I reboot the computer. I don't even close the lid and it happens. It isn't dim, it doesn't come on at all. No posting of CMOS (BIOS), nothing. Please note... this happens sometimes, not every time. Frustrating! When plugged into an external monitor, which works fine, Vista display properties can't even "sense" the laptop LCD. I try to enable the laptop LCD for dual display, turning on the laptop LCD, and it does nothing. It's like the laptop LCD is not even there. Manually taking a magnet in my hand to the laptop lid sensing switch (the sensor that turns off display/sleep mode when you close lid), sometimes causes the LCD backlight to "turn on" but not display any images. By "turn on" I mean I can see the screen backlight turn on to a 'dark gray' screen instead of pitch black. Subsequent reboot the laptop display is not working again! Here are the facts: Only happens at random and only after a reboot. Waking from Sleep mode isn't a problem. Pressing F4 function key for dual display does nothing when this happens. Closing lid doesn't seem to be related. (unless it is only after reboot.) using external magnet from laptop screen sensor sometimes triggers backlight to turn on but reboot back to square one with no LCD display. an external display always works fine. I have taken apart LCD, checked all wires and ribbons for loose connections or damage. I have replaced the Inverter. It doesn't seem to be heat related as I can put in sleep mode and resume fine when very hot. (external monitor works fine too). Sometimes the screen works fine as if there is not a problem at all. Even after a reboot... This is random. Any ideas out there? If it is a bad part... which one? The LCD seems to be fine. What are the odds of 2 bad inverters? The backlight is fine. The LCD wires/ribbons seem to be fine. I am at a loss. No warranty left and Gateway tech support is clueless. Thanks for any feedback that might help.

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• Synchronize the same set of files to 2 different locations with 2 different programs for 2 different purposes

  - by Hedgetrimmer

  Because of stupid questionable IT policies at my not-to-be-named place of occupation, I have been (and will be, for the forseeable future) carrying on an external hard drive a unison-synchronized copy of all of my documents and code, including code which resides in some of my "dotfiles" and other code which resides in ~/bin (things I've made are there because ~/bin is in my $PATH) along with some cruft generated (and to be generated) by conscript and its related "giter8" templating system for Scala project boilerplates. Despite this, I do use a symlinking program to store all of my important dotfiles in a subdirectory. Thanks to that somewhat complicated setup, I have resorted to making a directory full of symlinks to every directory (or file, as is the case with stuff under ~/bin) that I want synchronized, and then follow = True is in my unison profile. It happens to be that this collection of odds and ends—plus an automatically-generated text file containing every package installed on my system—is everything under ~ that needs to be backed up to a remote (rsync-over-ssh) host with client-side encryption and signing from GPG. I already believe that duplicity is the most appropriate program to do that. What isn't as clear-cut is how to make duplicity use the exact same set of files when it runs a backup; it would be simple if duplicity would follow symlinks, but it does not and the manpage lists no option for enabling any such behavior. Comparing unison's file selection algorithm to duplicity's, I don't think I can write a program that could compute a ruleset for one program given one for the other. For the record, I would rather not keep the symlinks manually synchronized with duplicity file-selection rules, as they can change thanks to the above-mentioned complications regarding ~/bin. I don't think running duplicity on the external hard disk is such a good idea either; I usually keep that hard disk unmounted and unplugged in case of a power failure or other physical problem with the computer, plus I'm not sure about duplicity's performance given that: the hard disk is NTFS-formatted in order to be useable at my Windows-imprisoned place of occupation. despite being a USB 3.0 disk, my computer has no USB 3.0 ports so it acts as a USB 2.0 disk. How can I have duplicity (or is there a better program that I have overlooked?) back up the exact same set of files that is bidirectionally synchronized with my external hard disk?

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• Developer Training – Various Options for Maximum Benefit – Part 4

  - by pinaldave

  Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 If you have been reading this series, by now you are aware of all the pros and cons that can come along with training.  We’ve asked and answered hard questions, and investigated them “whys” and “hows” of training.  Now it is time to talk about all the different kinds of training that are out there! On Job Training The most common type of training is on the job training.  Everyone receives this kind of education – even experts who come in to consult have to be taught where the printer, pens, and copy machines are.  If you are thinking about more concrete topics, though, on the job training can be some of the easiest to come across.  Picture this: someone in the company whom you really admire is hard at work on a project.  You come up to them and ask to help them out – if they are a busy developer, the odds are that they will say “yes, please!”   If you phrase your question as an offer of help, you can receive training without ever putting someone in the awkward position of acting as a mentor.  However, some people may want the task of being a mentor.  It can never hurt to ask.  Most people will be more than willing to pass their knowledge along. Extreme Programming If your company and coworkers are willing, you can even investigate Extreme Programming.  This is a type of programming that allows small teams to quickly develop code and products that are released with almost immediate user feedback.  You can find more information at http://www.extremeprogramming.org/.  If this is something your company could use, suggest it to your supervisor.  Even if they say no, it will make it clear that you are a go-getter who is interested in new and exciting projects.  If the answer is yes, then you have the opportunity to get some of the best on the job training around. In Person Training Click on Image to Enlarge When you say the word “training,” most people’s minds go back to the classroom, an image they are familiar with.  While training doesn’t always have to be in a traditional setting, because it is so familiar it can also be the most valuable type of training.  There are many ways to get training through a live instructor.  Some companies may be willing to send a representative to you, where employees will get training, sometimes food and coffee, and a live instructor who can answer questions immediately.  Sometimes these trainers are also able to do consultations at the same time, which can invaluable to a company.  If you are the one to asks your supervisor for a training session that can also be turned into a consultation, you may stick in their minds as an incredibly dedicated employee.  If you can’t find a representative, local colleges can also be a good resource for free or cheap classes – or they may have representatives coming who are willing to take on a few more students. Benefits of On Demand Developer Training Of course, you can often get the best of all these types of training with online or On Demand training.  You can get the benefit of a live instructor who is willing to answer questions (although in this case, usually through e-mail or other online venues), there are often real-world examples to follow along – like on the job training – and best of all you can learn whenever you have the time or need.  Did a problem with your server come up at midnight when all your supervisors are safe at home and probably in bed?  No problem!  On Demand training is especially useful if you need to slow down, pause, or rewind a training session.  Not even a real-life instructor can do that! When I was writing this blog post, I felt that each of the subject, which I have covered can be blog posts of itself. However, I wanted to keep the the blog post concise and so touch based on three major training aspects 1) On Job Training 2) In Person Training and 3) Online training. Here is the question for you – is there any other kind of training methods available, which are effective and one should consider it? If yes, what are those, I may write a follow up blog post on the same subject next week. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• How to Collect Debug Info for Oracle SQL Developer

  - by thatjeffsmith

  In a perfect world, there would be no software bugs. Developers would always test their code. QA would find any scenarios and bugs the developers hadn’t already thought of. Regression tests would be complete and flawless. But alas, we can only afford to pay mere humans here, so we will have bugs from time to time. Or sometimes you are trying to do something the software wasn’t designed for, or perhaps your machine has exhausted it’s resources trying to build the un-buildable. When you run into problems, you will need help. Developers need your help so they can help you. Surprisingly enough, feedback like this isn’t very helpful: Your program isn’t working. How can I make it work? When you are ready to work with us on the SQL Developer OTN forum, you will most likely be asked to run SQL Developer and capture the output from the command console. In case you need help with this, ere’s a step-by-step process you can follow in Windows 7 (should work in XP too.) Open a windows command window Start – Run – CMD Once it’s open, click on the window icon and select ‘Defaults.’ Change the default buffer size to be something bigger, much bigger. Set the CMD window default buffer size HIGHER Note: you only need to do this once. Navigate to your SQL Developer Installation Folder Instead of running the ‘sqldeveloper.exe’ file in the root directory, we are going to go several sub-directories down. Find the ‘bin’ sub-directory and run the ‘sqldeveloper.exe’ there. When you do this, a CMD window will open, and then you’ll see the SQL Developer application load. The SQL Developer bin directory - run the tool from here and get a logging window Use SQL Developer as normal, until it ‘breaks’ or ‘hangs’ Now, you are ready to grab the nitty-gritty information that MIGHT tell the developer what is going wrong or happening in your scenario. Click back into the CMD window Send a Ctrl+Break or a Ctrl+Pause. If you on a newer laptop that doesn’t have this key, be sure to check the ‘Fn’ subset of keys. If you need to map the BREAK or PAUSE buttons, this article might help. You can also try the on-screen keyboard in windows – just type ‘OSK’ in your START – RUN prompt. Copy the logging information from the command window – all of it We need this information, help us get it! Open a case with Oracle Support or Start a Thread on the Forums Or email me. If you’re on my blog reading this, it’s the least I can do to help Now, before you hit ‘Send’ or ‘Post’ or ‘Submit’ – be sure to add a brief description of what you were doing in the application when you ran into the problem. Even if you were doing ‘nothing,’ let us know how many connections you had open, what windows were active, etc. The more you can tell us, the higher your odds go up to getting a quick fix or at least an answer as to what is happening. Also include the following information: The version of SQL Developer you are running The version of the JDK you are using The OS you are using The version of Oracle you are connected to Now, don’t be surprised if you get asked to upgrade to a supported configuration, say ‘version 3.1 and the 1.6 JDK.’ Supporting older versions of software is fun, and while we enjoy a challenge, it may be easier for you to upgrade your way out of the problem at hand.

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• Simple-Talk development: a quick history lesson

  - by Michael Williamson

  Up until a few months ago, Simple-Talk ran on a pure .NET stack, with IIS as the web server and SQL Server as the database. Unfortunately, the platform for the site hadn’t quite gotten the love and attention it deserved. On the one hand, in the words of our esteemed editor Tony “I’d consider the current platform to be a “success”; it cost $10K, has lasted for 6 years, was finished, end to end in 6 months, and although we moan about it has got us quite a long way.” On the other hand, it was becoming increasingly clear that it needed some serious work. Among other issues, we had authors that wouldn’t blog because our current blogging platform, Community Server, was too painful for them to use. Forgetting about Simple-Talk for a moment, if you ask somebody what blogging platform they’d choose, the odds are they’d say WordPress. Regardless of its technical merits, it’s probably the most popular blogging platform, and it certainly seemed easier to use than Community Server. The issue was that WordPress is normally hosted on a Linux stack running PHP, Apache and MySQL — quite a difference from our Microsoft technology stack. We certainly didn’t want to rewrite the entire site — we just wanted a better blogging platform, with the rest of the existing, legacy site left as is. At a very high level, Simple-Talk’s technical design was originally very straightforward: when your browser sends an HTTP request to Simple-Talk, IIS (the web server) takes the request, does some work, and sends back a response. In order to keep the legacy site running, except with WordPress running the blogs, a different design is called for. We now use nginx as a reverse-proxy, which can then delegate requests to the appropriate application: So, when your browser sends a request to Simple-Talk, nginx takes that request and checks which part of the site you’re trying to access. Most of the time, it just passes the request along to IIS, which can then respond in much the same way it always has. However, if your request is for the blogs, then nginx delegates the request to WordPress. Unfortunately, as simple as that diagram looks, it hides an awful lot of complexity. In particular, the legacy site running on IIS was made up of four .NET applications. I’ve already mentioned one of these applications, Community Server, which handled the old blogs as well as managing membership and the forums. We have a couple of other applications to manage both our newsletters and our articles, and our own custom application to do some of the rendering on the site, such as the front page and the articles. When I say that it was made up of four .NET applications, this might conjure up an image in your mind of how they fit together: You might imagine four .NET applications, each with their own database, communicating over well-defined APIs. Sadly, reality was a little disappointing: We had four .NET applications that all ran on the same database. Worse still, there were many queries that happily joined across tables from multiple applications, meaning that each application was heavily dependent on the exact data schema that each other application used. Add to this that many of the queries were at least dozens of lines long, and practically identical to other queries except in a few key spots, and we can see that attempting to replace one component of the system would be more than a little tricky. However, the problems with the old system do give us a good place to start thinking about desirable qualities from any changes to the platform. Specifically: Maintainability — the tight coupling between each .NET application made it difficult to update any one application without also having to make changes elsewhere Replaceability — the tight coupling also meant that replacing one component wouldn’t be straightforward, especially if it wasn’t on a similar Microsoft stack. We’d like to be able to replace different parts without having to modify the existing codebase extensively Reusability — we’d like to be able to combine the different pieces of the system in different ways for different sites Repeatable deployments — rather than having to deploy the site manually with a long list of instructions, we should be able to deploy the entire site with a single command, allowing you to create a new instance of the site easily whether on production, staging servers, test servers or your own local machine Testability — if we can deploy the site with a single command, and each part of the site is no longer dependent on the specifics of how every other part of the site works, we can begin to run automated tests against the site, and against individual parts, both to prevent regressions and to do a little test-driven development In the next part, I’ll describe the high-level architecture we now have that hopefully brings us a little closer to these five traits.

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• Deep in the Heart of Texas

  - by Applications User Experience

  Author: Erika Webb, Manager, Fusion Applications UX User Assistance When I was first working in the usability field, the only way I could consider conducting a usability study was to bring a potential user to a lab environment where I could show them whatever I was interested in learning more about and ask them questions. While I hate to reveal just how long I have been working in this field, let's just say that pads of paper and a stopwatch were key tools for any test I conducted. Over the years, I have worked in simple labs with basic video taping equipment and not much else, and I have worked in corporate environments with sophisticated usability labs and state-of-the-art equipment. Years ago, we conducted all usability studies at the location of the user. If we wanted to see if there were any differences between users in New York, Chicago, and Los Angeles, we went to those places to run the test. A lab environment is very useful for many test situations. However, there has always been a debate in the usability field about whether bringing someone into a lab environment, however friendly we make it, somehow intrinsically changes the behavior of the user as compared to having them work in their own environment, at their own desk, and on their own computer. We developed systems to create a portable usability lab, so that we could go to the users that we needed to test.  Do lab environments change user behavior patterns? Then 9/11 hit. You may not remember, but no planes flew for weeks afterwards. Companies all over the world couldn't fly-in employees for meetings. Suddenly, traveling to the location of the users had an additional difficulty. The company I was working for at the time had usability specialists stuck in New York for days before they could finally rent a car and drive home to Colorado. This changed the world pretty suddenly, and technology jumped on the change. Companies offering Internet meeting tools were strugglinguntil no one could travel. The Internet boomed with collaboration tools that enabled people to work together wherever they happened to be. This change in technology has made a huge difference in my world. We use collaborative tools to bring our product concepts and ideas to the user across the Internet. As a global company, we benefit from having users from all over the world inform our designs. We now run usability studies with users all over the world in a single day, a feat we couldn't have accomplished 10 years ago by plane! Other technology companies have started to do more of this type of usability testing, since the tools have improved so dramatically. Plus, in our busy world, it's not always easy to find users who can take the time away from their jobs to come to our labs. reaching users where it is convenient for them greatly improves the odds that people do participate. I manage a team of usability specialists who live in India and California, whlie I live in Colorado. We have wonderful labs that we bring users into to show them our products. But very often, we run our studies remotely. We used to take the lab to the users now we use the labs, but we let the users stay where they are. We gain users who might not have been able to leave work to come to our labs, and they get to use the system they are familiar with. And we gain users nearly anywhere that we can set up an Internet connection, as long as the users have a phone, a broadband connection, and a compatible Web browser (with no pop-up blockers). After we recruit participants in a traditional manner, we send them an invitation to participate through the use of a telephone conference call and Web conferencing tool. At Oracle, we use Oracle Web Conference part of Oracle Collaboration Suite, which enables us to give the user control of the mouse, while we present a prototype or wireframe pictures. We can record the sessions over the Web and phone conference. We send the users instructions, plus tips to ensure that we won't have problems sharing screens. In some cases, when time is tight, we even run a five-minute "test session" with users a day in advance to be sure that we can connect. Prior to the test, we send users a participant script that contains information about the study, including any questionnaires. This is exactly the same script we give to participants who come to the labs. We ask users to print this before the beginning of the session. We generally run these studies by having a usability engineer in our usability labs, so that we can record the session as though the user were in the lab with us. Roughly 80% of our application software usability testing at Oracle is performed using remote methods. The probability of getting a   remote test participant decreases the higher up the person is in the target organization. We have a methodology checklist available to help our usability engineers work through the remote processes.

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• More Quick Interview Tips

  - by Ajarn Mark Caldwell

  In the last couple of years I have conducted a lot of interviews for application and database developers for my company, and I can tell you that the little things can mean a lot.  Here are a few quick tips to help you make a good first impression. A year ago I gave you my #1 interview tip: Do some basic research!  And a year later, I am still stunned by how few technical people do the most basic of research.  I can only guess that it is because it is so engrained in our psyche that technical competence is everything (see How to Manage Technical Employees for more on this idea) that we forget or ignore the importance of soft skills and the art of the interview.  Or maybe it is because we have heard the stories of the uber-geek who has zero personal skills but still makes a fortune working for Microsoft.  Well, here’s another quick tip:  You’re probably not as good as he is; and a large number of companies actually run small to medium sized teams and can’t really afford to have the social outcast in the group.  In a small team, everyone has to get along well, and that’s an important part of what I’m evaluating during the interview process. My #2 tip is to act alive!  I typically conduct screening interviews by phone before I bring someone in for an in-person.  I don’t care how laid-back you are or if you have a “quiet personality”, when we are talking, ACT like you are happy I called and you are interested in getting the job.  If you sound like you are bored-to-death and that you would be perfectly happy to never work again, I am perfectly happy to help you attain that goal, and I’ll move on to the next candidate. And closely related to #2, perhaps we’ll call it #2.1 is this tip:  When I call you on the phone for the interview, don’t answer your phone by just saying, “Hello”.  You know that the odds are about 999-to-1 that it is me calling for the interview because we have specifically arranged this time slot for the call.  And you can see on the caller ID that it is not one of your buddies calling, so identify yourself.  Don’t make me question whether I dialed the right number.  Answer your phone with a, “Hello, this is ___<your full name preferred, but at least your first name>___.”.  And when I say, “Hi, <your name>, this is Mark from <my company>” it would be really nice to hear you say, “Hi, Mark, I have been expecting your call.”  This sets the perfect tone for our conversation.  I know I have the right person; you are professional enough and interested enough in the job or contract to remember your appointments; and now we can move on to a little intro segment and get on with the reason for our call. As crazy as it sounds, I’ve actually had phone interviews that went like this: <Ring…> You:  “Hello?” Me:  “Hi, this is Mark from _______” You:  “Yeah?” Me:  “Is this <your name>?” You:  “Yeah.” Me:  “I had this time in my calendar for us to talk…were you expecting my call?” You:  “Oh, yeah, sure…” I used to be nice and would try to go ahead with the interview even after this bad start, thinking I was giving the candidate the benefit of the doubt…a second chance…but more often than not it was a struggle and 10 minutes into what was supposed to be a 45-minute call, I’m looking for a way to hang up without being rude myself.  It never worked out.  I never brought that person in for an in-person interview, much less offered them the job or contract.  Who knows, maybe they were some sort of wunderkind that we missed out on.  What I know is that they would never fit in with the rest of the team, and around here that is absolutely critical. So, in conclusion… Act alive!  Identify yourself!  And do at least the very basic of research.

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• Find location using only distance and range?

  - by pinnacler

  Triangulation works by checking your angle to three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and it's to my right at 90 degrees." Repeat 2 more times for different targets and angles. Trilateration works by checking your distance from three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and I'm 100 meters away from that." Repeat 2 more times for different targets and ranges. But both of those methods rely on knowing WHAT you're looking at. Say you're in a forest and you can't differentiate between trees, but you know where key trees are. These trees have been hand picked as "landmarks." You have a robot moving through that forest slowly. Do you know of any ways to determine location based solely off of angle and range, exploiting geometry between landmarks? Note, you will see other trees as well, so you won't know which trees are key trees. Ignore the fact that a target may be occluded. Our pre-algorithm takes care of that. 1) If this exists, what's it called? I can't find anything. 2) What do you think the odds are of having two identical location 'hits?' I imagine it's fairly rare. 3) If there are two identical location 'hits,' how can I determine my exact location after I move the robot next. (I assume the chances of having 2 occurrences of EXACT angles in a row, after I reposition the robot, would be statistically impossible, barring a forest growing in rows like corn). Would I just calculate the position again and hope for the best? Or would I somehow incorporate my previous position estimate into my next guess? If this exists, I'd like to read about it, and if not, develop it as a side project. I just don't have time to reinvent the wheel right now, nor have the time to implement this from scratch. So if it doesn't exist, I'll have to figure out another way to localize the robot since that's not the aim of this research, if it does, lets hope it's semi-easy.

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• Find location using only distance and bearing?

  - by pinnacler

  Triangulation works by checking your angle to three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and it's to my right at 90 degrees." Repeat 2 more times for different targets and angles. Trilateration works by checking your distance from three KNOWN targets. "I know the that's the Lighthouse of Alexandria, it's located here (X,Y) on a map, and I'm 100 meters away from that." Repeat 2 more times for different targets and ranges. But both of those methods rely on knowing WHAT you're looking at. Say you're in a forest and you can't differentiate between trees, but you know where key trees are. These trees have been hand picked as "landmarks." You have a robot moving through that forest slowly. Do you know of any ways to determine location based solely off of angle and range, exploiting geometry between landmarks? Note, you will see other trees as well, so you won't know which trees are key trees. Ignore the fact that a target may be occluded. Our pre-algorithm takes care of that. 1) If this exists, what's it called? I can't find anything. 2) What do you think the odds are of having two identical location 'hits?' I imagine it's fairly rare. 3) If there are two identical location 'hits,' how can I determine my exact location after I move the robot next. (I assume the chances of having 2 occurrences of EXACT angles in a row, after I reposition the robot, would be statistically impossible, barring a forest growing in rows like corn). Would I just calculate the position again and hope for the best? Or would I somehow incorporate my previous position estimate into my next guess? If this exists, I'd like to read about it, and if not, develop it as a side project. I just don't have time to reinvent the wheel right now, nor have the time to implement this from scratch. So if it doesn't exist, I'll have to figure out another way to localize the robot since that's not the aim of this research, if it does, lets hope it's semi-easy.

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• Java Error When correct code is put together

  - by Eric

  I have a few string problems that I need to put together for a complete homework assignment. They all work correctly by themselves, but when I put them together in the main function, the last one that finds the smallest word in a string gives an error. Anyone know why? public static void main(String[] args){ Scanner sc = new Scanner(System.in); //Length of Word String word1 = sc.next(); System.out.println(word1.length()); //Evens in one string odds in the other String word2 = sc.next(); StringBuilder even = new StringBuilder(); StringBuilder odd = new StringBuilder(); for(int i = 0; i < word2.length(); i++){ if(i % 2 == 0){ even.append(word2.charAt(i)); } else{ odd.append(word2.charAt(i)); } } System.out.println(even + " " + odd); //Diminishing Suffix String word3 = sc.next(); for(int j = 0; j < word3.length(); j++){ System.out.print(word3.substring(j, word3.length()) + " "); } System.out.printf("\n"); //Letter Replacement String word4 = sc.next(); String word5 = sc.next(); String word6 = sc.next(); String word7 = word4.replace(word5, word6); System.out.println(word7); //How many times x appears in xstring String word8 = sc.next(); String word9 = sc.next(); int index = word8.indexOf(word9); int count = 0; while (index != -1) { count++; word8 = word8.substring(index + 1); index = word8.indexOf(word9); } System.out.println(count); System.out.println(); //Lexicographically smallest word String Sentence = sc.nextLine(); String[] myWords = Sentence.split(" "); int shortestLengths, shortestLocation; shortestLengths=(myWords[1]).length(); shortestLocation=1; for (int i = 1; i <myWords.length; i++) { if ((myWords[i]).length() < shortestLengths) { shortestLengths=(myWords[i]).length(); shortestLocation=i; } } System.out.println(myWords[shortestLocation]); } } Talking about the lexicographically smallest one

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• disk-to-disk backup without costly backup redundancy?

  - by AaronLS

  A good backup strategy involves a combination of 1) disconnected backups/snapshots that will not be affected by bugs, viruses, and/or security breaches 2) geographically distributed backups to protect against local disasters 3) testing backups to ensure that they can be restored as needed Generally I take an onsite backup daily, and an offsite backup weekly, and do test restores periodically. In the rare circumstance that I need to restore files, I do some from the local backup. Should a catastrophic event destroy the servers and local backups, then the offsite weekly tape backup would be used to restore the files. I don't need multiple offsite backups with redundancy. I ALREADY HAVE REDUNDANCY THROUGH THE USE OF BOTH LOCAL AND REMOTE BACKUPS. I have recovery blocks and par files with the backups, so I already have protection against a small percentage of corrupt bits. I perform test restores to ensure the backups function properly. Should the remote backups experience a dataloss, I can replace them with one of the local backups. There are historical offsite backups as well, so if a dataloss was not noticed for a few weeks(such as a bug/security breach/virus), the data could be restored from an older backup. By doing this, the only scenario that poses a risk to complete data loss would be one where both the local, remote, and servers all experienced a data loss in the same time period. I'm willing to risk that happening since the odds of that trifecta negligibly small, and the data isn't THAT valuable to me. So I hope I have emphasized that I don't need redundancy in my offsite backups because I have covered all the bases. I know this exact technique is employed by numerous businesses. Of course there are some that take multiple offsite backups, because the data is so incredibly valuable that they don't even want to risk that trifecta disaster, but in the majority of cases the trifecta disaster is an accepted risk. I HAD TO COVER ALL THIS BECAUSE SOME PEOPLE DON'T READ!!! I think I have justified my backup strategy and the majority of businesses who use offsite tape backups do not have any additional redundancy beyond what is mentioned above(recovery blocks, par files, historical snapshots). Now I would like to eliminate the use of tapes for offsite backups, and instead use a backup service. Most however are extremely costly for $/gb/month storage. I don't mind paying for transfer bandwidth, but the cost of storage is way to high. All of them advertise that they maintain backups of the data, and I imagine they use RAID as well. Obviously if you were using them to host servers this would all be necessary, but for my scenario, I am simply replacing my offsite backups with such a service. So there is no need for RAID, and absolutely no value in another layer of backups of backups. My one and only question: "Are there online data-storage/backup services that do not use redundancy or offer backups(backups of my backups) as part of their packages, and thus are more reasonably priced?" NOT my question: "Is this a flawed strategy?" I don't care if you think this is a good strategy or not. I know it pretty standard. Very few people make an extra copy of their offsite backups. They already have local backups that they can use to replace the remote backups if something catastrophic happens at the remote site. Please limit your responses to the question posed. Sorry if I seem a little abrasive, but I had some trolls in my last post who didn't read my requirements nor my question, and were trying to go off answering a totally different question. I made it pretty clear, but didn't try to justify my strategy, because I didn't ask about whether my strategy was justifyable. So I apologize if this was lengthy, as it really didn't need to be, but since there are so many trolls here who try to sidetrack questions by responding without addressing the question at hand.

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• Movement prediction for non-shooters

  - by ShadowChaser

  I'm working on an isometric 2D game with moderate-scale multiplayer, approximately 20-30 players connected at once to a persistent server. I've had some difficulty getting a good movement prediction implementation in place. Physics/Movement The game doesn't have a true physics implementation, but uses the basic principles to implement movement. Rather than continually polling input, state changes (ie/ mouse down/up/move events) are used to change the state of the character entity the player is controlling. The player's direction (ie/ north-east) is combined with a constant speed and turned into a true 3D vector - the entity's velocity. In the main game loop, "Update" is called before "Draw". The update logic triggers a "physics update task" that tracks all entities with a non-zero velocity uses very basic integration to change the entities position. For example: entity.Position += entity.Velocity.Scale(ElapsedTime.Seconds) (where "Seconds" is a floating point value, but the same approach would work for millisecond integer values). The key point is that no interpolation is used for movement - the rudimentary physics engine has no concept of a "previous state" or "current state", only a position and velocity. State Change and Update Packets When the velocity of the character entity the player is controlling changes, a "move avatar" packet is sent to the server containing the entity's action type (stand, walk, run), direction (north-east), and current position. This is different from how 3D first person games work. In a 3D game the velocity (direction) can change frame to frame as the player moves around. Sending every state change would effectively transmit a packet per frame, which would be too expensive. Instead, 3D games seem to ignore state changes and send "state update" packets on a fixed interval - say, every 80-150ms. Since speed and direction updates occur much less frequently in my game, I can get away with sending every state change. Although all of the physics simulations occur at the same speed and are deterministic, latency is still an issue. For that reason, I send out routine position update packets (similar to a 3D game) but much less frequently - right now every 250ms, but I suspect with good prediction I can easily boost it towards 500ms. The biggest problem is that I've now deviated from the norm - all other documentation, guides, and samples online send routine updates and interpolate between the two states. It seems incompatible with my architecture, and I need to come up with a better movement prediction algorithm that is closer to a (very basic) "networked physics" architecture. The server then receives the packet and determines the players speed from it's movement type based on a script (Is the player able to run? Get the player's running speed). Once it has the speed, it combines it with the direction to get a vector - the entity's velocity. Some cheat detection and basic validation occurs, and the entity on the server side is updated with the current velocity, direction, and position. Basic throttling is also performed to prevent players from flooding the server with movement requests. After updating its own entity, the server broadcasts an "avatar position update" packet to all other players within range. The position update packet is used to update the client side physics simulations (world state) of the remote clients and perform prediction and lag compensation. Prediction and Lag Compensation As mentioned above, clients are authoritative for their own position. Except in cases of cheating or anomalies, the client's avatar will never be repositioned by the server. No extrapolation ("move now and correct later") is required for the client's avatar - what the player sees is correct. However, some sort of extrapolation or interpolation is required for all remote entities that are moving. Some sort of prediction and/or lag-compensation is clearly required within the client's local simulation / physics engine. Problems I've been struggling with various algorithms, and have a number of questions and problems: Should I be extrapolating, interpolating, or both? My "gut feeling" is that I should be using pure extrapolation based on velocity. State change is received by the client, client computes a "predicted" velocity that compensates for lag, and the regular physics system does the rest. However, it feels at odds to all other sample code and articles - they all seem to store a number of states and perform interpolation without a physics engine. When a packet arrives, I've tried interpolating the packet's position with the packet's velocity over a fixed time period (say, 200ms). I then take the difference between the interpolated position and the current "error" position to compute a new vector and place that on the entity instead of the velocity that was sent. However, the assumption is that another packet will arrive in that time interval, and it's incredibly difficult to "guess" when the next packet will arrive - especially since they don't all arrive on fixed intervals (ie/ state changes as well). Is the concept fundamentally flawed, or is it correct but needs some fixes / adjustments? What happens when a remote player stops? I can immediately stop the entity, but it will be positioned in the "wrong" spot until it moves again. If I estimate a vector or try to interpolate, I have an issue because I don't store the previous state - the physics engine has no way to say "you need to stop after you reach position X". It simply understands a velocity, nothing more complex. I'm reluctant to add the "packet movement state" information to the entities or physics engine, since it violates basic design principles and bleeds network code across the rest of the game engine. What should happen when entities collide? There are three scenarios - the controlling player collides locally, two entities collide on the server during a position update, or a remote entity update collides on the local client. In all cases I'm uncertain how to handle the collision - aside from cheating, both states are "correct" but at different time periods. In the case of a remote entity it doesn't make sense to draw it walking through a wall, so I perform collision detection on the local client and cause it to "stop". Based on point #2 above, I might compute a "corrected vector" that continually tries to move the entity "through the wall" which will never succeed - the remote avatar is stuck there until the error gets too high and it "snaps" into position. How do games work around this?

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• Need personal advice on how to get out of a company..

  - by SOfan

  Hi, I am an SO user since past 6 months and this is the first time I am turning to SO for personal help. I have asked technical questions before with my real ID. I am stuck inside a service based IT company for the past one year and haven't been able to decide if to leave it, when to leave it and how to leave it. I had taken 2 weeks LWP on medical reason roughly at end of 1 year and then soon after reporting, I applied for 2 months more LWP (on medical/personal ground) with the intention of working on my health,take up a hobby class to ward off depression,pessimism, to have some fun in life, and to look for a job which I really would be excited about - that interests me and which matches with my strength. My leave starts from this Monday. So in any case, I had hard set in mind that I will leave the company after I join them back hopefully with some job offer already in hand (after figuring out what I want do). Neither I can stand the past project,past colleagues,company, HR, pathetically low salary. But if I really listen to my heart, I don't want to have to go back to that office after my sabbatical and again have to see those people. I will have to resign it after my sabbatical ends. Then HR people perhaps wont like it, may even accuse me on face or behind back that primary purpose of my leave must have been to hunt for a better job and I lied about medical and person reasons. Also, if they get nasty and force me to serve 2 months notice period. There is no way I see myself after sabbatical resuming in old project or starting new work. It will be a pain. Since they have already approved 2 months leave and stuff, ideally if they want, they should be just able to relieve me right on the next day after I join back. But, I don't know if they want to get nasty, will they mention about my 2 months sabbatical leave in my experience letter or more scary, the term medical/personal reason. I have hard earned my experience here, have worked against my will, mostly it has been painful and slogged like anything, because I realize the importance of work experience in IT industry. I don't have greed to have those 2 months included extra in my experience letter, but I don't want to mess up with my experience letter in a way which makes my next employer ask question, get suspicious, or be wary if I have any medical reason going on. Being an emotional,moody person or somebody who can't be in an environment, once my mind and heart starts hating it. I think it perhaps is best, if I resign on Monday itself telling them (in polite manner) something that look I took sabbatical for some reason but I don't want to resume working in the company after my sabbatical ends. So please accept my resignation. Now tell me what you want to do about my leave request, my notice period and when you are willing to relieve me. What should I write and how? Some background: I am working in an IT company in India.I am overqualified in the company. It is grossly underpaying me. My education qualifications far exceed anyone's in the whole company being a CS undergrad as well as a CS grad. I joined this company after finishing the grad. I had self-doubts about my skills and interest as a programmer. I like doing research oriented work, though didn't have any particular success during grad. My life here has been very hectic. The project containing many many sub-projects has kept me on my toes and I have never really liked the work. I have been playing against my strength. Also the company strict internet usage policy (you can't read gmails, can't browse any non-work related sites not even news). When working for a client, from the machine we can't even check company related emails.For this one has to go to kiosk like 5 machines in a small room etc. Most of the times those machines are not available, so it was not unusual to keep making rounds to these kiosk machines to check company emails, browse company related emails etc.So it was not so easy to keep in touch with company related basic affairs for a not particular careful person. Things like this which are new to me, make me feel restricted. I am an undecisive person with a sense of failure, self-doubt, not meeting up unrealistic expectation. Somewhere at back of mind, I envy my classmates who make a smooth transition from company to company without causing any gap in their resume. I on other hand have gaps in resume. I get tired after working in a place for sometime. problem with colleagues in general. I am not particular great with people, have few friends, not known for a fun nature, rather serious, scholar. I am not a typical conventional female. I think females are usually more disciplined. But I am not so. I reach office late (though after informing manager). I don't want to blame them entirely, because from my past, it is not unusual for me to get undecisive on things. Also I had doubts about my ability as researched and to succeed there. of building a relationship in a group, to have something to talk about, newspaper. I get cut-off from people. peer pressure. I make blunders in coding, lose patience. Consciously or unconsciously I feel contempt for people here, work here, environment here. I have doubts that either I go to a place which does innovation, does research oriented work, product biggies, have great motivated people, have competent people passionate about products they are building. But then I also doubt my ability to survive there. I have identified that an idea job for me would be 4 days a week, a high salary job. When among people in company/team, I can't think much. I need some time at home to read good authentic books written in good style on what work I am doing.So that I am comfortable with my understanding of work. I get into pressure easily under deadline and need 5th day to cool myself off. I took for 2 weeks leave, because each day was hell for me. May be the depression phase of bipolar is on and also partially it could be that being a work centered person, who derives happiness,self-esteem from work, haven't been enjoying work and have been working for the sole person of proving stability, and ability to stick, against all odds, and facing what challenges I see, bonding with people, identifying opportunities to learn in given task etc.have been averaging one day LWP in 1 week or 10 days. or may be because of my nature,ADD,not being able to switch context,out of touch with news, don't have a circle of friends with who I enjoy. less knowledge in general to talk about, just some technical stuff.anyway, so due to emotional reason, some practical reason etc, I wanted to be very sure before leaving. So my leave starts from Monday and I should feel happy about it. I have taken the leave to for a few purposes - to take care of my health by regular yoga/exercise (with project on, I just can't do anything regular), reassess myself to see what I want to try next which work I might like, look for next job, take up a hobby which I like say singing. I am not clear on my career,job aspiration. I have tried my hands on research. During this year appraisal yesterday, I even had some conflict with my last manager. In meeting with me one on one, he would say all nice things about me, but in feedback to new manager, he hasn't given any excellent feedback. It is all only good. I am angry at this old Manager. Also new manager also scolded me as I didn't agree to his appraisal and waited to hear myself from old Manager. He kind of scolded me for wasting his time. Am I being unethical somewhere? I am always very conscious of if I am cheating anywhere. What advice I am seeking? How to resign and what to write in resignation letter

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• HTG Explains: Should You Buy Extended Warranties?

  - by Chris Hoffman

  Buy something at an electronics store and you’ll be confronted by a pushy salesperson who insists you need an extended warranty. You’ll also see extended warranties pushed hard when shopping online. But are they worth it? There’s a reason stores push extended warranties so hard. They’re almost always pure profit for the store involved. An electronics store may live on razor-thin product margins and make big profits on extended warranties and overpriced HDMI cables. You’re Already Getting Multiple Warranties First, back up. The product you’re buying already includes a warranty. In fact, you’re probably getting several different types of warranties. Store Return and Exchange: Most electronics stores allow you to return a malfunctioning product within the first 15 or 30 days and they’ll provide you with a new one. The exact period of time will vary from store to store. If you walk out of the store with a defective product and have to swap it for a new one within the first few weeks, this should be easy. Manufacturer Warranty: A device’s manufacturer — whether the device is a laptop, a television, or a graphics card — offers their own warranty period. The manufacturer warranty covers you after the store refuses to take the product back and exchange it. The length of this warranty depends on the type of product. For example, a cheap laptop may only offer a one-year manufacturer warranty, while a more expensive laptop may offer a two-year warranty. Credit Card Warranty Extension: Many credit cards offer free extended warranties on products you buy with that credit card. Credit card companies will often give you an additional year of warranty. For example, if you buy a laptop with a two year warranty and it fails in the third year, you could then contact your credit card company and they’d cover the cost of fixing or replacing it. Check your credit card’s benefits and fine print for more information. Why Extended Warranties Are Bad You’re already getting a fairly long warranty period, especially if you have a credit card that offers you a free extended warranty — these are fairly common. If the product you get is a “lemon” and has a manufacturing error, it will likely fail pretty soon — well within your warranty period. The extended warranty matters after all your other warranties are exhausted. In the case of a laptop with a two-year warranty that you purchase with a credit card giving you a one-year warranty extension, your extended warranty will kick in three years after you purchase the laptop. In that many years, your current laptop will likely feel pretty old and laptops that are as good — or better — will likely be pretty cheap. If it’s a television, better television displays will be available at a lower price point. You’ll either want to upgrade to a newer model or you’ll be able to buy a new, just-as-good product for very cheap. You’ll only have to pay out-of-pocket if your device fails after the normal warranty period — in over two or three years for typical laptops purchased with a decent credit card. Save the money you would have spent on the warranty and put it towards a future upgrade. How Much Do Extended Warranties Cost? Let’s look at an example from a typical pushy retail outlet, Best Buy. We went to Best Buy’s website and found a pretty standard $600 Samsung laptop. This laptop comes with a one-year warranty period. If purchased with a fairly common credit card, you can easily get a two-year warranty period on this laptop without spending an additional penny. (Yes, such credit cards are available with no yearly fees.) During the check-out process, Best Buy tries to sell you a Geek Squad “Accidental Protection Plan.” To get an additional year of Best Buy’s extended warranty, you’d have to pay $324.98 for a “3-Year Accidental Protection Plan”. You’d basically be paying more than half the price of your laptop for an additional year of warranty — remember, the standard warranties would cover you anyway for the first two years. If this laptop did break sometime between two and three years from now, we wouldn’t be surprised if you could purchase a comparable laptop for about $325 anyway. And, if you don’t need to replace it, you’ve saved that money. Best Buy would object that this isn’t a standard extended warranty. It’s a supercharged warranty plan that will also provide coverage if you spill something on your laptop or drop it and break it. You just have to ask yourself a question. What are the odds that you’ll drop your laptop or spill something on it? They’re probably pretty low if you’re a typical human being. Is it worth spending more than half the price of the laptop just in case you’ll make an uncommon mistake? Probably not. There may be occasional exceptions to this — some Apple users swear by Apple’s AppleCare, for example — but you should generally avoid buying these things. There’s a reason stores are so pushy about extended warranties, and it’s not because they want to help protect you. It’s because they’re making lots of profit from these plans, and they’re making so much profit because they’re not a good deal for customers. Image Credit: Philip Taylor on Flickr     

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• Messing with the Team

  - by Robert May

  Good Product Owners will help the team be the best that they can be.  Bad product owners will mess with the team and won’t care about the team.  If you’re a product owner, seek to do good and avoid bad behavior at all costs.  Remember, this is for YOUR benefit and you have much power given to you.  Use that power wisely. Scope Creep The product owner has several tools at his disposal to inject scope into an iteration.  First, the product owner can use defects to inject scope.  To do this, they’ll tell the team what functionality that they want to see in a feature.  Then, after the feature is developed, the Product Owner will decide that they don’t really like how the functionality behaves.  To change it, rather than creating a new story, they’ll add a defect.  The functionality is correct, as designed, but the Product Owner doesn’t like it.  By creating the defect, the Product Owner destroys the trust that the team has of the product owner.  They may not be able to count the story, because the Product Owner changed the story in the iteration, and the team then ends up looking like they have low velocity for something over which they have no control.  This is bad.  One way to deal with this is to add “Product Owner Time” to the iteration.  This will slow the velocity, but then the ScrumMaster can tell stake holders that this time is strictly in place to deal with bad behavior of the Product Owner. Another mechanism often used to inject Scope is the concept of directed development.  Outside of planning, stand-ups, or any other meeting, the Product Owner will take a developer aside and ask them to complete a task for them.  This is bad!  The team should be allocating all of their time to development.  If the Product Owner asks for a favor, then time that would normally be used for development will be used for a pet project of the Product Owner and the team will not get credit for this work.  Selfish product owners do this, and I typically see people who were “managers” do this behavior.  Authoritarian command and control development environments also see this happen.  The best thing that can happen is for the team member to report the issue to the ScrumMaster and the ScrumMaster to get very aggressive with management and the Product Owner to try and stop the behavior.  This may result in the ScrumMaster being fired, but if the behavior continues, Scrum is doomed.  This problem is especially bad in cases where the team member’s direct supervisor is the Product Owner.  I don’t recommend that the Product Owner or ScrumMaster have a direct report relationship with team members, since team members need the ability to say no.  To work around this issue, team members need to say no.  If that fails, team members need to add extra time to the iteration to deal with the scope creep injection and accept the lower velocity. As discussed above, another mechanism for injecting scope is by changing acceptance tests after the work is complete.  This is similar to adding defects to change scope and is bad.  To get around, add time for Product Owner uncertainty to the iteration and make sure that stakeholders are aware of the need to add this time because of the Product Owner. Refusing to Prioritize Refusing to prioritize causes chaos for the team.  From the team’s perspective, things that are not important will be worked on while things that the team knows are vital will be ignored.  A poor Product Owner will often pick the stories for the iteration on a whim.  This leads to the team working on many different aspects of the product and results in a lower velocity, since each iteration the team must switch context to the new area of development. The team will also experience confusion about priorities.  In one iteration, Feature X was the highest priority and had to be done.  Then, the following iteration, even though parts of Feature X still need to be completed, no stories to address them will be in the iteration.  However, three iterations later, Feature X will again become high priority. This will cause the team to not trust the Product Owner, and eventually, they’ll stop caring about the features they implement.  They won’t know what is important, so to insulate themselves from the ever changing chaos, they’ll become apathetic to all features.  Team members are some of the most creative people in a company.  By losing their engagement, the company is going to have a substandard product because the passion for the product won’t be in the team. Other signs that the Product Owner refuses to prioritize is that no one outside of the product owner will be consulted on priorities.  Additionally, the product, release, and iteration backlogs will be weak or non-existent. Dealing with this issue is not easy.  This really isn’t something the team can fix, short of taking over the role of Product Owner themselves.  An appeal to the stake holders might work, but only if the Product Owner isn’t a “manager” themselves.  The ScrumMaster needs to protect the team and do what they can to either get the Product Owner to prioritize or have the Product Owner replaced. Managing the Team A Product Owner that is also the “boss” of team members is a Scrum team that is waiting to fail.  If your boss tells you to do something, failing to do that something can cause you to be fired.  The team needs the ability to tell the Product Owner NO.  If the product owner introduces scope creep, the team has a responsibility to tell the Product Owner no.  If the Product Owner tries to get the team to commit to more than they can accomplish in an iteration, the team needs the ability to tell the Product Owner no. If the Product Owner is your boss and determines your pay increases, you’re probably not going to ever tell them no, and Scrum will likely fail.  The team can’t do much in this situation. Another aspect of “managing the team” that often happens is the Product Owner tries to tell the team how to develop the stories that are in the iteration.  This is one reason why I recommend that Product Owners are NOT technical people.  That way, the team can come up with the tasks that are needed to accomplish the stories and the Product Owner won’t know better.  If the Product Owner is technical, the ScrumMaster will need to take great care to protect the team from the ScrumMaster changing how the team thinks they need to implement the stories. Product Owners can also try to manage the team by their body language.  If the team says a task is going to take 6 hours to complete, and the Product Owner disagrees, they will use some kind of sour body language to indicate this disagreement.  In weak teams, this may cause the team to revise their estimate down, which will result in them taking longer than estimated and may result in them missing the iteration.  The ScrumMaster will need to make sure that the Product Owner doesn’t send such messages and that the team ignores them and estimates what they REALLY think it will take to complete the tasks.  Forcing the team to deal with such items in the retrospective can be helpful. Absenteeism The team is completely dependent upon the Product Owner to develop features for the customer.  The Product Owner IS the voice of the customer and without them, the team will lack direction.  Being the Product Owner is a full time job!  If the Product Owner cannot dedicate daily time with the team, a different product owner should be found. The Product Owner needs to attend every stand-up, planning meeting, showcase, and retrospective that the team has.  The team also must be able to have instant communication with the product owner.  They must not be required to schedule meetings to speak with their product owner.  The team must be the highest priority task that the Product Owner has. The best way to work around an absent Product Owner is to appoint a new Product Owner in the team.  This person will be responsible for making the decisions that the Product Owner should be making and to act as the liaison to the absent Product Owner.  If the delegate Product Owner doesn’t have authority to make decisions for the team, Scrum will fail.  If the Product Owner is absent, the ScrumMaster should seek to have that Product Owner replaced by someone who has the time and ability to be a real Product Owner. Making it Personal Too often Product Owners will become convinced that their ideas are the ones that matter and that anyone who disagrees is making a personal attack on them.  Remember that Product Owners will inherently be at odds with many people, simply because they have the need to prioritize.  Others will frequently question prioritization because they only see part of the picture that Product Owners face. Product Owners must have a thick skin and think egos.  If they don’t, they tend to make things personal, which causes them to become emotional and causes them to take actions that can destroy the trust that team members have in the Product Owner. If a Product Owner is making things person, the best thing that team members can do is reassure them that its not personal, but be firm about doing what is best for the Company and for the users.  The ScrumMaster should also spend significant time coaching the Product Owner on how to not react emotionally and how to accept criticism without becoming defensive. Conclusion I’m sure there are other ways that a Product Owner can mess with the team, but these are the most common that I’ve seen.  I would encourage all Product Owners to seek to be a good Product Owner.  If you find yourself behaving in any of the bad product owner ways, change your behavior today!  Your team will thank you. Remember, being Product Owner is very difficult!  Product Owner is one of the most difficult roles in Scrum.  However, it can also be one of the most rewarding roles in Scrum, since Product Owners literally see their ideas brought to life on the computer screen.  Product Owners need to be very patient, even in the face of criticism and need to be willing to make tough decisions on priority, but then not become offended when others disagree with those decisions.  Companies should spend the time needed to find the right product owners for their teams.  Doing so will only help the company to write better software. Technorati Tags: Scrum,Product Owner

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• If 'Architect' is a dirty word - what's the alternative; when not everyone can actually design a goo

  - by Andras Zoltan

  Now - I'm a developer first and foremost; but whenever I sit down to work on a big project with lots of interlinking components and areas, I will forward-plan my interfaces, base classes etc as best I can - putting on my Architect hat. For a few weeks I've been doing this for a huge project - designing whole swathes of interfaces etc for a business-wide platform that we're developing. The basic structure is a couple of big projects that consists of service and data interfaces, with some basic implementations of all of these. On their own, these assemblies are useless though, as they are simply intended intended as a scaffold on which to build a business-specific implementation (we have a lot of businesses). Therefore, the design of the core platform is absolutely crucial, since consumers of the system are not intended to know which implementation they are actually using. In the past it's not worked so well, but after a few proof-of-concepts and R&D projects this new platform is now growing nicely and is already proving itself. Then somebody else gets involved in the project - he's a TDD man who sees code-level architecture as an irrelevance and is definitely from the camp that 'architect' is a dirty word - I should add that our working relationship is very good despite this :) He's open about the fact that he can't architect in advance and obviously TDD really helps him because it allows him to evolve his systems over time. That I get, and totally understand; but it means that his coding style, basically, doesn't seem to be able to honour the architecture that I've been putting in place. Now don't get me wrong - he's an awesome coder; but the other day he needed to extend one of his components (an implementation of a core interface) to bring in an extra implementation-specific dependency; and in doing so he extended the core interface as well as his implementation (he uses ReSharper), thus breaking the independence of the whole interface. When I pointed out his error to him, he was dismayed. Being test-first, all that mattered to him was that he'd made his tests pass, and just said 'well, I need that dependency, so can't we put it in?'. Of course we could put it in, but I was frustrated that he couldn't see that refactoring the generic interface to incorporate an implementation-specific feature was just wrong! But it is all very Charlie Brown to him (you know the sound the adults make when they're talking to the children) - as far as he's concerned we don't need to worry about it because we can always refactor. The problem is, the culture of test-write-refactor is all very well and good - but not when you're dealing with a platform that is going to be shared out among so many projects that you could never get them all in one place to make the refactorings work. In my opinion, sometimes you actually have to think about what you're doing, and not just let nature take its course. Am I simply fulfilling the role of Architect as a dirty word here? I believe that architecture is important and should be thought about before code gets written; unless it's a particularly small project. But when you're working in a team of people who don't think that way, or even can't think that way how can you actually get this across? Is it a case of simply making the architecture off-limits to changes by other people? I don't want to start having bloody committees just to be able to grow the system; but equally I don't want to be the only one responsible for it all. Do you think the architect role is a waste of time? Is it at odds with TDD and other practises? Can this mix of different practises be made to work, or should I just be a lot less precious (and in so doing allow a generic platform become useless!)? Or do I just lay down the law? Any ideas/experiences/views gratefully received.

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• The Art of Productivity

  - by dwahlin

  Getting things done has always been a challenge regardless of gender, age, race, skill, or job position. No matter how hard some people try, they end up procrastinating tasks until the last minute. Some people simply focus better when they know they’re out of time and can’t procrastinate any longer. How many times have you put off working on a term paper in school until the very last minute? With only a few hours left your mental energy and focus seem to kick in to high gear especially as you realize that you either get the paper done now or risk failing. It’s amazing how a little pressure can turn into a motivator and allow our minds to focus on a given task. Some people seem to specialize in procrastinating just about everything they do while others tend to be the “doers” who get a lot done and ultimately rise up the ladder at work. What’s the difference between these types of people? Is it pure laziness or are other factors at play? I think that some people are certainly more motivated than others, but I also think a lot of it is based on the process that “doers” tend to follow - whether knowingly or unknowingly. While I’ve certainly fought battles with procrastination, I’ve always had a knack for being able to get a lot done in a relatively short amount of time. I think a lot of my “get it done” attitude goes back to the the strong work ethic my parents instilled in me at a young age. I remember my dad saying, “You need to learn to work hard!” when I was around 5 years old. I remember that moment specifically because I was on a tractor with him the first time I heard it while he was trying to move some large rocks into a pile. The tractor was big but so were the rocks and my dad had to balance the tractor perfectly so that it didn’t tip forward too far. It was challenging work and somewhat tedious but my dad finished the task and taught me a few important lessons along the way including persistence, the importance of having a skill, and getting the job done right without skimping along the way. In this post I’m going to list a few of the techniques and processes I follow that I hope may be beneficial to others. I blogged about the general concept back in 2009 but thought I’d share some updated information and lessons learned since then. Most of the ideas that follow came from learning and refining my daily work process over the years. However, since most of the ideas are common sense (at least in my opinion), I suspect they can be found in other productivity processes that are out there. Let’s start off with one of the most important yet simple tips: Start Each Day with a List. Start Each Day with a List What are you planning to get done today? Do you keep track of everything in your head or rely on your calendar? While most of us think that we’re pretty good at managing “to do” lists strictly in our head you might be surprised at how affective writing out lists can be. By writing out tasks you’re forced to focus on the most important tasks to accomplish that day, commit yourself to those tasks, and have an easy way to track what was supposed to get done and what actually got done. Start every morning by making a list of specific tasks that you want to accomplish throughout the day. I’ll even go so far as to fill in times when I’d like to work on tasks if I have a lot of meetings or other events tying up my calendar on a given day. I’m not a big fan of using paper since I type a lot faster than I write (plus I write like a 3rd grader according to my wife), so I use the Sticky Notes feature available in Windows. Here’s an example of yesterday’s sticky note: What do you add to your list? That’s the subject of the next tip. Focus on Small Tasks It’s no secret that focusing on small, manageable tasks is more effective than trying to focus on large and more vague tasks. When you make your list each morning only add tasks that you can accomplish within a given time period. For example, if I only have 30 minutes blocked out to work on an article I don’t list “Write Article”. If I do that I’ll end up wasting 30 minutes stressing about how I’m going to get the article done in 30 minutes and ultimately get nothing done. Instead, I’ll list something like “Write Introductory Paragraphs for Article”. The next day I may add, “Write first section of article” or something that’s small and manageable – something I’m confident that I can get done. You’ll find that once you’ve knocked out several smaller tasks it’s easy to continue completing others since you want to keep the momentum going. In addition to keeping my tasks focused and small, I also make a conscious effort to limit my list to 4 or 5 tasks initially. I’ve found that if I list more than 5 tasks I feel a bit overwhelmed which hurts my productivity. It’s easy to add additional tasks as you complete others and you get the added benefit of that confidence boost of knowing that you’re being productive and getting things done as you remove tasks and add others. Getting Started is the Hardest (Yet Easiest) Part I’ve always found that getting started is the hardest part and one of the biggest contributors to procrastination. Getting started working on tasks is a lot like getting a large rock pushed to the bottom of a hill. It’s difficult to get the rock rolling at first, but once you manage to get it rocking some it’s really easy to get it rolling on its way to the bottom. As an example, I’ve written 100s of articles for technical magazines over the years and have really struggled with the initial introductory paragraphs. Keep in mind that these are the paragraphs that don’t really add that much value (in my opinion anyway). They introduce the reader to the subject matter and nothing more. What a waste of time for me to sit there stressing about how to start the article. On more than one occasion I’ve spent more than an hour trying to come up with 2-3 paragraphs of text.  Talk about a productivity killer! Whether you’re struggling with a writing task, some code for a project, an email, or other tasks, jumping in without thinking too much is the best way to get started I’ve found. I’m not saying that you shouldn’t have an overall plan when jumping into a task, but on some occasions you’ll find that if you simply jump into the task and stop worrying about doing everything perfectly that things will flow more smoothly. For my introductory paragraph problem I give myself 5 minutes to write out some general concepts about what I know the article will cover and then spend another 10-15 minutes going back and refining that information. That way I actually have some ideas to work with rather than a blank sheet of paper. If I still find myself struggling I’ll write the rest of the article first and then circle back to the introductory paragraphs once I’m done. To sum this tip up: Jump into a task without thinking too hard about it. It’s better to to get the rock at the top of the hill rocking some than doing nothing at all. You can always go back and refine your work.   Learn a Productivity Technique and Stick to It There are a lot of different productivity programs and seminars out there being sold by companies. I’ve always laughed at how much money people spend on some of these motivational programs/seminars because I think that being productive isn’t that hard if you create a re-useable set of steps and processes to follow. That’s not to say that some of these programs/seminars aren’t worth the money of course because I know they’ve definitely benefited some people that have a hard time getting things done and staying focused. One of the best productivity techniques I’ve ever learned is called the “Pomodoro Technique” and it’s completely free. This technique is an extremely simple way to manage your time without having to remember a bunch of steps, color coding mechanisms, or other processes. The technique was originally developed by Francesco Cirillo in the 80s and can be implemented with a simple timer. In a nutshell here’s how the technique works: Pick a task to work on Set the timer to 25 minutes and work on the task Once the timer rings record your time Take a 5 minute break Repeat the process Here’s why the technique works well for me: It forces me to focus on a single task for 25 minutes. In the past I had no time goal in mind and just worked aimlessly on a task until I got interrupted or bored. 25 minutes is a small enough chunk of time for me to stay focused. Any distractions that may come up have to wait until after the timer goes off. If the distraction is really important then I stop the timer and record my time up to that point. When the timer is running I act as if I only have 25 minutes total for the task (like you’re down to the last 25 minutes before turning in your term paper….frantically working to get it done) which helps me stay focused and turns into a “beat the clock” type of game. It’s actually kind of fun if you treat it that way and really helps me focus on a the task at hand. I automatically know how much time I’m spending on a given task (more on this later) by using this technique. I know that I have 5 minutes after each pomodoro (the 25 minute sprint) to waste on anything I’d like including visiting a website, stepping away from the computer, etc. which also helps me stay focused when the 25 minute timer is counting down. I use this technique so much that I decided to build a program for Windows 8 called Pomodoro Focus (I plan to blog about how it was built in a later post). It’s a Windows Store application that allows people to track tasks, productive time spent on tasks, interruption time experienced while working on a given task, and the number of pomodoros completed. If a time estimate is given when the task is initially created, Pomodoro Focus will also show the task completion percentage. I like it because it allows me to track my tasks, time spent on tasks (very useful in the consulting world), and even how much time I wasted on tasks (pressing the pause button while working on a task starts the interruption timer). I recently added a new feature that charts productive and interruption time for tasks since I wanted to see how productive I was from week to week and month to month. A few screenshots from the Pomodoro Focus app are shown next, I had a lot of fun building it and use it myself to as I work on tasks.   There are certainly many other productivity techniques and processes out there (and a slew of books describing them), but the Pomodoro Technique has been the simplest and most effective technique I’ve ever come across for staying focused and getting things done.   Persistence is Key Getting things done is great but one of the biggest lessons I’ve learned in life is that persistence is key especially when you’re trying to get something done that at times seems insurmountable. Small tasks ultimately lead to larger tasks getting accomplished, however, it’s not all roses along the way as some of the smaller tasks may come with their own share of bumps and bruises that lead to discouragement about the end goal and whether or not it is worth achieving at all. I’ve been on several long-term projects over my career as a software developer (I have one personal project going right now that fits well here) and found that repeating, “Persistence is the key!” over and over to myself really helps. Not every project turns out to be successful, but if you don’t show persistence through the hard times you’ll never know if you succeeded or not. Likewise, if you don’t persistently stick to the process of creating a daily list, follow a productivity process, etc. then the odds of consistently staying productive aren’t good.   Track Your Time How much time do you actually spend working on various tasks? If you don’t currently track time spent answering emails, on phone calls, and working on various tasks then you might be surprised to find out that a task that you thought was going to take you 30 minutes ultimately ended up taking 2 hours. If you don’t track the time you spend working on tasks how can you expect to learn from your mistakes, optimize your time better, and become more productive? That’s another reason why I like the Pomodoro Technique – it makes it easy to stay focused on tasks while also tracking how much time I’m working on a given task.   Eliminate Distractions I blogged about this final tip several years ago but wanted to bring it up again. If you want to be productive (and ultimately successful at whatever you’re doing) then you can’t waste a lot of time playing games or on Twitter, Facebook, or other time sucking websites. If you see an article you’re interested in that has no relation at all to the tasks you’re trying to accomplish then bookmark it and read it when you have some spare time (such as during a pomodoro break). Fighting the temptation to check your friends’ status updates on Facebook? Resist the urge and realize how much those types of activities are hurting your productivity and taking away from your focus. I’ll admit that eliminating distractions is still tough for me personally and something I have to constantly battle. But, I’ve made a conscious decision to cut back on my visits and updates to Facebook, Twitter, Google+ and other sites. Sure, my Klout score has suffered as a result lately, but does anyone actually care about those types of scores aside from your online “friends” (few of whom you’ve actually met in person)? :-) Ultimately it comes down to self-discipline and how badly you want to be productive and successful in your career, life goals, hobbies, or whatever you’re working on. Rather than having your homepage take you to a time wasting news site, game site, social site, picture site, or others, how about adding something like the following as your homepage? Every time your browser opens you’ll see a personal message which helps keep you on the right track. You can download my ubber-sophisticated homepage here if interested. Summary Is there a single set of steps that if followed can ultimately lead to productivity? I don’t think so since one size has never fit all. Every person is different, works in their own unique way, and has their own set of motivators, distractions, and more. While I certainly don’t consider myself to be an expert on the subject of productivity, I do think that if you learn what steps work best for you and gradually refine them over time that you can come up with a personal productivity process that can serve you well. Productivity is definitely an “art” that anyone can learn with a little practice and persistence. You’ve seen some of the steps that I personally like to follow and I hope you find some of them useful in boosting your productivity. If you have others you use please leave a comment. I’m always looking for ways to improve.

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