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• Webserver optimization

  - by f-aminov

  Hi guys! I have a website hosted on a VPS (512Mb - minimum guranteed memory, 510Mhz proccessor, Debian 5.0 Lenny, Apache 2.2.9 with nginx 0.7.65 as a frontend to serve static content, MySQL 5.1.44, PHP 5.3.2 with APC caching). I'm a web developer, so I'm not very good at optimizing servers, but I've managed to install and setup all those neccessary components (LAMP, nginx, etc.). After that I decided to stress test my website (which uses Drupal 6.16 with caching and all possible optimization enabled) using a utility called "Webserver Stress Tool 7". And it seems to me that the results aren't any good - here is a graph (sorry, as a new user I'm not allowed to post images) As you can see the response time depending on amount of simultaneous users increases very quickly. With 10 simultaneous users the time is about 1000ms, with 100 simultaneous users it's about 15000ms (15s!). The question is do you think this is normal behavior for such a server or something is wrong with the settings and optimization? If you think something is wrong what particulary could be wrong? Any other suggestion how to speed this a little bit up?

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• Measuring Code Quality

  - by DotNetBlues

  Several months back, I was tasked with measuring the quality of code in my organization. Foolishly, I said, "No problem." I figured that Visual Studio has a built-in code metrics tool (Analyze -> Calculate Code Metrics) and that would be a fine place to start with. I was right, but also very wrong. The Visual Studio calculates five primary metrics: Maintainability Index, Cyclomatic Complexity, Depth of Inheritance, Class Coupling, and Lines of Code. The first two are figured at the method level, the second at (primarily) the class level, and the last is a simple count. The first question any reasonable person should ask is "Which one do I look at first?" The first question any manager is going to ask is, "What one number tells me about the whole application?" My answer to both, in a way, was "Maintainability Index." Why? Because each of the other numbers represent one element of quality while MI is a composite number that includes Cyclomatic Complexity. I'd be lying if I said no consideration was given to the fact that it was abstract enough that it's harder for some surly developer (I've been known to resemble that remark) to start arguing why a high coupling or inheritance is no big deal or how complex requirements are to blame for complex code. I should also note that I don't think there is one magic bullet metric that will tell you objectively how good a code base is. There are a ton of different metrics out there, and each one was created for a specific purpose in mind and has a pet theory behind it. When you've got a group of developers who aren't accustomed to measuring code quality, picking a 0-100 scale, non-controversial metric that can be easily generated by tools you already own really isn't a bad place to start. That sort of answers the question a developer would ask, but what about the management question; how do you dashboard this stuff when Visual Studio doesn't roll up the numbers to the solution level? Since VS does roll up the MI to the project level, I thought I could just figure out what sort of weighting Microsoft used to roll method scores up to the class level and then to the namespace and project levels. I was a bit surprised by the answer: there is no weighting. That means that a class with one 1300 line method (which will score a 0 MI) and one empty constructor (which will score a 100 MI) will have an overall MI of a respectable 50. Throw in a couple of DTOs that are nothing more than getters and setters (which tend to score 95 or better) and the project ends up looking really, really healthy. The next poor bastard who has to work on the application is probably not going to be singing the praises of its maintainability, though. For the record, that 1300 line method isn't a hypothetical, either. So, what does one do with that? Well, I decided to weight the average by the Lines of Code per method. For our above example, the formula for the class's MI becomes ((1300 * 0) + (1 * 100))/1301 = .077, rounded to 0. Sounds about right. Continue the pattern for namespace, project, solution, and even multi-solution application MI scores. This can be done relatively easily by using the "export to Excel" button and running a quick formula against the data. On the short list of follow-up questions would be, "How do I improve my application's score?" That's an answer for another time, though.

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• Do we still have a case against the goto statement? [closed]

  - by FredOverflow

  Possible Duplicate: Is it ever worthwhile using goto? In a recent article, Andrew Koenig writes: When asked why goto statements are harmful, most programmers will say something like "because they make programs hard to understand." Press harder, and you may well hear something like "I don't really know, but that's what I was taught." For that reason, I'd like to summarize Dijkstra's arguments. He then shows two program fragments, one without a goto and and one with a goto: if (n < 0) n = 0; Assuming that n is a variable of a built-in numeric type, we know that after this code, n is nonnegative. Suppose we rewrite this fragment: if (n >= 0) goto nonneg; n = 0; nonneg: ; In theory, this rewrite should have the same effect as the original. However, rewriting has changed something important: It has opened the possibility of transferring control to nonneg from anywhere else in the program. I emphasized the part that I don't agree with. Modern languages like C++ do not allow goto to transfer control arbitrarily. Here are two examples: You cannot jump to a label that is defined in a different function. You cannot jump over a variable initialization. Now consider composing your code of tiny functions that adhere to the single responsibility principle: int clamp_to_zero(int n) { if (n >= 0) goto n_is_not_negative: n = 0; n_is_not_negative: return n; } The classic argument against the goto statement is that control could have transferred from anywhere inside your program to the label n_is_not_negative, but this simply is not (and was never) true in C++. If you try it, you will get a compiler error, because labels are scoped. The rest of the program doesn't even see the name n_is_not_negative, so it's just not possible to jump there. This is a static guarantee! Now, I'm not saying that this version is better then the one without the goto, but to make the latter as expressive as the first one, we would at least have to insert a comment, or even better yet, an assertion: int clamp_to_zero(int n) { if (n < 0) n = 0; // n is not negative at this point assert(n >= 0); return n; } Note that you basically get the assertion for free in the goto version, because the condition n >= 0 is already written in line 1, and n = 0; satisfies the condition trivially. But that's just a random observation. It seems to me that "don't use gotos!" is one of those dogmas like "don't use multiple returns!" that stem from a time where the real problem were functions of hundreds or even thousand of lines of code. So, do we still have a case against the goto statement, other than that it is not particularly useful? I haven't written a goto in at least a decade, but it's not like I was running away in terror whenever I encountered one. 1 Ideally, I would like to see a strong and valid argument against gotos that still holds when you adhere to established programming principles for clean code like the SRP. "You can jump anywhere" is not (and has never been) a valid argument in C++, and somehow I don't like teaching stuff that is not true. 1: Also, I have never been able to resurrect even a single velociraptor, no matter how many gotos I tried :(

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• Is there a good [and modern] reason to not have static HTML pages with AJAX content , rather than generate pages?

  - by user1725

  Assumptions: We don't care about IE6, and Noscript users. Lets pretend we have the following design concept: All your pages are HTML/CSS that create the ascetics, layout, colours, general design related things. Lets pretend this basic code below is that: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <head> <link href="/example.css" rel="stylesheet" type="text/css"/> <script src="example.js" type="text/javascript"></script> <head> <body> <div class="left"> </div> <div class="mid"> </div> <div class="right"> </div> </body> </html> Which in theory should produce, with the right CSS, three vertical columns on the web page. Now, here's the root of the question, what are the serious advantages and/or disadvantages of loading the content of these columns (lets assume they are all indeed dynamic content, not static) via AJAX requests, or have the content pre-set with a scripting language? So for instance, we would have, in the AJAX example, lets asume jquery is used on-load: //Multiple http requests $("body > div.left").load("./script.php?content=news"); $("body > div.right").load("./script.php?content=blogs"); $("body > div.mid").load("./script.php?content=links"); OR--- //Single http request $.ajax({ url: './script.php?content=news|blogs|links', method: 'json', type: 'text', success: function (data) { $("body > div.left").html(data.news); $("body > div.right").html(data.blogs); $("body > div.mid").html(data.links); } }) Verses doing this: <body> <div class="left"> <?php echo function_returning_news(); ?> </div> <div class="mid"> <?php echo function_returning_blogs(); ?> </div> <div class="right"> <?php echo function_returning_links(); ?> </div> </body> I'm personally thinking right now that doing static HTML pages is a better method, my reasoning is: I've separated my data, logic, and presentation (ie, "MVC") code. I can make changes to one without others. Browser caches mean I'm just getting server load mostly for the content, not the presentation wrapped around it. I could turn my "script.php" into a more robust API for the website. But I'm not certain or clear that these are legitimately good reasons, and I'm not confidently aware of other issues that could happen, so I would like to know the pros-and-cons, so to speak.

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• Today's Links (6/30/2011)

  - by Bob Rhubart

  James Gosling Says He Doesn't Care About Java But here's the rest of the story: "What I really care about is the Java Virtual Machine as a concept," says Gosling, "because that is the thing that ties it all together; it's the thing that makes Java the language possible; it's the thing that makes things work on all kinds of different platforms; and it makes all kinds of languages able to coexist." Virtual Developer Day: SOA Accelerate Your Development with Oracle SOA Suite. Learn how in this FREE on-line workshop with Hands-on labs July 12th 9 am to 1:30 PM PST" July 12th 9 am to 1:30 PM PST Podcast: Toronto Architect Day Panel Discussion Part 3 (of 4) is now available, in which the panel (including Oracle ACE Director Cary Millsap and InfoQ editor and co-founder Floyd Marinescu) discusses public vs private cloud as the best strategy for small businesses and start-ups. WebLogic Weekly for June 27th, 2011 | James Bayer Bayer shares the latest resources for those with WebLogic on the brain. Griffiths Waite at Oracle Open World | Mark Simpson Oracle ACE Director Mark Simpson share information on the presentations he's scheduled to give at Oracle OpenWorld San Francisco 2011. Kscope Solid Service Bus Implementations Peter Paul van de Beek's Kscope11 presentation "is aimed at supporting architects and especially developers to choose the right integration infrastructure for a job." Migration To Java EE 6 With Spring 3 - ...Could Become "Interesting" | Adam Bien "Put simply, big data implies datasets so large they can't normally be processed using a standard transactional database," says David Dorf. "The term 'noSQL' is often used in this context as well." Book Review: "Designing With the Mind In Mind" | Abhinav Agarwal According to Abhinav Agarwal, Jeff Johnson's new book is about "the theory of how the mind perceives information, of how humans understand what they read, and how our eyes are attuned to paying attention to not just what's happening in front of us but also at the periphery of our vision." BPM 11g Advanced Workshop | Martien van den Akker Martien van den Akker shares his thoughts on both the workshop he recently attended and on the Oracle BPM 11g product. Fusion Applications - What You Need To Know: Product Families | Floyd Teter "Fusion Applications are organized into seven groups of related products called Product Families," observes Oracle ACE Director Floyd Teter. "While the product features are organized according to the Business Process Model and can cross the boundaries of product families, the product family groupings are an easy way to wrap your mind around Fusion Apps." Grid Control: Refreshing Weblogic Domains | Dave Best Dave Best shares tips for avoiding problems when using grid control to centrally manage/monitor your environment. Webcast: Oracle to Announce Datanomic Integration Plans The combination of Datanomic technology and the previous acquisition of Silver Creek Systems will deliver a complete, integrated and best-of-breed solution for Data Quality. Learn about Oracle’s strategy and product plans and how the new products acquired from Datanomic will impact your organization. July 19, 2011, 8:00am PT / 11:00am ET. Speakers include Michael Weingartner (Vice President, Product Development, Oracle), Martin Boyd (Senior Director, Product Strategy, Oracle), and Dain Hansen (Director, Product Marketing, Fusion Middleware, Oracle).

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• How do I get sound output on HDMI without the need to start X?

  - by Magnus Hoff

  I have a headless machine connected to my sound system, and I am using it to run a music playing daemon that I control over the network. (Among other things) However, I can't seem to be able to have sound come out of my speakers without running X. I am running pulse audio in a system wide instance and my daemon is not running within X. Nevertheless, when my daemon is playing music without me hearing it, I can fix it by running startx in an unrelated session. After X starts, I can hear the sound. The sound disappears again if I kill the X server. Interestingly/annoyingly, the sound also stops after X has been running for a few minutes. This could possibly be because of a screen saver of some sort, but I haven't been able to verify or falsify this theory. So my current workaround is to ssh into the box whenever I want music and startx, and restart it every fifteen minutes or so. I'd like to do better. I have been able to verify the following: Adjustments in alsamixer have no effect on this problem. The relevant output channel is never muted In alsamixer, I can see no difference between when the sound is working and when it isn't Nothing is muted in pactl list There is no difference in the output from pactl list between before starting X and after it's started. (Except the identifier of the pactl instance connected to pulse, which is different each time you run pactl) The user running the music daemon is a member of the groups audio, pulse and pulse-access The music daemon program does not report any error messages and acts as if it is playing the music like it should Some form of dbus daemon is running. ps aux|grep dbus reports dbus-daemon --system --fork --activation=upstart before and after I have started X Some details about my hardware: Motherboard: http://www.asus.com/Motherboards/AT5IONTI_DELUXE/ Sound chip: Nvidia GPU 0b HDMI/DP (from alsamixer) Using HDMI for output (Machine also has an Intel Realtek ALC887 that I am not using) Output of lsmod: Module Size Used by deflate 12617 0 zlib_deflate 27139 1 deflate ctr 13201 0 twofish_generic 16635 0 twofish_x86_64_3way 25287 0 twofish_x86_64 12907 1 twofish_x86_64_3way twofish_common 20919 3 twofish_generic,twofish_x86_64_3way,twofish_x86_64 camellia 29348 0 serpent 29125 0 blowfish_generic 12530 0 blowfish_x86_64 21466 0 blowfish_common 16739 2 blowfish_generic,blowfish_x86_64 cast5 25112 0 des_generic 21415 0 xcbc 12815 0 rmd160 16744 0 bnep 18281 2 rfcomm 47604 12 sha512_generic 12796 0 crypto_null 12918 0 parport_pc 32866 0 af_key 36389 0 ppdev 17113 0 binfmt_misc 17540 1 nfsd 281980 2 ext2 73795 1 nfs 436929 1 lockd 90326 2 nfsd,nfs fscache 61529 1 nfs auth_rpcgss 53380 2 nfsd,nfs nfs_acl 12883 2 nfsd,nfs sunrpc 255224 16 nfsd,nfs,lockd,auth_rpcgss,nfs_acl btusb 18332 2 vesafb 13844 2 pl2303 17957 1 ath3k 12961 0 bluetooth 180153 24 bnep,rfcomm,btusb,ath3k snd_hda_codec_hdmi 32474 4 nvidia 11308613 0 ftdi_sio 40679 1 usbserial 47113 6 pl2303,ftdi_sio psmouse 97485 0 snd_hda_codec_realtek 224173 1 snd_hda_intel 33719 5 snd_hda_codec 127706 3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel serio_raw 13211 0 snd_seq_midi 13324 0 snd_hwdep 17764 1 snd_hda_codec snd_pcm 97275 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec snd_rawmidi 30748 1 snd_seq_midi snd_seq_midi_event 14899 1 snd_seq_midi snd_seq 61929 2 snd_seq_midi,snd_seq_midi_event snd_timer 29990 2 snd_pcm,snd_seq snd_seq_device 14540 3 snd_seq_midi,snd_rawmidi,snd_seq snd 79041 20 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device asus_atk0110 18078 0 mac_hid 13253 0 jc42 13948 0 soundcore 15091 1 snd snd_page_alloc 18529 2 snd_hda_intel,snd_pcm coretemp 13554 0 i2c_i801 17570 0 lp 17799 0 parport 46562 3 parport_pc,ppdev,lp r8169 62154 0 Any ideas? What does X do that's so important?

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• Normalisation and 'Anima notitia copia' (Soul of the Database)

  - by Phil Factor

  (A Guest Editorial for Simple-Talk) The other day, I was staring  at the sys.syslanguages  table in SQL Server with slightly-raised eyebrows . I’d just been reading Chris Date’s  interesting book ‘SQL and Relational Theory’. He’d made the point that you’re not necessarily doing relational database operations by using a SQL Database product.  The same general point was recently made by Dino Esposito about ASP.NET MVC.  The use of ASP.NET MVC doesn’t guarantee you a good application design: It merely makes it possible to test it. The way I’d describe the sentiment in both cases is ‘you can hit someone over the head with a frying-pan but you can’t call it cooking’. SQL enables you to create relational databases. However,  even if it smells bad, it is no crime to do hideously un-relational things with a SQL Database just so long as it’s necessary and you can tell the difference; not only that but also only if you’re aware of the risks and implications. Naturally, I’ve never knowingly created a database that Codd would have frowned at, but around the edges are interfaces and data feeds I’ve written  that have caused hissy fits amongst the Normalisation fundamentalists. Part of the problem for those who agonise about such things  is the misinterpretation of Atomicity.  An atomic value is one for which, in the strange virtual universe you are creating in your database, you don’t have any interest in any of its component parts.  If you aren’t interested in the electrons, neutrinos,  muons,  or  taus, then  an atom is ..er.. atomic. In the same way, if you are passed a JSON string or XML, and required to store it in a database, then all you need to do is to ask yourself, in your role as Anima notitia copia (Soul of the database) ‘have I any interest in the contents of this item of information?’.  If the answer is ‘No!’, or ‘nequequam! Then it is an atomic value, however complex it may be.  After all, you would never have the urge to store the pixels of images individually, under the misguided idea that these are the atomic values would you?  I would, of course,  ask the ‘Anima notitia copia’ rather than the application developers, since there may be more than one application, and the applications developers may be designing the application in the absence of full domain knowledge, (‘or by the seat of the pants’ as the technical term used to be). If, on the other hand, the answer is ‘sure, and we want to index the XML column’, then we may be in for some heavy XML-shredding sessions to get to store the ‘atomic’ values and ensure future harmony as the application develops. I went back to looking at the sys.syslanguages table. It has a months column with the months in a delimited list January,February,March,April,May,June,July,August,September,October,November,December This is an ordered list. Wicked? I seem to remember that this value, like shortmonths and days, is treated as a ‘thing’. It is merely passed off to an external  C++ routine in order to format a date in a particular language, and never accessed directly within the database. As far as the database is concerned, it is an atomic value.  There is more to normalisation than meets the eye.

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• 45 minutes to talk about C# [closed]

  - by Philip

  I have the opportunity to give a 45 minute talk on C# in the theory of programming languages class I'm taking. The college teaches Java almost exclusively, so that's what all the students are most familiar with. (There's a little C, assembly, Prolog and LISP as well.) I decide what to talk about. It seems to me the best approach is to focus on a few of the big, obvious differences between C# and Java. I don't intend it to be a recommendation to use C# -- there are reasons to use each, mostly because of their ecosystems. So I want to focus on C# as a language. I don't want to go too fast and end up listing a whole bunch of features without showing their usefulness. My current plan is this: Functions as first class objects. This is, in my opinion, one of the biggest differences between C# and Java. The professor briefly mentioned this notion and showed a LISP example, but many of the students have probably never used it. I can show real world examples where it's made my code more readable. Lambda expressions as concise syntax for anonymous functions. Obviously with examples to show how this is useful. The real hit-home examples will be at the end when it's combined with the rest. I don't see an advantage to first showing the old delegate syntax and then replacing it with lambdas -- most of us won't have ever seen delegates anyway so it would just be confusing. The yield keyword and how it's different from returning an array. I have the impression that a lot of C# developers aren't familiar with how to use this. It will likely be very foreign to Java developers. I have some examples from my own work where it was really useful, such as iterating over a tree traversal, or iterating over neighbors in a graph where the neighbors aren't stored in memory. In both cases, doing it in Java would likely mean returning a complete list -- with yield I can stop iterating if I find what I want early on, without using memory for superfluous lists or arrays. Extension methods as a way to write implementation on interfaces. We'll all be familiar with how interfaces don't allow method implementation, and how this leads to code duplication. I'll show a specific example of this and how the extension method can solve the problem. Demonstrate how the above can be combined by implementing some simple Linq methods and using them. Where, Select, First, maybe more depending on how much time is left. Ideas on which ones might 'hit home' the best? There are other things I could talk about such as generics, value types, properties and more. I haven't yet though of good ways to incorporate these. In the case of generics and value types, the advantages might not be obvious or as relevant. Properties are obviously useful, particularly since we're taught strict JavaBeans here, but I don't know if I could integrate it with the "path to Linq" discussion above without it feeling tacked on. So I'm looking for thoughts on how to talk about C#, and what to talk about. Even minor details. I'm sure there are more experienced C# developers than me here who have good insight about what's really important in the language, and what would miss the point.

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• MIX 2010 Covert Operations Day 3

  - by GeekAgilistMercenary

  I rolled over to the Mandalay for breakfast.  There I met a couple guys that were really excited about the new Windows 7 Phone.  They, as I, are also hopeful that the phone really gets a big push and some penetration into the market.  Not because we don’t like any other of the phones, but because this phone is so much better in many ways.  From a developer's perspective creating applications in Windows 7 Mobile will be vastly superior in ease, capabilities, and other aspects.  The architectural, existing code base, examples, and provisions to create things on the 7 Mobile Device are already existing as of RIGHT NOW.  There is no reason, except for fickle market conditions, for this phone to not just explode onto the market.  But alas, I won't hold my breath. Day three keynote had a whole new slew of things provided.  It also seemed that things got a lot more technical on this second keynote.  The oData was one of the very technical bits, yet it included almost no code.  Starting with a Netflix example and all the way to the Codename "Dallas" effort the oData Services provide some expansive possibilities. A mash up going 4 ways was then shown for finding a movie, finding local places to have a viewing, and information about the movie and were to prospectively find and buy additional movie bits.  The display was of course, in a Windows 7 Mobile device with literally a click to view each set of data.  The backend and the front end of this was beautifully smooth. The Dallas Project has a lot of potential for analytics in dashboard and scorecard creation also.  If there is a need or reason to provide data to a vast and wide range of clients, Dallas is a prime example of how to do that. Azure Clouds After the main keynote I checked out (while developing a working WPF & Silverlight Application for work) the session on deploying ASP.NET Applications, services, etc, into the cloud.  The session was pretty good, but I'll admit I got a little unfocused from it a few times.  It is after all hard to do two things at one time. I did take note that the cloud still is a multiple step process for deploying to.  This is a good thing and a bad thing.  There needs to be more checks and verifications when deploying something into the cloud just for technical reasons.  However, I feel that there should be some streamlining to the process.  Going back and forth between web and Visual Studio as the interface also seems kind of clunky.  Deployment should be able to be completed from within Visual Studio in my perspective.  Overall, the cloud is getting more and more impressive in function as well as theory. That's it from me so far on the third day of MIX.  I'll be note taking and studying hard to have more good tidbits to provide. Thanks for reading, if you're curious about more of my writing, check out this original entry at my other blog Agilist Mercenary.

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• SQL SERVER – #TechEdIn – Presenting Tomorrow on Speed Up! – Parallel Processes and Unparalleled Performance at TechEd India 2012

  - by pinaldave

  Performance tuning is always a very hot topic when it is about SQL Server. SQL Server Performance Tuning is a very challenging subject that requires expertise in Database Administration and Database Development. I always have enjoyed talking about SQL Server Performance tuning subject. However, in India, it’s actually the very first time someone is presenting on this interesting subject, so this time I had the biggest challenge to present this session. Frequently enough, we get these two kind of questions: How to turn off parallelism as it is reducing performance? How to turn on parallelism as I want more performance? The reality is that not everyone knows what exactly is needed by their system. In this session, I have attempted to answer this very question. I’ve decided to provide a balanced view but stay away from theory, which leads us to say “It depends”. The session will have a clear message about this towards its end. Deck Details Slides: 45+ Demos: 7+ Bonus Quiz: 5 Images: 10+ Session delivery time: 52 Mins + 8 Mins of Q & A I have presented this session a couple of times to my friends and so far have received good feedback. Oftentimes, when people hear that I am going to present 45 slides, they all say it is too much to cover. However, when I am done with the session the usual reaction is that I truly gave justice to those slides. Action Item Here are a few of the action items for all of those who are going to attend this session: If you want to attend the session, just come early. There’s a good chance that you may not get a seat because right before me, there is a session from SQL Guru Vinod Kumar. He performs a powerful delivery of million concepts in just a little time. Quiz. I will be asking few questions during the session as well as before the session starts. If you get the correct answer, I will give unique learning material for you. You may not want to miss this learning opportunity at any cosst. Session Details Title: Speed Up! – Parallel Processes and Unparalleled Performance (Add to Calendar) Abstract: “More CPU, More Performance” – A  very common understanding is that usage of multiple CPUs can improve the performance of the query. To get a maximum performance out of any query, one has to master various aspects of the parallel processes. In this deep-dive session, we will explore this complex subject with a very simple interactive demo. Attendees will walk away with proper understanding of CX_PACKET wait types, MAXDOP, parallelism threshold and various other concepts. Date and Time: March 23, 2012, 12:15 to 13:15 Location: Hotel Lalit Ashok - Kumara Krupa High Grounds, Bengaluru – 560001, Karnataka, India. Add to Calendar Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• Error while installing boost_1_54

  - by Farhat

  On trying to install boost I get this error during configuration checks. Googling did not give any pointers. [root@heracles boost_1_54_0]# ./b2 install Performing configuration checks - 32-bit : no (cached) - 64-bit : yes (cached) - arm : no (cached) - mips1 : no (cached) - power : no (cached) - sparc : no (cached) - x86 : yes (cached) error: No best alternative for libs/coroutine/build/allocator_sources next alternative: required properties: <link>static <target-os>windows <threading>multi not matched next alternative: required properties: <link>static <segmented-stacks>on <threading>multi not matched next alternative: required properties: <link>static <threading>multi not matched - has_icu builds : no (cached) warning: Graph library does not contain MPI-based parallel components. note: to enable them, add "using mpi ;" to your user-config.jam - zlib : yes (cached) - iconv (libc) : yes (cached) - icu : no (cached) - icu (lib64) : no (cached) - compiler-supports-ssse3 : yes (cached) - compiler-supports-avx2 : no (cached) - gcc visibility : yes (cached) - long double support : yes (cached) warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. error: No best alternative for libs/coroutine/build/allocator_sources next alternative: required properties: <link>static <target-os>windows <threading>multi not matched next alternative: required properties: <link>static <segmented-stacks>on <threading>multi not matched next alternative: required properties: <link>static <threading>multi not matched - zlib : yes (cached) How can the alternative for allocator sources be located? Thanks.

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• Improving browser performance while using lots of tabs?

  - by Andrew

  My browsing habits cause me to open lots of windows and tabs, either related to different projects I'm working on or things I may want to read later. I use OSX and use about 5 spaces with multiple windows in each space. The problem is eventually I'll have around 200 or more tabs open (spread over 15-20 windows) that I don't want to close. Needless to say, my computer's performance starts to degrade. As I write this on my mobile, Safari on my laptop is locking up the computer. I used to use Chrome but found better performance with Safari. What I'd like to know, is there a graph of browser performance based on tab usage? I don't need a browser that keeps all tabs active. It would be great if the browser could increase performance by "putting tabs to sleep". Or if there was some sort of tool for saving a "workspace" of tabs that you could reactivate the next time you are working on that project. What sort of solution can you recommend to solve this problem?

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• Windows7 shows a drive as full in summary but files, including backup folder, shown on drive are ver

  - by Rob

  I have a drive partitioned so it is seen by Windows as 2 drives: C:\ and D:\ Windows7 shows D:\ as full up in the graphical summary in 'My Computer' summary of all the drives, e.g. the bar graph indicates full and nearly all of the drive's capacity, 108Gb, is full. So I go into the D:\ drive to look at the files, I see several folders. I select them all and the right click menu Properties to count their size, expecting the value to be about the same as what Windows reports in the summary, i.e. nearly 108Gb. But the properties shows the files are very small, Kbs and Mbs, nowhere near 108Gbs. One of the folders is a backup, but its size is very small. I've checked the folder options to show all system files and hidden files too - and counted these in the properties. Something invisible is holding the space. What is happening here? I'm afraid to delete anything if it removes valuable backups. Have I got huge backups here? Why can't I see them? How do I see them?

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• Exploring TCP throughput with DTrace

  - by user12820842

  One key measure to use when assessing TCP throughput is assessing the amount of unacknowledged data in the pipe. This is sometimes termed the Bandwidth Delay Product (BDP) (note that BDP is often used more generally as the product of the link capacity and the end-to-end delay). In DTrace terms, the amount of unacknowledged data in bytes for the connection is the different between the next sequence number to send and the lowest unacknoweldged sequence number (tcps_snxt - tcps_suna). According to the theory, when the number of unacknowledged bytes for the connection is less than the receive window of the peer, the path bandwidth is the limiting factor for throughput. In other words, if we can fill the pipe without the peer TCP complaining (by virtue of its window size reaching 0), we are purely bandwidth-limited. If the peer's receive window is too small however, the sending TCP has to wait for acknowledgements before it can send more data. In this case the round-trip time (RTT) limits throughput. In such cases the effective throughput limit is the window size divided by the RTT, e.g. if the window size is 64K and the RTT is 0.5sec, the throughput is 128K/s. So a neat way to visually determine if the receive window of clients may be too small should be to compare the distribution of BDP values for the server versus the client's advertised receive window. If the BDP distribution overlaps the send window distribution such that it is to the right (or lower down in DTrace since quantizations are displayed vertically), it indicates that the amount of unacknowledged data regularly exceeds the client's receive window, so that it is possible that the sender may have more data to send but is blocked by a zero-window on the client side. In the following example, we compare the distribution of BDP values to the receive window advertised by the receiver (10.175.96.92) for a large file download via http. # dtrace -s tcp_tput.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 6 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 9 4096 | 14 8192 | 27 16384 | 67 32768 |@@ 1464 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 32396 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 16384 | 0 32768 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 17067 65536 | 0 Here we have a puzzle. We can see that the receiver's advertised window is in the 32768-65535 range, while the amount of unacknowledged data in the pipe is largely in the 65536-131071 range. What's going on here? Surely in a case like this we should see zero-window events, since the amount of data in the pipe regularly exceeds the window size of the receiver. We can see that we don't see any zero-window events since the SWND distribution displays no 0 values - it stays within the 32768-65535 range. The explanation is straightforward enough. TCP Window scaling is in operation for this connection - the Window Scale TCP option is used on connection setup to allow a connection to advertise (and have advertised to it) a window greater than 65536 bytes. In this case the scaling shift is 1, so this explains why the SWND values are clustered in the 32768-65535 range rather than the 65536-131071 range - the SWND value needs to be multiplied by two since the reciever is also scaling its window by a shift factor of 1. Here's the simple script that compares BDP and SWND distributions, fixed to take account of window scaling. #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @bdp["BDP(bytes)", args[2]-ip_daddr, args[4]-tcp_sport] = quantize(args[3]-tcps_snxt - args[3]-tcps_suna); } tcp:::receive / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @swnd["SWND(bytes)", args[2]-ip_saddr, args[4]-tcp_dport] = quantize((args[4]-tcp_window)*(1 tcps_snd_ws)); } And here's the fixed output. # dtrace -s tcp_tput_scaled.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 39 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 4 4096 | 9 8192 | 22 16384 | 37 32768 |@ 99 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 3858 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 512 | 0 1024 | 1 2048 | 0 4096 | 2 8192 | 4 16384 | 7 32768 | 14 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1956 131072 | 0

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• Best tool for monitoring backups, etc. and trending statstics from that data

  - by Randy Syring

  I have done some research on nagios, opennms, and zenoss but am not confident that I have found what I am looking for. The main driving force for me right now is being able to monitor backups. This includes mysql, mssql, and eventually some file system backups. We have a tool that wraps the backup process for these different systems and collects statistics. So, items like: number of databases backed up size of db backup file size of db backup file compressed time to make backup time to zip file I want to be able to A) have notifications if the jobs are not run according to schedule B) be able to set thresholds on the statistics which would trigger notifications C) I want to be able to trend and graph the statistics I am planning on sending this information to the monitoring application through an HTTP POST. Or, the monitoring application could pull it from a log file as well. However, we will have other processes with other "arbitrary" (from the monitoring system's perspective) statics that will want to monitor and trend, so flexibility is very important. The tool or tools should also be able to do general monitoring and trending of network interfaces, server load, etc. Once we get the backup monitoring in place, we will want to include those items as well. Thanks.

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• Website Use Monitoring for 3 People

  - by linkedlinked

  I work in an IT startup with 2 partners, and I'm the programmer/IT guy -- in other words, the work horse. To make a long story short, I'm doing most of the work right now, while they spend all day on Facebook. That's OK, because they're paying my salary, but if the project fails, I'm sure they'll blame me for it (I'm doing my best to make sure that doesn't happen!), and I want some sort of recourse. I already have an app that blocks time-wasters on my local PC, and keeps logs of when the app is enabled (so I can say "I had Facebook blocked from 9am-5pm today.") Is there any way I can get a brief summary of the most heavily visited sites, split up by client PC? At the end of the month, I want to be able to say "You both load Facebook, on average, every 10 minutes. You spend hours a day on Youtube, and haven't opened up our bugtracker in weeks" and maybe have a nifty chart or graph to match it. We have a crappy D-Link router, and no IT budget. They are both on Windows Vista, I run Ubuntu Linux. I don't want to install any monitoring software on their PC, but I'm totally fine with, say, routing all the network traffic through my machine. I guess I can think of lots of ways to accomplish this (telnet into JSSH and list open tabs? log all the DNS requests, per-domain? even thinking of setting up a webcam on my desk and just keeping 5-minute snapshots...), I just don't really know where to start. Any advice is appreciated, thanks!

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• Programmatically disclosing a node in af:tree and af:treeTable

  - by Frank Nimphius

  A common developer requirement when working with af:tree or af:treeTable components is to programmatically disclose (expand) a specific node in the tree. If the node to disclose is not a top level node, like a location in a LocationsView -> DepartmentsView -> EmployeesView hierarchy, you need to also disclose the node's parent node hierarchy for application users to see the fully expanded tree node structure. Working on ADF Code Corner sample #101, I wrote the following code lines that show a generic option for disclosing a tree node starting from a handle to the node to disclose. The use case in ADF Coder Corner sample #101 is a drag and drop operation from a table component to a tree to relocate employees to a new department. The tree node that receives the drop is a department node contained in a location. In theory the location could be part of a country and so on to indicate the depth the tree may have. Based on this structure, the code below provides a generic solution to parse the current node parent nodes and its child nodes. The drop event provided a rowKey for the tree node that received the drop. Like in af:table, the tree row key is not of type oracle.jbo.domain.Key but an implementation of java.util.List that contains the row keys. The JUCtrlHierBinding class in the ADF Binding layer that represents the ADF tree binding at runtime provides a method named findNodeByKeyPath that allows you to get a handle to the JUCtrlHierNodeBinding instance that represents a tree node in the binding layer. CollectionModel model = (CollectionModel) your_af_tree_reference.getValue(); JUCtrlHierBinding treeBinding = (JUCtrlHierBinding ) model.getWrappedData(); JUCtrlHierNodeBinding treeDropNode = treeBinding.findNodeByKeyPath(dropRowKey); To disclose the tree node, you need to create a RowKeySet, which you do using the RowKeySetImpl class. Because the RowKeySet replaces any existing row key set in the tree, all other nodes are automatically closed. RowKeySetImpl rksImpl = new RowKeySetImpl(); //the first key to add is the node that received the drop //operation (departments).            rksImpl.add(dropRowKey);    Similar, from the tree binding, the root node can be obtained. The root node is the end of all parent node iteration and therefore important. JUCtrlHierNodeBinding rootNode = treeBinding.getRootNodeBinding(); The following code obtains a reference to the hierarchy of parent nodes until the root node is found. JUCtrlHierNodeBinding dropNodeParent = treeDropNode.getParent(); //walk up the tree to expand all parent nodes while(dropNodeParent != null && dropNodeParent != rootNode){    //add the node's keyPath (remember its a List) to the row key set    rksImpl.add(dropNodeParent.getKeyPath());      dropNodeParent = dropNodeParent.getParent(); } Next, you disclose the drop node immediate child nodes as otherwise all you see is the department node. Its not quite exactly "dinner for one", but the procedure is very similar to the one handling the parent node keys ArrayList<JUCtrlHierNodeBinding> childList = (ArrayList<JUCtrlHierNodeBinding>) treeDropNode.getChildren();                     for(JUCtrlHierNodeBinding nb : childList){   rksImpl.add(nb.getKeyPath()); } Next, the row key set is defined as the disclosed row keys on the tree so when you refresh (PPR) the tree, the new disclosed state shows tree.setDisclosedRowKeys(rksImpl); AdfFacesContext.getCurrentInstance().addPartialTarget(tree.getParent()); The refresh in my use case is on the tree parent component (a layout container), which usually shows the best effect for refreshing the tree component. 

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• PHP crashing during oAuth scripts

  - by FunkyChicken

  I just installed Nginx 1.2.4 and PHP 5.4.0 (from svn) (php fpm). CentOs 5.8 64 The problem I have is that PHP crashes the moment I run any social oAuth scripts. I have tried to log into Facebook, Twitter and Google with various scripts that I know work on my other servers. When I load the scripts I get a 502 error from Nginx. And I find these errors in the log: in php-fpm log: WARNING: [pool www] child 23821 exited on signal 11 (SIGSEGV) after 1132.862984 seconds from start in nginx log: ERROR: recv() failed (104: Connection reset by peer) while reading response header from upstream From what I can see, it goes wrong when PHP tries to make a request to any of the oAuth servers. https://github.com/mahmudahsan/PHP-SDK-3.0---Graph-API-base-Facebook-Connect-Tutorial-Source for example is one of the scripts that works perfectly on my other machines, but causes PHP to crash. I found: http://stackoverflow.com/questions/3616191/nginx-php-fpm-502-bad-gateway which seems to be a similar problem, but I cannot find a way to solve it. +++ UPDATE +++ Now I have been doing some debugging in 1 of the scripts that is playing up. If you go to line 808 http://pastebin.com/gSnzRtXb it runs the curl_exec() command. When that is ran, it crashes. If i echo'test';exit; just above that line, it echo's correctly, if i do it below that line, php crashes. Which means it's that line 808 which causes the crash. So I made a very simple script to do some testing: http://pastebin.com/Rshnyhcm which also uses curl_exec, but that runs just fine. So I started to dig deeper into that query from the facebook script to see what values the $opts array contains from line 806. Output of that array is: http://pastebin.com/Cq9ffd3R What the problem is, I still have no clue :(

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• How can I make sound work without starting X?

  - by Magnus Hoff

  I have a headless machine connected to my sound system, and I am using it to run a music playing daemon that I control over the network. (Among other things) However, I can't seem to be able to have sound come out of my speakers without running X. I am running pulse audio in a system wide instance and my daemon is not running within X. Nevertheless, when my daemon is playing music without me hearing it, I can fix it by running startx in an unrelated session. After X starts, I can hear the sound. The sound disappears again if I kill the X server. Interestingly/annoyingly, the sound also stops after X has been running for a few minutes. This could possibly be because of a screen saver of some sort, but I haven't been able to verify or falsify this theory. So my current workaround is to ssh into the box whenever I want music and startx, and restart it every fifteen minutes or so. I'd like to do better. I have been able to verify the following: Adjustments in alsamixer have no effect on this problem. The relevant output channel is never muted In alsamixer, I can see no difference between when the sound is working and when it isn't Nothing is muted in pactl list There is no difference in the output from pactl list between before starting X and after it's started. (Except the identifier of the pactl instance connected to pulse, which is different each time you run pactl) The user running the music daemon is a member of the groups audio, pulse and pulse-access The music daemon program does not report any error messages and acts as if it is playing the music like it should Some form of dbus daemon is running. ps aux|grep dbus reports dbus-daemon --system --fork --activation=upstart before and after I have started X Some details about my hardware: Motherboard: http://www.asus.com/Motherboards/AT5IONTI_DELUXE/ Sound chip: Nvidia GPU 0b HDMI/DP (from alsamixer) Using HDMI for output (Machine also has an Intel Realtek ALC887 that I am not using) Output of lsmod: Module Size Used by deflate 12617 0 zlib_deflate 27139 1 deflate ctr 13201 0 twofish_generic 16635 0 twofish_x86_64_3way 25287 0 twofish_x86_64 12907 1 twofish_x86_64_3way twofish_common 20919 3 twofish_generic,twofish_x86_64_3way,twofish_x86_64 camellia 29348 0 serpent 29125 0 blowfish_generic 12530 0 blowfish_x86_64 21466 0 blowfish_common 16739 2 blowfish_generic,blowfish_x86_64 cast5 25112 0 des_generic 21415 0 xcbc 12815 0 rmd160 16744 0 bnep 18281 2 rfcomm 47604 12 sha512_generic 12796 0 crypto_null 12918 0 parport_pc 32866 0 af_key 36389 0 ppdev 17113 0 binfmt_misc 17540 1 nfsd 281980 2 ext2 73795 1 nfs 436929 1 lockd 90326 2 nfsd,nfs fscache 61529 1 nfs auth_rpcgss 53380 2 nfsd,nfs nfs_acl 12883 2 nfsd,nfs sunrpc 255224 16 nfsd,nfs,lockd,auth_rpcgss,nfs_acl btusb 18332 2 vesafb 13844 2 pl2303 17957 1 ath3k 12961 0 bluetooth 180153 24 bnep,rfcomm,btusb,ath3k snd_hda_codec_hdmi 32474 4 nvidia 11308613 0 ftdi_sio 40679 1 usbserial 47113 6 pl2303,ftdi_sio psmouse 97485 0 snd_hda_codec_realtek 224173 1 snd_hda_intel 33719 5 snd_hda_codec 127706 3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel serio_raw 13211 0 snd_seq_midi 13324 0 snd_hwdep 17764 1 snd_hda_codec snd_pcm 97275 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec snd_rawmidi 30748 1 snd_seq_midi snd_seq_midi_event 14899 1 snd_seq_midi snd_seq 61929 2 snd_seq_midi,snd_seq_midi_event snd_timer 29990 2 snd_pcm,snd_seq snd_seq_device 14540 3 snd_seq_midi,snd_rawmidi,snd_seq snd 79041 20 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device asus_atk0110 18078 0 mac_hid 13253 0 jc42 13948 0 soundcore 15091 1 snd snd_page_alloc 18529 2 snd_hda_intel,snd_pcm coretemp 13554 0 i2c_i801 17570 0 lp 17799 0 parport 46562 3 parport_pc,ppdev,lp r8169 62154 0 Any ideas? What does X do that's so important?

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• Going by the eBook

  - by Tony Davis

  The book and magazine publishing world is rapidly going digital, and the industry is faced with making drastic changes to their ways of doing business. The sudden take-up of digital readers by the book-buying public has surprised even the most technological-savvy of the industry. Printed books just aren't selling like they did. In contrast, eBooks are doing well. The ePub file format is the standard around which all publishers are converging. ePub is a standard for formatting book content, so that it can be reflowed for various devices, with their widely differing screen-sizes, and can be read offline. If you unzip an ePub file, you'll find familiar formats such as XML, XHTML and CSS. This is both a blessing and a curse. Whilst it is good to be able to use familiar technologies that have been developed to a level of considerable sophistication, it doesn't get us all the way to producing a viable publication. XHTML is a page-description language, not a book-description language, as we soon found out during our initial experiments, when trying to specify headers, footers, indexes and chaptering. As a result, it is difficult to predict how any particular eBook application will decide to render a book. There isn't even a consensus as to how the cover image is specified. All of this is awkward for the publisher. Each book must be created and revised in a form from which can be generated a whole range of 'printed media', from print books, to Mobi for kindles, ePub for most Tablets and SmartPhones, HTML for excerpted chapters on websites, and a plethora of other formats for other eBook readers, each with its own idiosyncrasies. In theory, if we can get our content into a clean, semantic XML form, such as DOCBOOKS, we can, from there, after every revision, perform a series of relatively simple XSLT transformations to output anything from a HTML article, to an ePub file for reading on an iPad, to an ICML file (an XML-based file format supported by the InDesign tool), ready for print publication. As always, however, the task looks bigger the closer you get to the detail. On the way to the utopian world of an XML-based book format that encompasses all the diverse requirements of the different publication media, ePub looks like a reasonable format to adopt. Its forthcoming support for HTML 5 and CSS 3, with ePub 3.0, means that features, such as widow-and-orphan controls, multi-column flow and multi-media graphics can be incorporated into eBooks. This starts to make it possible to build an "app-like" experience into the eBook and to free publishers to think of putting context before container; to think of what content is required, be it graphical, textual or audio, from the point of view of the user, rather than what's possible in a given, traditional book "Container". In the meantime, there is a gap between what publishers require and what current technology can provide and, of course building this app-like experience is far from plain sailing. Real portability between devices is still a big challenge, and achieving the sort of wizardry seen in the likes of Theodore Grey's "Elements" eBook will require some serious device-specific programming skills. Cheers, Tony.

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• How do I collect SNMP readings from intermittently-connected sites?

  - by Luke404

  I am collecting SNMP data on-site for a number of systems, currently using Cacti. These systems are spread on a number of sites that aren't always connected to internet, but I also need to centralize the data on a single system (datacenter housed server) and get graphs out of it. If I directly poll remote systems with a centralized Cacti I'd loose data when a site is not connected to internet. I should record data on-site (I have a server at each site and I can run whatever I want on it) and then 'sync' everything to the central system. One hack could be a cacti or directly an rrdtool on site and then periodically rsync RRD data to the central Cacti system, but that doesn't sound like a 'clean' solution: every RRD would have to be defined at both places and rsync scripts setup with the specific file names. Can you suggest a better solution? Cacti is not a requirement but I'd like to use something like that on the central system. On-site systems need only to collect data I don't need to graph it there or manage users rights to view data and stuff like that, users will only access the centralized system.

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• Problems with moving 2D circle/box collision detection

  - by dario3004

  This is my first game ever and I'm a newbie in computer physics. I've got this code for the collision detection and it works fine for BOTTOM and TOP collision.It miss the collision detection with the paddle's edge and angles so I've (roughly) tried to implement it. Main method that is called for bouncing, it checks if it bounce with wall, or with top (+ right/left side) or with bottom (+ right/left side): protected void handleBounces(float px, float py) { handleWallBounce(px, py); if(mBall.y < getHeight()/4){ if (handleRedFastBounce(mRed, px, py)) return; if (handleRightSideBounce(mRed,px,py)) return; if (handleLeftSideBounce(mRed,px,py)) return; } if(mBall.y > getHeight()/4 * 3){ if (handleBlueFastBounce(mBlue, px, py)) return; if (handleRightSideBounce(mBlue,px,py)) return; if (handleLeftSideBounce(mBlue,px,py)) return; } } This is the code for the BOTTOM bounce: protected boolean handleRedFastBounce(Paddle paddle, float px, float py) { if (mBall.goingUp() == false) return false; // next position tx = mBall.x; ty = mBall.y - mBall.getRadius(); // actual position ptx = px; pty = py - mBall.getRadius(); dyp = ty - paddle.getBottom(); xc = tx + (tx - ptx) * dyp / (ty - pty); if ((ty < paddle.getBottom() && pty > paddle.getBottom() && xc > paddle.getLeft() && xc < paddle.getRight())) { mBall.x = xc; mBall.y = paddle.getBottom() + mBall.getRadius(); mBall.bouncePaddle(paddle); playSound(mPaddleSFX); increaseDifficulty(); return true; } else return false; } As long as I understood it should be something like this: So I tried to make the "left side" and "right side" bounce method: protected boolean handleLeftSideBounce(Paddle paddle, float px, float py){ // next position tx = mBall.x + mBall.getRadius(); ty = mBall.y; // actual position ptx = px + mBall.getRadius(); pty = py; dyp = tx - paddle.getLeft(); yc = ty + (pty - ty) * dyp / (ptx - tx); if (ptx < paddle.getLeft() && tx > paddle.getLeft()){ System.out.println("left side bounce1"); System.out.println("yc: " + yc + "top: " + paddle.getTop() + " bottom: " + paddle.getBottom()); if (yc > paddle.getTop() && yc < paddle.getBottom()){ System.out.println("left side bounce2"); mBall.y = yc; mBall.x = paddle.getLeft() - mBall.getRadius(); mBall.bouncePaddle(paddle); playSound(mPaddleSFX); increaseDifficulty(); return true; } } return false; } I think I'm quite near to the solution but I'm having big troubles with the new "yc" formula. I tried so many versions of it but since I don't know the theory behind it I can't adjust for the Y axis. Since the Y axis is inverted I even tried this: yc = ty - (pty - ty) * dyp / (ptx - tx); I tried Googling it but I can't seem to find a solution for it. Also this method fails when ball touches the angle and I don't think is a nice way because it just test "one" point of the ball and probably there will be many cases in which the ball won't bounce.

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• Connect Chrome to TOR

  - by Jack M

  I'm having difficulty connecting Chrome to TOR. I started trying yesterday. I started Vidalia and the TOR Browser and then followed the advice at http://lifehacker.com/5614732/create-a-tor-button-in-chrome-for-on+demand-anonymous-browsing - downloading Proxy Switchy and setting it up as stated. This resulted in Error 130 (net::ERR_PROXY_CONNECTION_FAILED) (in Chrome, when I tried to load a webpage). So I looked into Vidalia's settings and noticed that it appeared to be using port 9051, so I set that instead of 8118 as everyone on the internet seems to be suggesting. Then I got a new error: Error 111 (net::ERR_TUNNEL_CONNECTION_FAILED). Digging a bit, I found that Tor should be set as a SOCKS proxy, not an HTTP proxy, so I unticked "use same settings for all protocols" in Proxy Switchy and just set localhost:9051 for SOCKS. That got me Error 7 (net::ERR_TIMED_OUT). And that's when I came here for help. I typed up the above question, but then at the last minute decided to do a bit more reading and found someone here suggested using some command line arguments via a Windows shortcut: "C:\snip\chrome.exe" --proxy-server=";socks=127.0.0.1:9051;sock4=127.0.0.1:9051;sock5=127.0.0.1:9051" --incognito check.torproject.org And that worked perfectly. Yesterday. Today it doesn't, so I'm having to post this question after all. check.torproject.org gives me a "no" with Chrome, but a "yes" with the default Tor Browser. I tried closing Chrome and restarting it (yes, with the correct shortcut) after Vidalia started, but still nothing. The port number hasn't changed or anything. What gives? EDIT: I realized I had a "non tor" instance of Chrome running and that possibly the was causing the command line args t be ignored when I started the new instance. Closed all instances of chrome and ran my Chrome Tor shortcut, and it did get rid of the "not using Tor" message -- because I got another Time Out error instead. Vidalia's bandwidth graph didn't even blink.

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• Looking for comprehensive computer monitoring software

  - by cornjuliox

  Summer in this country is insanely hot. So hot in fact, that I think we just lost a machine due to overheating (last recorded CPU/GPU temp was close to 100 C, now it wont start and lets out a long series of short beeps on power up), but that's not my concern here. Since heat is such a problem for me, I use several different pieces of software to monitor temperatures in my machine. I use MSI Afterburner to monitor GPU temp, control GPU fan speed and for some light overclocking, and then I use Speccy and SpeedFan to monitor the rest of the system, CPU temp and everything. The setup works fine for now, but I want to consolidate all this into one program so I'm not juggling several windows at once. Is there any program out there that will let me monitor the following from a single window: CPU Temp and Fan Speed CPU clock GPU Temp and Fan Speed GPU clock, both core and memory Additionally, mobo temp (Speccy lists both CPU and Motherboard temp, I assume that the latter is referring to North and Southbridge temperatures. I'm also looking for the ability to chart these data points on a graph over time, basically to see just how high the temperatures spike under load and for general analysis. It'd be nice if it could handle overclocking of both CPU and GPU in real time too. Any suggestions? Edit: I forgot to mention that I'm on Windows 7, 64-bit

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• Windows 7 shows a drive as full in summary but files shown on drive are very small

  - by Rob

  I have a drive partitioned so it is seen by Windows as 2 drives: C:\ and D:\ Windows 7 shows D:\ as full up in the graphical summary in 'My Computer' summary of all the drives, e.g. the bar graph indicates full and nearly all of the drive's capacity, 108Gb, is full. So I go into the D:\ drive to look at the files, I see several folders. I select them all and the right-click menu Properties to count their size, expecting the value to be about the same as what Windows reports in the summary, i.e. nearly 108Gb. But the properties window shows the files are very small, Kbs and Mbs, nowhere near 108Gbs. One of the folders is a backup, but its size is very small. I've checked the folder options to show all system files and hidden files too - and counted these in the properties. Something invisible is holding the space. What is happening here? I'm afraid to delete anything if it removes valuable backups. Have I got huge backups here? Why can't I see them? How do I see them?

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