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• Connecting a 2560x1440 display to a laptop?

  - by tjollans

  Having read Jeff Atwood's blog post on Korean 27" IPS LCDs, I've been wondering to what extent these are useful in a notebook + large display situation. I own a Lenovo Thinkpad Edge E320 with 2nd gen. integrated Intel graphics. According to the spec from Intel, this should support HDMI version 1.4, and, using DisplayPort, resolutions up to 2560x1600. HDMI version 1.4 supports resolutions up to 4096×2160, however, according to c't (German), the HDMI interface used with Intel chips only supports 1920x1200. The same goes for the DVI output - dual-link DVI-D, apparently, is not supported by Intel. It would appear that my laptop cannot digitally drive this kind of resolution. Now what about other laptops? According to the article in c't above, AMD's integrated graphics chips have the same limitation as Intel's. NVIDIA graphics cards, apparently, only offer resolutions up to 1900x1200 over HDMI out of the box, but it's possible, when using Linux at least, to trick the driver into enabling higher resolutions. Is this still true? What's the situation on Windows and OSX? I found no information on whether discrete AMD chips support ultra-high resolutions over HDMI. Owners of laptops with (Mini) DisplayPort / Thunderbolt won't have any issues with displays this large, but if you're planning to go for a display with dual-link DVI-D input only (like the Korean ones), you're going to need an adapter, which will set you back something like €70-€100 (since the protocols are incompatible). The big question mark in this equation is VGA: a lot of laptops have it, and I don't see any reason to think this resolution is not supported by the hardware (an oft-quoted figure appears to be 2048x1536@75Hz, so 2560x1440@60Hz should be possible, right?), but are the drivers likely to cause problems? Perhaps more critically, you'd need a VGA to dual-link DVI-D adapter that converts analog to digital signals. Do these exist? How good are they? How expensive are they? Is there a performance penalty involved? Please correct me if I'm wrong on any points. In summary, what are the requirements on a laptop to drive an external LCD at 2560x1440, in particular one that supports dual-link DVI-D only, and what tools and adapters can be used to lower the bar?

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• DCHP and Router load testing

  - by John H

  I manage a campground wifi network with an average of 10 - 60 active users. I have encountered issues where the router starts acting flaky (failing to assign DHCP or failing to pass traffic) without any clear warning (low cpu utilization, etc). I upgraded the router a couple times and ended up with a Netgear ProSafe VPN router that seems to be handling the traffic. The interesting thing is that the Netgear has lower specs than the Buffalo router it replaced, indicating the issue is with the DD-WRT firmware. While I'll be pursuing this issue on the dd-wrt forums, I need a way to test routers. My vision is having 1-2 computers connected on the LAN side and 1-2 computers connected on the WAN side. I want the LAN computers to be generating various type of traffic and connections, as well as requesting DCHP addresses. A few notes: The wireless aspect should be a non-issue. Most clients would connect to a wireless bridge and come into the router through a network cable. I had a monitoring server with Nagios running check_dhcp against the router. This server was connected directly by a network cable, eliminating wifi bridges and other devices from the equation. This question is somewhat related, but not exactly: Load testing wireless LANs I am going to look at IxChariot. While I'd ideally like to use a 1 computer on each side running Linux and preferably free software, I can entertain running Windows, multiple computers, or non-free software. Total bandwidth doesn't seem to be the issue. I can transfer large files all day. Even on the busiest days, the users seemed to only pull ~5Mbps. There is very little "LAN to LAN traffic" and most of it might never have reached the main router. The issue I need to test for seems to be tied to active users, or more appropriately, active sessions. I know active users or active clients is a meaningless term from a router standpoint and wouldn't mind having more appropriate terms to use. Summary: I need a way to test a routers ability in handling traffic from a large number of clients. My current strategy is to purchase a router, deploy it, and see how it fails in the live environment.

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• Preventing 'Reply-All' to Exchange Distribution Groups

  - by Larold

  This is another question in a short series regarding a challenging Exchange project my co-workers have been asked to implement. (I'm helping even though I'm primarily a Unix guy because I volunteered to learn powershell and implement as much of the project in code as I could.) Background: We have been asked to create many distribution groups, say about 500+. These groups will contain two types of members. (Apologies if I get these terms wrong.) One type will be internal AD users, and the other type will be external users that I create Mail Contact entries for. We have been asked to make it so that a "Reply All" is not possible to any messages sent to these groups. I don't believe that is 100% possible to enforce for the following reasons. My question is - is my following reasoning sound? If not, please feel free to educate me on if / how things can properly be implemeneted. Thanks! My reasoning on why it's impossible to prevent 100% of potential reply-all actions: An interal AD user could put the DL in their To: field. They then click the '+' to expand the group. The group contains two external mail contacts. The message is sent to everyone, including those external contacts. External user #1 decides to reply-all, and his mail goes to, at least, external user #2, which wouldn't even involve our Exchange mail relays. An internal AD user could place the DL in their Outlook To: field, then click the '+' button to expand the DL. They then fire off an email to everyone that was in the group. (But the individual addresses are listed in the 'To:' field.) Because we now have a message sent to multiple recipients in the To: field, the addresses have been "exposed", and anyone is free to reply-all, and the messages just get sent to everyone in the To: field. Even if we try to set a Reply-To: field for all of these DLs, external mail clients are not obligated to abide by it, or force users to abide by it. Are my two points above valid? (I admit, they are somewhat similar.) Am I correct to tell our leadership "It is not possible to prevent 100% of the cases where someone will want to Reply-All to these groups UNLESS we train the users sending emails to these groups that the Bcc: field is to be used at all times." I am dying for any insight or parts of the equation I'm not seeing clearly. Thank you!!!

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• MySQL 5.5 - Lost connection to MySQL server during query

  - by bully

  I have an Ubuntu 12.04 LTS server running at a german hoster (virtualized system). # uname -a Linux ... 3.2.0-27-generic #43-Ubuntu SMP Fri Jul 6 14:25:57 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux I want to migrate a Web CMS system, called Contao. It's not my first migration, but my first migration having connection issues with mysql. Migration went successfully, I have the same Contao version running (it's more or less just copy / paste). For the database behind, I did: apt-get install mysql-server phpmyadmin I set a root password and added a user for the CMS which has enough rights on its own database (and only its database) for doing the stuff it has to do. Data import via phpmyadmin worked just fine. I can access the backend of the CMS (which needs to deal with the database already). If I try to access the frontend now, I get the following error: Fatal error: Uncaught exception Exception with message Query error: Lost connection to MySQL server during query (<query statement here, nothing special, just a select>) thrown in /var/www/system/libraries/Database.php on line 686 (Keep in mind: I can access mysql with phpmyadmin and through the backend, working like a charme, it's just the frontend call causing errors). If I spam F5 in my browser I can sometimes even kill the mysql deamon. If I run # mysqld --log-warnings=2 I get this: ... 120921 7:57:31 [Note] mysqld: ready for connections. Version: '5.5.24-0ubuntu0.12.04.1' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu) 05:57:37 UTC - mysqld got signal 4 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. key_buffer_size=16777216 read_buffer_size=131072 max_used_connections=1 max_threads=151 thread_count=1 connection_count=1 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 346679 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x7f1485db3b20 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 7f1480041e60 thread_stack 0x30000 mysqld(my_print_stacktrace+0x29)[0x7f1483b96459] mysqld(handle_fatal_signal+0x483)[0x7f1483a5c1d3] /lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f1482797cb0] /lib/x86_64-linux-gnu/libm.so.6(+0x42e11)[0x7f14821cae11] mysqld(_ZN10SQL_SELECT17test_quick_selectEP3THD6BitmapILj64EEyyb+0x1368)[0x7f1483b26cb8] mysqld(+0x33116a)[0x7f148397916a] mysqld(_ZN4JOIN8optimizeEv+0x558)[0x7f148397d3e8] mysqld(_Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select_lex+0xdd)[0x7f148397fd7d] mysqld(_Z13handle_selectP3THDP3LEXP13select_resultm+0x17c)[0x7f1483985d2c] mysqld(+0x2f4524)[0x7f148393c524] mysqld(_Z21mysql_execute_commandP3THD+0x293e)[0x7f14839451de] mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x10f)[0x7f1483948bef] mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1365)[0x7f148394a025] mysqld(_Z24do_handle_one_connectionP3THD+0x1bd)[0x7f14839ec7cd] mysqld(handle_one_connection+0x50)[0x7f14839ec830] /lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a)[0x7f148278fe9a] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f1481eba4bd] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (7f1464004b60): is an invalid pointer Connection ID (thread ID): 1 Status: NOT_KILLED From /var/log/syslog: Sep 21 07:17:01 s16477249 CRON[23855]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) Sep 21 07:18:51 s16477249 kernel: [231923.349159] type=1400 audit(1348204731.333:70): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/mysqld" pid=23946 comm="apparmor_parser" Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[23990]: Upgrading MySQL tables if necessary. Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[23993]: /usr/bin/mysql_upgrade: the '--basedir' option is always ignored Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[23993]: Looking for 'mysql' as: /usr/bin/mysql Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[23993]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[23993]: This installation of MySQL is already upgraded to 5.5.24, use --force if you still need to run mysql_upgrade Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[24004]: Checking for insecure root accounts. Sep 21 07:18:53 s16477249 /etc/mysql/debian-start[24009]: Triggering myisam-recover for all MyISAM tables I'm using MyISAM tables all over, nothing with InnoDB there. Starting / stopping mysql is done via sudo service mysql start sudo service mysql stop After using google a little bit, I experimented a little bit with timeouts, correct socket path in the /etc/mysql/my.cnf file, but nothing helped. There are some old (from 2008) Gentoo bugs, where re-compiling just solved the problem. I already re-installed mysql via: sudo apt-get remove mysql-server mysql-common sudo apt-get autoremove sudo apt-get install mysql-server without any results. This is the first time I'm running into this problem, and I'm not very experienced with this kind of mysql 'administration'. So mainly, I want to know if anyone of you could help me out please :) Is it a mysql bug? Is something broken in the Ubuntu repositories? Is this one of those misterious 'use-tcp-connection-instead-of-socket-stuff-because-there-are-problems-on-virtualized-machines-with-sockets'-problem? Or am I completly on the wrong way and I just miss-configured something? Remember, phpmyadmin and access to the backend (which uses the database, too) is just fine. Maybe something with Apache? What can I do? Any help is appreciated, so thanks in advance :)

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• Seriously, It’s Time to Get Your Content Act Together

  - by Mike Stiles

  Branded content, content marketing, social content, brand journalism, we’re seeing those terms more and more. Why? The technology tools are coming together. We should know. We can gather big data, crunch it, listen to the public, moderate, respond, get to know the customer intimately, know what they like, know what they want, we can target, distribute, amplify, measure engagement and reaction, modify strategy and even automate a great deal of all that. An amazing machine, a sleek, smooth-running engine has been built such that all the parts can interact and work together to deliver peak performance and maximum output. But that engine isn’t going anywhere without any gas. Content is the gas. Yes, we curate other people’s content. We can siphon their gas. There’s tech to help with that too. But as for the creation of original, worthwhile content made for a specific audience, our audience, machines can’t do that…at least not yet. Curated content is great. But somebody has to originate the content for it to be curated and shared. And since the need for good, curated content is obviously large and the desire to share is there, it’s a winning proposition for a brand to be a consistent producer of original content. And yet, it feels like content is an issue we’re avoiding. There’s a reluctance to build a massive pipeline if you have no idea what you’re going to run through it. The C-suite often doesn’t know what content is, that it’s different from ads, where to get it, who makes it, how long it should be, what the point of it is if there’s no hard sell of the product, what it costs, how to use it, how to measure it, how to make sure it’s good, or how to make sure it will keep flowing. It could be the reason many brands aren’t pulling the trigger on socially enabling the enterprise. And that’s a shame, because there are a lot of creative, daring, experimental, uniquely talented entertainers and journalists chomping at the bit to execute content for brands. But for many corporate executives, content is “weird,” and the people who make it are even weirder. The content side of the equation is human. It’s art, but art that can be informed by data. The natural inclination is for brands to turn to their agencies for such creative endeavors. But agencies are falling into one of two categories. They’re failing to transition from ads to content. In “Content Era, What’s the Role of Agencies?” Alexander Jutkowitz says agencies were made for one-hit campaigns, not ongoing content. Or, they’re ready and capable but can’t get clients to do the right things. Agencies have to make money, even if it means continuing to do the wrong things because that’s all the client will agree to. So what we wind up with in the pipeline is advertising, marketing-heavy content, content that was obviously created or spearheaded by non-creative executives, random & inconsistent content, copy written for SEO bots, and other completely uninteresting nightmares. Frank Rose, author of “The Art of Immersion,” writes, “Content without story and excitement is noise pollution.” In the old days, you made an ad and inserted it into shows made by people who knew what they were doing. You could bask in that show’s success and leverage their audience. Now, you are tasked with attracting, amassing and holding your own audience. You may just want to make, advertise and sell your widgets. But now there’s a war on for a precious commodity, attention. People are busy. They have filters to keep uninteresting and irrelevant things out. They value their time and expect value back when they give it up. Joe Pulizzi, founder of the Content Marketing Institute, says, "Your customers don't care about you, your products, your services…they care about themselves, their wants and their needs." Is it worth getting serious about content and doing it right? 61% of consumers feel better about a company that delivers custom content (Custom Content Council). Interesting content is one of the top 3 reasons people follow brands on social (Content+). 78% of consumers think organizations that provide custom content want to build good relationships with them (TMG Custom Media). On the B2B side, 80% of business decision makers prefer to get company info in a series of articles vs. an ad. So what’s the hang-up? Cited barriers to content marketing are lack of human resources (42%) and lack of budget (35%). 54% of brands don’t have a single on-site, dedicated content creator. And only 38% of brands have a content marketing strategy. Tech has built the biggest, most incredible stage for brands that’s ever been built. Putting something on that stage is your responsibility. Do a bad show, or no show at all, and you’ll be the beautiful, talented actress that never got discovered. @mikestilesPhoto: Gabriella Fabbri, stock.xchng

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• NET Math Libraries

  - by JoshReuben

  NET Mathematical Libraries   .NET Builder for Matlab The MathWorks Inc. - http://www.mathworks.com/products/netbuilder/ MATLAB Builder NE generates MATLAB based .NET and COM components royalty-free deployment creates the components by encrypting MATLAB functions and generating either a .NET or COM wrapper around them. .NET/Link for Mathematica www.wolfram.com a product that 2-way integrates Mathematica and Microsoft's .NET platform call .NET from Mathematica - use arbitrary .NET types directly from the Mathematica language. use and control the Mathematica kernel from a .NET program. turns Mathematica into a scripting shell to leverage the computational services of Mathematica. write custom front ends for Mathematica or use Mathematica as a computational engine for another program comes with full source code. Leverages MathLink - a Wolfram Research's protocol for sending data and commands back and forth between Mathematica and other programs. .NET/Link abstracts the low-level details of the MathLink C API. Extreme Optimization http://www.extremeoptimization.com/ a collection of general-purpose mathematical and statistical classes built for the.NET framework. It combines a math library, a vector and matrix library, and a statistics library in one package. download the trial of version 4.0 to try it out. Multi-core ready - Full support for Task Parallel Library features including cancellation. Broad base of algorithms covering a wide range of numerical techniques, including: linear algebra (BLAS and LAPACK routines), numerical analysis (integration and differentiation), equation solvers. Mathematics leverages parallelism using .NET 4.0's Task Parallel Library. Basic math: Complex numbers, 'special functions' like Gamma and Bessel functions, numerical differentiation. Solving equations: Solve equations in one variable, or solve systems of linear or nonlinear equations. Curve fitting: Linear and nonlinear curve fitting, cubic splines, polynomials, orthogonal polynomials. Optimization: find the minimum or maximum of a function in one or more variables, linear programming and mixed integer programming. Numerical integration: Compute integrals over finite or infinite intervals, over 2D and higher dimensional regions. Integrate systems of ordinary differential equations (ODE's). Fast Fourier Transforms: 1D and 2D FFT's using managed or fast native code (32 and 64 bit) BigInteger, BigRational, and BigFloat: Perform operations with arbitrary precision. Vector and Matrix Library Real and complex vectors and matrices. Single and double precision for elements. Structured matrix types: including triangular, symmetrical and band matrices. Sparse matrices. Matrix factorizations: LU decomposition, QR decomposition, singular value decomposition, Cholesky decomposition, eigenvalue decomposition. Portability and performance: Calculations can be done in 100% managed code, or in hand-optimized processor-specific native code (32 and 64 bit). Statistics Data manipulation: Sort and filter data, process missing values, remove outliers, etc. Supports .NET data binding. Statistical Models: Simple, multiple, nonlinear, logistic, Poisson regression. Generalized Linear Models. One and two-way ANOVA. Hypothesis Tests: 12 14 hypothesis tests, including the z-test, t-test, F-test, runs test, and more advanced tests, such as the Anderson-Darling test for normality, one and two-sample Kolmogorov-Smirnov test, and Levene's test for homogeneity of variances. Multivariate Statistics: K-means cluster analysis, hierarchical cluster analysis, principal component analysis (PCA), multivariate probability distributions. Statistical Distributions: 25 29 continuous and discrete statistical distributions, including uniform, Poisson, normal, lognormal, Weibull and Gumbel (extreme value) distributions. Random numbers: Random variates from any distribution, 4 high-quality random number generators, low discrepancy sequences, shufflers. New in version 4.0 (November, 2010) Support for .NET Framework Version 4.0 and Visual Studio 2010 TPL Parallellized – multicore ready sparse linear program solver - can solve problems with more than 1 million variables. Mixed integer linear programming using a branch and bound algorithm. special functions: hypergeometric, Riemann zeta, elliptic integrals, Frensel functions, Dawson's integral. Full set of window functions for FFT's. Product  Price Update subscription Single Developer License $999  $399  Team License (3 developers) $1999  $799  Department License (8 developers) $3999  $1599  Site License (Unlimited developers in one physical location) $7999  $3199    NMath http://www.centerspace.net .NET math and statistics libraries matrix and vector classes random number generators Fast Fourier Transforms (FFTs) numerical integration linear programming linear regression curve and surface fitting optimization hypothesis tests analysis of variance (ANOVA) probability distributions principal component analysis cluster analysis built on the Intel Math Kernel Library (MKL), which contains highly-optimized, extensively-threaded versions of BLAS (Basic Linear Algebra Subroutines) and LAPACK (Linear Algebra PACKage). Product  Price Update subscription Single Developer License $1295 $388 Team License (5 developers) $5180 $1554   DotNumerics http://www.dotnumerics.com/NumericalLibraries/Default.aspx free DotNumerics is a website dedicated to numerical computing for .NET that includes a C# Numerical Library for .NET containing algorithms for Linear Algebra, Differential Equations and Optimization problems. The Linear Algebra library includes CSLapack, CSBlas and CSEispack, ports from Fortran to C# of LAPACK, BLAS and EISPACK, respectively. Linear Algebra (CSLapack, CSBlas and CSEispack). Systems of linear equations, eigenvalue problems, least-squares solutions of linear systems and singular value problems. Differential Equations. Initial-value problem for nonstiff and stiff ordinary differential equations ODEs (explicit Runge-Kutta, implicit Runge-Kutta, Gear's BDF and Adams-Moulton). Optimization. Unconstrained and bounded constrained optimization of multivariate functions (L-BFGS-B, Truncated Newton and Simplex methods).   Math.NET Numerics http://numerics.mathdotnet.com/ free an open source numerical library - includes special functions, linear algebra, probability models, random numbers, interpolation, integral transforms. A merger of dnAnalytics with Math.NET Iridium in addition to a purely managed implementation will also support native hardware optimization. constants & special functions complex type support real and complex, dense and sparse linear algebra (with LU, QR, eigenvalues, ... decompositions) non-uniform probability distributions, multivariate distributions, sample generation alternative uniform random number generators descriptive statistics, including order statistics various interpolation methods, including barycentric approaches and splines numerical function integration (quadrature) routines integral transforms, like fourier transform (FFT) with arbitrary lengths support, and hartley spectral-space aware sequence manipulation (signal processing) combinatorics, polynomials, quaternions, basic number theory. parallelized where appropriate, to leverage multi-core and multi-processor systems fully managed or (if available) using native libraries (Intel MKL, ACMS, CUDA, FFTW) provides a native facade for F# developers

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• What Counts For a DBA: Simplicity

  - by Louis Davidson

  Too many computer processes do an apparently simple task in a bizarrely complex way. They remind me of this strip by one of my favorite artists: Rube Goldberg. In order to keep the boss from knowing one was late, a process is devised whereby the cuckoo clock kisses a live cuckoo bird, who then pulls a string, which triggers a hat flinging, which in turn lands on a rod that removes a typewriter cover…and so on. We rely on creating automated processes to keep on top of tasks. DBAs have a lot of tasks to perform: backups, performance tuning, data movement, system monitoring, and of course, avoiding being noticed.  Every day, there are many steps to perform to maintain the database infrastructure, including: checking physical structures, re-indexing tables where needed, backing up the databases, checking those backups, running the ETL, and preparing the daily reports and yes, all of these processes have to complete before you can call it a day, and probably before many others have started that same day. Some of these tasks are just naturally complicated on their own. Other tasks become complicated because the database architecture is excessively rigid, and we often discover during “production testing” that certain processes need to be changed because the written requirements barely resembled the actual customer requirements.   Then, with no time to change that rigid structure, we are forced to heap layer upon layer of code onto the problematic processes. Instead of a slight table change and a new index, we end up with 4 new ETL processes, 20 temp tables, 30 extra queries, and 1000 lines of SQL code.  Report writers then need to build reports and make magical numbers appear from those toxic data structures that are overly complex and probably filled with inconsistent data. What starts out as a collection of fairly simple tasks turns into a Goldbergian nightmare of daily processes that are likely to cause your dinner to be interrupted by the smartphone doing the vibration dance that signifies trouble at the mill. So what to do? Well, if it is at all possible, simplify the problem by either going into the code and refactoring the complex code to simple, or taking all of the processes and simplifying them into small, independent, easily-tested steps.  The former approach usually requires an agreement on changing underlying structures that requires countless mind-numbing meetings; while the latter can generally be done to any complex process without the same frustration or anger, though it will still leave you with lots of steps to complete, the ability to test each step independently will definitely increase the quality of the overall process (and with each step reporting status back, finding an actual problem within the process will be definitely less unpleasant.) We all know the principle behind simplifying a sequence of processes because we learned it in math classes in our early years of attending school, starting with elementary school. In my 4 years (ok, 9 years) of undergraduate work, I remember pretty much one thing from my many math classes that I apply daily to my career as a data architect, data programmer, and as an occasional indentured DBA: “show your work”. This process of showing your work was my first lesson in simplification. Each step in the process was in fact, far simpler than the entire process.  When you were working an equation that took both sides of 4 sheets of paper, showing your work was important because the teacher could see every step, judge it, and mark it accordingly.  So often I would make an error in the first few lines of a problem which meant that the rest of the work was actually moving me closer to a very wrong answer, no matter how correct the math was in the subsequent steps. Yet, when I got my grade back, I would sometimes be pleasantly surprised. I passed, yet missed every problem on the test. But why? While I got the fact that 1+1=2 wrong in every problem, the teacher could see that I was using the right process. In a computer process, the process is very similar. We take complex processes, show our work by storing intermediate values, and test each step independently. When a process has 100 steps, each step becomes a simple step that is tested and verified, such that there will be 100 places where data is stored, validated, and can be checked off as complete. If you get step 1 of 100 wrong, you can fix it and be confident (that if you did your job of testing the other steps better than the one you had to repair,) that the rest of the process works. If you have 100 steps, and store the state of the process exactly once, the resulting testable chunk of code will be far more complex and finding the error will require checking all 100 steps as one, and usually it would be easier to find a specific needle in a stack of similarly shaped needles.  The goal is to strive for simplicity either in the solution, or at least by simplifying every process down to as many, independent, testable, simple tasks as possible.  For the tasks that really can’t be done completely independently, minimally take those tasks and break them down into simpler steps that can be tested independently.  Like working out division problems longhand, have each step of the larger problem verified and tested.

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• Visual Studio Load Testing using Windows Azure

  - by Tarun Arora

  In my opinion the biggest adoption barrier in performance testing on smaller projects is not the tooling but the high infrastructure and administration cost that comes with this phase of testing. Only if a reusable solution was possible and infrastructure management wasn’t as expensive, adoption would certainly spike. It certainly is possible if you bring Visual Studio and Windows Azure into the equation. It is possible to run your test rig in the cloud without getting tangled in SCVMM or Lab Management. All you need is an active Azure subscription, Windows Azure endpoint enabled developer workstation running visual studio ultimate on premise, windows azure endpoint enabled worker roles on azure compute instances set up to run as test controllers and test agents. My test rig is running SQL server 2012 and Visual Studio 2012 RC agents. The beauty is that the solution is reusable, you can open the azure project, change the subscription and certificate, click publish and *BOOM* in less than 15 minutes you could have your own test rig running in the cloud. In this blog post I intend to show you how you can use the power of Windows Azure to effectively abstract the administration cost of infrastructure management and lower the total cost of Load & Performance Testing. As a bonus, I will share a reusable solution that you can use to automate test rig creation for both VS 2010 agents as well as VS 2012 agents. Introduction The slide show below should help you under the high level details of what we are trying to achive... Leveraging Azure for Performance Testing View more PowerPoint from Avanade Scenario 1 – Running a Test Rig in Windows Azure To start off with the basics, in the first scenario I plan to discuss how to, - Automate deployment & configuration of Windows Azure Worker Roles for Test Controller and Test Agent - Automate deployment & configuration of SQL database on Test Controller on the Test Controller Worker Role - Scaling Test Agents on demand - Creating a Web Performance Test and a simple Load Test - Managing Test Controllers right from Visual Studio on Premise Developer Workstation - Viewing results of the Load Test - Cleaning up - Have the above work in the shape of a reusable solution for both VS2010 and VS2012 Test Rig Scenario 2 – The scaled out Test Rig and sharing data using SQL Azure A scaled out version of this implementation would involve running multiple test rigs running in the cloud, in this scenario I will show you how to sync the load test database from these distributed test rigs into one SQL Azure database using Azure sync. The selling point for this scenario is being able to collate the load test efforts from across the organization into one data store. - Deploy multiple test rigs using the reusable solution from scenario 1 - Set up and configure Windows Azure Sync - Test SQL Azure Load Test result database created as a result of Windows Azure Sync - Cleaning up - Have the above work in the shape of a reusable solution for both VS2010 and VS2012 Test Rig The Ingredients Though with an active MSDN ultimate subscription you would already have access to everything and more, you will essentially need the below to try out the scenarios, 1. Windows Azure Subscription 2. Windows Azure Storage – Blob Storage 3. Windows Azure Compute – Worker Role 4. SQL Azure Database 5. SQL Data Sync 6. Windows Azure Connect – End points 7. SQL 2012 Express or SQL 2008 R2 Express 8. Visual Studio All Agents 2012 or Visual Studio All Agents 2010 9. A developer workstation set up with Visual Studio 2012 – Ultimate or Visual Studio 2010 – Ultimate 10. Visual Studio Load Test Unlimited Virtual User Pack. Walkthrough To set up the test rig in the cloud, the test controller, test agent and SQL express installers need to be available when the worker role set up starts, the easiest and most efficient way is to pre upload the required software into Windows Azure Blob storage. SQL express, test controller and test agent expose various switches which we can take advantage of including the quiet install switch. Once all the 3 have been installed the test controller needs to be registered with the test agents and the SQL database needs to be associated to the test controller. By enabling Windows Azure connect on the machines in the cloud and the developer workstation on premise we successfully create a virtual network amongst the machines enabling 2 way communication. All of the above can be done programmatically, let’s see step by step how… Scenario 1 Video Walkthrough–Leveraging Windows Azure for performance Testing Scenario 2 Work in progress, watch this space for more… Solution If you are still reading and are interested in the solution, drop me an email with your windows live id. I’ll add you to my TFS preview project which has a re-usable solution for both VS 2010 and VS 2012 test rigs as well as guidance and demo performance tests.   Conclusion Other posts and resources available here. Possibilities…. Endless!

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• Oracle WebCenter at the Enterprise 2.0 Conference

  - by Brian Dirking

  We had a great week at the E20 Conference, presenting in four sessions – Andy MacMillan gave a session titled Today’s Successful Enterprises are Social Enterprises and was on a panel that Tony Byrne moderated; Christian Finn spoke on a panel on Unified Communications Unified Communications + Social Computing = Best of Both Worlds?, Mark Bennett spoke on a panel on The Evolution of Talent Management. The key areas of focus this year were sentiment analysis, adoption and community building, the benefits of failure, and social’s role in process applications. Sentiment analysis. This was focused not on external audiences but more on employee sentiment. Tim Young showed his internal "NikoNiko" project, where employees use smilies to report their current mood. The result was a dashboard that showed the company mood by department. Since the goal is to improve productivity, people can see which departments are running into issues and try and address them. A company might otherwise wait until the end of the quarter financials to find out that there was a problem and product didn’t ship. This is a way to identify issues immediately. Tim is great – he had the crowd laughing as soon as he hit the stage, with his proposed hastag for his session: by making it 138 characters long, people couldn’t say much behind his back. And as I tweeted during his session, I loved his comment that complexity diffuses energy - it sounds like something Sun Tzu would say. Another example of employee sentiment analysis was CubeVibe. Founder and CEO Aaron Aycock, in his 3 minute pitch or die session talked about how engaged employees perform better. It was too bad he got gonged, he was just picking up speed, but CubeVibe did win the vote – congratulations to them. Internal adoption, community building, and involvement. On this topic I spoke to Terri Griffith, and she said there is some good work going on at University of Indiana regarding this, and hinted that she might be blogging about it in the near future. This area holds lots of interest for me. Amongst our customers, - CPAC stands out as an organization that has successfully built a community. So, I wonder - what are the building blocks? A strong leader? A common or unifying purpose? A certain level of engagement? I imagine someone has created an equation that says “for a community to grow at 30% per month, there must be an engagement level x to the square root of y, where x equals current community size, and y equals the expected growth rate, and the result is how many engagements the average user must contribute to maintain that growth.” Does anyone have a framework like that? The net result of everyone’s experience is that there is nothing to do but start early and fail often. Kevin Jones made this the focus of his keynote. He talked about the types of failure and what they mean. And he showed his famous kids at work video: Kevin’s blog also has this post: Social Business Failure #8: Workflow Integration. This is something that we’ve been working on at Oracle. Since so much of business is based in enterprise applications such as ERP and CRM (and since Oracle offers e-Business Suite, Siebel, PeopleSoft, and JD Edwards, as well as Fusion Applications), it makes sense that the social capabilities of Oracle WebCenter is built right into these applications. There are two types of social collaboration – ad-hoc, and exception handling. When you are in a business process and encounter an exception, you immediately look for 1) the document that tells you how to handle it, or 2) the person who can tell you how to handle it. With WebCenter built into these processes, people either search their content management system, or engage in expertise location and conversation. The great thing is, THEY DON’T HAVE TO LEAVE THE APPLICATION TO DO IT. Oracle has built the social capabilities right into the applications and business processes. I don’t think enough folks were able to see that at the event, but I expect that over the next six months folks will become very aware of it. WebCenter also provides the ability to have ad-hoc collaboration, search, and expertise location that folks need when they are innovating or collaborating. We demonstrated Oracle Social Network. It’s built on our Oracle WebCenter product to provide social collaboration inside and outside of your company. When we showed it to people, there were a number of areas that they commented on that were different from the other products being shown at the conference: Screenshots from within the product Many authors working on documents simultaneously Flagging people for follow up Direct ability to call out to people Ability to see presence not just if someone is online, but which conversation they are actively in Great stuff, the conference was full of smart people that that we enjoy spending time with. We’ll keep up in the meantime, but we look forward to seeing you in Boston.

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• The Joy Of Hex

  - by Jim Giercyk

  While working on a mainframe integration project, it occurred to me that some basic computer concepts are slipping into obscurity. For example, just about anyone can tell you that a 64-bit processor is faster than a 32-bit processer. A grade school child could tell you that a computer “speaks” in ‘1’s and ‘0’s. Some people can even tell you that there are 8 bits in a byte. However, I have found that even the most seasoned developers often can’t explain the theory behind those statements. That is not a knock on programmers; in the age of IntelliSense, what reason do we have to work with data at the bit level? Many computer theory classes treat bit-level programming as a thing of the past, no longer necessary now that storage space is plentiful. The trouble with that mindset is that the world is full of legacy systems that run programs written in the 1970’s.  Today our jobs require us to extract data from those systems, regardless of the format, and that often involves low-level programming. Because it seems knowledge of the low-level concepts is waning in recent times, I thought a review would be in order.       CHARACTER: See Spot Run HEX: 53 65 65 20 53 70 6F 74 20 52 75 6E DECIMAL: 83 101 101 32 83 112 111 116 32 82 117 110 BINARY: 01010011 01100101 01100101 00100000 01010011 01110000 01101111 01110100 00100000 01010010 01110101 01101110 In this example, I have broken down the words “See Spot Run” to a level computers can understand – machine language.     CHARACTER:  The character level is what is rendered by the computer.  A “Character Set” or “Code Page” contains 256 characters, both printable and unprintable.  Each character represents 1 BYTE of data.  For example, the character string “See Spot Run” is 12 Bytes long, exclusive of the quotation marks.  Remember, a SPACE is an unprintable character, but it still requires a byte.  In the example I have used the default Windows character set, ASCII, which you can see here:  http://www.asciitable.com/ HEX:  Hex is short for hexadecimal, or Base 16.  Humans are comfortable thinking in base ten, perhaps because they have 10 fingers and 10 toes; fingers and toes are called digits, so it’s not much of a stretch.  Computers think in Base 16, with numeric values ranging from zero to fifteen, or 0 – F.  Each decimal place has a possible 16 values as opposed to a possible 10 values in base 10.  Therefore, the number 10 in Hex is equal to the number 16 in Decimal.  DECIMAL:  The Decimal conversion is strictly for us humans to use for calculations and conversions.  It is much easier for us humans to calculate that [30 – 10 = 20] in decimal than it is for us to calculate [1E – A = 14] in Hex.  In the old days, an error in a program could be found by determining the displacement from the entry point of a module.  Since those values were dumped from the computers head, they were in hex. A programmer needed to convert them to decimal, do the equation and convert back to hex.  This gets into relative and absolute addressing, a topic for another day.  BINARY:  Binary, or machine code, is where any value can be expressed in 1s and 0s.  It is really Base 2, because each decimal place can have a possibility of only 2 characters, a 1 or a 0.  In Binary, the number 10 is equal to the number 2 in decimal. Why only 1s and 0s?  Very simply, computers are made up of lots and lots of transistors which at any given moment can be ON ( 1 ) or OFF ( 0 ).  Each transistor is a bit, and the order that the transistors fire (or not fire) is what distinguishes one value from  another in the computers head (or CPU).  Consider 32 bit vs 64 bit processing…..a 64 bit processor has the capability to read 64 transistors at a time.  A 32 bit processor can only read half as many at a time, so in theory the 64 bit processor should be much faster.  There are many more factors involved in CPU performance, but that is the fundamental difference.    DECIMAL HEX BINARY 0 0 0000 1 1 0001 2 2 0010 3 3 0011 4 4 0100 5 5 0101 6 6 0110 7 7 0111 8 8 1000 9 9 1001 10 A 1010 11 B 1011 12 C 1100 13 D 1101 14 E 1110 15 F 1111   Remember that each character is a BYTE, there are 2 HEX characters in a byte (called nibbles) and 8 BITS in a byte.  I hope you enjoyed reading about the theory of data processing.  This is just a high-level explanation, and there is much more to be learned.  It is safe to say that, no matter how advanced our programming languages and visual studios become, they are nothing more than a way to interpret bits and bytes.  There is nothing like the joy of hex to get the mind racing.

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• Unexpected advantage of Engineered Systems

  - by user12244672

  It's not surprising that Engineered Systems accelerate the debugging and resolution of customer issues. But what has surprised me is just how much faster issue resolution is with Engineered Systems such as SPARC SuperCluster. These are powerful, complex, systems used by customers wanting extreme database performance, app performance, and cost saving server consolidation. A SPARC SuperCluster consists or 2 or 4 powerful T4-4 compute nodes, 3 or 6 extreme performance Exadata Storage Cells, a ZFS Storage Appliance 7320 for general purpose storage, and ultra fast Infiniband switches.  Each with its own firmware. It runs Solaris 11, Solaris 10, 11gR2, LDoms virtualization, and Zones virtualization on the T4-4 compute nodes, a modified version of Solaris 11 in the ZFS Storage Appliance, a modified and highly tuned version of Oracle Linux running Exadata software on the Storage Cells, another Linux derivative in the Infiniband switches, etc. It has an Infiniband data network between the components, a 10Gb data network to the outside world, and a 1Gb management network. And customers can run whatever middleware and apps they want on it, clustered in whatever way they want. In one word, powerful.  In another, complex. The system is highly Engineered.  But it's designed to run general purpose applications. That is, the physical components, configuration, cabling, virtualization technologies, switches, firmware, Operating System versions, network protocols, tunables, etc. are all preset for optimum performance and robustness. That improves the customer experience as what the customer runs leverages our technical know-how and best practices and is what we've tested intensely within Oracle. It should also make debugging easier by fixing a large number of variables which would otherwise be in play if a customer or Systems Integrator had assembled such a complex system themselves from the constituent components.  For example, there's myriad network protocols which could be used with Infiniband.  Myriad ways the components could be interconnected, myriad tunable settings, etc. But what has really surprised me - and I've been working in this area for 15 years now - is just how much easier and faster Engineered Systems have made debugging and issue resolution. All those error opportunities for sub-optimal cabling, unusual network protocols, sub-optimal deployment of virtualization technologies, issues with 3rd party storage, issues with 3rd party multi-pathing products, etc., are simply taken out of the equation. All those error opportunities for making an issue unique to a particular set-up, the "why aren't we seeing this on any other system ?" type questions, the doubts, just go away when we or a customer discover an issue on an Engineered System. It enables a really honed response, getting to the root cause much, much faster than would otherwise be the case. Here's a couple of examples from the last month, one found in-house by my team, one found by a customer: Example 1: We found a node eviction issue running 11gR2 with Solaris 11 SRU 12 under extreme load on what we call our ExaLego test system (mimics an Exadata / SuperCluster 11gR2 Exadata Storage Cell set-up).  We quickly established that an enhancement in SRU12 enabled an 11gR2 process to query Infiniband's Subnet Manager, replacing a fallback mechanism it had used previously.  Under abnormally heavy load, the query could return results which were misinterpreted resulting in node eviction.  In several daily joint debugging sessions between the Solaris, Infiniband, and 11gR2 teams, the issue was fully root caused, evaluated, and a fix agreed upon.  That fix went back into all Solaris releases the following Monday.  From initial issue discovery to the fix being put back into all Solaris releases was just 10 days. Example 2: A customer reported sporadic performance degradation.  The reasons were unclear and the information sparse.  The SPARC SuperCluster Engineered Systems support teams which comprises both SPARC/Solaris and Database/Exadata experts worked to root cause the issue.  A number of contributing factors were discovered, including tunable parameters.  An intense collaborative investigation between the engineering teams identified the root cause to a CPU bound networking thread which was being starved of CPU cycles under extreme load.  Workarounds were identified.  Modifications have been put back into 11gR2 to alleviate the issue and a development project already underway within Solaris has been sped up to provide the final resolution on the Solaris side.  The fixed SPARC SuperCluster configuration greatly aided issue reproduction and dramatically sped up root cause analysis, allowing the correct workarounds and fixes to be identified, prioritized, and implemented.  The customer is now extremely happy with performance and robustness.  Since the configuration is common to other customers, the lessons learned are being proactively rolled out to other customers and incorporated into the installation procedures for future customers.  This effectively acts as a turbo-boost to performance and reliability for all SPARC SuperCluster customers.  If this had occurred in a "home grown" system of this complexity, I expect it would have taken at least 6 months to get to the bottom of the issue.  But because it was an Engineered System, known, understood, and qualified by both the Solaris and Database teams, we were able to collaborate closely to identify cause and effect and expedite a solution for the customer.  That is a key advantage of Engineered Systems which should not be underestimated.  Indeed, the initial issue mitigation on the Database side followed by final fix on the Solaris side, highlights the high degree of collaboration and excellent teamwork between the Oracle engineering teams.  It's a compelling advantage of the integrated Oracle Red Stack in general and Engineered Systems in particular.

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• Mark Hurd on the Customer Revolution: Oracle's Top 10 Insights

  - by Richard Lefebvre

  Reprint of an article from Forbes Businesses that fail to focus on customer experience will hear a giant sucking sound from their vanishing profitability. Because in today’s dynamic global marketplace, consumers now hold the power in the buyer-seller equation, and sellers need to revamp their strategy for this new world order. The ability to relentlessly deliver connected, personalized and rewarding customer experiences is rapidly becoming one of the primary sources of competitive advantage in today’s dynamic global marketplace. And the inability or unwillingness to realize that the customer is a company’s most important asset will lead, inevitably, to decline and failure. Welcome to the lifecycle of customer experience, in which consumers explore, engage, shop, buy, ask, compare, complain, socialize, exchange, and more across multiple channels with the unconditional expectation that each of those interactions will be completed in an efficient and personalized manner however, wherever, and whenever the customer wants. While many niche companies are offering point solutions within that sprawling and complex spectrum of needs and requirements, businesses looking to deliver superb customer experiences are still left having to do multiple product evaluations, multiple contract negotiations, multiple test projects, multiple deployments, and–perhaps most annoying of all–multiple and never-ending integration projects to string together all those niche products from all those niche vendors. With its new suite of customer-experience solutions, Oracle believes it can help companies unravel these challenges and move at the speed of their customers, anticipating their needs and desires and creating enduring and profitable relationships. Those solutions span the full range of marketing, selling, commerce, service, listening/insights, and social and collaboration tools for employees. When Oracle launched its suite of Customer Experience solutions at a recent event in New York City, president Mark Hurd analyzed the customer experience revolution taking place and presented Oracle’s strategy for empowering companies to capitalize on this important market shift. From Hurd’s presentation and related materials, I’ve extracted a list of Hurd’s Top 10 Insights into the Customer Revolution. 1. Please Don’t Feed the Competitor’s Pipeline!After enduring a poor experience, 89% of consumers say they would immediately take their business to your competitor. (Except where noted, the source for these findings is the 2011 Customer Experience Impact (CEI) Report including a survey commissioned by RightNow (acquired by Oracle in March 2012) and conducted by Harris Interactive.) 2. The Addressable Market Is Massive. Only 1% of consumers say their expectations were always met by their actual experiences. 3. They’re Willing to Pay More! In return for a great experience, 86% of consumers say they’ll pay up to 25% more. 4. The Social Media Microphone Is Always Live. After suffering through a poor experience, more than 25% of consumers said they posted a negative comment on Twitter or Facebook or other social media sites. Conversely, of those consumers who got a response after complaining, 22% posted positive comments about the company. 5.  The New Deal Is Never Done: Embrace the Entire Customer Lifecycle. An appropriately active and engaged relationship, says Hurd, extends across every step of the entire processs: need, research, select, purchase, receive, use, maintain, and recommend. 6. The 360-Degree Commitment. Customers want to do business with companies that actively and openly demonstrate the desire to establish strong and seamless connections across employees, the company, and the customer, says research firm Temkin Group in its report called “The CX Competencies.” 7. Understand the Emotional Drivers Behind Brand Love. What makes consumers fall in love with a brand? Among the top factors are friendly employees and customer reps (73%), easy access to information and support (55%), and personalized experiences, such as when companies know precisely what products or services customers have purchased in the past and what issues those customers have raised (36%). 8.  The Importance of Immediate Action. You’ve got one week to respond–and then the opportunity’s lost. If your company needs more than a week to answer a prospect’s question or request, most of those prospects will terminate the relationship. 9.  Want More Revenue, Less Churn, and More Referrals? Then improve the overall customer experience: Forrester’s research says that approach put an extra $900 million in the pockets of wireless service providers, $800 million for hotels, and $400 million for airlines. 10. The Formula for CX Success.  Hurd says it includes three elegantly interlaced factors: Connected Engagement, to personalize the experience; Actionable Insight, to maximize the engagement; and Optimized Execution, to deliver on the promise of value. RECOMMENDED READING: The Top 10 Strategic CIO Issues For 2013 Wal-Mart, Amazon, eBay: Who’s the Speed King of Retail? Career Suicide and the CIO: 4 Deadly New Threats Memo to Marc Benioff: Social Is a Tool, Not an App

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• Determining the angle to fire a shot when target and shooter moves, and bullet moves with shooter velocity added in

  - by Azaral

  I saw this question: Predicting enemy position in order to have an object lead its target and followed the link in the answer to stack overflow. In the stack overflow page I used the 2nd answer, the one that is a large mathematical derivation. My situation is a little different though. My first question though is will the answer provided in the stack overflow page even work to begin with, assuming the original circumstances of moving target and stationary shooter. My situation is a little different than that situation. My target moves, the shooter moves, and the bullets from the shooter start off with the velocities in x and y added to the bullets' x and y velocities. If you are sliding to the right, the bullets will remain in front of you as you move so as long as your velocity remains constant. What I'm trying to do is to get the enemy to be able to determine where they need to shoot in order to hit the player. Unless the player and enemy is stationary, the velocity from the ship adding to the velocity of the bullets will cause a miss. I'd rather like to prevent that. I used the formula in the stack overflow answer and did what I thought were the appropriate adjustments. I've been banging at this for the last four hours and I just can't make it click. It is probably something really simple and boneheaded that I am missing (that seems to be a lot of my problems lately). Here is the solution presented from the stack overflow answer: It boils down to solving a quadratic equation of the form: a * sqr(x) + b * x + c == 0 Note that by sqr I mean square, as opposed to square root. Use the following values: a := sqr(target.velocityX) + sqr(target.velocityY) - sqr(projectile_speed) b := 2 * (target.velocityX * (target.startX - cannon.X) + target.velocityY * (target.startY - cannon.Y)) c := sqr(target.startX - cannon.X) + sqr(target.startY - cannon.Y) Now we can look at the discriminant to determine if we have a possible solution. disc := sqr(b) - 4 * a * c If the discriminant is less than 0, forget about hitting your target -- your projectile can never get there in time. Otherwise, look at two candidate solutions: t1 := (-b + sqrt(disc)) / (2 * a) t2 := (-b - sqrt(disc)) / (2 * a) Note that if disc == 0 then t1 and t2 are equal. If there are no other considerations such as intervening obstacles, simply choose the smaller positive value. (Negative t values would require firing backward in time to use!) Substitute the chosen t value back into the target's position equations to get the coordinates of the leading point you should be aiming at: aim.X := t * target.velocityX + target.startX aim.Y := t * target.velocityY + target.startY Here is my code, after being corrected by Sam Hocevar (thank you again for your help!). It still doesn't work. For some reason it never enters the section of code inside the if(disc = 0) (obviously because it is always less than zero but...). However, if I plug the numbers from my game log on the enemy and player positions and velocities it outputs a valid firing solution. I have looked at the code side by side a couple of times now and I can't find any differences. There has got to be something simple I'm missing here. If someone else could look at this code and determine what is going on here I'd appreciate it. I know it's not going through that section because if it were, shouldShoot would become true and the enemy would be blasting away at the player. This section calls the function in question, CalculateShootHeading() if(shouldMove) { UseEngines(); } x += xVelocity; y += yVelocity; CalculateShootHeading(); if(shouldShoot) { ShootWeapons(); } UpdateWeapons(); This is CalculateShootHeading(). This is inside the enemy class so x and y are the enemy's x and y and the same with velocity. One output from my game log gives Player X = 2108, Player Y = -180.956, Player X velocity = 10.9949, Player Y Velocity = -6.26017, Enemy X = 1988.31, Enemy Y = -339.051, Enemy X velocity = 1.81666, Enemy Y velocity = -9.67762, 0 enemy projectiles. The output from the console tester is Bullet position = 2210.49, -239.313 and Player Position = 2210.49, -239.313. This doesn't make any sense. The only thing that could be different is the code or the input into my function in the game and I've checked that and I don't think that it is wrong as it's updated before this and never changed. float const bulletSpeed = 30.f; float const dx = playerX - x; float const dy = playerY - y; float const vx = playerXVelocity - xVelocity; float const vy = playerYVelocity - yVelocity; float const a = vx * vx + vy * vy - bulletSpeed * bulletSpeed; float const b = 2.f * (vx * dx + vy * dy); float const c = dx * dx + dy * dy; float const disc = b * b - 4.f * a * c; shouldShoot = false; if (disc >= 0.f) { float t0 = (-b - std::sqrt(disc)) / (2.f * a); float t1 = (-b + std::sqrt(disc)) / (2.f * a); if (t0 < 0.f || (t1 < t0 && t1 >= 0.f)) { t0 = t1; } if (t0 >= 0.f) { float shootx = vx + dx / t0; float shooty = vy + dy / t0; heading = std::atan2(shooty, shootx) * RAD2DEGREE; } shouldShoot = true; }

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• Runge-Kutta (RK4) integration for game physics

  - by Kai

  Gaffer on Games has a great article about using RK4 integration for better game physics. The implementation is straightforward but the math behind it confuses me. I understand derivatives and integrals on a conceptual level but I haven't manipulated equations in a long time. Here's the brunt of Gaffer's implementation: void integrate(State &state, float t, float dt) { Derivative a = evaluate(state, t, 0.0f, Derivative()); Derivative b = evaluate(state, t+dt*0.5f, dt*0.5f, a); Derivative c = evaluate(state, t+dt*0.5f, dt*0.5f, b); Derivative d = evaluate(state, t+dt, dt, c); const float dxdt = 1.0f/6.0f * (a.dx + 2.0f*(b.dx + c.dx) + d.dx); const float dvdt = 1.0f/6.0f * (a.dv + 2.0f*(b.dv + c.dv) + d.dv) state.x = state.x + dxdt * dt; state.v = state.v + dvdt * dt; } Can anybody explain in simple terms how RK4 works? Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? After reading the accepted answer below, and several other articles, I have a grasp on how RK4 works. To answer my own questions: Can anybody explain in simple terms how RK4 works? RK4 takes advantage of the fact that we can get a much better approximation of a function if we use its higher-order derivatives rather than just the first or second derivative. That's why the Taylor series converges much faster than Euler approximations. (take a look at the animation on the right side of that page) Specifically, why are we averaging the derivatives at 0.0f, 0.5f, 0.5f, and 1.0f? The Runge-Kutta method is an approximation of a function that samples derivatives of several points within a timestep, unlike the Taylor series which only samples derivatives of a single point. After sampling these derivatives we need to know how to weigh each sample to get the closest approximation possible. An easy way to do this is to pick constants that coincide with the Taylor series, which is how the constants of a Runge-Kutta equation are determined. This article made it clearer for me: http://web.mit.edu/10.001/Web/Course%5FNotes/Differential%5FEquations%5FNotes/node5.html. Notice how (15) is the Taylor series expansion while (17) is the Runge-Kutta derivation. How is averaging derivatives up to the 4th order different from doing a simple euler integration with a smaller timestep? Mathematically it converges much faster than doing many Euler approximations. Of course, with enough Euler approximations we can gain equal accuracy to RK4, but the computational power needed doesn't justify using Euler.

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• iPhone OpenGL ES: How do I use gravity vector to correctly transform scene for augmented reality

  - by gpdawson

  I'm trying figure out how to get an OpenGL specified object to be displayed correctly according to the device orientation (ie. according to the gravity vector from the accelerometer, and heading from compass). The GLGravity sample project has an example which is almost like this (despite ignoring heading), but it has some glitches. For example, the teapot jumps 180deg as the device viewing angle crosses the horizon, and it also rotates spuriously if you tilt the device from portrait into landscape. This is fine for the context of this app, as it just shows off an object and it doesn't matter that it does these things. But it means that the code just doesn't work when you attempt to emulate real life viewing of an OpenGL object according to the device's orientation. What happens is that it almost works, but the heading rotation you apply from the compass gets "corrupted" by the spurious additional rotations seen in the GLGravity example project. Can anyone provide sample code that shows how to adjust correctly for the device orientation (ie. gravity vector), or to fix the GLGravity example so that it doesn't include spurious heading changes? //Clear matrix to be used to rotate from the current referential to one based on the gravity vector bzero(matrix, sizeof(matrix)); matrix[3][3] = 1.0; //Setup first matrix column as gravity vector matrix[0][0] = accel[0] / length; matrix[0][1] = accel[1] / length; matrix[0][2] = accel[2] / length; //Setup second matrix column as an arbitrary vector in the plane perpendicular to the gravity vector {Gx, Gy, Gz} defined by by the equation "Gx * x + Gy * y + Gz * z = 0" in which we arbitrarily set x=0 and y=1 matrix[1][0] = 0.0; matrix[1][1] = 1.0; matrix[1][2] = -accel[1] / accel[2]; length = sqrtf(matrix[1][0] * matrix[1][0] + matrix[1][1] * matrix[1][1] + matrix[1][2] * matrix[1][2]); matrix[1][0] /= length; matrix[1][1] /= length; matrix[1][2] /= length; //Setup third matrix column as the cross product of the first two matrix[2][0] = matrix[0][1] * matrix[1][2] - matrix[0][2] * matrix[1][1]; matrix[2][1] = matrix[1][0] * matrix[0][2] - matrix[1][2] * matrix[0][0]; matrix[2][2] = matrix[0][0] * matrix[1][1] - matrix[0][1] * matrix[1][0]; //Finally load matrix glMultMatrixf((GLfloat*)matrix);

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• How do I use the gravity vector to correctly transform scene for augmented reality?

  - by gpdawson

  I'm trying figure out how to get an OpenGL specified object to be displayed correctly according to the device orientation (ie. according to the gravity vector from the accelerometer, and heading from compass). The GLGravity sample project has an example which is almost like this (despite ignoring heading), but it has some glitches. For example, the teapot jumps 180deg as the device viewing angle crosses the horizon, and it also rotates spuriously if you tilt the device from portrait into landscape. This is fine for the context of this app, as it just shows off an object and it doesn't matter that it does these things. But it means that the code just doesn't work when you attempt to emulate real life viewing of an OpenGL object according to the device's orientation. What happens is that it almost works, but the heading rotation you apply from the compass gets "corrupted" by the spurious additional rotations seen in the GLGravity example project. Can anyone provide sample code that shows how to adjust correctly for the device orientation (ie. gravity vector), or to fix the GLGravity example so that it doesn't include spurious heading changes? //Clear matrix to be used to rotate from the current referential to one based on the gravity vector bzero(matrix, sizeof(matrix)); matrix[3][3] = 1.0; //Setup first matrix column as gravity vector matrix[0][0] = accel[0] / length; matrix[0][1] = accel[1] / length; matrix[0][2] = accel[2] / length; //Setup second matrix column as an arbitrary vector in the plane perpendicular to the gravity vector {Gx, Gy, Gz} defined by by the equation "Gx * x + Gy * y + Gz * z = 0" in which we arbitrarily set x=0 and y=1 matrix[1][0] = 0.0; matrix[1][1] = 1.0; matrix[1][2] = -accel[1] / accel[2]; length = sqrtf(matrix[1][0] * matrix[1][0] + matrix[1][1] * matrix[1][1] + matrix[1][2] * matrix[1][2]); matrix[1][0] /= length; matrix[1][1] /= length; matrix[1][2] /= length; //Setup third matrix column as the cross product of the first two matrix[2][0] = matrix[0][1] * matrix[1][2] - matrix[0][2] * matrix[1][1]; matrix[2][1] = matrix[1][0] * matrix[0][2] - matrix[1][2] * matrix[0][0]; matrix[2][2] = matrix[0][0] * matrix[1][1] - matrix[0][1] * matrix[1][0]; //Finally load matrix glMultMatrixf((GLfloat*)matrix);

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• MooseX::Types declaration issue, tight test case :)

  - by TJ Thompson

  So after an embarrassing amount of time debugging, I've finally stripped this issue ([http://stackoverflow.com/questions/4621589/perl-moose-typedecorator-error-how-do-i-debug][1]) down to a simple test case. I would humbly request some help understanding why it's failing :) Here is the error message I'm getting: plxc16479 $h2/tmp/tmp18.pl This method [new] requires a single argument. at /nfs/pdx/disks/nehalem.pde.077/perl/5.12.2/lib64/site_perl/MooseX/Types/TypeDecorator.pm line 91 MooseX::Types::TypeDecorator::new('MooseX::Types::TypeDecorator=HASH(0x655b90)') called at /nfs/pdx/disks/nehalem.pde.077/projects/lib/Program-Plist-Pl/lib/Program/Plist/Pl.pm line 10 Program::Plist::Pl::BUILD('Program::Plist::Pl=HASH(0x63d478)', 'HASH(0x63d220)') called at generated method (unknown origin) line 29 Program::Plist::Pl::new('Program::Plist::Pl') called at /nfs/pdx/disks/nehalem.pde.077/tmp/tmp18.pl line 10 Wrapper test script: use strict; use warnings; BEGIN {push(@INC, split(':', $ENV{PERL_TEST_LIBS}))}; use Program::Plist::Pl; my $obj = Program::Plist::Pl->new(); Program::Plist::Pl file: package Program::Plist::Pl; use Moose; use namespace::autoclean; use Program::Types qw(Pattern); # <-- Removing this fixes error use Program::Plist::Pl::Pattern; sub BUILD { my $pattern_obj = Program::Plist::Pl::Pattern->new(); } __PACKAGE__->meta->make_immutable; 1; Program::Types file: package Program::Types; use MooseX::Types -declare => [qw(Pattern)]; class_type Pattern, {class => 'Program::Plist::Pl::Pattern'}; 1; And the Program::Plist::Pl::Pattern file: package Program::Plist::Pl::Pattern; use Moose; use namespace::autoclean; __PACKAGE__->meta->make_immutable; 1; Notes: While I don't need the Pattern type from Program::Types in the above code, I do in other code that is stripped out. The PERL_TEST_LIBS env var I'm pulling INC paths from only contains paths to the project modules. There are no other modules loaded from these paths. It appears the MooseX::Types definition for Pattern is causing problems, but I'm not sure why. Documentation shows the syntax I am using, but it's possible I'm misusing class_type as there isn't much said about it. Intent is to be able to use Pattern for type checking via MooseX::Params::Validate to verify the argument is a 'Program::Plist::Pl::Program' object. I've found that removing the intervening class Program::Plist::Pl from the equation by directly calling Pattern-new from the tmp18.pl wrapper results in no error, even when the Program::Types Pattern type is imported.

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• Mercurial over ssh client and server on Windows

  - by Ben Von Handorf

  I'm trying to configure Mercurial for use with both a windows server (freeSSHd) and client (both command line and TortoiseHG). I'm using the most recent versions of everything... all downloaded in the past few days. Using public key auth, I have been able to get connected to the server and I'm able to use plink to execute "hg version" and get a response, but when I try to clone a repository from the ssh server the command appears to hang. Running with -v yields: hg -v clone ssh://<username>@<server>//hg/repositoryA testRepositoryA running "plink.exe -i "<path to private key file>" <username>@<server> "hg -R /hg/repositoryA serve --stdio"" with nothing more forthcoming. Running the hg serve command directly on the server yields an apparently responsive Mercurial server, but the clients do not seem to make any further requests. Running "hg serve" in the repository directory and cloning over http works perfectly. What should I be looking for to help debug this? Is there something the clients (hg and TortoiseHG) aren't sending to continue the request stream? Additional Information: If I change to an invalid repository on the target machine, the appropriate error is displayed, so it does appear that the remote hg is running and correctly evaluating the path. Running with --debug and --traceback results in: sending hello command sending between command It hangs here, until I CTRL-C Traceback (most recent call last): File "mercurial\dispatch.pyo", line 46, in _runcatch File "mercurial\dispatch.pyo", line 452, in _dispatch File "mercurial\dispatch.pyo", line 320, in runcommand File "mercurial\dispatch.pyo", line 504, in _runcommand File "mercurial\dispatch.pyo", line 457, in checkargs File "mercurial\dispatch.pyo", line 451, in <lambda> File "mercurial\util.pyo", line 402, in check File "mercurial\commands.pyo", line 636, in clone File "mercurial\hg.pyo", line 187, in clone File "mercurial\hg.pyo", line 63, in repository File "mercurial\sshrepo.pyo", line 51, in __init__ File "mercurial\sshrepo.pyo", line 73, in validate_repo KeyboardInterrupt interrupted! Responding to Ryan: There does not appear to be any CPU usage or increasing memory usage on the server. It appears to be waiting for the client to send a request or something similar. 11/19/2009 : More information: The problem is definitely in the freeSSHd/server side of the equation. Connecting to bitbucket over ssh with the same keyset works fine. Still working on this.

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• point light illumination using Phong model

  - by Myx

  Hello: I wish to render a scene that contains one box and a point light source using the Phong illumination scheme. The following are the relevant code snippets for my calculation: R3Rgb Phong(R3Scene *scene, R3Ray *ray, R3Intersection *intersection) { R3Rgb radiance; if(intersection->hit == 0) { radiance = scene->background; return radiance; } ... // obtain ambient term ... // this is zero for my test // obtain emissive term ... // this is also zero for my test // for each light in the scene, obtain calculate the diffuse and specular terms R3Rgb intensity_diffuse(0,0,0,1); R3Rgb intensity_specular(0,0,0,1); for(unsigned int i = 0; i < scene->lights.size(); i++) { R3Light *light = scene->Light(i); R3Rgb light_color = LightIntensity(scene->Light(i), intersection->position); R3Vector light_vector = -LightDirection(scene->Light(i), intersection->position); // check if the light is "behind" the surface normal if(normal.Dot(light_vector)<=0) continue; // calculate diffuse reflection if(!Kd.IsBlack()) intensity_diffuse += Kd*normal.Dot(light_vector)*light_color; if(Ks.IsBlack()) continue; // calculate specular reflection ... // this I believe to be irrelevant for the particular test I'm doing } radiance = intensity_diffuse; return radiance; } R3Rgb LightIntensity(R3Light *light, R3Point position) { R3Rgb light_intensity; double distance; double denominator; if(light->type != R3_DIRECTIONAL_LIGHT) { distance = (position-light->position).Length(); denominator = light->constant_attenuation + (light->linear_attenuation*distance) + (light->quadratic_attenuation*distance*distance); } switch(light->type) { ... case R3_POINT_LIGHT: light_intensity = light->color/denominator; break; ... } return light_intensity; } R3Vector LightDirection(R3Light *light, R3Point position) { R3Vector light_direction; switch(light->type) { ... case R3_POINT_LIGHT: light_direction = position - light->position; break; ... } light_direction.Normalize(); return light_direction; } I believe that the error must be somewhere in either LightDirection(...) or LightIntensity(...) functions because when I run my code using a directional light source, I obtain the desired rendered image (thus this leads me to believe that the Phong illumination equation is correct). Also, in Phong(...), when I computed the intensity_diffuse and while debugging, I divided light_color by 10, I was obtaining a resulting image that looked more like what I need. Am I calculating the light_color correctly? Thanks.

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• <plugin> not a function

  - by bah

  Hi, I've been trying to solve this mystery almost 2 hours, this is giving me a headache. I tried 2 plug-ins already and I'm always getting "* is not a function". My code is exactly like examples so I don't know why it's not working. <!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8" /> <title>asd</title> <script type="text/javascript" src="jquery.js"></script> <script type='text/javascript' src='serial/jquery.scrollTo'></script> <script type='text/javascript' src='serial/jquery.serialScroll'></script> <script type="text/javascript"> $(document).ready(function(){ $('#slider').serialScroll({ items:'li', offset:-230, //when scrolling to photo, stop 230 before reaching it (from the left) start:1, //as we are centering it, start at the 2nd duration:1200, force:true, stop:true, lock:false, cycle:false, //don't pull back once you reach the end easing:'easeOutQuart', //use this easing equation for a funny effect jump: true //click on the images to scroll to them }); }); </script> </head> <body> <div id="slider"> <ul> <li><img width="500" height="500" src="dummy/dummy.jpg" alt="Css Template Preview" /></li> <li><img width="500" height="500" src="dummy/dummy1.jpg" alt="Css Template Preview" /></li> <li><img width="500" height="500" src="dummy/dummy2.jpg" alt="Css Template Preview" /></li> <li><img width="500" height="500" src="dummy/dummy3.jpg" alt="Css Template Preview" /></li> </ul> </div> </body> </html> I must be missing something essential there because I see nothing what's wrong. I'm using jQuery 1.4.2. and there are plug-ins I've tried - Easy Slider, jQuery serial scroll

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• average velocity, as3

  - by VideoDnd

  Hello, I need something accurate I can plug equations in to if you can help. How would you apply the equation bellow? Thanks guys. AVERAGE VELOCITY AND DISPLACEMENT average velocity V=X/T displacement x=v*T more info example I have 30 seconds and a field that is 170 yards. What average velocity would I need my horse to travel at to reach the end of the field in 30 seconds. I moved the decimal places around and got this. Here's what I tried 'the return value is close, but not close enough' FLA here var TIMER:int = 10; var T:int = 0; var V:int = 5.6; var X:int = 0; var Xf:int = 17000/10*2; var timer:Timer = new Timer(TIMER,Xf); timer.addEventListener(TimerEvent.TIMER, incrementCounter); timer.start(); function formatCount(i:int):String { var fraction:int = Math.abs(i % 100); var whole:int = Math.abs(i / 100); return ("0000000" + whole).substr(-7, 7) + "." + (fraction < 10 ? "0" + fraction : fraction); } function incrementCounter(event:TimerEvent) { T++; X = Math.abs(V*T); text.text = formatCount(X); } tests TARGET 5.6yards * 30seconds = 168yards INTEGERS 135.00 in 30 seconds MATH.ROUND 135.00 in 30 seconds NUMBERS 140.00 in 30 seconds control timer 'I tested with this and the clock on my desk' var timetest:Timer = new Timer(1000,30); var Dplus:int = 17000; timetest.addEventListener(TimerEvent.TIMER, cow); timetest.start(); function cow(evt:TimerEvent):void { tx.text = String("30 SECONDS: " + timetest.currentCount); if(timetest.currentCount> Dplus){ timetest.stop(); } } //far as I got...couldn't get delta to work... T = (V*timer.currentCount); X += Math.round(T);

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• C# Extend array type to overload operators

  - by Episodex

  I'd like to create my own class extending array of ints. Is that possible? What I need is array of ints that can be added by "+" operator to another array (each element added to each), and compared by "==", so it could (hopefully) be used as a key in dictionary. The thing is I don't want to implement whole IList interface to my new class, but only add those two operators to existing array class. I'm trying to do something like this: class MyArray : Array<int> But it's not working that way obviously ;). Sorry if I'm unclear but I'm searching solution for hours now... UPDATE: I tried something like this: class Zmienne : IEquatable<Zmienne> { public int[] x; public Zmienne(int ilosc) { x = new int[ilosc]; } public override bool Equals(object obj) { if (obj == null || GetType() != obj.GetType()) { return false; } return base.Equals((Zmienne)obj); } public bool Equals(Zmienne drugie) { if (x.Length != drugie.x.Length) return false; else { for (int i = 0; i < x.Length; i++) { if (x[i] != drugie.x[i]) return false; } } return true; } public override int GetHashCode() { int hash = x[0].GetHashCode(); for (int i = 1; i < x.Length; i++) hash = hash ^ x[i].GetHashCode(); return hash; } } Then use it like this: Zmienne tab1 = new Zmienne(2); Zmienne tab2 = new Zmienne(2); tab1.x[0] = 1; tab1.x[1] = 1; tab2.x[0] = 1; tab2.x[1] = 1; if (tab1 == tab2) Console.WriteLine("Works!"); And no effect. I'm not good with interfaces and overriding methods unfortunately :(. As for reason I'm trying to do it. I have some equations like: x1 + x2 = 0.45 x1 + x4 = 0.2 x2 + x4 = 0.11 There are a lot more of them, and I need to for example add first equation to second and search all others to find out if there is any that matches the combination of x'es resulting in that adding. Maybe I'm going in totally wrong direction?

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• Algorithm for finding symmetries of a tree

  - by Paxinum

  I have n sectors, enumerated 0 to n-1 counterclockwise. The boundaries between these sectors are infinite branches (n of them). The sectors live in the complex plane, and for n even, sector 0 and n/2 are bisected by the real axis, and the sectors are evenly spaced. These branches meet at certain points, called junctions. Each junction is adjacent to a subset of the sectors (at least 3 of them). Specifying the junctions, (in pre-fix order, lets say, starting from junction adjacent to sector 0 and 1), and the distance between the junctions, uniquely describes the tree. Now, given such a representation, how can I see if it is symmetric wrt the real axis? For example, n=6, the tree (0,1,5)(1,2,4,5)(2,3,4) have three junctions on the real line, so it is symmetric wrt the real axis. If the distances between (015) and (1245) is equal to distance from (1245) to (234), this is also symmetric wrt the imaginary axis. The tree (0,1,5)(1,2,5)(2,4,5)(2,3,4) have 4 junctions, and this is never symmetric wrt either imaginary or real axis, but it has 180 degrees rotation symmetry if the distance between the first two and the last two junctions in the representation are equal. Edit: This is actually for my research. I have posted the question at mathoverflow as well, but my days in competition programming tells me that this is more like an IOI task. Code in mathematica would be excellent, but java, python, or any other language readable by a human suffices. Here are some examples (pretend the double edges are single and we have a tree) http://www2.math.su.se/~per/files.php?file=contr_ex_1.pdf http://www2.math.su.se/~per/files.php?file=contr_ex_2.pdf http://www2.math.su.se/~per/files.php?file=contr_ex_5.pdf Example 1 is described as (0,1,4)(1,2,4)(2,3,4)(0,4,5) with distances (2,1,3). Example 2 is described as (0,1,4)(1,2,4)(2,3,4)(0,4,5) with distances (2,1,1). Example 5 is described as (0,1,4,5)(1,2,3,4) with distances (2). So, given the description/representation, I want to find some algorithm to decide if it is symmetric wrt real, imaginary, and rotation 180 degrees. The last example have 180 degree symmetry. (These symmetries corresponds to special kinds of potential in the Schroedinger equation, which has nice properties in quantum mechanics.)

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• If Then Statement Condition Being Ignored With Optimisations On

  - by Matma

  I think im going mad but can some show me what im missing, it must be some stupidly simple i just cant see the wood for the trees. BOTH side of this if then else statement are being executed? Ive tried commenting out the true side and moving the condition to a seperate variable with the same result. However if i explicitly set the condition to 1=0 or 1=1 then the if then statement is operating as i would expect. i.e. only executing one side of the equation... The only time ive seen this sort of thing is when the compiler has crashed and is no longer compiling (without visible indication that its not) but ive restarted studio with the same results, ive cleaned the solution, built and rebuilt with no change? please show me the stupid mistake im making using vs2005 if it matters. Dim dset As DataSet = New DataSet If (CboCustomers.SelectedValue IsNot Nothing) AndAlso (CboCustomers.SelectedValue <> "") Then Dim Sql As String = "Select sal.SalesOrderNo As SalesOrder,cus.CustomerName,has.SerialNo, convert(varchar,sal.Dateofpurchase,103) as Date from [dbo].[Customer_Table] as cus " & _ " inner join [dbo].[Hasp_table] as has on has.CustomerID=cus.CustomerTag " & _ " inner join [dbo].[salesorder_table] as sal On sal.Hasp_ID =has.Hasp_ID Where cus.CustomerTag = '" & CboCustomers.SelectedValue.ToString & "'" Dim dap As SqlDataAdapter = New SqlDataAdapter(Sql, FormConnection) dap.Fill(dset, "dbo.Customer_Table") DGCustomer.DataSource = dset.Tables("dbo.Customer_Table") Else Dim erm As String = "wtf" End If EDIT: i have found that this is something to do with the release config settings im using, i guesing its the optimisations bit. does anyone know of any utils/addons for vs that show if a line has been optimised out. delphi, my former language showed blue dots in the left margin to show that it was a compiled line, no dot meaning it wasnt compiled in, is there anything like that for vs? alternatively can someone explain how optimisations would affect this simple if statement causeing it to run both sides? EDIT2: using this thread as possible causes/solutions : http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled. It does the same with release = optimisations on, x86, x64 and AnyCPU Goes away with optimisations off. Im using V2005 on a x64 win7 machine, if that matters. Thanks

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• HTML5 <audio> Safari live broadcast vs not

  - by Peter Parente

  I'm attempting to embed an HTML5 audio element pointing to MP3 or OGG data served by a PHP file . When I view the page in Safari, the controls appear, but the UI says "Live Broadcast." When I click play, the audio starts as expected. Once it ends, however, I can't start it playing again by clicking play. Even using the JS API on the audio element and setting currentTime to 0 fails with an index error exception. I suspected the headers from the PHP script were the problem, particularly missing a content length. But that's not the case. The response headers include a proper Content- Length to indicate the audio has finite size. Furthermore, everything works as expected in Firefox 3.5+. I can click play on the audio element multiple times to hear the sound replay. If I remove the PHP script from the equation and serve up a static copy of the MP3 file, everything works fine in Safari. Does this mean Safari is treating audio src URLs with query parameters differently than URLs that don't have them? Anyone have any luck getting this to work? My simple example page is: <!DOCTYPE html> <html> <head></head> <body> <audio controls autobuffer> <source src="say.php?text=this%20is%20a%20test&format=.ogg" /> <source src="say.php?text=this%20is%20a%20test&format=.mp3" /> </audio> </body> </html> HTTP Headers from PHP script: HTTP/1.x 200 OK Date: Sun, 03 Jan 2010 15:39:34 GMT Server: Apache X-Powered-By: PHP/5.2.10 Content-Length: 8993 Keep-Alive: timeout=2, max=98 Connection: Keep-Alive Content-Type: audio/mpeg HTTP Headers from direct file access: HTTP/1.x 200 OK Date: Sun, 03 Jan 2010 20:06:59 GMT Server: Apache Last-Modified: Sun, 03 Jan 2010 03:20:02 GMT Etag: "a404b-c3f-47c3a14937c80" Accept-Ranges: bytes Content-Length: 8993 Keep-Alive: timeout=2, max=100 Connection: Keep-Alive Content-Type: audio/mpeg I tried hard-coding the Accept-Ranges header into the script too, but no luck.

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