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• Impressions from VMworld - Clearing up Misconceptions

  - by Monica Kumar

  Gorgeous sunny weather…none of the usual summer fog…the Oracle Virtualization team has been busy at VMworld in San Francisco this week. From the time exhibits opened on Sunday, our booth staff was fully engaged with visitors. It was great to meet with customers and prospects, and there were many…most with promises to meet again in October at Oracle OpenWorld 2012. Interests and questions ran the gamut - from implementation details to consolidating applications to how does Oracle VM enable rapid application deployment to Oracle support and licensing. All good stuff! Some inquiries are poignant and really help us get at the customer pain points. Some are just based on misconceptions. We’d like to address a couple of common misconceptions that we heard: 1) Rapid deployment of enterprise applications is great but I don’t do this all the time. So why bother? While production applications don’t get updated or upgraded as often, development and QA staging environments are much more dynamic. Also, in today’s Cloud based computing environments, end users expect an entire solution, along with the virtual machine, to be provisioned instantly, on-demand, as and when they need to scale. Whether it’s adding a new feature to meet customer demands or updating applications to meet business/service compliance, these environments undergo change frequently. The ability to rapidly stand up an entire application stack with all the components such as database tier, mid-tier, OS, and applications tightly integrated, can offer significant value. Hand patching, installation of the OS, application and configurations to ensure the entire stack works well together can take days and weeks. Oracle VM Templates provide a much faster path to standing up a development, QA or production stack in a matter of hours or minutes. I see lots of eyes light up as we get to this point of the conversation. 2) Oracle Software licensing on VMware vSphere In the world of multi-vendor IT stacks, understanding license boundaries and terms and conditions for each product in the stack can be challenging.  Oracle’s licensing, though, is straightforward.  Oracle software is licensed per physical processor in the server or cluster where the Oracle software is installed and/or running.  The use of third party virtualization technologies such as VMware is not allowed as a means to change the way Oracle software is licensed.  Exceptions are spelled out in the licensing document labeled “Hard Partitioning". Here are some fun pictures! Visitors to our booth told us they loved the Oracle SUV courtesy shuttles that are helping attendees get to/from hotels. Also spotted were several taxicabs sporting an Oracle banner! Stay tuned for more highlights across desktop and server virtualization as we wrap up our participation at VMworld.

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• Memories about Tadeusz Golonka

  - by Damian

  Today at 10:55 AM, Tadeusz Golonka - my greatest  Mentor and Teacher  passed away. I had te opportunity to met Tadek in person several times last years. It was always a great experience to see how he shared his energy and passion. I was always impressed and had a lot of new ideas after such meeting or lecture. I can remember the meeting  in early 2009 and his briliant speech he did for us, the MVP community in Poland. We spent two days together and he talked to us all the time. He gave us examples how to share IT passion to other people and how to be better person for others. He was the greates Mentor I have ever met - I realized this during that meeting. My greates dream was and still is to be "like Tadek". Many Times I just went to events to see / hear him on stage ("in action"). I always wanted to have his energy, empathy and passion. Now I have to live without his good words and advices....Let me put here the words that Adam Cogan wrote on Tadek's profile on Facebook. I just can't write about that fatal accident. "The circumstances of Tadeusz Golonka death are too tragic. Tad stood up to offer his seat to an elderly lady, he lost his balance and then he slipped and hit the tram door hard. He then fell out of the tram and hit the metal barriers that separate the tram rails from the street. It was a severe accident...... So horrible.  At first it was a miracle is that he survived... he fought for several days.  My thoughts are with his lovely family. The family have asked for blood donations as a symbolic gift. Tad received a lot of blood.  Thank you Tad, you were a wonderful person. I will remember you as a kind man, a gentleman. "RIP Tadeusz- You will never ever be forgotten. You are with us all the time  

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• how do I set quad buffering with jogl 2.0

  - by tony danza

  I'm trying to create a 3d renderer for stereo vision with quad buffering with Processing/Java. The hardware I'm using is ready for this so that's not the problem. I had a stereo.jar library in jogl 1.0 working for Processing 1.5, but now I have to use Processing 2.0 and jogl 2.0 therefore I have to adapt the library. Some things are changed in the source code of Jogl and Processing and I'm having a hard time trying to figure out how to tell Processing I want to use quad buffering. Here's the previous code: public class Theatre extends PGraphicsOpenGL{ protected void allocate() { if (context == null) { // If OpenGL 2X or 4X smoothing is enabled, setup caps object for them GLCapabilities capabilities = new GLCapabilities(); // Starting in release 0158, OpenGL smoothing is always enabled if (!hints[DISABLE_OPENGL_2X_SMOOTH]) { capabilities.setSampleBuffers(true); capabilities.setNumSamples(2); } else if (hints[ENABLE_OPENGL_4X_SMOOTH]) { capabilities.setSampleBuffers(true); capabilities.setNumSamples(4); } capabilities.setStereo(true); // get a rendering surface and a context for this canvas GLDrawableFactory factory = GLDrawableFactory.getFactory(); drawable = factory.getGLDrawable(parent, capabilities, null); context = drawable.createContext(null); // need to get proper opengl context since will be needed below gl = context.getGL(); // Flag defaults to be reset on the next trip into beginDraw(). settingsInited = false; } else { // The following three lines are a fix for Bug #1176 // http://dev.processing.org/bugs/show_bug.cgi?id=1176 context.destroy(); context = drawable.createContext(null); gl = context.getGL(); reapplySettings(); } } } This was the renderer of the old library. In order to use it, I needed to do size(100, 100, "stereo.Theatre"). Now I'm trying to do the stereo directly in my Processing sketch. Here's what I'm trying: PGraphicsOpenGL pg = ((PGraphicsOpenGL)g); pgl = pg.beginPGL(); gl = pgl.gl; glu = pg.pgl.glu; gl2 = pgl.gl.getGL2(); GLProfile profile = GLProfile.get(GLProfile.GL2); GLCapabilities capabilities = new GLCapabilities(profile); capabilities.setSampleBuffers(true); capabilities.setNumSamples(4); capabilities.setStereo(true); GLDrawableFactory factory = GLDrawableFactory.getFactory(profile); If I go on, I should do something like this: drawable = factory.getGLDrawable(parent, capabilities, null); but drawable isn't a field anymore and I can't find a way to do it. How do I set quad buffering? If I try this: gl2.glDrawBuffer(GL.GL_BACK_RIGHT); it obviously doesn't work :/ Thanks.

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• Is it okay to have people with multiple roles in a Scrum team?

  - by Wayne M

  I'm evaluating some Agile-style methodologies for possible introduction to my team. With Scrum, is it allowable to have the same person perform multiple roles? We have a small team of four developers and a web designer; we don't really have a lead (I fulfill this role), QA testers or business analysts, and all of our development tasks come from the CIO. Automated testing is seen as a total waste of time, and everything focuses on speed and not quality. What will happen is the CIO will come up with a development task (whether a feature or a bug) and give it to a developer (not to the whole team, to an individual, often in private or out of the blue) who is then expected to get it completed. The CIO doesn't gather requirements beyond the initial idea (and this has bitten us before as we'll implement something only to find out that none of the end users can use the feature, because they weren't consulted or even informed about it before we developed it, and in a panic we'll be told to revert the change) but requires say in/approval of everything that we do. First things first, is a Scrum style something to consider to introduce some standards and practices? From reading, Scrum seems to rely on a bit more trust and communication and focuses more on project management than on development, which is something we are completely devoid of as we don't have any semblance of project management at present. Second, if it can work is it unreasonable for someone, let's say myself, to act as both ScrumMaster and a developer? Or for a developer to also be the Product Owner (although chances are this will be the CIO, who isn't a developer)? I realize the Scrum Master and the Product Owner should be different people but at the same time I don't think we have anyone who has the qualities of a Product Owner (chances are it would turn into a "I need all these stories, I don't care how but get it done" type of deal and/or any freeze would be unfrozen on a whim). It seems to me that I might need to pick and choose pieces of Scrum/XP/Lean to compensate for how things are done currently, as it's highly unlikely that the mentality can be changed; for instance Pair Programming would never fly (seen as a waste, you get half the tasks done if you need two people for everything), TDD would be a hard sell, but short cycles would be welcomed.

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• Planning Bulletin for JRE 7: What EBS Customers Can Do Today

  - by Steven Chan (Oracle Development)

  An initiative to certify Oracle E-Business Suite with JRE 7 desktop clients is underway.  We have tested EBS 11.5.10.2, 12.0, and 12.1 with JRE 7. We have fixes for nearly all of the compatibility issues now, and are working hard to produce the remaining fixes quickly. A. When will JRE 7 be certified with Oracle E-Business Suite? We will announce the certification of the E-Business Suite with JRE 7 once all fixes are available, verified, and documented.  Certification announcements will be distributed through My Oracle Support, My Oracle Support Community Forums, Oracle Technology Network Forums, newsletters, and user group news outlets. Oracle's Revenue Recognition rules prohibit us from discussing certification and release dates.  In addition to the standard communication channels listed above, customers are encouraged to monitor or subscribe to this blog.    B. What can customers do to prepare for the JRE 7 certification? Customers should ensure that they are on the latest available JRE 6 update. Of the compatibility issues identified so far with JRE 7, the most critical is an issue that prevents E-Business Suite Forms-based products from launching on Windows desktops that are running JRE 7.  Customers can prevent this issue today by ensuring that they have applied the latest certified patches documented for JRE 6 configurations to their EBS application tier servers: Apply Forms patch 14615390 to EBS 11i environments (Note 125767.1) Apply Forms patch 14614795 to EBS 12.0 and 12.1 environments (Note 437878.1) These patches are compatible with JRE 6 and 7, production ready, and fully-tested with the E-Business Suite.  These patches may be applied immediately to all E-Business Suite environments. All other Forms prerequisites documented in the Notes above should also be applied now. C. What else will be required by the final certified configuration? Oracle expects that all other compatibility issues will be resolved by installing a specific JRE 7 release, at minimum.  That specific release has not been finalized yet, and this is subject to change. D.  Where will the official patch requirements be documented? All patches required for ensuring full compatibility of the E-Business Suite with JRE 7 will be documented in updates to these published Notes: For EBS 11i: Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 11i (Note 290807.1) Upgrading Developer 6i with Oracle E-Business Suite 11i (Note 125767.1) For EBS 12 Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 12 (Note 393931.1) Upgrading OracleAS 10g Forms and Reports in Oracle E-Business Suite Release 12 (Note 437878.1) Disclaimer The preceding is intended to outline our general product direction.  It is intended for information purposes only, and may not be incorporated into any contract.   It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decision.  The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.

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• 6 Ways to Modernize Your Customer Experience

  - by Mike Stiles

  If customers have changed, if the way they research and shop have changed, if their expectations have changed, if their ability to act on dissatisfaction has changed, but your customer experience has NOT changed, what was once “good enough” may now be crippling. Well, the customer has changed, and why wouldn’t they? You’ve probably changed too in your role as consumer. There’s more info available, it’s easier to get, there’s more choice, you’re more mobile, you’re more connected, it’s easier to buy, and yes, it’s easier to switch brands if experiences don’t meet your now higher expectations. Thanks to technological advances, we as marketers can increasingly work borderline miracles. But if we’re still not adamantly adopting customer centricity, and if we aren’t making the customer experience paramount amongst business goals, the tech is wasted. A far more modern customer experience is called for. Here are 6 ways to get there: 1. Modern Marketing: Marketing data is aggregated and targeted to the right customers, who are getting personal, relevant communications. In return, you’re getting insight that finally properly attributes revenue to your marketing efforts. 2. Modern Selling: Demand is being driven across all channels with modern selling tools. Productivity is up thanks to coordinated communication and selling, and performance is ever optimized using powerful analytics. 3. Modern CPQ: You’re cross-selling and upselling more effectively since reps and channel partners have been empowered with the ability to quickly, automatically generate 100% accurate, customer-friendly quotes complete with price controls and automated approvals. 4. Modern Commerce: You’re leveraging data and delivering personalized, targeted digital experiences to everyone. You’re attracting more visitors, and you’re able to scale and keep up with the market and control the experience. 5. Modern Service: You’re better serving your customers by making it easier for them to engage with your brand, plus you’re lowering your costs by increasing agent and tech support efficiencies. 6. Modern Social: You’re getting faster, deeper, more accurate insights from social and turning content around faster, which then goes out to the right people at the right time in the right place. You’ve also gotten proactive in your service, and customers love that. For far too many brands, the buying journey of Need, Research, Select, Buy, Use, Recommend across the multiple connect points of Social, Mobile, Store, Call Center, Site, Ecommerce is a disconnected mess. Oracle’s approach to CX is to connect every interaction your customer has with your brand, avoiding the revenue losses lousy customer experiences bring. How important is the experience to customers? 94% are willing to pay more of their hard-earned money to have better ones, while a meager 1% say they get the good, consistent experiences they expect. Brands, your words aren’t as loud anymore, so your actions as they relate to customer experience are going to have to do the talking. @mikestiles @oraclesocialPhoto: Julien Tromeur, freeimages.com

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• How to solve conflicts with another programmer..

  - by Tio

  Hi all.. I've read this question, but I think it doesn't really applies in my case.. I started to work at new company about 2 months ago with the position of senior web developer, there was already one programmer there, my position is above his, but I'm not his boss.. I don't tell him what to do.. Since the day I started to work at the company, I managed to implement a kind of a test server which he refuses to use, implemented a project management tool which he refuses to use also, and I'm in the process of implementing version control using mercurial ( damn Mercurial that's giving me so much headaches ), which he is going to use.. He is a nice guy, but just the other day we had a big discussion about "best practices", and "coding standards".. for me it's absolutely necessary to have this two things, at the place I'm currently working... otherwise it's not going to work.. This discussion, basically revolved about using short tags and the echo shortcut, and how we shouldn't use it anymore ( because I sometimes use short tags ).. this went for about 15 minutes, until I finally dropped the subject because I had work to do.. and of course he didn't budge even a millimeter, he's continuing to use short tags, and the echo shortcut and he not even cares about what I think.. When I mentioned that we are a team, he told me: "We are not a team, you work on your projects and I work on mine".. Let's just say, that the switch in my brain flipped, I raised my voice, and I told him that he was going nuts.. this was the most improper way to deal it with, I know, but there are certain things that can't be said to me.. The question here, is how do I deal with this? I want, to implement more changes on our work workflow, and I know that it's going to be a pain, with him always complaining and saying things like this.. Our boss is going to intervene in a few days, I talked to him today, the other programmer send him an email the day we had the discussion complaining.. Just to clarify, when I talk about implementing changes, I just don't appear at work, the next day with a sheet of paper, and say: "This is our we are doing things from now on! And there is no discussion.." For example, when I was trying to implement the project management tool, I took the time to talk to everybody that was going to be involved in it, to see what they think about it.. everyone was positive except him, he responded that it was just a mean to control us even more.. Does anyone has any idea on how to deal with this? PS: Truth to be told, I didn't start the best way with him, in the 4º day of work at the company, I found a really bad piece of code on our custom CMS, one of those things that I only expect to find in code produced by a programmer that has only 1 month of training in programming, and I talked to my boss about it... he showed up at the time I saw that piece of code, he saw my face and asked about it, so I told him.. I know the worst thing that can be said to a programmer is saying that their code is awful, but I've already learned that my code isn't the best of the world, so I take criticism in a completely different way now.. maybe he doesn't..

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• Dont Throw Duplicate Exceptions

  In your code, youll sometimes have write code that validates input using a variety of checks.  Assuming you havent embraced AOP and done everything with attributes, its likely that your defensive coding is going to look something like this: public void Foo(SomeClass someArgument) { if(someArgument == null) { throw new InvalidArgumentException("someArgument"); } if(!someArgument.IsValid()) { throw new InvalidArgumentException("someArgument"); }   // Do Real Work } Do you see a problem here?  Heres the deal Exceptions should be meaningful.  They have value at a number of levels: In the code, throwing an exception lets the develop know that there is an unsupported condition here In calling code, different types of exceptions may be handled differently At runtime, logging of exceptions provides a valuable diagnostic tool Its this last reason I want to focus on.  If you find yourself literally throwing the exact exception in more than one location within a given method, stop.  The stack trace for such an exception is likely going to be identical regardless of which path of execution led to the exception being thrown.  When that happens, you or whomever is debugging the problem will have to guess which exception was thrown.  Guessing is a great way to introduce additional problems and/or greatly increase the amount of time require to properly diagnose and correct any bugs related to this behavior. Dont Guess Be Specific When throwing an exception from multiple code paths within the code, be specific.  Virtually ever exception allows a custom message use it and ensure each case is unique.  If the exception might be handled differently by the caller, than consider implementing a new custom exception type.  Also, dont automatically think that you can improve the code by collapsing the if-then logic into a single call with short-circuiting (e.g. if(x == null || !x.IsValid()) ) that will guarantee that you cant easily throw different information into the message as easily as constructing the exception separately in each case. The code above might be refactored like so:   public void Foo(SomeClass someArgument) { if(someArgument == null) { throw new ArgumentNullException("someArgument"); } if(!someArgument.IsValid()) { throw new InvalidArgumentException("someArgument"); }   // Do Real Work } In this case its taking advantage of the fact that there is already an ArgumentNullException in the framework, but if you didnt have an IsValid() method and were doing validation on your own, it might look like this: public void Foo(SomeClass someArgument) { if(someArgument.Quantity < 0) { throw new InvalidArgumentException("someArgument", "Quantity cannot be less than 0. Quantity: " + someArgument.Quantity); } if(someArgument.Quantity > 100) { throw new InvalidArgumentException("someArgument", "SomeArgument.Quantity cannot exceed 100. Quantity: " + someArgument.Quantity); }   // Do Real Work }   Note that in this last example, Im throwing the same exception type in each case, but with different Message values.  Im also making sure to include the value that resulted in the exception, as this can be extremely useful for debugging.  (How many times have you wished NullReferenceException would tell you the name of the variable it was trying to reference?) Dont add work to those who will follow after you to maintain your application (especially since its likely to be you).  Be specific with your exception messages follow DRY when throwing exceptions within a given method by throwing unique exceptions for each interesting case of invalid state. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• iwlwifi on lenovo z570 disabled by hardware switch

  - by Kevin Gallagher

  It was working fine with windows 7. The hardware switch is not disabled. I've toggled it back and forth dozens of times. The wifi light never turns on and it always lists as hardware disabled. I have the latest updates installed. I've been searching for solutions, but none of them seem to work for me. I've tried removing acer-wmi. I've tried setting 11n_disable=1. I've tried resetting the bios. I've tried using rfkill to unblock (only removes soft block). I've rebooted dozens of times. The wifi light turns off as soon as grub loads. Edit: I have a usb edimax wireless nic. It shows hardware disabled as well (although rfkill lists as unblocked). If I unload iwlwifi the usb nic works fine. uname -a `Linux xxx-Ideapad-Z570 3.2.0-55-generic #85-Ubuntu SMP Wed Oct 2 12:29:27 UTC 2013 x86_64 x86_64 x86_64 GNU/Linu`x rfkill list 19: phy18: Wireless LAN Soft blocked: no Hard blocked: yes dmesg [43463.022996] Intel(R) Wireless WiFi Link AGN driver for Linux, in-tree: [43463.023002] Copyright(c) 2003-2011 Intel Corporation [43463.023107] iwlwifi 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [43463.023190] iwlwifi 0000:03:00.0: setting latency timer to 64 [43463.023253] iwlwifi 0000:03:00.0: pci_resource_len = 0x00002000 [43463.023257] iwlwifi 0000:03:00.0: pci_resource_base = ffffc900057c8000 [43463.023261] iwlwifi 0000:03:00.0: HW Revision ID = 0x0 [43463.023797] iwlwifi 0000:03:00.0: irq 43 for MSI/MSI-X [43463.024013] iwlwifi 0000:03:00.0: Detected Intel(R) Centrino(R) Wireless-N 1000 BGN, REV=0x6C [43463.024250] iwlwifi 0000:03:00.0: L1 Enabled; Disabling L0S [43463.045496] iwlwifi 0000:03:00.0: device EEPROM VER=0x15d, CALIB=0x6 [43463.045501] iwlwifi 0000:03:00.0: Device SKU: 0X50 [43463.045504] iwlwifi 0000:03:00.0: Valid Tx ant: 0X1, Valid Rx ant: 0X3 [43463.045542] iwlwifi 0000:03:00.0: Tunable channels: 13 802.11bg, 0 802.11a channels [43463.045744] iwlwifi 0000:03:00.0: RF_KILL bit toggled to disable radio. [43463.047652] iwlwifi 0000:03:00.0: loaded firmware version 39.31.5.1 build 35138 [43463.047823] Registered led device: phy18-led [43463.047895] cfg80211: Ignoring regulatory request Set by core since the driver uses its own custom regulatory domain [43463.048037] ieee80211 phy18: Selected rate control algorithm 'iwl-agn-rs' [43463.055533] ADDRCONF(NETDEV_UP): wlan0: link is not ready nm-tool State: connected (global) - Device: wlan0 ---------------------------------------------------------------- Type: 802.11 WiFi Driver: iwlwifi State: unavailable Default: no HW Address: 74:E5:0B:4A:9F:C2 Capabilities: Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points lshw -C network *-network DISABLED description: Wireless interface product: Centrino Wireless-N 1000 [Condor Peak] vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 00 serial: 74:e5:0b:4a:9f:c2 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-55-generic firmware=39.31.5.1 build 35138 latency=0 link=no multicast=yes wireless=IEEE 802.11bg resources: irq:43 memory:f1500000-f1501fff lspci 03:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000 [Condor Peak]

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• Why is multithreading often preferred for improving performance?

  - by user1849534

  I have a question, it's about why programmers seems to love concurrency and multi-threaded programs in general. I'm considering 2 main approaches here: an async approach basically based on signals, or just an async approach as called by many papers and languages like the new C# 5.0 for example, and a "companion thread" that manages the policy of your pipeline a concurrent approach or multi-threading approach I will just say that I'm thinking about the hardware here and the worst case scenario, and I have tested this 2 paradigms myself, the async paradigm is a winner at the point that I don't get why people 90% of the time talk about multi-threading when they want to speed up things or make a good use of their resources. I have tested multi-threaded programs and async program on an old machine with an Intel quad-core that doesn't offer a memory controller inside the CPU, the memory is managed entirely by the motherboard, well in this case performances are horrible with a multi-threaded application, even a relatively low number of threads like 3-4-5 can be a problem, the application is unresponsive and is just slow and unpleasant. A good async approach is, on the other hand, probably not faster but it's not worst either, my application just waits for the result and doesn't hangs, it's responsive and there is a much better scaling going on. I have also discovered that a context change in the threading world it's not that cheap in real world scenario, it's in fact quite expensive especially when you have more than 2 threads that need to cycle and swap among each other to be computed. On modern CPUs the situation it's not really that different, the memory controller it's integrated but my point is that an x86 CPUs is basically a serial machine and the memory controller works the same way as with the old machine with an external memory controller on the motherboard. The context switch is still a relevant cost in my application and the fact that the memory controller it's integrated or that the newer CPU have more than 2 core it's not bargain for me. For what i have experienced the concurrent approach is good in theory but not that good in practice, with the memory model imposed by the hardware, it's hard to make a good use of this paradigm, also it introduces a lot of issues ranging from the use of my data structures to the join of multiple threads. Also both paradigms do not offer any security abut when the task or the job will be done in a certain point in time, making them really similar from a functional point of view. According to the X86 memory model, why the majority of people suggest to use concurrency with C++ and not just an async approach ? Also why not considering the worst case scenario of a computer where the context switch is probably more expensive than the computation itself ?

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• Disk drive for / not ready on boot after upgrade from 10.04 to 12.04

  - by Mathieu M-Gosselin

  After upgrading (using the Upgrade button from the update manager) from 10.04.4 to 12.04.1, I cannot boot anymore. Upon booting, I am greeted with the Ubuntu logo and the error "The disk drive for / is not ready yet or not present". I have the option to wait, to skip and to access a basic shell. Waiting overnight did nothing, skipping just gives me the same error for /tmp, /home, then for a UUID and finally it just goes to a black screen with a white "_" in the top left corner. My setup is a dual boot one with XP on a single hard drive, I use separate partitions for / and /home. Back in the day I installed 8.04 directly from the CD while leaving a partition for XP, which I installed after. This setup had never caused any such issues, even when upgrading from 8.04 to 10.04. I have done plenty of research regarding this issue, as many others seem to have had similar issues after doing the same upgrade as me. However, while for most what fixed the problem was running: apt-get -f install after remounting / in read-write, it didn't do it for me. I got dependency errors (see here), which I also investigated. I found https://bugs.launchpad.net/ubuntu/+source/python-defaults/+bug/990740 where most people say the solution that worked is (prior to running the above command) running: apt-get install -o APT::Immediate-Configure=false -f apt python-minimal but that also got me a lot of dependencies errors as output (see here), similar to #34 in the above thread. I also read that running: dpkg --configure -a could help, at first it wouldn't run because it had trouble parsing /var/lib/dpkg/status since there was an extra blank line in a package description (see https://bugs.launchpad.net/ubuntu/+source/dpkg/+bug/916799) but I removed it using vim (and then reran the command). It still gives me output that looks like an error, though. Here it is: http://paste.ubuntu.com/1338074/. I also tried re-running the above apt-get commands after that, to no avail. I'm running out of things to try in the hope of getting this fixed, your help would be very much appreciated! Thank you in advance.

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• Using HBase or Cassandra for a token server

  - by crippy

  I've been trying to figure out how to use HBase/Cassandra for a token system we're re-implementing. I can probably squeeze quite a lot more from MySQL, but it just seems it has come to clinging on to the wrong tool for the task just because we know it well. Eventually will hit a wall (like happened to us in other areas). Naturally I started looking into possible NoSQL solutions. The prominent ones (at least in terms of buzz) are HBase and Cassandra. The story is more or less like this: A user can send a gift other users. Each gift has a list of recipients or is public in which case limited by number or expiration date For each gift sent we generate some token that uniquely identifies that gift. For each gift we track the list of potential recipients and their current status relating to that gift (accepted, declinded etc). A user can request to see all his currently pending gifts A can request a list of users he has sent a gift to today (used to limit number of gifts sent) Required the ability to "dump" or "ignore" expired gifts (x day old gifts are considered expired) There are some other requirements but I believe the above covers the essentials. How would I go and model that using HBase or Cassandra? Well, the wall was performance. A few 10s of millions of records per day over 2 tables kept for 2 weeks (wish I could have kept it for more but there was no way). The response times kept getting slower and slower until eventually we had to start cutting down number of days we kept data. Caching helps here but it's not an ideal solution since a big part of the ops are updates. Also, as I hinted in my original post. We use MySQL extensively. We know exactly what it can and can't do both in naive implementations followed by native partitioning and finally by horizontally sharding our dataset on the application level to reside on multiple DB nodes. It can be done, but that's not really what I'm trying to get from this. I asked a very specific question about designing a solution using a NoSQL solution since it's very hard to find examples for designs out there. Brainlag, not trying to come off as rude. I actually appreciate it a lot that you are the only one who even bothered to respond. but I see it over and over again. People ask questions and others assume they have no idea what they're talking about and give an irrelevant answer. Ignore RDBMS please. The question is about nosql.

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• SQL: empty string vs NULL value

  - by Jacek Prucia

  I know this subject is a bit controversial and there are a lot of various articles/opinions floating around the internet. Unfortunatelly, most of them assume the person doesn't know what the difference between NULL and empty string is. So they tell stories about surprising results with joins/aggregates and generally do a bit more advanced SQL lessons. By doing this, they absolutely miss the whole point and are therefore useless for me. So hopefully this question and all answers will move subject a bit forward. Let's suppose I have a table with personal information (name, birth, etc) where one of the columns is an email address with varchar type. We assume that for some reason some people might not want to provide an email address. When inserting such data (without email) into the table, there are two available choices: set cell to NULL or set it to empty string (''). Let's assume that I'm aware of all the technical implications of choosing one solution over another and I can create correct SQL queries for either scenario. The problem is even when both values differ on the technical level, they are exactly the same on logical level. After looking at NULL and '' I came to a single conclusion: I don't know email address of the guy. Also no matter how hard i tried, I was not able to sent an e-mail using either NULL or empty string, so apparently most SMTP servers out there agree with my logic. So i tend to use NULL where i don't know the value and consider empty string a bad thing. After some intense discussions with colleagues i came with two questions: am I right in assuming that using empty string for an unknown value is causing a database to "lie" about the facts? To be more precise: using SQL's idea of what is value and what is not, I might come to conclusion: we have e-mail address, just by finding out it is not null. But then later on, when trying to send e-mail I'll come to contradictory conclusion: no, we don't have e-mail address, that @!#$ Database must have been lying! Is there any logical scenario in which an empty string '' could be such a good carrier of important information (besides value and no value), which would be troublesome/inefficient to store by any other way (like additional column). I've seen many posts claiming that sometimes it's good to use empty string along with real values and NULLs, but so far haven't seen a scenario that would be logical (in terms of SQL/DB design). P.S. Some people will be tempted to answer, that it is just a matter of personal taste. I don't agree. To me it is a design decision with important consequences. So i'd like to see answers where opion about this is backed by some logical and/or technical reasons.

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• Learn Many Languages

  - by Jeff Foster

  My previous blog, Deliberate Practice, discussed the need for developers to “sharpen their pencil” continually, by setting aside time to learn how to tackle problems in different ways. However, the Sapir-Whorf hypothesis, a contested and somewhat-controversial concept from language theory, seems to hold reasonably true when applied to programming languages. It states that: “The structure of a language affects the ways in which its speakers conceptualize their world.” If you’re constrained by a single programming language, the one that dominates your day job, then you only have the tools of that language at your disposal to think about and solve a problem. For example, if you’ve only ever worked with Java, you would never think of passing a function to a method. A good developer needs to learn many languages. You may never deploy them in production, you may never ship code with them, but by learning a new language, you’ll have new ideas that will transfer to your current “day-job” language. With the abundant choices in programming languages, how does one choose which to learn? Alan Perlis sums it up best. “A language that doesn‘t affect the way you think about programming is not worth knowing“ With that in mind, here’s a selection of languages that I think are worth learning and that have certainly changed the way I think about tackling programming problems. Clojure Clojure is a Lisp-based language running on the Java Virtual Machine. The unique property of Lisp is homoiconicity, which means that a Lisp program is a Lisp data structure, and vice-versa. Since we can treat Lisp programs as Lisp data structures, we can write our code generation in the same style as our code. This gives Lisp a uniquely powerful macro system, and makes it ideal for implementing domain specific languages. Clojure also makes software transactional memory a first-class citizen, giving us a new approach to concurrency and dealing with the problems of shared state. Haskell Haskell is a strongly typed, functional programming language. Haskell’s type system is far richer than C# or Java, and allows us to push more of our application logic to compile-time safety. If it compiles, it usually works! Haskell is also a lazy language – we can work with infinite data structures. For example, in a board game we can generate the complete game tree, even if there are billions of possibilities, because the values are computed only as they are needed. Erlang Erlang is a functional language with a strong emphasis on reliability. Erlang’s approach to concurrency uses message passing instead of shared variables, with strong support from both the language itself and the virtual machine. Processes are extremely lightweight, and garbage collection doesn’t require all processes to be paused at the same time, making it feasible for a single program to use millions of processes at once, all without the mental overhead of managing shared state. The Benefits of Multilingualism By studying new languages, even if you won’t ever get the chance to use them in production, you will find yourself open to new ideas and ways of coding in your main language. For example, studying Haskell has taught me that you can do so much more with types and has changed my programming style in C#. A type represents some state a program should have, and a type should not be able to represent an invalid state. I often find myself refactoring methods like this… void SomeMethod(bool doThis, bool doThat) { if (!(doThis ^ doThat)) throw new ArgumentException(“At least one arg should be true”); if (doThis) DoThis(); if (doThat) DoThat(); } …into a type-based solution, like this: enum Action { DoThis, DoThat, Both }; void SomeMethod(Action action) { if (action == Action.DoThis || action == Action.Both) DoThis(); if (action == Action.DoThat || action == Action.Both) DoThat(); } At this point, I’ve removed the runtime exception in favor of a compile-time check. This is a trivial example, but is just one of many ideas that I’ve taken from one language and implemented in another.

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• Bullet Physics - Casting a ray straight down from a rigid body (first person camera)

  - by Hydrocity

  I've implemented a first person camera using Bullet--it's a rigid body with a capsule shape. I've only been using Bullet for a few days and physics engines are new to me. I use btRigidBody::setLinearVelocity() to move it and it collides perfectly with the world. The only problem is the Y-value moves freely, which I temporarily solved by setting the Y-value of the translation vector to zero before the body is moved. This works for all cases except when falling from a height. When the body drops off a tall object, you can still glide around since the translate vector's Y-value is being set to zero, until you stop moving and fall to the ground (the velocity is only set when moving). So to solve this I would like to try casting a ray down from the body to determine the Y-value of the world, and checking the difference between that value and the Y-value of the camera body, and disable or slow down movement if the difference is large enough. I'm a bit stuck on simply casting a ray and determining the Y-value of the world where it struck. I've implemented this callback: struct AllRayResultCallback : public btCollisionWorld::RayResultCallback{ AllRayResultCallback(const btVector3& rayFromWorld, const btVector3& rayToWorld) : m_rayFromWorld(rayFromWorld), m_rayToWorld(rayToWorld), m_closestHitFraction(1.0){} btVector3 m_rayFromWorld; btVector3 m_rayToWorld; btVector3 m_hitNormalWorld; btVector3 m_hitPointWorld; float m_closestHitFraction; virtual btScalar addSingleResult(btCollisionWorld::LocalRayResult& rayResult, bool normalInWorldSpace) { if(rayResult.m_hitFraction < m_closestHitFraction) m_closestHitFraction = rayResult.m_hitFraction; m_collisionObject = rayResult.m_collisionObject; if(normalInWorldSpace){ m_hitNormalWorld = rayResult.m_hitNormalLocal; } else{ m_hitNormalWorld = m_collisionObject->getWorldTransform().getBasis() * rayResult.m_hitNormalLocal; } m_hitPointWorld.setInterpolate3(m_rayFromWorld, m_rayToWorld, m_closestHitFraction); return 1.0f; } }; And in the movement function, I have this code: btVector3 from(pos.x, pos.y + 1000, pos.z); // pos is the camera's rigid body position btVector3 to(pos.x, 0, pos.z); // not sure if 0 is correct for Y AllRayResultCallback callback(from, to); Base::getSingletonPtr()->m_btWorld->rayTest(from, to, callback); So I have the callback.m_hitPointWorld vector, which seems to just show the position of the camera each frame. I've searched Google for examples of casting rays, as well as the Bullet documentation, and it's been hard to just find an example. An example is really all I need. Or perhaps there is some method in Bullet to keep the rigid body on the ground? I'm using Ogre3D as a rendering engine, and casting a ray down is quite straightforward with that, however I want to keep all the ray casting within Bullet for simplicity. Could anyone point me in the right direction? Thanks.

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• With AMD style modules in JavaScript is there any benefit to namespaces?

  - by gman

  Coming from C++ originally and seeing lots of Java programmers doing the same we brought namespaces to JavaScript. See Google's closure library as an example where they have a main namespace, goog and under that many more namespaces like goog.async, goog.graphics But now, having learned the AMD style of requiring modules it seems like namespaces are kind of pointless in JavaScript. Not only pointless but even arguably an anti-pattern. What is AMD? It's a way of defining and including modules that removes all direct dependencies. Effectively you do this // some/module.js define([ 'name/of/needed/module', 'name/of/someother/needed/module', ], function( RefToNeededModule, RefToSomeOtherNeededModule) { ...code... return object or function }); This format lets the AMD support code know that this module needs name/of/needed/module.js and name/of/someother/needed/module.js loaded. The AMD code can load all the modules and then, assuming no circular dependencies, call the define function on each module in the correct order, record the object/function returned by the module as it calls them, and then call any other modules' define function with references to those modules. This seems to remove any need for namespaces. In your own code you can call the reference to any other module anything you want. For example if you had 2 string libraries, even if they define similar functions, as long as they follow the AMD pattern you can easily use both in the same module. No need for namespaces to solve that. It also means there's no hard coded dependencies. For example in Google's closure any module could directly reference another module with something like var value = goog.math.someMathFunc(otherValue) and if you're unlucky it will magically work where as with AMD style you'd have to explicitly include the math library otherwise the module wouldn't have a reference to it since there are no globals with AMD. On top of that dependency injection for testing becomes easy. None of the code in the AMD module references things by namespace so there is no hardcoded namespace paths, you can easily mock classes at testing time. Is there any other point to namespaces or is that something that C++ / Java programmers are bringing to JavaScript that arguably doesn't really belong?

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• Why should I not do a masters degree

  - by aurel

  I have left university on July 2010 where I studied web design (as we all know you learn more by your self but that’s not the issue at the moment). Since then I have not managed to find a job (apart from a one month work experience), from the way things are going, and by taking into account the fact that all my university friends are in the same situation, I don’t think that I am going to find a job soon (within the industry) Now as we all do, even though I don’t have a job, I am still working on personal projects and try to keep up to date (I don’t need a job or uni to do this) – but I am thinking, because there is not work available, would it be worth going back to uni for a master degree? I know I don’t need it and I know that is unlikely that I will learn anything important, as I believe in self learning, and in most cases it is a lot more effective (but I have to say I don’t mind going back to school) The only reason I am thinking of doing the master is, (and this is where I need your help): If it takes me a year to get a job, then on the interview, would the employer think “what the hell did this guy do since he left university” – now if I go to university that would solve this problem. Or I’m I making up a problem that does not exist Plus, I know that employers need examples of sites that I have been working on, at the moment I only have 3 (as when working on personal projects, where their is not time limit I tend drag things in order to get them perfect, and they never get perfect) – so by going back to uni, then this problem maybe solved I said all this as I have read a lot about the fact that you don’t need to have a masters degree to work on web design market (and I totally agree) but considering my concern, the question is should I do a masters course to avoid just spending hours in my room working and learning in my own (but that it would be hard to convince employers that I was really learning in my room) Maybe because I’m still young age 22 not that old anyway :), but I don’t have the “dream” of being rich, so if I were to tell the truth I don’t really care of the fact that I don’t have a job (at the moment), because regardless, I am working on what I love every day, but I know that in the future when I will need the job I may find it harder to get one, if I neglect doing so now Every time I ask a question that I’m not sure about, I keep going on and on, but I really hope you get what I am trying to get across. By the way the course that I am looking at for a masters says that it would teach me how to do these: e-commerce e-government e-science e-learning I don’t know any of them, a part from e-commerce Thanks

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• Oracle At QCon SF 2012

  - by Cassandra Clark - OTN

  Oracle Technology Network is a Platinum sponsor at QCon San Francisco.  (qconsf.com).  Don’t miss these great developer focused sessions: Shay ShmeltzerHow we simplified Web, Mobile and Cloud development for our own developers? - the Oracle StoryOver the past several years, Oracle has beendeveloping a new set of enterprise applications in what is probably one of thelargest Java based development project in the world. How do you take 3000 developers and make them productive? How do you insure the delivery of cutting edge UIs for both Mobile and Web channels? How do you enable Cloud baseddevelopment and deployment?  Come and learn how we did it at Oracle, and see how the same technologies and methodologies can apply to your development efforts. Dan SmithProject Lambda in Java 8Java SE 8 will include major enhancements to the Java Programming Language and its core libraries.  This suite of new features, known as Project Lambda in the OpenJDK community, includes lambda expressions, default methods, and parallel collections (and much more!).  The result will be a next-generation Java programming experience with more flexibility and better abstractions.   This talk will introduce the new Java features and offer a behind-the-scenes view of how they evolved and why they work the way that they do. Arun GuptaJSR 356: Building HTML5 WebSocket Applications in JavaThe family of HTML5 technologies has pushed the pendulum away from rich client technologies and toward ever-more-capable Web clients running on today’s browsers. In particular, WebSocket brings new opportunities for efficient peer-to-peer communication, providing the basis for a new generation of interactive and “live” Web applications. This session examines the efforts under way to support WebSocket in the Java programming model, from its base-level integration in the Java Servlet and Java EE containers to a new, easy-to-use API and toolset that are destined to become part of the standard Java platform. The full conference schedule is here: http://qconsf.com/sf2012/schedule/wednesday.jsp But wait, there’s more!  At the Oracle booth, we’ll also be covering: ·         Oracle ADF Mobile·         Oracle Developer Cloud Service·         Oracle ADF Essentials·         NetBeans Project Easel Lastly we’ll share the results of a short cloud survey at QConSF ater this week.  If you attended this year's Oracle OpenWorld and JavaOne conferences, it would be hard not to notice that Oracle is clearly "all-in" when it comes to the Cloud.  With Cloud computing being such a hot topic on many OTN members' minds, we'd like to know what you're doing in the cloud and invite you to take this short cloud survey.

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• What do you do when practical problems get in the way of practical goals?

  - by P.Brian.Mackey

  UPDATE Source control is good to use. Sometimes, real world issues make it impractical to use. For example: If the team is not used to using source control, training problems can arise If a team member directly modifies code on the server, various issues can arise. Merge problems, lack of history, etc Let's say there's a project that is way out of sync. The physical files on the server differ in unknown ways over ~100 files. Merging would take not only a great knowledge of the project, but is also well beyond the ability to complete in the given time. Other projects are falling out of sync. Developers continue to have a distrust of source control and therefore compound the issue by not using source control. Developers argue that using source control is wasteful because merging is error prone and difficult. This is a difficult point to argue, because when source control is being so badly mis-used and source control continually bypassed, it is error prone indeed. Therefore, the evidence "speaks for itself" in their view. Developers argue that directly modifying source control saves time. This is also difficult to argue. Because the merge required to synchronize the code to start with is time consuming, across ~10 projects. Permanent files are often stored in the same directory as the web project. So publishing (full publish) erases these files that are not in source control. This also drives distrust for source control. Because "publishing breaks the project". Fixing this (moving stored files out of the solution subfolders) takes a great deal of time and debugging as these locations are not set in web.config and often exist across multiple code points. So, the culture persists itself. Bad practice begets more bad practice. Bad solutions drive new hacks to "fix" much deeper, much more time consuming problems. Servers, hard drive space are extremly difficult to come by. Yet, user expectations are rising. What can be done in this situation?

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• Monitor the Weather from Your Windows 7 Taskbar

  - by Asian Angel

  Keeping up with the weather forecast can be hard when you are extra busy with work. If you need a simple but nice looking way to integrate weather monitoring into your Taskbar then join us as we look at WeatherBar. Setting Up & Using WeatherBar To get started unzip the following files, place them in an appropriate “Program Files Folder”, and create a shortcut. When you start WeatherBar for the first time you will be presented with the following window and a random/default location. To get WeatherBar set up for your location there are only two settings to adjust (using the “Pencil & Gear Buttons”). Clicking on the “Pencil Button” will open up this small window…enter the name of your location and click “OK”. Next click on the “Gear Button” where you can choose the “Update Interval” and “Measurement Format” that best suits your needs. Click “OK” when finished and WeatherBar will be ready to go. That definitely looks nice. When you are finished viewing this window minimize it to the “Taskbar Icon” instead of clicking on the “Close Button”…otherwise the entire app will close. Left click on the “Taskbar Icon” to bring the window back up… Hovering the mouse over the “Taskbar Icon” provides a nice thumbnail of the weather forecast. Right clicking on the “Taskbar Icon” will display a nice mini forecast. Conclusion While WeatherBar may not be for everyone it does provide a nice easy way to monitor the weather from your “Taskbar” without taking up a lot of room. Links Download WeatherBar Similar Articles Productive Geek Tips Monitor the Weather for Your Location in ChromeCheck Weather Conditions in Real-time with Weather WatcherMonitor CPU, Memory, and Disk IO In Windows 7 with Taskbar MetersTaskbar Eliminator Does What the Name Implies: Hides Your Windows TaskbarBring Misplaced Off-Screen Windows Back to Your Desktop (Keyboard Trick) TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow Combine MP3 Files Easily QuicklyCode Provides Cheatsheets & Other Programming Stuff Download Free MP3s from Amazon

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• How to handle encryption key conflicts when synchronizing data?

  - by Rafael

  Assume that there is data that gets synchronized between several devices. The data is protected with a symmetric encryption algorithm and a key. The key is stored on each device and encrypted with a password. When a user changes the password only the key gets re-encrypted. Under normal circumstances, when there is a good network connection to other peers, the current key gets synchronized and all data on the new device gets encrypted with the same key. But how to handle situations where a new device doesn’t have a network connection and e.g. creates its own new, but incompatible key? How to keep the usability as high as possible under such circumstances? The application could detect that there is no network and hence refuse to start. That’s very bad usability in my opinion, because the application isn’t functional at all in this case. I don’t consider this a solution. The application could ignore the missing network connection and create a new key. But what to do when the application gains a network connection? There will be several incompatible keys and some parts of the underlying data could only be encrypted with one key and other parts with another key. The situation would get worse if there would be more keys than just two and the application would’ve to ask every time for a password when another object that should get decrypted with another key would be needed. It is very messy and time consuming to try to re-encrypt all data that is encrypted with another key with a main key. What should be the main key at all in this case? The oldest key? The key with the most encrypted objects? What if the key got synchronized but not all objects that got encrypted with this particular key? How should the user know for which particular password the application asks and why it takes probably very long to re-encrypt the data? It’s very hard to describe encryption “issues” to users. So far I didn’t find an acceptable solution, nor some kind of generic strategy. Do you have some hints about a concrete strategy or some books / papers that describe synchronization of symmetrically encrypted data with keys that could cause conflicts?

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• Can't install alternate CD from USB?

  - by mattias

  Hi im trying to install ubuntu 12.04 with full hard disk encryption. After downloading and installing the Ubuntu live CD, I learned that truecrypt doesnt support full disk encryption on linux. I also learned that the best way to get "nearly full disk encryption" on ubuntu is by installing it from the alternate install CD. I tried that, but something is wrong with my CD reader/burner so it doesnt boot up when i insert the cd. My thought here was to take the .iso that I downloaded on my unencrypted Ubuntu system, use Unetbootin to make the usb drive. The usb drive used for this is exactly the same brand as one that I know has worked with a previous ubuntu live system on the same computer. I also used unetbootin for that usb, but I created it from windows that time. The usb stick boots up fine and i get through the first couple of steps in the installation process. However, After a while I get a "box" with the following error message "Load Installer components from CD" There was a problem reading data from the CD-ROM. Please make sure it is in the drive. If retrying does not work, you should check the integrity of your CD-ROM. "Failed to copy file from CD-ROM. Retry? " Then I cant get any further. I googled a lot and found this page which seems to tackle this very problem: http://www.dotkam.com/2010/11/29/ins...mage-from-usb/ I tried to do what it said. After pressing TAB, I wrote : cdrom-detect/try-usb=true without quotes because that's what i think is right. When I press TAB, there already is a text saying : /ubnkern initrd=/ubninit vga=788 -- quiet which can be removed. I have tried to both delete the text before the "--" and just inserting cdrom-detect/try-usb=true before it. Any idea of what can be wrong? I would like to do a full system encryption, or as full as it is possible. I dont want to just encrypt my /home folder. Maybe this isn't the easiest way. I use SanDisk usb sticks. I know there is a problem with U3 launcher on some SanDisks, but I never had to remove U3 before from similar disks, and the alternate install does boot up, so I dont think using U3 removal would help me. Any help or indication to an easier way to do this would be appreciated

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• Achieving decoupling in Model classes

  - by Guven

  I am trying to test-drive (or at least write unit tests) my Model classes but I noticed that my classes end up being too coupled. Since I can't break this coupling, writing unit tests is becoming harder and harder. To be more specific: Model Classes: These are the classes that hold the data in my application. They resemble pretty much the POJO (plain old Java objects), but they also have some methods. The application is not too big so I have around 15 model classes. Coupling: Just to give an example, think of a simple case of Order Header - Order Item. The header knows the item and the item knows the header (needs some information from the header for performing certain operations). Then, let's say there is the relationship between Order Item - Item Report. The item report needs the item as well. At this point, imagine writing tests for Item Report; you need have a Order Header to carry out the tests. This is a simple case with 3 classes; things get more complicated with more classes. I can come up with decoupled classes when I design algorithms, persistence layers, UI interactions, etc... but with model classes, I can't think of a way to separate them. They currently sit as one big chunk of classes that depend on each other. Here are some workarounds that I can think of: Data Generators: I have a package that generates sample data for my model classes. For example, the OrderHeaderGenerator class creates OrderHeaders with some basic data in it. I use the OrderHeaderGenerator from my ItemReport unit-tests so that I get an instance to OrderHeader class. The problem is these generators get complicated pretty fast and then I also need to test these generators; defeating the purpose a little bit. Interfaces instead of dependencies: I can come up with interfaces to get rid of the hard dependencies. For example, the OrderItem class would depend on the IOrderHeader interface. So, in my unit tests, I can easily mock the behaviour of an OrderHeader with a FakeOrderHeader class that implements the IOrderHeader interface. The problem with this approach is the complexity that the Model classes would end up having. Would you have other ideas on how to break this coupling in the model classes? Or, how to make it easier to unit-test the model classes?

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• AI to move custom-shaped spaceships (shape affecting movement behaviour)

  - by kaoD

  I'm designing a networked turn based 3D-6DOF space fleet combat strategy game which relies heavily on ship customization. Let me explain the game a bit, since you need to know a bit about it to set the question. What I aim for is the ability to create your own fleet of ships with custom shapes and attached modules (propellers, tractor beams...) which would give advantages and disadvantages to each ship, so you have lots of different fleet distributions. E.g., long ship with two propellers at the side would let the ship spin around that plane easily, bigger ships would move slowly unless you place lots of propellers at the back (therefore spending more "construction" points and energy when moving, and it will only move fast towards that direction.) I plan to balance all the game around this feature. The game would revolve around two phases: orders and combat phase. During the orders phase, you command the different ships. When all players finish the order phase, the combat phase begins and the ship orders get resolved in real-time for some time, then the action pauses and there's a new orders phase. The problem comes when I think about player input. To move a ship, you need to turn on or off different propellers if you want to steer, travel forward, brake, rotate in place... These propellers don't have to work at their whole power, so you can achieve more movement combinations with less propellers. I think this approach is a bit boring. The player doesn't want to fiddle with motors or anything, you just want to MOVE and KILL. The way I intend the player to give orders to these ships is by a destination and a rotation, and then the AI would calculate the correct propeller power to achive that movement and rotation. Propulsion doesn't have to be the same throught the entire turn calculation (after the orders have been given) so it would be cool if the ships reacted as they move, adjusting the power of the propellers for their needs dynamically, but it may be too hard to implement and it's not really needed for the game to work. In both cases, how would that AI decide which propellers to activate for the best (or at least not worst) trajectory to be achieved? I though about some approaches: Learning AI: The ship types would learn about their movement by trial and error, adjusting their behaviour with more uses, and finally becoming "smart". I don't want to get involved THAT far in AI coding, and I think it can be frustrating for the player (even if you can let it learn without playing.) Pre-calculated timestep movement: Upon ship creation, ALL possible movements are calculated for each propeller configuration and power for a given delta-time. Memory intensive, ugly, bad. Pre-calculated trajectories: The same as above but not for each delta-time but the whole trajectory, which would then be fitted as much as possible. Requires a fixed propeller configuration for the whole combat phase and is still memory intensive, ugly and bad. Continuous brute forcing: The AI continously checks ALL possible propeller configurations throughout the entire combat phase, precalculates a few time steps and decides which is the best one based on that. Con: what's good now might not be that good later, and it's too CPU intensive, ugly, and bad too. Single brute forcing: Same as above, but only brute forcing at the beginning of the simulation, so it needs constant propeller configuration throughout the entire combat phase. Coninuous angle check: This is not a full movement method, but maybe a way to discard "stupid" propeller configurations. Given the current propeller's normal vector and the final one, you can approximate the power needed for the propeller based on the angle. You must do this continuously throughout the whole combat phase. I figured this one out recently so I didn't put in too much thought. A priori, it has the "what's good now might not be that good later" drawback too, and it doesn't care about the other propellers which may act together to make a better propelling configuration. I'm really stuck here. Any ideas?

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• Comparing Apples and Pairs

  - by Tony Davis

  A recent study, High Costs and Negative Value of Pair Programming, by Capers Jones, pulls no punches in its assessment of the costs-to- benefits ratio of pair programming, two programmers working together, at a single computer, rather than separately. He implies that pair programming is a method rushed into production on a wave of enthusiasm for Agile or Extreme Programming, without any real regard for its effectiveness. Despite admitting that his data represented a far from complete study of the economics of pair programming, his conclusions were stark: it was 2.5 times more expensive, resulted in a 15% drop in productivity, and offered no significant quality benefits. The author provides a more scientific analysis than Jon Evans’ Pair Programming Considered Harmful, but the theme is the same. In terms of upfront-coding costs, pair programming is surely more expensive. The claim of productivity loss is dubious and contested by other studies. The third claim, though, did surprise me. The author’s data suggests that if both the pair and the individual programmers employ static code analysis and testing, then there is no measurable difference in the resulting code quality, in terms of defects per function point. In other words, pair programming incurs a massive extra cost for no tangible return in investment. There were, inevitably, many criticisms of his data and his conclusions, a few of which are persuasive. Firstly, that the driver/observer model of pair programming, on which the study bases its findings, is far from the most effective. For example, many find Ping-Pong pairing, based on use of test-driven development, far more productive. Secondly, that it doesn’t distinguish between “expert” and “novice” pair programmers– that is, independently of other programming skills, how skilled was an individual at pair programming. Thirdly, that his measure of quality is too narrow. This point rings true, certainly at Red Gate, where developers don’t pair program all the time, but use the method in short bursts, while tackling a tricky problem and needing a fresh perspective on the best approach, or more in-depth knowledge in a particular domain. All of them argue that pair programming, and collective code ownership, offers significant rewards, if not in terms of immediate “bug reduction”, then in removing the likelihood of single points of failure, and improving the overall quality and longer-term adaptability/maintainability of the design. There is also a massive learning benefit for both participants. One developer told me how he once worked in the same team over consecutive summers, the first time with no pair programming and the second time pair-programming two-thirds of the time, and described the increased rate of learning the second time as “phenomenal”. There are a great many theories on how we should develop software (Scrum, XP, Lean, etc.), but woefully little scientific research in their effectiveness. For a group that spends so much time crunching other people’s data, I wonder if developers spend enough time crunching data about themselves. Capers Jones’ data may be incomplete, but should cause a pause for thought, especially for any large IT departments, supporting commerce and industry, who are considering pair programming. It certainly shouldn’t discourage teams from exploring new ways of developing software, as long as they also think about how to gather hard data to gauge their effectiveness.

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