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• In the Mobile and Tablet World, How Much is Too Much?

  - by andrewbrust

  The week of April 26th was a huge one in the world of mobile and tablet devices,  There were so many individual developments, announcements and solidifications of strategy, it’s almost impossible to believe they occurred in the same month, let alone the same week. Things started with Apple and Gizmodo having a Law and Order moment over the latter’s procurement of what appears to be the former’s 4th gen iPhone prototype.  We found out on the 26th that Gizmodo blogger Jason Chen’s apartment was raided by police and, honestly, that was a bit much. But Apple didn’t stop there.  They also published Steve Job’s critique of Adobe Flash and his explanation of Cupertino’s embargo of Flash on iPhones, iPods and iPads.  If you ask me, this too, was a bit much. Apple finished up the week by releasing the 3G version of its iPad product to the US market. I like (iLike?) my WiFi iPad.  The idea of getting a version of it that required a second 3G service monthly subscription, is, well, a bit  much. Microsoft was in the news too.  It killed a project it hadn’t even acknowledged the existence of: the Courier tablet.  That’s a bit much too.  If a tree falls in the woods, and Microsoft says they can’t hear it anyway, could they really have chopped it down? Maybe Microsoft Research should have licensed some of Courier’s technology from other parts of Microsoft.  Then maybe they could have kept the product alive.  Ask HTC: they’re going to be licensing technology from Microsoft because Redmond insists that Google’s Android operating system infringes on certain of their patents.  And since HTC now builds a number of handsets on Android, instead of being beholden, as they once were, to Windows Mobile, that means they can keep making their products.  Why does HTC have to pay the royalties, and not Google?  Maybe Microsoft decided that going after GOOG would have been a bit much, even for them. The agreement came not a moment to soon: HTC released their “Droid Incredible” (that name’s a bit much), an Android 2.1 handset with amazing hardware and HTC’s own Sense UI, on April 30th (this past Friday). This phone is very well-reviewed.  Maybe that’s why Google basically decided to beg off introducing a version of its Nexus One phone (also manufactured by HTC) on the Verizon Wireless network.  Google backing down?  That’s incredible, if not also a bit much. And that brings us to HP.  Which this week announced its acquisition of Palm and its webOS mobile phone touch-oriented operating system.  HP also killed its own Slate initiative.  Apparently HP realized that Windows 7, even with a proprietary HP touch UI added on top, is no match for the iPad.  I’m guessing they think webOS might work a bit better,  And I’m wondering if HP even wants to use webOS for phone handsets, beyond the Pre and Pixi.  Using it just for slate devices would be a bit extreme, but maybe not too much. Honestly, this was not Microsoft’s best week.  It killed a project and a close partner did likewise.  Then that same partner bought a competing OS product, while another partner released their new product that uses yet another competing OS platform. What did Microsoft actually produce this past week? An update to its Windows Phone 7 developer tools that actually works with the version of Visual Studio 2010 released on April 12th, and the version of Silverlight released three days later. That took three weeks to get synced up, and that’s a bit much too. But at least it happened. Windows Phone 7 is Microsoft’s best hope for a comeback in the SmartPhone market and to offer a credible touch-based tablet device.  This week, two of Microsoft’s slate initiatives died, and its only mobile phone victory was around its competitor’s operating system.  I hope the new platform gets Redmond out of the PC ghetto and into the classes of device that get people really excited today.  If it can’t, that would be a bit much; probably too much.  And, as the signs at the Lonestar Cafe in NYC used to say, too much ain’t enough.

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• PeopleSoft at Alliance 2012 Executive Forum

  - by John Webb

  Guest Posting From Rebekah Jackson This week I jointed over 4,800 Higher Ed and Public Sector customers and partners in Nashville at our annual Alliance conference.   I got lost easily in the hallways of the sprawling Gaylord Opryland Hotel. I carried the resort map with me, and I would still stand for several minutes at a very confusing junction, studying the map and the signage on the walls. Hallways led off in many directions, some with elevators going down here and stairs going up there. When I took a wrong turn I would instantly feel stuck, lose my bearings, and occasionally even have to send out a call for help.    It strikes me that the theme for the Executive Forum this year outlines a less tangible but equally disorienting set of challenges that our higher education customer’s CIOs are facing: Making Decisions at the Intersection of Business Value, Strategic Investment, and Enterprise Technology. The forces acting upon higher education institutions today are not neat, straight-forward decision points, where one can glance to the right, glance to the left, and then quickly choose the best course of action. The operational, technological, and strategic factors that must be considered are complex, interrelated, messy…and the stakes are high. Michael Horn, co-author of “Disrupting Class: How Disruptive Innovation Will Change the Way the World Learns”, set the tone for the day. He introduced the model of disruptive innovation, which grew out of the research he and his colleagues have done on ‘Why Successful Organizations Fail’. Highly simplified, the pattern he shared is that things start out decentralized, take a leap to extreme centralization, and then experience progressive decentralization. Using computers as an example, we started with a slide rule, then developed the computer which centralized in the form of mainframes, and gradually decentralized to mini-computers, desktop computers, laptops, and now mobile devices. According to Michael, you have more computing power in your cell phone than existed on the planet 60 years ago, or was on the first rocket that went to the moon. Applying this pattern to Higher Education means the introduction of expensive and prestigious private universities, followed by the advent of state schools, then by community colleges, and now online education. Michael shared statistics that indicate 50% of students will be taking at least one on line course by 2014…and by some measures, that’s already the case today. The implication is that technology moves from being the backbone of the campus, the IT department’s domain, and pushes into the academic core of the institution. Innovative programs are underway at many schools like Bellevue and BYU Idaho, joined by startups and disruptive new players like the Khan Academy.   This presents both threat and opportunity for higher education institutions, and means that IT decisions cannot afford to be disconnected from the institution’s strategic plan. Subsequent sessions explored this theme.    Theo Bosnak, from Attain, discussed the model they use for assessing the complete picture of an institution’s financial health. Compounding the issue are the dramatic trends occurring in technology and the vendors that provide it. Ovum analyst Nicole Engelbert, shared her insights next and suggested that incremental changes are no longer an option, instead fundamental changes are affecting the landscape of enterprise technology in higher ed.    Nicole closed with her recommendation that institutions focus on the trends in higher education with an eye towards the strategic requirements and business value first. Technology then is the enabler.   The last presentation of the day was from Tom Fisher, Sr. Vice President of Cloud Services at Oracle. Tom runs the delivery arm of the Cloud Services group, and shared his thoughts candidly about his experiences with cloud deployments as well as key issues around managing costs and security in cloud deployments. Okay, we’ve covered a lot of ground at this point, from financials planning, business strategy, and cloud computing, with the possibility that half of the institutions in the US might not be around in their current form 10 years from now. Did I forget to mention that was raised in the morning session? Seems a little hard to believe, and yet Michael Horn made a compelling point. Apparently 100 years ago, 8 of the top 10 education institutions in the world were German. Today, the leading German school is ranked somewhere in the 40’s or 50’s. What will the landscape be 100 years from now? Will there be an institution from China, India, or Brazil in the top 10? As Nicole suggested, maybe US parents will be sending their children to schools overseas much sooner, faced with the ever-increasing costs of a US based education. Will corporations begin to view skill-based certification from an online provider as a viable alternative to a 4 year degree from an accredited institution, fundamentally altering the education industry as we know it?

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• Is this how dynamic language copes with dynamic requirement?

  - by Amumu

  The question is in the title. I want to have my thinking verified by experienced people. You can add more or disregard my opinion, but give me a reason. Here is an example requirement: Suppose you are required to implement a fighting game. Initially, the game only includes fighters, who can attack each other. Each fighter can punch, kick or block incoming attacks. Fighters can have various fighting styles: Karate, Judo, Kung Fu... That's it for the simple universe of the game. In an OO like Java, it can be implemented similar to this way: abstract class Fighter { int hp, attack; void punch(Fighter otherFighter); void kick(Fighter otherFighter); void block(Figther otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; This is fine if the game stays like this forever. But, somehow the game designers decide to change the theme of the game: instead of a simple fighting game, the game evolves to become a RPG, in which characters can not only fight but perform other activities, i.e. the character can be a priest, an accountant, a scientist etc... At this point, to make it more generic, we have to change the structure of our original design: Fighter is not used to refer to a person anymore; it refers to a profession. The specialized classes of Fighter (KaraterFighter, JudoFighter, KungFuFighter) . Now we have to create a generic class named Person. However, to adapt this change, I have to change the method signatures of the original operations: class Person { int hp, attack; List<Profession> skillSet; }; abstract class Profession {}; class Fighter extends Profession { void punch(Person otherFighter); void kick(Person otherFighter); void block(Person otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; class Accountant extends Profession { void calculateTax(Person p) { //...implementation...}; void calculateTax(Company c) { //...implementation...}; }; //... more professions... Here are the problems: To adapt to the method changes, I have to fix the places where the changed methods are called (refactoring). Every time a new requirement is introduced, the current structural design has to be broken to adapt the changes. This leads to the first problem. Rigid structure makes it hard for code reuse. A function can only accept the predefined types, but it cannot accept future unknown types. A written function is bound to its current universe and has no way to accommodate to the new types, without modifications or rewrite from scratch. I see Java has a lot of deprecated methods. OO is an extreme case because it has inheritance to add up the complexity, but in general for statically typed language, types are very strict. In contrast, a dynamic language can handle the above case as follow: ;;fighter1 punch fighter2 (defun perform-punch (fighter1 fighter2) ...implementation... ) ;;fighter1 kick fighter2 (defun perform-kick (fighter1 fighter2) ...implementation... ) ;;fighter1 blocks attacks from fighter2 (defun perform-block (fighter1 fighter2) ...implementation... ) fighter1 and fighter2 can be anything as long as it has the required data for calculation; or methods (duck typing). You don't have to change from the type Fighter to Person. In the case of Lisp, because Lisp only has a single data structure: list, it's even easier to adapt to changes. However, other dynamic languages can have similar behaviors as well. I work primarily with static languages (mainly C and Java, but working with Java was a long time ago). I started learning Lisp and some other dynamic languages this year. I can see how it helps improving my productivity.

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• Computer Networks UNISA - Chap 14 &ndash; Insuring Integrity &amp; Availability

  - by MarkPearl

  After reading this section you should be able to Identify the characteristics of a network that keep data safe from loss or damage Protect an enterprise-wide network from viruses Explain network and system level fault tolerance techniques Discuss issues related to network backup and recovery strategies Describe the components of a useful disaster recovery plan and the options for disaster contingencies What are integrity and availability? Integrity – the soundness of a networks programs, data, services, devices, and connections Availability – How consistently and reliably a file or system can be accessed by authorized personnel A number of phenomena can compromise both integrity and availability including… security breaches natural disasters malicious intruders power flaws human error users etc Although you cannot predict every type of vulnerability, you can take measures to guard against the most damaging events. The following are some guidelines… Allow only network administrators to create or modify NOS and application system users. Monitor the network for unauthorized access or changes Record authorized system changes in a change management system’ Install redundant components Perform regular health checks on the network Check system performance, error logs, and the system log book regularly Keep backups Implement and enforce security and disaster recovery policies These are just some of the basics… Malware Malware refers to any program or piece of code designed to intrude upon or harm a system or its resources. Types of Malware… Boot sector viruses Macro viruses File infector viruses Worms Trojan Horse Network Viruses Bots Malware characteristics Some common characteristics of Malware include… Encryption Stealth Polymorphism Time dependence Malware Protection There are various tools available to protect you from malware called anti-malware software. These monitor your system for indications that a program is performing potential malware operations. A number of techniques are used to detect malware including… Signature Scanning Integrity Checking Monitoring unexpected file changes or virus like behaviours It is important to decide where anti-malware tools will be installed and find a balance between performance and protection. There are several general purpose malware policies that can be implemented to protect your network including… Every compute in an organization should be equipped with malware detection and cleaning software that regularly runs Users should not be allowed to alter or disable the anti-malware software Users should know what to do in case the anti-malware program detects a malware virus Users should be prohibited from installing any unauthorized software on their systems System wide alerts should be issued to network users notifying them if a serious malware virus has been detected. Fault Tolerance Besides guarding against malware, another key factor in maintaining the availability and integrity of data is fault tolerance. Fault tolerance is the ability for a system to continue performing despite an unexpected hardware or software malfunction. Fault tolerance can be realized in varying degrees, the optimal level of fault tolerance for a system depends on how critical its services and files are to productivity. Generally the more fault tolerant the system, the more expensive it is. The following describe some of the areas that need to be considered for fault tolerance. Environment (Temperature and humidity) Power Topology and Connectivity Servers Storage Power Typical power flaws include Surges – a brief increase in voltage due to lightening strikes, solar flares or some idiot at City Power Noise – Fluctuation in voltage levels caused by other devices on the network or electromagnetic interference Brownout – A sag in voltage for just a moment Blackout – A complete power loss The are various alternate power sources to consider including UPS’s and Generators. UPS’s are found in two categories… Standby UPS – provides continuous power when mains goes down (brief period of switching over) Online UPS – is online all the time and the device receives power from the UPS all the time (the UPS is charged continuously) Servers There are various techniques for fault tolerance with servers. Server mirroring is an option where one device or component duplicates the activities of another. It is generally an expensive process. Clustering is a fault tolerance technique that links multiple servers together to appear as a single server. They share processing and storage responsibilities and if one unit in the cluster goes down, another unit can be brought in to replace it. Storage There are various techniques available including the following… RAID Arrays NAS (Storage (Network Attached Storage) SANs (Storage Area Networks) Data Backup A backup is a copy of data or program files created for archiving or safekeeping. Many different options for backups exist with various media including… These vary in cost and speed. Optical Media Tape Backup External Disk Drives Network Backups Backup Strategy After selecting the appropriate tool for performing your servers backup, devise a backup strategy to guide you through performing reliable backups that provide maximum data protection. Questions that should be answered include… What data must be backed up At what time of day or night will the backups occur How will you verify the accuracy of the backups Where and for how long will backup media be stored Who will take responsibility for ensuring that backups occurred How long will you save backups Where will backup and recovery documentation be stored Different backup methods provide varying levels of certainty and corresponding labour cost. There are also different ways to determine which files should be backed up including… Full backup – all data on all servers is copied to storage media Incremental backup – Only data that has changed since the last full or incremental backup is copied to a storage medium Differential backup – Only data that has changed since the last backup is coped to a storage medium Disaster Recovery Disaster recovery is the process of restoring your critical functionality and data after an enterprise wide outage has occurred. A disaster recovery plan is for extreme scenarios (i.e. fire, line fault, etc). A cold site is a place were the computers, devices, and connectivity necessary to rebuild a network exist but they are not appropriately configured. A warm site is a place where the computers, devices, and connectivity necessary to rebuild a network exists with some appropriately configured devices. A hot site is a place where the computers, devices, and connectivity necessary to rebuild a network exists and all are appropriately configured.

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• Add Widget via Action in Toolbar

  - by Geertjan

  The question of the day comes from Vadim, who asks on the NetBeans Platform mailing list: "Looking for example showing how to add Widget to Scene, e.g. by toolbar button click." Well, the solution is very similar to this blog entry, where you see a solution provided by Jesse Glick for VisiTrend in Boston: https://blogs.oracle.com/geertjan/entry/zoom_capability Other relevant articles to read are as follows: http://netbeans.dzone.com/news/which-netbeans-platform-action http://netbeans.dzone.com/how-to-make-context-sensitive-actions Let's go through it step by step, with this result in the end, a solution involving 4 classes split (optionally, since a central feature of the NetBeans Platform is modularity) across multiple modules: The Customer object has a "name" String and the Droppable capability has a method "doDrop" which takes a Customer object: public interface Droppable {    void doDrop(Customer c);} In the TopComponent, we use "TopComponent.associateLookup" to publish an instance of "Droppable", which creates a new LabelWidget and adds it to the Scene in the TopComponent. Here's the TopComponent constructor: public CustomerCanvasTopComponent() {    initComponents();    setName(Bundle.CTL_CustomerCanvasTopComponent());    setToolTipText(Bundle.HINT_CustomerCanvasTopComponent());    final Scene scene = new Scene();    final LayerWidget layerWidget = new LayerWidget(scene);    Droppable d = new Droppable(){        @Override        public void doDrop(Customer c) {            LabelWidget customerWidget = new LabelWidget(scene, c.getTitle());            customerWidget.getActions().addAction(ActionFactory.createMoveAction());            layerWidget.addChild(customerWidget);            scene.validate();        }    };    scene.addChild(layerWidget);    jScrollPane1.setViewportView(scene.createView());    associateLookup(Lookups.singleton(d));} The Action is displayed in the toolbar and is enabled only if a Droppable is currently in the Lookup: @ActionID(        category = "Tools",        id = "org.customer.controler.AddCustomerAction")@ActionRegistration(        iconBase = "org/customer/controler/icon.png",        displayName = "#AddCustomerAction")@ActionReferences({    @ActionReference(path = "Toolbars/File", position = 300)})@NbBundle.Messages("AddCustomerAction=Add Customer")public final class AddCustomerAction implements ActionListener {    private final Droppable context;    public AddCustomerAction(Droppable droppable) {        this.context = droppable;    }    @Override    public void actionPerformed(ActionEvent ev) {        NotifyDescriptor.InputLine inputLine = new NotifyDescriptor.InputLine("Name:", "Data Entry");        Object result = DialogDisplayer.getDefault().notify(inputLine);        if (result == NotifyDescriptor.OK_OPTION) {            Customer customer = new Customer(inputLine.getInputText());            context.doDrop(customer);        }    }} Therefore, when the Properties window, for example, is selected, the Action will be disabled. (See the Zoomable example referred to in the link above for another example of this.) As you can see above, when the Action is invoked, a Droppable must be available (otherwise the Action would not have been enabled). The Droppable is obtained in the Action and a new Customer object is passed to its "doDrop" method. The above in pictures, take note of the enablement of the toolbar button with the red dot, on the extreme left of the toolbar in the screenshots below: The above shows the JButton is only enabled if the relevant TopComponent is active and, when the Action is invoked, the user can enter a name, after which a new LabelWidget is created in the Scene. The source code of the above is here: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.3/misc/WidgetCreationFromAction Note: Showing this as an MVC example is slightly misleading because, depending on which model object ("Customer" and "Droppable") you're looking at, the V and the C are different. From the point of view of "Customer", the TopComponent is the View, while the Action is the Controler, since it determines when the M is displayed. However, from the point of view of "Droppable", the TopComponent is the Controler, since it determines when the Action, i.e., which is in this case the View, displays the presence of the M.

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• Namespaces are obsolete

  - by Bertrand Le Roy

  To those of us who have been around for a while, namespaces have been part of the landscape. One could even say that they have been defining the large-scale features of the landscape in question. However, something happened fairly recently that I think makes this venerable structure obsolete. Before I explain this development and why it’s a superior concept to namespaces, let me recapitulate what namespaces are and why they’ve been so good to us over the years… Namespaces are used for a few different things: Scope: a namespace delimits the portion of code where a name (for a class, sub-namespace, etc.) has the specified meaning. Namespaces are usually the highest-level scoping structures in a software package. Collision prevention: name collisions are a universal problem. Some systems, such as jQuery, wave it away, but the problem remains. Namespaces provide a reasonable approach to global uniqueness (and in some implementations such as XML, enforce it). In .NET, there are ways to relocate a namespace to avoid those rare collision cases. Hierarchy: programmers like neat little boxes, and especially boxes within boxes within boxes. For some reason. Regular human beings on the other hand, tend to think linearly, which is why the Windows explorer for example has tried in a few different ways to flatten the file system hierarchy for the user. 1 is clearly useful because we need to protect our code from bleeding effects from the rest of the application (and vice versa). A language with only global constructs may be what some of us started programming on, but it’s not desirable in any way today. 2 may not be always reasonably worth the trouble (jQuery is doing fine with its global plug-in namespace), but we still need it in many cases. One should note however that globally unique names are not the only possible implementation. In fact, they are a rather extreme solution. What we really care about is collision prevention within our application. What happens outside is irrelevant. 3 is, more than anything, an aesthetical choice. A common convention has been to encode the whole pedigree of the code into the namespace. Come to think about it, we never think we need to import “Microsoft.SqlServer.Management.Smo.Agent” and that would be very hard to remember. What we want to do is bring nHibernate into our app. And this is precisely what you’ll do with modern package managers and module loaders. I want to take the specific example of RequireJS, which is commonly used with Node. Here is how you import a module with RequireJS: var http = require("http"); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is of course importing a HTTP stack module into the code. There is no noise here. Let’s break this down. Scope (1) is provided by the one scoping mechanism in JavaScript: the closure surrounding the module’s code. Whatever scoping mechanism is provided by the language would be fine here. Collision prevention (2) is very elegantly handled. Whereas relocating is an afterthought, and an exceptional measure with namespaces, it is here on the frontline. You always relocate, using an extremely familiar pattern: variable assignment. We are very much used to managing our local variable names and any possible collision will get solved very easily by picking a different name. Wait a minute, I hear some of you say. This is only taking care of collisions on the client-side, on the left of that assignment. What if I have two libraries with the name “http”? Well, You can better qualify the path to the module, which is what the require parameter really is. As for hierarchical organization, you don’t really want that, do you? RequireJS’ module pattern does elegantly cover the bases that namespaces used to cover, but it also promotes additional good practices. First, it promotes usage of self-contained, single responsibility units of code through the closure-based, stricter scoping mechanism. Namespaces are somewhat more porous, as using/import statements can be used bi-directionally, which leads us to my second point… Sane dependency graphs are easier to achieve and sustain with such a structure. With namespaces, it is easy to construct dependency cycles (that’s bad, mmkay?). With this pattern, the equivalent would be to build mega-components, which are an easier problem to spot than a decay into inter-dependent namespaces, for which you need specialized tools. I really like this pattern very much, and I would like to see more environments implement it. One could argue that dependency injection has some commonalities with this for example. What do you think? This is the half-baked result of some morning shower reflections, and I’d love to read your thoughts about it. What am I missing?

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• CPU Usage in Very Large Coherence Clusters

  - by jpurdy

  When sizing Coherence installations, one of the complicating factors is that these installations (by their very nature) tend to be application-specific, with some being large, memory-intensive caches, with others acting as I/O-intensive transaction-processing platforms, and still others performing CPU-intensive calculations across the data grid. Regardless of the primary resource requirements, Coherence sizing calculations are inherently empirical, in that there are so many permutations that a simple spreadsheet approach to sizing is rarely optimal (though it can provide a good starting estimate). So we typically recommend measuring actual resource usage (primarily CPU cycles, network bandwidth and memory) at a given load, and then extrapolating from those measurements. Of course there may be multiple types of load, and these may have varying degrees of correlation -- for example, an increased request rate may drive up the number of objects "pinned" in memory at any point, but the increase may be less than linear if those objects are naturally shared by concurrent requests. But for most reasonably-designed applications, a linear resource model will be reasonably accurate for most levels of scale. However, at extreme scale, sizing becomes a bit more complicated as certain cluster management operations -- while very infrequent -- become increasingly critical. This is because certain operations do not naturally tend to scale out. In a small cluster, sizing is primarily driven by the request rate, required cache size, or other application-driven metrics. In larger clusters (e.g. those with hundreds of cluster members), certain infrastructure tasks become intensive, in particular those related to members joining and leaving the cluster, such as introducing new cluster members to the rest of the cluster, or publishing the location of partitions during rebalancing. These tasks have a strong tendency to require all updates to be routed via a single member for the sake of cluster stability and data integrity. Fortunately that member is dynamically assigned in Coherence, so it is not a single point of failure, but it may still become a single point of bottleneck (until the cluster finishes its reconfiguration, at which point this member will have a similar load to the rest of the members). The most common cause of scaling issues in large clusters is disabling multicast (by configuring well-known addresses, aka WKA). This obviously impacts network usage, but it also has a large impact on CPU usage, primarily since the senior member must directly communicate certain messages with every other cluster member, and this communication requires significant CPU time. In particular, the need to notify the rest of the cluster about membership changes and corresponding partition reassignments adds stress to the senior member. Given that portions of the network stack may tend to be single-threaded (both in Coherence and the underlying OS), this may be even more problematic on servers with poor single-threaded performance. As a result of this, some extremely large clusters may be configured with a smaller number of partitions than ideal. This results in the size of each partition being increased. When a cache server fails, the other servers will use their fractional backups to recover the state of that server (and take over responsibility for their backed-up portion of that state). The finest granularity of this recovery is a single partition, and the single service thread can not accept new requests during this recovery. Ordinarily, recovery is practically instantaneous (it is roughly equivalent to the time required to iterate over a set of backup backing map entries and move them to the primary backing map in the same JVM). But certain factors can increase this duration drastically (to several seconds): large partitions, sufficiently slow single-threaded CPU performance, many or expensive indexes to rebuild, etc. The solution of course is to mitigate each of those factors but in many cases this may be challenging. Larger clusters also lead to the temptation to place more load on the available hardware resources, spreading CPU resources thin. As an example, while we've long been aware of how garbage collection can cause significant pauses, it usually isn't viewed as a major consumer of CPU (in terms of overall system throughput). Typically, the use of a concurrent collector allows greater responsiveness by minimizing pause times, at the cost of reducing system throughput. However, at a recent engagement, we were forced to turn off the concurrent collector and use a traditional parallel "stop the world" collector to reduce CPU usage to an acceptable level. In summary, there are some less obvious factors that may result in excessive CPU consumption in a larger cluster, so it is even more critical to test at full scale, even though allocating sufficient hardware may often be much more difficult for these large clusters.

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• A Knights Tale

  - by Phil Factor

  There are so many lessons to be learned from the story of Knight Capital losing nearly half a billion dollars as a result of a deployment gone wrong. The Knight Capital Group (KCG N) was an American global financial services firm engaging in market making, electronic execution, and institutional sales and trading. According to the recent order (File No.3.15570) against Knight Capital by U.S. Securities and Exchange Commission?, Knight had, for many years used some software which broke up incoming “parent” orders into smaller “child” orders that were then transmitted to various exchanges or trading venues for execution. A tracking ‘cumulative quantity’ function counted the number of ‘child’ orders and stopped the process once the total of child orders matched the ‘parent’ and so the parent order had been completed. Back in the mists of time, some code had been added to it  which was excuted if a particular flag was set. It was called ‘power peg’ and seems to have had a similar design and purpose, but, one guesses, would have shared the same tracking function. This code had been abandoned in 2003, but never deleted. In 2005, The tracking function was moved to an earlier point in the main process. It would seem from the account that, from that point, had that flag ever been set, the old ‘Power Peg’ would have been executed like Godzilla bursting from the ice, making child orders without limit without any tracking function. It wasn’t, presumably because the software that set the flag was removed. In 2012, nearly a decade after ‘Power Peg’ was abandoned, Knight prepared a new module to their software to cope with the imminent Retail Liquidity Program (RLP) for the New York Stock Exchange. By this time, the flag had remained unused and someone made the fateful decision to reuse it, and replace the old ‘power peg’ code with this new RLP code. Had the two actions been done together in a single automated deployment, and the new deployment tested, all would have been well. It wasn’t. To quote… “Beginning on July 27, 2012, Knight deployed the new RLP code in SMARS in stages by placing it on a limited number of servers in SMARS on successive days. During the deployment of the new code, however, one of Knight’s technicians did not copy the new code to one of the eight SMARS computer servers. Knight did not have a second technician review this deployment and no one at Knight realized that the Power Peg code had not been removed from the eighth server, nor the new RLP code added. Knight had no written procedures that required such a review.” (para 15) “On August 1, Knight received orders from broker-dealers whose customers were eligible to participate in the RLP. The seven servers that received the new code processed these orders correctly. However, orders sent with the repurposed flag to the eighth server triggered the defective Power Peg code still present on that server. As a result, this server began sending child orders to certain trading centers for execution. Because the cumulative quantity function had been moved, this server continuously sent child orders, in rapid sequence, for each incoming parent order without regard to the number of share executions Knight had already received from trading centers. Although one part of Knight’s order handling system recognized that the parent orders had been filled, this information was not communicated to SMARS.” (para 16) SMARS routed millions of orders into the market over a 45-minute period, and obtained over 4 million executions in 154 stocks for more than 397 million shares. By the time that Knight stopped sending the orders, Knight had assumed a net long position in 80 stocks of approximately $3.5 billion and a net short position in 74 stocks of approximately $3.15 billion. Knight’s shares dropped more than 20% after traders saw extreme volume spikes in a number of stocks, including preferred shares of Wells Fargo (JWF) and semiconductor company Spansion (CODE). Both stocks, which see roughly 100,000 trade per day, had changed hands more than 4 million times by late morning. Ultimately, Knight lost over $460 million from this wild 45 minutes of trading. Obviously, I’m interested in all this because, at one time, I used to write trading systems for the City of London. Obviously, the US SEC is in a far better position than any of us to work out the failings of Knight’s IT department, and the report makes for painful reading. I can’t help observing, though, that even with the breathtaking mistakes all along the way, that a robust automated deployment process that was ‘all-or-nothing’, and tested from soup to nuts would have prevented the disaster. The report reads like a Greek Tragedy. All the way along one wants to shout ‘No! not that way!’ and ‘Aargh! Don’t do it!’. As the tragedy unfolds, the audience weeps for the players, trapped by a cruel fate. All application development and deployment requires defense in depth. All IT goes wrong occasionally, but if there is a culture of defensive programming throughout, the consequences are usually containable. For financial systems, these defenses are required by statute, and ignored only by the foolish. Knight’s mistakes weren’t made by just one hapless sysadmin, but were progressive errors by an  IT culture spanning at least ten years.  One can spell these out, but I think they’re obvious. One can only hope that the industry studies what happened in detail, learns from the mistakes, and draws the right conclusions.

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• Rules for Naming

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Naming Documents (or is it “Document, Naming”?) Tis but thy name that is my enemy; Thou art thyself, though not a Montague. What's Montague? It is nor hand, nor foot, Nor arm, nor face, nor any other part Belonging to a man. O, be some other name! What's in a name? That which we call a rose By any other name would smell as sweet; So Romeo would, were he not Romeo call'd, Retain that dear perfection which he owes Without that title. Romeo, doff thy name And for that name which is no part of thee Take all myself.  Shakespeare – Romeo and Juliet Act II, Scene 2 We normally only use the bold portion of the famous Shakespearean quote above, but it is really out of context. As the play unfolds, we learn that a name is all too powerful. Indeed it is because of their names that the doomed lovers die. There might be life and death in a name (BTW, when I wrote this monogram, I was in Hatfield, PA. Remember the Hatfields and the McCoys?) This is a bit extreme, but in the field of Knowledge Management (KM) names are of the utmost importance as well. When I write an article about managing SharePoint sites, how should I name it? “Managing a site” or “Site, managing”? Nine times out of ten I’d opt for the latter. Almost everything we do is “Managing” so to make life easier for a person looking for meaningful content, we title our articles starting with the differentiator rather than the common factor. As a rule of thumb, we start the name with the noun rather than the verb. It is not what we do that is the primary key; it is what we do it to. So, answer this – is it a “rule of thumb” or a “thumb rule?” This is tough. A lot of what we do when naming is a judgment call. Both thumb and rule are nouns, albeit concrete and abstract (more about this later), but to most people “thumb rule” is meaningless while “rule of thumb” is an idiom. The difference between knowledge and information is that knowledge is meaningful information placed in context. Thus I elect the “rule of thumb”. It is the more meaningful title. Abstract and Concrete are relative terms. Many nouns (and verbs) that are abstract to a commoner, are concrete to a practitioner of one profession or another and may even have different concrete meanings in different professional jargons. Think about “running”. To an executive it means running a business, to a marathoner its meaning is much more literal. Generally speaking, we store and disseminate knowledge within a practice more than we do it in general. Even dictionaries encyclopedias define terms as they apply to different audiences. The rule of thumb is to put the more concrete first, but within the audience’s jargon. Even the title of this monogram is a question. Do I name it “Naming Documents” or “Documents, Naming”? Well, my own rule of thumb (“Here he goes again!?”) states that the latter is better because it starts with a noun, but this is a document about naming more than it about documents. The rules of naming also apply to graphs and charts, excel spreadsheets, and so on. Thus, I vote for the former.  A better title could have been “Naming Objects” only the word “Object” is a bit too abstract. How about just “Naming” or “Naming, rules of”? You get the drift. One of the ways to resolve all of this is to store the documents in Knowledge-Bases, which may become the subjects of a future punditry. Knowledge bases use keywords to describe their content.  Use a Metadata store for the keywords to at least attempt some common grounds. Here is another general rule (rule of thumb?!!) – put at least the one keyword in the title. Use subtitles. Here is an example: Migrating documents – Screening, cleaning, and organizing our knowledge. The main keyword is “documents”, next is “migrating”, other keywords also appear in the subtitle. They are “screening”, “cleaning”, and “organizing”. Any questions? Send me an amply named document by email: [email protected]

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• SOA, Governance, and Drugs

  Why is IT governance important in service oriented architecture (SOA)? IT Governance provides a framework for making appropriate decisions based on company guidelines and accepted standards. This framework also outlines each stakeholder’s responsibilities and authority when making important architectural or design decisions. Furthermore, this framework of governance defines parameters and constraints that are used to give context and perspective when making decisions. The use of governance as it applies to SOA ensures that specific design principles and patterns are used when developing and maintaining services. When governance is consistently applied systems the following benefits are achieved according to Anne Thomas Manes in 2010. Governance makes sure that services conform to standard interface patterns, common data modeling practices, and promotes the incorporation of existing system functionality by building on top of other available services across a system. Governance defines development standards based on proven design principles and patterns that promote reuse and composition. Governance provides developers a set of proven design principles, standards and practices that promote the reduction in system based component dependencies.  By following these guidelines, individual components will be easier to maintain. For me personally, I am a fan of IT governance, and feel that it valuable part of any corporate IT department. However, depending on how it is implemented can really affect the value of using IT governance.  Companies need to find a way to ensure that governance does not become extreme in its policies and procedures. I know for me personally, I would really dislike working under a completely totalitarian or laissez-faire version of governance. Developers need to be able to be creative in their designs and too much governance can really impede the design process and prevent the most optimal design from being developed. On the other hand, with no governance enforced, no standards will be followed and accepted design patterns will be ignored. I have personally had to spend a lot of time working on this particular scenario and I have found that the concept of code reuse and composition is almost nonexistent.  Based on this, too much time and money is wasted on redeveloping existing aspects of an application that already exist within the system as a whole. I think moving forward we will see a staggered form of IT governance, regardless if it is for SOA or IT in general.  Depending on the size of a company and the size of its IT department,  I can see IT governance as a layered approach in that the top layer will be defined by enterprise architects that focus on abstract concepts pertaining to high level design, general  guidelines, acceptable best practices, and recommended design patterns.  The next layer will be defined by solution architects or department managers that further expand on abstracted guidelines defined by the enterprise architects. This layer will contain further definitions as to when various design patterns, coding standards, and best practices are to be applied based on the context of the solutions that are being developed by the department. The final layer will be defined by the system designer or a solutions architect assed to a project in that they will define what design patterns will be used in a solution, naming conventions, as well as outline how a system will function based on the best practices defined by the previous layers. This layered approach allows for IT departments to be flexible in that system designers have creative leeway in designing solutions to meet the needs of the business, but they must operate within the confines of the abstracted IT governance guidelines.  A real world example of this can be seen in the United States as it pertains to governance of the people in that the US government defines rules and regulations in the abstract and then the state governments take these guidelines and applies them based on the will of the people in each individual state. Furthermore, the county or city governments are the ones that actually enforce these rules based on how they are interpreted by local community.  To further define my example, the United States government defines that marijuana is illegal. Each individual state has the option to determine this regulation as it wishes in that the state of Florida determines that all uses of the drug are illegal, but the state of California legally allows the use of marijuana for medicinal purposes only. Based on these accepted practices each local government enforces these rules in that a police officer will arrest anyone in the state of Florida for having this drug on them if they walk down the street, but in California if a person has a medical prescription for the drug they will not get arrested.  REFERENCESThomas Manes, Anne. (2010). Understanding SOA Governance: http://www.soamag.com/I40/0610-2.php

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• Waiting for Windows 8: A Long, Hot Summer

  - by andrewbrust

  Microsoft has revealed some things about Windows 8, and revealed a part of the developer story for new Windows 8 “tailored,” “immersive” applications.  In retrospect, very little was shared.  The bit that was revealed to us is that those applications can be developed using a combination of HTML 5 and JavaScript.  Not much else was said, except that additional details would be revealed at Microsoft’s //Build/ conference in Anaheim, California in September. This has left a lot of people in suspense, and it seems that suspended state is going to last all summer.  The problem, of course, is that in the absence of hard information, people fill the void with Speculation, Rumor and Gloom.  That’s a bit like Fear, Uncertainty and Doubt, except that it’s self-imposed by the Microsoft community and not planted by Microsoft’s competitors. This is a less-than-perfect situation.  Not only is it causing developers to worry about the value of their skill sets, but I am already hearing from consulting shops that customers are getting nervous too and, in extreme cases, opting for non-Microsoft tools for their projects as a result.  I’m also hearing from dev tool ISVs that sales have suffered as a result. It’s quite possible that the customers moving off .NET wanted to do so anyway and it’s also possible that dev tool ISVs are suffering slower sales this year due a slowed rate of economic recovery. Without hard information, tend to people interpret things negatively.  Actually, that’s the major point in all of this. While there is multitude of opinions about what the Windows 8 development platform will look like once fully revealed, there is an emerging consensus around one thing: it sure would help if Microsoft revealed more of its strategy…just enough to quash absurd rumors, stabilize the .NET ecosystem and get people to stay calm. We’ve had some reassurances thus far: there will be a Windows desktop mode; we’ll still have Windows Explorer, we’ll still run Office, we’ll still have a task bar, and all the skills and tools we use now will still work there.  But with reassurances like that…people still feel insecure.  Because telling us that Windows 8 will have what is essentially a “classic” mode sure makes it sound like today’s skill sets will soon be “classic” too…and then maybe they’ll just become obsolete. Humans find change scary; it’s natural.  And when left alone with their fears – because no one is saying anything to dispel them – people can go from frightened to paranoid, and can start to viewing things in a downright conspiratorial light.  It would be great if Microsoft stepped into the void now and told us what is coming – especially because whatever they tell us is bound to be at least a little better than what people think they are going to hear. I don’t know what the announcements will be, but I do have it on authority, from a number of sources, that Microsoft isn’t gong to talk until //Build/.  That means no news until September September 13th.  Nothing until after Labor Day.  You get zippo until after the Back-to-School sales are done. What to do?  Try not to let the dark voices of gloom and doom fill your head.  Even in the absence of answers, we still have some important facts: The .NET developer community is huge. Microsoft’s customers have major investments in .NET, and in .NET skills. Political infighting in Redmond might make for irrational decisions, but ultimately public companies can’t just alienate their advocates and piss off their customers.  Spite doesn’t trump fiduciary responsibility. The computing device markets are changing, software is changing, software business models are changing and developers are changing.  Microsoft has to keep up. The HTML + JavaScript community is huge too, and it includes many of the “changed” developers. Public companies can’t ignore new markets nor the popular standards that can help them enter those new markets.  Loyalty doesn’t trump fiduciary responsibility either. If Microsoft can appeal to new developers, then it should. If Microsoft can keep catering to its existing developers and customers -- not just through legacy support, but also through empowering futures -- then it probably will. You don’t have to shove your old friends out into the rain to make room for new ones; you can bring those new constituents in under a bigger tent.  I hope Microsoft will enlarge the tent, and I have trouble imagining why it would not.

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• Implementing a Custom Coherence PartitionAssignmentStrategy

  - by jpurdy

  A recent A-Team engagement required the development of a custom PartitionAssignmentStrategy (PAS). By way of background, a PAS is an implementation of a Java interface that controls how a Coherence partitioned cache service assigns partitions (primary and backup copies) across the available set of storage-enabled members. While seemingly straightforward, this is actually a very difficult problem to solve. Traditionally, Coherence used a distributed algorithm spread across the cache servers (and as of Coherence 3.7, this is still the default implementation). With the introduction of the PAS interface, the model of operation was changed so that the logic would run solely in the cache service senior member. Obviously, this makes the development of a custom PAS vastly less complex, and in practice does not introduce a significant single point of failure/bottleneck. Note that Coherence ships with a default PAS implementation but it is not used by default. Further, custom PAS implementations are uncommon (this engagement was the first custom implementation that we know of). The particular implementation mentioned above also faced challenges related to managing multiple backup copies but that won't be discussed here. There were a few challenges that arose during design and implementation: Naive algorithms had an unreasonable upper bound of computational cost. There was significant complexity associated with configurations where the member count varied significantly between physical machines. Most of the complexity of a PAS is related to rebalancing, not initial assignment (which is usually fairly simple). A custom PAS may need to solve several problems simultaneously, such as: Ensuring that each member has a similar number of primary and backup partitions (e.g. each member has the same number of primary and backup partitions) Ensuring that each member carries similar responsibility (e.g. the most heavily loaded member has no more than one partition more than the least loaded). Ensuring that each partition is on the same member as a corresponding local resource (e.g. for applications that use partitioning across message queues, to ensure that each partition is collocated with its corresponding message queue). Ensuring that a given member holds no more than a given number of partitions (e.g. no member has more than 10 partitions) Ensuring that backups are placed far enough away from the primaries (e.g. on a different physical machine or a different blade enclosure) Achieving the above goals while ensuring that partition movement is minimized. These objectives can be even more complicated when the topology of the cluster is irregular. For example, if multiple cluster members may exist on each physical machine, then clearly the possibility exists that at certain points (e.g. following a member failure), the number of members on each machine may vary, in certain cases significantly so. Consider the case where there are three physical machines, with 3, 3 and 9 members each (respectively). This introduces complexity since the backups for the 9 members on the the largest machine must be spread across the other 6 members (to ensure placement on different physical machines), preventing an even distribution. For any given problem like this, there are usually reasonable compromises available, but the key point is that objectives may conflict under extreme (but not at all unlikely) circumstances. The most obvious general purpose partition assignment algorithm (possibly the only general purpose one) is to define a scoring function for a given mapping of partitions to members, and then apply that function to each possible permutation, selecting the most optimal permutation. This would result in N! (factorial) evaluations of the scoring function. This is clearly impractical for all but the smallest values of N (e.g. a partition count in the single digits). It's difficult to prove that more efficient general purpose algorithms don't exist, but the key take away from this is that algorithms will tend to either have exorbitant worst case performance or may fail to find optimal solutions (or both) -- it is very important to be able to show that worst case performance is acceptable. This quickly leads to the conclusion that the problem must be further constrained, perhaps by limiting functionality or by using domain-specific optimizations. Unfortunately, it can be very difficult to design these more focused algorithms. In the specific case mentioned, we constrained the solution space to very small clusters (in terms of machine count) with small partition counts and supported exactly two backup copies, and accepted the fact that partition movement could potentially be significant (preferring to solve that issue through brute force). We then used the out-of-the-box PAS implementation as a fallback, delegating to it for configurations that were not supported by our algorithm. Our experience was that the PAS interface is quite usable, but there are intrinsic challenges to designing PAS implementations that should be very carefully evaluated before committing to that approach.

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• Oracle OpenWorld ?? Oracle|Sun

  - by user13137902

  Oracle|Sun @ Oracle OpenWorld Tokyo 2012 ?? Solaris?????@Oracle Develop@Tokyo 2011 ??????????????????Oracle|Sun????????????? ??????????????????????????????(^ ^;) ?????? Oracle OpenWorld Tokyo 2012 ??4?4???4?6??3??? ???????? ????? ??????????????????? ???&?????????? Oracle OpenWorld Tokyo 2012 ???? ???&????? ????????????????????????????????????? ???Exa*???????????????????????????????? ????????????????????????????? ????Oracle OpenWorld Tokyo 2012???? Oracle|Sun ?????????????????????? ??????????????? K1-014/4(?) 9:00-11:15 ENGINEERED FOR INNOVATION ??????????????????·???????? ?????? ???·??? ????·???????? ???????·????????? ???·????? ????·???????? ???·??????·?????? ?????·?????? ?????????? ??????? ??????? ?? ?? S1-014/4(?) 11:50-12:35 Oracle Engineered Systems Strategy-?????????????????????????????????????·???????? ????·????????? ????·??? S1-334/4(?) 15:20-16:05 ??????????????????????????????????????????????????????????? ????????????????? ?? ?? S1-424/4(?) 16:30-17:15 ?????Engineered Systems?????????????IT?????????????? ????????????????? ?? ? K2-014/5(?) 9:30-11:15 Extreme Innovation????·???????? ???????(CEO) ???·???? G2-014/5(?) 11:50-13:20 ??????&???????????IT??????????????·???????? ???????·????????? ???·???? S2-424/5(?) 16:30-17:15 ??UNIX??????????-SPARC SuperCluster?????????? ????????????????? ?? ? S2-534/5(?) 17:40-18:25 Oracle E-Business Suite????????????????????/??????????????????????”SPARC SuperCluster”?????????? ????????????????? ?? ?? S3-134/6(?) 13:00-13:45 ?????SNS??????????????? Sun ZFS Storage Appliance ????????????????? ???????? ?? ?? S3-214/6(?) 14:10-14:55 ???????????????????????????????????????? ???????? ????? ?? ?? ? S3-334/6(?) 15:20-16:05 ????????·????????????????????????????????????????? ???? ?????????? ?? ??(????) ?? ?? ? 1?????????????K1-01?????? ????????????????????????????????????????? ??????????????????? ??????1???????·?????????? ???????Solaris???????????? ???????????????S1-01?Engineered System??????????? S1-33?????????????????????????????????????? S1-42?????????????????????????????????? ???????·?????????K2-01?????????? ?????????????????????????? ???????????????????????????????????? ?????????????????????? ??????????????????????? ??????????????????????????? ????????Engineered System? ??????????????????????????? ??G2-01??????·???????????? ???????????????????????? ??????????????????????? S2-42??????????????? SPARC?????Engineered System???SPARC SuperCluster T4-4????????? ???????????????????????????????? S2-53?????SuperCluster???? ???????????SuperCluster??????????????? ??????????????????????????????????? ????????????Oracle Optimized Solution?????? ?????????Oracle Develop???????? ????????????ZFS Storage Appliance????3????????????? ??????????????????????????????? ?????????????????????????? ???ZFS Storage Appliance???????????????????? ????????????? ???? ?????????????? ??????????????7324????????? (?????????????????? facebook ????????????? ????????????)? ????????????????????????????????????????????

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• Sunrise / set calculations

  - by dassouki

  I'm trying to calculate the sunset / rise times using python based on the link provided below. My results done through excel and python do not match the real values. Any ideas on what I could be doing wrong? My Excel sheet can be found under .. http://transpotools.com/sun_time.xls # Created on 2010-03-28 # @author: dassouki # @source: [http://williams.best.vwh.net/sunrise_sunset_algorithm.htm][2] # @summary: this is based on the Nautical Almanac Office, United States Naval # Observatory. import math, sys class TimeOfDay(object): def calculate_time(self, in_day, in_month, in_year, lat, long, is_rise, utc_time_zone): # is_rise is a bool when it's true it indicates rise, # and if it's false it indicates setting time #set Zenith zenith = 96 # offical = 90 degrees 50' # civil = 96 degrees # nautical = 102 degrees # astronomical = 108 degrees #1- calculate the day of year n1 = math.floor( 275 * in_month / 9 ) n2 = math.floor( ( in_month + 9 ) / 12 ) n3 = ( 1 + math.floor( in_year - 4 * math.floor( in_year / 4 ) + 2 ) / 3 ) new_day = n1 - ( n2 * n3 ) + in_day - 30 print "new_day ", new_day #2- calculate rising / setting time if is_rise: rise_or_set_time = new_day + ( ( 6 - ( long / 15 ) ) / 24 ) else: rise_or_set_time = new_day + ( ( 18 - ( long/ 15 ) ) / 24 ) print "rise / set", rise_or_set_time #3- calculate sun mean anamoly sun_mean_anomaly = ( 0.9856 * rise_or_set_time ) - 3.289 print "sun mean anomaly", sun_mean_anomaly #4 calculate true longitude true_long = ( sun_mean_anomaly + ( 1.916 * math.sin( math.radians( sun_mean_anomaly ) ) ) + ( 0.020 * math.sin( 2 * math.radians( sun_mean_anomaly ) ) ) + 282.634 ) print "true long ", true_long # make sure true_long is within 0, 360 if true_long < 0: true_long = true_long + 360 elif true_long > 360: true_long = true_long - 360 else: true_long print "true long (360 if) ", true_long #5 calculate s_r_a (sun_right_ascenstion) s_r_a = math.degrees( math.atan( 0.91764 * math.tan( math.radians( true_long ) ) ) ) print "s_r_a is ", s_r_a #make sure it's between 0 and 360 if s_r_a < 0: s_r_a = s_r_a + 360 elif true_long > 360: s_r_a = s_r_a - 360 else: s_r_a print "s_r_a (modified) is ", s_r_a # s_r_a has to be in the same Quadrant as true_long true_long_quad = ( math.floor( true_long / 90 ) ) * 90 s_r_a_quad = ( math.floor( s_r_a / 90 ) ) * 90 s_r_a = s_r_a + ( true_long_quad - s_r_a_quad ) print "s_r_a (quadrant) is ", s_r_a # convert s_r_a to hours s_r_a = s_r_a / 15 print "s_r_a (to hours) is ", s_r_a #6- calculate sun diclanation in terms of cos and sin sin_declanation = 0.39782 * math.sin( math.radians ( true_long ) ) cos_declanation = math.cos( math.asin( sin_declanation ) ) print " sin/cos declanations ", sin_declanation, ", ", cos_declanation # sun local hour cos_hour = ( math.cos( math.radians( zenith ) ) - ( sin_declanation * math.sin( math.radians ( lat ) ) ) / ( cos_declanation * math.cos( math.radians ( lat ) ) ) ) print "cos_hour ", cos_hour # extreme north / south if cos_hour > 1: print "Sun Never Rises at this location on this date, exiting" # sys.exit() elif cos_hour < -1: print "Sun Never Sets at this location on this date, exiting" # sys.exit() print "cos_hour (2)", cos_hour #7- sun/set local time calculations if is_rise: sun_local_hour = ( 360 - math.degrees(math.acos( cos_hour ) ) ) / 15 else: sun_local_hour = math.degrees( math.acos( cos_hour ) ) / 15 print "sun local hour ", sun_local_hour sun_event_time = sun_local_hour + s_r_a - ( 0.06571 * rise_or_set_time ) - 6.622 print "sun event time ", sun_event_time #final result time_in_utc = sun_event_time - ( long / 15 ) + utc_time_zone return time_in_utc #test through main def main(): print "Time of day App " # test: fredericton, NB # answer: 7:34 am long = 66.6 lat = -45.9 utc_time = -4 d = 3 m = 3 y = 2010 is_rise = True tod = TimeOfDay() print "TOD is ", tod.calculate_time(d, m, y, lat, long, is_rise, utc_time) if __name__ == "__main__": main()

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• List of freely available programming books

  - by Karan Bhangui

  I'm trying to amass a list of programming books with opensource licenses, like Creative Commons, GPL, etc. The books can be about a particular programming language or about computers in general. Hoping you guys could help: Languages BASH Advanced Bash-Scripting Guide (An in-depth exploration of the art of shell scripting) C The C book C++ Thinking in C++ C++ Annotations How to Think Like a Computer Scientist C# .NET Book Zero: What the C or C++ Programmer Needs to Know About C# and the .NET Framework Illustrated C# 2008 (Dead Link) Data Structures and Algorithms with Object-Oriented Design Patterns in C# Threading in C# Common Lisp Practical Common Lisp On Lisp Java Thinking in Java How to Think Like a Computer Scientist Java Thin-Client Programming JavaScript Eloquent JavaScript Haskell Real world Haskell Learn You a Haskell for Great Good! Objective-C The Objective-C Programming Language Perl Extreme Perl (license not specified - home page is saying "freely available") The Mason Book (Open Publication License) Practical mod_perl (CreativeCommons Attribution Share-Alike License) Higher-Order Perl Learning Perl the Hard Way PHP Practical PHP Programming Zend Framework: Survive the Deep End PowerShell Mastering PowerShell Prolog Building Expert Systems in Prolog Adventure in Prolog Prolog Programming A First Course Logic, Programming and Prolog (2ed) Introduction to Prolog for Mathematicians Learn Prolog Now! Natural Language Processing Techniques in Prolog Python Dive Into Python Dive Into Python 3 How to Think Like a Computer Scientist A Byte of Python Python for Fun Invent Your Own Computer Games With Python Ruby Why's (Poignant) Guide to Ruby Programming Ruby - The Pragmatic Programmer's Guide Mr. Neighborly's Humble Little Ruby Book SQL Practical PostgreSQL x86 assembly Paul Carter's tutorial Lua Programming In Lua (for v5 but still largely relevant) Algorithms and Data Structures Algorithms Data Structures and Algorithms with Object-Oriented Design Patterns in Java Planning Algorithms Frameworks/Projects The Django Book The Pylons Book Introduction to Design Patterns in C++ with Qt 4 (Open Publication License) Version control The SVN Book Mercurial: The Definitive Guide Pro Git UNIX / Linux The Art of Unix Programming Linux Device Drivers, Third Edition Others Structure and Interpretation of Computer Programs The Little Book of Semaphores Mathematical Logic - an Introduction An Introduction to the Theory of Computation Developers Developers Developers Developers Linkers and loaders Beej's Guide to Network Programming Maven: The Definitive Guide I will expand on this list as I get comments or when I think of more :D Related: Programming texts and reference material for my Kindle What are some good free programming books? Can anyone recommend a free software engineering book? Edit: Oh I didn't notice the community wiki feature. Feel free to edit your suggestions right in!

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• R Install/Update on Mac OS X (Snow Leopard): where does R put files during install/config?

  - by doug

  In sum, there's a stray preference-like file or two (probably just one) that i can't find. Here's the whole story: I recently attempted to update my R install from 2.10 to 2.11. As i have done before, i installed from source. I know that all of the dependencies are correctly installed and made available to R, because my prior install worked fine. When i upgraded to 2.11, i am unable to install packages (no exception thrown, it just doesn't appear to complete the install and is unresponsive so i have to quit + restart R. Given i install from source, there are any number of points in the process that i could have messed up. What i need to do now is "start over" which requires that i clear out my my prior install. I am having trouble doing that. There is still at least one preference file or something like that i can't find and one of these is causing the problem, so i need to find it and terminate it with extreme prejudice before i do a fresh install. Although i set a number of flags during the install, i have never opted out of the default install locations during the config step. There has to be one or more preference files still in my file structure (and that's also accessible to the new install of R) because after i follow all of the steps below, then do a fresh install, when i start R for the first time, some of my preferences have persisted (e.g., quartz settings, GUI background color, editor selection, etc.). Again, the problem is that i just cannot locate those files. Finally, the problem can't be that during my last install from source, i inadvertently caused a preference file to be sent to an off-spec location--because again, a fresh R install (whether from source or from the OS X binaries) is finding those files Here's what i've done prior to attempting a clean install of R: Removed files from these locations: ~/.RData ~/.RHistory /Applications/R64.app /Applications/R.app /Library/Frameworks/R.framework (i also removed all symlinks from these) Cleared all RAM and disk caches, in particular the directory where i know R caches: ~/Library/Caches/R* (in fact i've cleared this entire directory) Checked for all 'hidden' files in the OS X directories where login/startup files are often placed: /etc/ ~/ In addition, i've checked R-help, and i've also read through the relevant portions of 'R Installation and Administration'--no luck. I've also searched searched my file structure using the various bash utilities, which nearly always solves problems of this sort quite easily, but in this case obviously searching by name or even pattern is more problematic.

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• Error using `loess.smooth` but not `loess` or `lowess`

  - by Sandy

  I need to smooth some simulated data, but occasionally run into problems when the simulated ordinates to be smoothed are mostly the same value. Here is a small reproducible example of the simplest case. > x <- 0:50 > y <- rep(0,51) > loess.smooth(x,y) Error in simpleLoess(y, x, w, span, degree, FALSE, FALSE, normalize = FALSE, : NA/NaN/Inf in foreign function call (arg 1) loess(y~x), lowess(x,y), and their analogue in MATLAB produce the expected results without error on this example. I am using loess.smooth here because I need the estimates evaluated at a set number of points. According to the documentation, I believe loess.smooth and loess are using the same estimation functions, but the former is an "auxiliary function" to handle the evaluation points. The error seems to come from a C function: > traceback() 3: .C(R_loess_raw, as.double(pseudovalues), as.double(x), as.double(weights), as.double(weights), as.integer(D), as.integer(N), as.double(span), as.integer(degree), as.integer(nonparametric), as.integer(order.drop.sqr), as.integer(sum.drop.sqr), as.double(span * cell), as.character(surf.stat), temp = double(N), parameter = integer(7), a = integer(max.kd), xi = double(max.kd), vert = double(2 * D), vval = double((D + 1) * max.kd), diagonal = double(N), trL = double(1), delta1 = double(1), delta2 = double(1), as.integer(0L)) 2: simpleLoess(y, x, w, span, degree, FALSE, FALSE, normalize = FALSE, "none", "interpolate", control$cell, iterations, control$trace.hat) 1: loess.smooth(x, y) loess also calls simpleLoess, but with what appears to be different arguments. Of course, if you vary enough of the y values to be nonzero, loess.smooth runs without error, but I need the program to run in even the most extreme case. Hopefully, someone can help me with one and/or all of the following: Understand why only loess.smooth, and not the other functions, produces this error and find a solution for this problem. Find a work-around using loess but still evaluating the estimate at a specified number of points that can differ from the vector x. For example, I might want to use only x <- seq(0,50,10) in the smoothing, but evaluate the estimate at x <- 0:50. As far as I know, using predict with a new data frame will not properly handle this situation, but please let me know if I am missing something there. Handle the error in a way that doesn't stop the program from moving onto the next simulated data set. Thanks in advance for any help on this problem.

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• get_or_create generic relations in Django & python debugging in general

  - by rabidpebble

  I ran the code to create the generically related objects from this demo: http://www.djangoproject.com/documentation/models/generic_relations/ Everything is good intially: >>> bacon.tags.create(tag="fatty") <TaggedItem: fatty> >>> tag, newtag = bacon.tags.get_or_create(tag="fatty") >>> tag <TaggedItem: fatty> >>> newtag False But then the use case that I'm interested in for my app: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome") Traceback (most recent call last): File "<console>", line 1, in <module> File "/usr/local/lib/python2.6/dist-packages/django/db/models/manager.py", line 123, in get_or_create return self.get_query_set().get_or_create(**kwargs) File "/usr/local/lib/python2.6/dist-packages/django/db/models/query.py", line 343, in get_or_create raise e IntegrityError: app_taggeditem.content_type_id may not be NULL I tried a bunch of random things after looking at other code: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome", content_type=TaggedItem) ValueError: Cannot assign "<class 'generics.app.models.TaggedItem'>": "TaggedItem.content_type" must be a "ContentType" instance. or: >>> tag, newtag = bacon.tags.get_or_create(tag="wholesome", content_type=TaggedItem.content_type) InterfaceError: Error binding parameter 3 - probably unsupported type. etc. I'm sure somebody can give me the correct syntax, but the real problem here is that I have no idea what is going on. I have developed in strongly typed languages for over ten years (x86 assembly, C++ and C#) but am new to Python. I find it really difficult to follow what is going on in Python when things like this break. In the languages I mentioned previously it's fairly straightforward to figure things like this out -- check the method signature and check your parameters. Looking at the Django documentation for half an hour left me just as lost. Looking at the source for get_or_create(self, **kwargs) didn't help either since there is no method signature and the code appears very generic. A next step would be to debug the method and try to figure out what is happening, but this seems a bit extreme... I seem to be missing some fundamental operating principle here... what is it? How do I resolve issues like this on my own in the future?

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• Exception opening TAdoDataset: Arguments are of the wrong type, are out of acceptable range, or are

  - by Dave Falkner

  I've been trying to debug the following problem for several weeks now - this method is called from several places within the same datamodule, but this exception (from the subject line of this post) only occurs when integers for a certain purpose (pickup orders vs. orders that we ship through a carrier) are used - and don't ask me how the application can tell the difference between one integer's purpose and another! Furthermore, I cannot duplicate this issue on my machine - the error occurs on a warehouse machine but not my own development machine, even when working with the same production database. I have suspected an MDAC version conflict between the two machines, but have run a version checker and confirmed that both machines are running 2.8, and additionally have confirmed this by logging the TAdoDataset's .Version property at runtime. function TdmESShip.SecondaryID(const PrimaryID : Integer ): String; begin try with qESPackage2 do begin if Active then Close; LogMessage('-----------------------------------'); LogMessage('Version: ' + FConnection.Version); LogMessage('DB Info: ' + FConnection.Properties['Initial Catalog'].Value + ' ' + FConnection.Properties['Data Source'].Value); LogMessage('Setting the parameter.'); Parameters.ParamByName('ParameterName').Value := PrimaryID; LogMessage('Done setting the parameter.'); Open; Ninety-nine times out of 100 this logging code logs a successful operation as follows: Version: 2.8 DB Info: (database name and instance) Setting the parameter. Done setting the parameter. Opened the dataset. But then whenever a "pickup" order is processed, this exception gets thrown whenever the dataset is opened: Version: 2.8 DB Info: (database name and instance) Setting the parameter. Done setting the parameter. GetESPackageID() threw an exception. Type: EOleException, Message: Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another Error: Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another for packageID 10813711 I've tried eliminating the parameter and have built the commandtext for this dataset programmatically, suspecting that some part of the TParameter's configuration might be out of whack, but the same error occurs under the same circumstances. I've tried every combination of TParameter properties that I can think of - this is the millionth TParameter I've created for my millionth dataset, and I've never encountered this error. I've even created a second dataset from scratch and removed all references to the original dataset in case some property of the original dataset in the .dfm might be corrupted, but the same error occurs under the same circumstances. The commandtext for this dataset is a simple select ValueA from TableName where ValueB = @ParameterB I'm about ready to do something extreme, such as writing a web service to look these values up - it feels right now as though I could destroy my machine, rebuild it, rewrite this entire application from scratch, and the application would still know to throw an exception whenever I try to look up a secondary value from a primary value, but only for pickup orders, and only from the one machine in the warehouse, but I'm probably missing something simple. So, any help anyone could provide would be greatly appreciated.

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• Why is cell phone software still so primitive?

  - by Tomislav Nakic-Alfirevic

  I don't do mobile development, but it strikes me as odd that features like this aren't available by default on most phones: full text search: searches all address book contents, messages, anything else being a plus better call management: e.g. a rotating audio call log, meaning you always have the last N calls recorded for your listening pleasure later (your little girl just said her first "da-da" while you were on a business trip, you had a telephone job interview, you received complex instructions to do something etc.) bluetooth remote control (like e.g. anyRemote, but available by default on a bluetooth phone) no multitasking capabilities worth mentioning and in general no e.g. weekly software updates, making the phone much more usable (even if it had to be done over USB, rather than over the network). I'm sure I was dumbfounded by the lack or design of other features as well, but they don't come to mind right now. To clarify, I'm not talking about smartphones here: my plain, 2-year old phone has a CPU an order of magnitude faster than my first PC, about as much storage space and it's ridiculous how bad (slow, unwieldy) the software is and it's not one phone or one manufacturer. What keeps the (to me) obvious software functionality vacuum on a capable hardware platform from being filled up? Edit: I believe a clarification on the multitasking point might be beneficial. I'll use my phone as an example, although the point is much more general. The phone can multitask and in fact does: you can listen to music and do something else at the same time. On the other hand, the way the software has been designed makes multitasking next to useless. (Ditto with the external touch screen: it can take touch commands, but only one application makes use of it, and only with 3 commands.) To take the multitasking example to the extreme, if I plug my phone into my laptop and it registers as an external disk, it doesn't allow any kind of operation: messages, calling, calendar, everything out of reach, although I can receive a call. No "battery life" issue there: it's charging while connected. BTW, another example of design below the current state of the art: I don't see a phone on the horizon which will remember where in an audio or video file you were when you stopped listening/watching it last time (podcasts are a good use case). Simplistic rewind/fast forward functionality only aggravates the problem.

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• What's the standard algorithm for syncing two lists of objects?

  - by Oliver Giesen

  I'm pretty sure this must be in some kind of text book (or more likely in all of them) but I seem to be using the wrong keywords to search for it... :( A common task I'm facing while programming is that I am dealing with lists of objects from different sources which I need to keep in sync somehow. Typically there's some sort of "master list" e.g. returned by some external API and then a list of objects I create myself each of which corresponds to an object in the master list. Sometimes the nature of the external API will not allow me to do a live sync: For instance the external list might not implement notifications about items being added or removed or it might notify me but not give me a reference to the actual item that was added or removed. Furthermore, refreshing the external list might return a completely new set of instances even though they still represent the same information so simply storing references to the external objects might also not always be feasible. Another characteristic of the problem is that both lists cannot be sorted in any meaningful way. You should also assume that initializing new objects in the "slave list" is expensive, i.e. simply clearing and rebuilding it from scratch is not an option. So how would I typically tackle this? What's the name of the algorithm I should google for? In the past I have implemented this in various ways (see below for an example) but it always felt like there should be a cleaner and more efficient way. Here's an example approach: Iterate over the master list Look up each item in the "slave list" Add items that do not yet exist Somehow keep track of items that already exist in both lists (e.g. by tagging them or keeping yet another list) When done iterate once more over the slave list Remove all objects that have not been tagged (see 4.) Update Thanks for all your responses so far! I will need some time to look at the links. Maybe one more thing worthy of note: In many of the situations where I needed this the implementation of the "master list" is completely hidden from me. In the most extreme cases the only access I might have to the master list might be a COM-interface that exposes nothing but GetFirst-, GetNext-style methods. I'm mentioning this because of the suggestions to either sort the list or to subclass it both of which is unfortunately not practical in these cases unless I copy the elements into a list of my own and I don't think that would be very efficient. I also might not have made it clear enough that the elements in the two lists are of different types, i.e. not assignment-compatible: Especially, the elements in the master list might be available as interface references only.

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• Runtime.exec causes duplicate JVM to hang indefinitely until killed (Solaris 10)

  - by John

  All, We are running a J2EE application on WebLogic server 9.2 MP2 with a jrockit 64-bit JVM (27.3.1) on Solaris 10. We call use runtime.exec to call an executable called jfmerge to create PDF documents. We have found that in Solaris, when runtime.exec is called, a duplicate JVM is temporarily spawned to kick off the jfmerge process. While this is inefficient (our JVM is 5 GB, thus the duplicated shell JVM is also 5 GB), the major problem lies in the fact that when there is heavy load on this functionality (PDF generation) in our application, sometimes the duplicated JVM never exits. When the JVM hangs, the servers create large issues (extreme application slowness and terminated user sessions) as the entire duplicate JVM get's all of its 5 GB of process size written to disk swap. We have noted the following hung thread correlated with a hung JVM process until the process is manually killed: "[STUCK] ExecuteThread: '17' for queue: 'weblogic.kernel.Default (self-tuning)'" id=3463 idx=0x158 tid=3460 prio=1 alive, in native, daemon at jrockit/io/FileNativeIO.readBytesPinned(Ljava/io/FileDescriptor;[BII)I(Native Method) at jrockit/io/FileNativeIO.readBytes(FileNativeIO.java:30) at java/io/FileInputStream.readBytes([BII)I(FileInputStream.java) at java/io/FileInputStream.read(FileInputStream.java:194) at java/lang/UNIXProcess$DeferredCloseInputStream.read(UNIXProcess.java:227) at java/io/BufferedInputStream.fill(BufferedInputStream.java:218) at java/io/BufferedInputStream.read(BufferedInputStream.java:235) ^-- Holding lock: java/io/BufferedInputStream@0xfffffffec6510470[thin lock] at gov/v3/common/formgeneration/sessionbean/FormsBean.getProcessStatus(FormsBean.java:809) at gov/v3/common/formgeneration/sessionbean/FormsBean.createPDF(FormsBean.java:750) at gov/v3/common/formgeneration/sessionbean/FormsBean.getTemplateDetails(FormsBean.java:450) at gov/v3/common/formgeneration/sessionbean/FormsBean.generateSinglePDF(FormsBean.java:1371) at gov/v3/common/formgeneration/sessionbean/FormsBean.generatePDF(FormsBean.java:263) at gov/v3/common/formgeneration/sessionbean/FormsBean.endorseDocument(FormsBean.java:2377) at gov/v3/common/formgeneration/sessionbean/Forms_qaco28_EOImpl.endorseDocument(Forms_qaco28_EOImpl.java:214) at gov/v3/delegates/common/FormsAndNoticesDelegate.endorseDocument(FormsAndNoticesDelegate.java:128) at gov/v3/actions/common/EndorseDocumentAction.executeRequest(EndorseDocumentAction.java:68) at gov/v3/fwk/controller/struts/action/V3CommonDispatchAction.dispatchToExecuteMethod(V3CommonDispatchAction.java:532) at gov/v3/fwk/controller/struts/action/V3CommonDispatchAction.executeBaseAction(V3CommonDispatchAction.java:336) at gov/v3/fwk/controller/struts/action/V3BaseDispatchAction.execute(V3BaseDispatchAction.java:69) at org/apache/struts/action/RequestProcessor.processActionPerform(RequestProcessor.java:484) at gov/v3/fwk/controller/struts/requestprocessor/V3TilesRequestProcessor.processActionPerform(V3TilesRequestProcessor.java:384) at org/apache/struts/action/RequestProcessor.process(RequestProcessor.java:274) at org/apache/struts/action/ActionServlet.process(ActionServlet.java:1482) at org/apache/struts/action/ActionServlet.doGet(ActionServlet.java:507) at gov/v3/fwk/controller/struts/servlet/V3ControllerServlet.doGet(V3ControllerServlet.java:110) at javax/servlet/http/HttpServlet.service(HttpServlet.java:743) at javax/servlet/http/HttpServlet.service(HttpServlet.java:856) at weblogic/servlet/internal/StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic/servlet/internal/StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic/servlet/internal/ServletStubImpl.execute(ServletStubImpl.java:283) at weblogic/servlet/internal/ServletStubImpl.execute(ServletStubImpl.java:175) at weblogic/servlet/internal/WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3231) at weblogic/security/acl/internal/AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic/security/service/SecurityManager.runAs(SecurityManager.java:121) at weblogic/servlet/internal/WebAppServletContext.securedExecute(WebAppServletContext.java:2002) at weblogic/servlet/internal/WebAppServletContext.execute(WebAppServletContext.java:1908) at weblogic/servlet/internal/ServletRequestImpl.run(ServletRequestImpl.java:1362) at weblogic/work/ExecuteThread.execute(ExecuteThread.java:209) at weblogic/work/ExecuteThread.run(ExecuteThread.java:181) at jrockit/vm/RNI.c2java(JJJJJ)V(Native Method) -- end of trace We would like to do a couple of things: 1.) Prevent the spawning of a duplicate JVM, as we do not need any of it's functions when executing the simple jfmerge executable, and it creates massive overhead. 2.) In the short term at least prevent this duplicate JVM from handing indefinitely.

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• Resize AIR app window while dragging

  - by matt lohkamp

  So I've noticed Windows 7 has a disturbing tendency to prevent you from dragging the title bar of windows off the top of the screen. If you try - in this case, using an air app with a draggable area at the bottom of the window, allowing you to push the top of the window up past the screen - it just kicks the window back down far enough that the title bar is at the top of what it considers the 'visible area.' One solution would be to resize the app window as it moves, so that the title bar is always where windows wants it. How would you resize the window while you're dragging it, though? Would you do it like this? dragHitArea.addEventListener(MouseEvent.MOUSE_DOWN, function(e:MouseEvent):void{ stage.nativeWindow.height += 50; stage.nativeWindow.startMove(); stage.nativeWindow.height -= 50; }); see what's going on there? When I click, I'm doing startMove(), which is hooking into the OS' function for dragging a window around. I'm also increasing and decreasing the height of the window by 50 pixels - which should give me no net increase, right? Wrong - the first '.height +=' gets executed, but the '.height -=' after the .startMove() never runs. Why? update - If you're curious, I'm programming an air widget with fly-out menus which expand rightwards and upwards - and since those element can only be displayed within the boundaries of the application window itself (even though the window is set to be chromeless and transparent) I have to expand the application's borders to include the area that the menu 'pops up' into. In the extreme case, with the widget positioned bottom left, and the menus expanded completely across to the right side and top edge of the screen, the application area could very well cover the entire desktop. The problem is, when it's expanded like this, if the user drags it up and to the right, it causes the 'title bar' area of the application window to move above the top edge of the desktop area, where it would normally be unreachable; and Windows automatically re-positions the window back below that edge once the .startMove() operation is completed. So what I want to do is continually resize the height of the application so that the visual effect will be the same for the user, but for the benefit of the operating system the window's title bar will never be above that top boundary of the desktop area.

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• Poor performance / speed of regex with lookahead

  - by Hugo Zaragoza

  I have been observing extremely slow execution times with expressions with several lookaheads. I suppose that this is due to underlying data structures, but it seems pretty extreme and I wonder if I do something wrong or if there are known work-arounds. The problem is determining if a set of words are present in a string, in any order. For example we want to find out if two terms "term1" AND "term2" are somewhere in a string. I do this with the expresion: (?=.*\bterm1\b)(?=.*\bterm2\b) But what I observe is that this is an order of magnitude slower than checking first just \bterm1\b and just then \bterm2\b This seems to indicate that I should use an array of patterns instead of a single pattern with lookaheads... is this right? it seems wrong... Here is an example test code and resulting times: public static void speedLookAhead() { Matcher m, m1, m2; boolean find; int its = 1000000; // create long non-matching string char[] str = new char[2000]; for (int i = 0; i < str.length; i++) { str[i] = 'x'; } String test = str.toString(); // First method: use one expression with lookaheads m = Pattern.compile("(?=.*\\bterm1\\b)(?=.*\\bterm2\\b)").matcher(test); long time = System.currentTimeMillis(); ; for (int i = 0; i < its; i++) { m.reset(test); find = m.find(); } time = System.currentTimeMillis() - time; System.out.println(time); // Second method: use two expressions and AND the results m1 = Pattern.compile("\\bterm1\\b").matcher(test); m2 = Pattern.compile("\\bterm2\\b").matcher(test); time = System.currentTimeMillis(); ; for (int i = 0; i < its; i++) { m1.reset(test); m2.reset(test); find = m1.find() && m2.find(); } time = System.currentTimeMillis() - time; System.out.println(time); } This outputs in my computer: 1754 150

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• Execution plan issue requires reset on SQL Server 2005, how to determine cause?

  - by Tony Brandner

  We have a web application that delivers training to thousands of corporate students running on top of SQL Server 2005. Recently, we started seeing that a single specific query in the application went from 1 second to about 30 seconds in terms of execution time. The application started throwing timeouts in that area. Our first thought was that we may have incorrect indexes, so we reviewed the tables and indexes. However, similar queries elsewhere in the application also run quickly. Reviewing the indexes showed us that they were configured as expected. We were able to narrow it down to a single query, not a stored procedure. Running this query in SQL Studio also runs quickly. We tried running the application in a different server environment. So a different web server with the same query, parameters and database. The query still ran slow. The query is a fairly large one related to determining a student's current list of training. It includes joins and left joins on a dozen tables and subqueries. A few of the tables are fairly large (hundreds of thousands of rows) and some of the other tables are small lookup tables. The query uses a grouping clause and a few where conditions. A few of the tables are quite active and the contents change often but the volume of added rows doesn't seem extreme. These symptoms led us to consider the execution plan. First off, as soon as we reset the execution plan cache with the SQL command 'DBCC FREEPROCCACHE', the problem went away. Unfortunately, the problem started to reoccur within a few days. The problem has continued to plague us for awhile now. It's usually the same query, but we did appear to see the problem occur in another single query recently. It happens enough to be a nuisance. We're having a heck of a time trying to fix it since we can't reproduce it in any other environment other than production. I have downloaded the High Availability guide from Red Gate and I read up more on execution plans. I hope to run the profiler on the live server, but I'm a bit concerned about impact. I would like to ask - what is the best way to figure out what is triggering this problem? Has anyone else seen this same issue?

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