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  • how to start LXDE session automatically after tightvncserver starts to make me able see desktop when connecting to the host via vncclient?

    - by Oleksandr Dudchenko
    I have system which is equipped with Intel Celeron processor 1.1 GHz s370 with 384 Mb of RAM on Intel d815egew motherboard which supports wake-on-lan function. I want to use such a PC for Internet sharing to the local network. Also this PC is a DHCP+DNS server as well as router/gateway. Based on above I decided to install Lubuntu as it is lightweight system. I installed Lubuntu 10.04.4 LTS from alternate ISO. System has no auto login. System boots and has acceptable performance. Host PC has onboard 4 network adapters: eth0 – ethernet controller which is used for Local Network connections. Has static address 10.0.0.1 eth1 – ethernet controller which is not used and not configured so far, I plan to connect printer here later on. eth2 - ethernet controller which is used to connect to Internet, which we plan to share for the local network wlan0 – wireless controller, it is used in role of access poit for local Network and has address 10.0.0.2 We want to control our gateway remotely. So, we need to be able to power it on remotely. To allow this I’ve done the following things: $ cd /etc/init.d/ made a new file with command $ sudo vim wakeonlanconfig Wrote the following lines to the newly created file, saved and closed it #!/bin/bash ethtool -s eth0 wol g ethtool -s eth2 wol g exit Made the abovementioned file executable $ sudo chmod a+x wakeonlanconfig Then included it into autostart sequence during boot. $ sudo update-rc.d -f wakeonlanconfig defaults after system reboot we will be able to poweron system remotely. Than we need to have a possibility to connect remotely to the host via SSH and VNC. So, I installed following packets with the following commands: $ sudo apt-get update $ sudo apt-get install openssh-server tightvncserver Add ssh daemon into autostart sequence during boot. $ sudo update-rc.d -f ssh defaults Power off the host PC $ sudo halt Then I went to remote place, send magic paket and powered the Host up. System started... And I connected to the host via Putty from remote system under Windows. Than logged in and run the command to start vnc server. $ tightvncserver -geometry 800x600 -depth 16 :2 VNC server successfully started and I got message like follows. New 'X' desktop is gateway:2 Starting applications specified in /home/dolv/.vnc/xstartup Log file is /home/dolv/.vnc/gateway:2.log Using UltraVNC Viewer programm under windows I connected to the host's vnc server, enterd the password and.... sow only mouse cursor in form of cross on a grey background of 800x600 dots, no desktop. Here is my .vnc/xstartup file #!/bin/sh xrdb $HOME/.Xresources xsetroot -solid grey #x-terminal-emulator -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" & #x-window-manager & # Fix to make GNOME work export XKL_XMODMAP_DISABLE=1 /etc/X11/Xsession The Question: What I have to change and where to make LXDE session start automatically after tightvncserver starts?

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  • Internal Mutation of Persistent Data Structures

    - by Greg Ros
    To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, and the same operations always produce the same results. The data structure allows Add, Remove, and similar methods that return new objects of its kind, modified as instructed, that may or may not share some of the data of the original object. However, while a data structure may seem to the user as persistent, it may do other things under the hood. To be sure, all data structures are, internally, at least somewhere, based on mutable storage. If I were to base a persistent vector on an array, and copy it whenever Add is invoked, it would still be persistent, as long as I modify only locally created arrays. However, sometimes, you can greatly increase performance by mutating a data structure under the hood. In more, say, insidious, dangerous, and destructive ways. Ways that might leave the abstraction untouched, not letting the user know anything has changed about the data structure, but being critical in the implementation level. For example, let's say that we have a class called ArrayVector implemented using an array. Whenever you invoke Add, you get a ArrayVector build on top of a newly allocated array that has an additional item. A sequence of such updates will involve n array copies and allocations. Here is an illustration: However, let's say we implement a lazy mechanism that stores all sorts of updates -- such as Add, Set, and others in a queue. In this case, each update requires constant time (adding an item to a queue), and no array allocation is involved. When a user tries to get an item in the array, all the queued modifications are applied under the hood, requiring a single array allocation and copy (since we know exactly what data the final array will hold, and how big it will be). Future get operations will be performed on an empty cache, so they will take a single operation. But in order to implement this, we need to 'switch' or mutate the internal array to the new one, and empty the cache -- a very dangerous action. However, considering that in many circumstances (most updates are going to occur in sequence, after all), this can save a lot of time and memory, it might be worth it -- you will need to ensure exclusive access to the internal state, of course. This isn't a question about the efficacy of such a data structure. It's a more general question. Is it ever acceptable to mutate the internal state of a supposedly persistent or immutable object in destructive and dangerous ways? Does performance justify it? Would you still be able to call it immutable? Oh, and could you implement this sort of laziness without mutating the data structure in the specified fashion?

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  • Do any languages other than haskell/agda have a hindley-milner type system and type classes?

    - by Jimmy Hoffa
    In pondering what gives Haskell such a layer of mental pain in becoming proficient the main thing I can think of are the Monads, Applicatives, Functors, and gaining an intuition to know how a list or maybe will behave in regards to sequence or alternate or bind etc. But why haven't other languages presented these same concepts given the usefulness of monads/applicatives/etc? It occurs to me, type classes are the key, so the question is: Have any languages other than Haskell/Agda actually implemented type classes in the same or similar way?

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  • In Social Relationship Management, the Spirit is Willing, but Execution is Weak

    - by Mike Stiles
    In our final talk in this series with Aberdeen’s Trip Kucera, we wanted to find out if enterprise organizations are actually doing anything about what they’re learning around the importance of communicating via social and using social listening for a deeper understanding of customers and prospects. We found out that if your brand is lagging behind, you’re not alone. Spotlight: How was Aberdeen able to find out if companies are putting their money where their mouth is when it comes to implementing social across the enterprise? Trip: One way to think about the relative challenges a business has in a given area is to look at the gap between “say” and “do.” The first of those words reveals the brand’s priorities, while the second reveals their ability to execute on those priorities. In Aberdeen’s research, we capture this by asking firms to rank the value of a set of activities from one on the low end to five on the high end. We then ask them to rank their ability to execute those same activities, again on a one to five, not effective to highly effective scale. Spotlight: And once you get their self-assessments, what is it you’re looking for? Trip: There are two things we’re looking for in this analysis. The first is we want to be able to identify the widest gaps between perception of value and execution. This suggests impediments to adoption or simply a high level of challenge, be it technical or otherwise. It may also suggest areas where we can expect future investment and innovation. Spotlight: So the biggest potential pain points surface, places where they know something is critical but also know they aren’t doing much about it. What’s the second thing you look for? Trip: The second thing we want to do is look at specific areas in which high-performing companies, the Leaders, are out-executing the Followers. This points to the business impact of these activities since Leaders are defined by a set of business performance metrics. Put another way, we’re correlating adoption of specific business competencies with performance, looking for what high-performers do differently. Spotlight: Ah ha, that tells us what steps the winners are taking that are making them winners. So what did you find out? Trip: Generally speaking, we see something of a glass curtain when it comes to the social relationship management execution gap. There isn’t a single social media activity in which more than 50% of respondents indicated effectiveness, which would be a 4 or 5 on that 1-5 scale. This despite the fact that 70% of firms indicate that generating positive social media mentions is valuable or very valuable, a 4 or 5 on our 1-5 scale. Spotlight: Well at least they get points for being honest. The verdict they’re giving themselves is that they just aren’t cutting it in these highly critical social development areas. Trip: And the widest gap is around directly engaging with customers and/or prospects on social networks, which 69% of firms rated as valuable but only 34% of companies say they are executing well. Perhaps even more interesting is that these two are interdependent since you’re most likely to generate goodwill on social through happy, engaged customers. This data also suggests that social is largely being used as a broadcast channel rather than for one-to-one engagement. As we’ve discussed previously, social is an inherently personal media. Spotlight: And if they’re still using it as a broadcast channel, that shows they still fail to understand the root of social and see it as just another outlet for their ads and push-messaging. That’s depressing. Trip: A second way to evaluate this data is by using Aberdeen’s performance benchmarking. The story is both a bit different, but consistent in its own way. The first thing we notice is that Leaders are more effective in their execution of several key social relationship management capabilities, namely generating positive mentions and engaging with “influencers” and customers. Based on the fact that Aberdeen uses a broad set of performance metrics to rank the respondents as either “Leaders” (top 35% in weighted performance) or “Followers” (bottom 65% in weighted performance), from website conversion to annual revenue growth, we can then correlated high social effectiveness with company performance. We can also connect the specific social capabilities used by Leaders with effectiveness. We spoke about a few of those key capabilities last time and also discuss them in a new report: Social Powers Activate: Engineering Social Engagement to Win the Hidden Sales Cycle. Spotlight: What all that tells me is there are rewards for making the effort and getting it right. That’s how you become a Leader. Trip: But there’s another part of the story, which is that overall effectiveness, even among Leaders, is muted. There’s just one activity in which more than a majority of Leaders cite high effectiveness, effectiveness being the generation of positive buzz. While 80% of Leaders indicate “directly engaging with customers” through social media channels is valuable, the highest rated activity among Leaders, only 42% say they’re effective. This gap even among Leaders shows the challenges still involved in effective social relationship management. @mikestilesPhoto: stock.xchng

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  • Dynamic Number Table

    - by Derek D.
    Using a numbers table is helpful for many things. Like finding gaps in a supposed sequence of primary keys, or generating date ranges or any numerical range. In some cases, you will be in a production system that does not already contain a numbers table and you will also be unable to add [...]

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  • We've completed the first iteration

    - by CliveT
    There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

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  • Workflow 4.5 is Awesome, cant wait for 5.0!

    - by JoshReuben
    About 2 years ago I wrote a blog post describing what I would like to see in Workflow vnext: http://geekswithblogs.net/JoshReuben/archive/2010/08/25/workflow-4.0---not-there-yet.aspx At the time WF 4.0 was a little rough around the edges – the State Machine was on codeplex and people were simulating state machines with Flowcharts. Last year I built a near- realtime machine management system using WF 4.0.1 – its managing the internal operations of this device: http://landanano.com/products/commercial   Well WF 4.5 has come a long way – many of my gripes have been addressed: C# expressions - no more VB 'AndAlso' clauses state machine awesomeness - can query current state many designer improvements - Document Outline is so much more succinct than Designer! Separate WCF Service Contract interfaces and ability to generate activities from contract operations ability to rehydrate to updated flow definitions via DynamicUpdateMap and WorkflowIdentity you can read about the new features here: http://msdn.microsoft.com/en-us/library/hh305677(VS.110).aspx   2013 could be the year of Workflow evangelism for .NET, as it comes together as the DSL language. Eg on Azure it could be used to graphically orchestrate between WebRoles, WorkerRoles and AppFabric Queues and the ServiceBus – that would be grand.   Here’s a list of things I’d like to see in Workflow 5.0: Stronger Parallelism support for true multithreaded workflows . A Workflow executes on a single thread – wouldn’t it be great if we had the ability to model TPL DataFlow? Parallel is not really parallel, just allows AsyncCodeActivity.     support for recursion an ExpressionTree activity with an editor design surface a math activity pack return of application level protocol (3.51 WF services) – automatically expose a state machine as a WCF service with bookmark Receive activities generated from OperationContract automatically placed in state transition triggers. A new HTML5 ActivityDesigner control – support with different CSS3  skinnable hooks,  remote connectivity (had to roll my own) A data flow view – crucial to understanding the big picture Ability to refactor a Sequence to custom activity in a separate .xaml file – like Expression Blend does for UserControl state machine global error handling - if all states goto an error state, you quickly get visual spagetti. Now you could nest a state machine, but what if you want an application level protocol whereby each state exposes certain WCF ops. DSL RAD editing - Make the Document Outline into a DSL editor for adding activities  – For WF to really succeed as a higher level of abstraction, It needs to be more productive than raw coding - drag & drop on the designer is currently too slow compared to just typing code. Extensible Wizard API - for pluggable WF editor experience other execution models beyond Sequence, Flowchart & StateMachine: SSIS, Behavior Trees,  Wolfram Model tool – surprise us! improvements to Designer debugging API - SourceLocation is tied to XAML file line number and char position, and ModelService access seems convoluted - why not leverage WPF LogicalTreeHelper / VisualTreeHelper ? Workflow Team , keep on rocking!

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  • How can I make a universal construction more efficient?

    - by VF1
    A "universal construction" is a wrapper class for a sequential object that enables it to be linearized (a strong consistency condition for concurrent objects). For instance, here's an adapted wait-free construction, in Java, from [1], which presumes the existence of a wait-free queue that satisfies the interface WFQ (which only requires one-time consensus between threads) and assumes a Sequential interface: public interface WFQ<T> // "FIFO" iteration { int enqueue(T t); // returns the sequence number of t Iterable<T> iterateUntil(int max); // iterates until sequence max } public interface Sequential { // Apply an invocation (method + arguments) // and get a response (return value + state) Response apply(Invocation i); } public interface Factory<T> { T generate(); } // generate new default object public interface Universal extends Sequential {} public class SlowUniversal implements Universal { Factory<? extends Sequential> generator; WFQ<Invocation> wfq = new WFQ<Invocation>(); Universal(Factory<? extends Sequential> g) { generator = g; } public Response apply(Invocation i) { int max = wfq.enqueue(i); Sequential s = generator.generate(); for(Invocation invoc : wfq.iterateUntil(max)) s.apply(invoc); return s.apply(i); } } This implementation isn't very satisfying, however, since it presumes determinism of a Sequential and is really slow. I attempted to add memory recycling: public interface WFQD<T> extends WFQ<T> { T dequeue(int n); } // dequeues only when n is the tail, else assists other threads public interface CopyableSequential extends Sequential { CopyableSequential copy(); } public class RecyclingUniversal implements Universal { WFQD<CopyableSequential> wfqd = new WFQD<CopyableSequential>(); Universal(CopyableSequential init) { wfqd.enqueue(init); } public Response apply(Invocation i) { int max = wfqd.enqueue(i); CopyableSequential cs = null; int ctr = max; for(CopyableSequential csq : wfq.iterateUntil(max)) if(--max == 0) cs = csq.copy(); wfqd.dequeue(max); return cs.apply(i); } } Here are my specific questions regarding the extension: Does my implementation create a linearizable multi-threaded version of a CopyableSequential? Is it possible extend memory recycling without extending the interface (perhaps my new methods trivialize the problem)? My implementation only reduces memory when a thread returns, so can this be strengthened? [1] provided an implementation for WFQ<T>, not WFQD<T> - one does exist, though, correct? [1] Herlihy and Shavit, The Art of Multiprocessor Programming.

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  • Speakers, Please Check Your Time

    - by AjarnMark
    Woodrow Wilson was once asked how long it would take him to prepare for a 10 minute speech. He replied "Two weeks". He was then asked how long it would take for a 1 hour speech. "One week", he replied. 2 hour speech? "I'm ready right now," he replied.  Whether that is a true story or an urban legend, I don’t really know, but either way, it is a poignant reminder for all speakers, and particularly apropos this week leading up to the PASS Community Summit. (Cross-posted to the PASS Professional Development Virtual Chapter blog #PASSProfDev.) What’s the point of that story?  Simply this…if you have plenty of time to do your presentation, you don’t need to prepare much because it is easy to throw in more and more material to stretch out to your allotted time.  But if you are on a tight time constraint, then it will take significant preparation to distill your talk down to only the essential points. I have attended seven of the last eight North American Summit events, and every one of them has been fantastic.  The speakers are great, the material is timely and relevant, and the networking opportunities are awesome.  And every year, there is one little thing that just bugs me…speakers going over their allotted time.  Why does it bother me so?  Well, if you look at a typical schedule for a Summit, you’ll see that there are six or more sessions going on at the same time, and only 15 minutes to move from one to another.  If you’re trying to maximize your training dollar by attending something during every session time slot, and you don’t want to be the last guy trying to squeeze into the middle of the row, then those 15 minutes can be critical.  All the more so if you need to stop and use the bathroom or if you have to hike to the opposite end of the convention center.  It is really a bad position to find yourself having to choose between learning the last key points of Speaker A who is going over time, and getting over to Speaker B on time so you don’t miss her key opening remarks. And frankly, I think it is just rude.  Yes, the speakers are the function, after all they are bringing the content that the rest of us are paying to learn.  But it is also an honor to be given the opportunity to speak at a conference like this, and no one speaker is so important that the conference would be a disaster without him.  Speakers know when they submit their abstract, long before the conference, how much time they will have.  It has been the same pattern at the Summit for at least the last eight years.  Program Sessions are 75 minutes long.  Some speakers who have a good track record, and meet other qualifying criteria, are extended an invitation to present a Spotlight Session which is 90 minutes (a 20% increase).  So there really is no excuse.  It’s not like you were promised a 2-hour segment and then discovered when you got here that it was only 75 minutes.  In fact, it’s not like PASS advertised 90-minute sessions for everyone and then a select few were cut back to only 75.  As a speaker, you know well before you get here which type of session you are doing and how long it is, so as a professional, you should plan accordingly. Now you might think that this only happens to rookies, but I’ll tell you that some of the worst offenders are big-name veterans who draw huge attendance numbers for their sessions.  Some attendees blow this off as, “Hey, it’s so-and-so, and I’d stay here for hours and listen to him/her talk.”  To which I would reply, “Then they should have submitted for a pre- or post-conference day-long seminar instead, but don’t try to squeeze your day-long talk into a 90-minute session.”  Now I don’t really believe that these speakers are being malicious or just selfishly trying to extend their time in the spotlight.  I think that most of them are merely being undisciplined and did not trim their presentation sufficiently, or allowed themselves to get off-track (often in a generous attempt to help someone in the audience with a question or problem that really should have been noted for further discussion after the session). So here is my recommendation…my plea, even.  TRIM THE FAT!  Now.  Before it’s too late.  Before you even get on the airplane, take a long, hard look at your presentation and eliminate some of the points that you originally thought you had to make, but in reality are not truly crucial to your main topic.  Delete a few slides.  Test your demos and have them already scripted rather than typing them during your talk.  It is better to cut out too much and end up with plenty of time at the end for Questions & Answers.  And you can always keep some notes on the stuff that you cut out so that you could fill it back in at the end as bonus material if you really do end up with a whole bunch of time on your hands.  But I don’t think you will.  And if you do, that will look even better to the audience as it will look like you’re giving them something extra that not every audience gets.  And they will thank you for that.

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  • Unity bar only shown in Desktop - Alt+Tab doesn't show anything

    - by Christian Vielma
    I've experienced something weird with Unity and that is that sometimes the Alt+Tab switcher stops showing (yes, only showing because I can still to blind switch between applications), and the left unity bar is only shown on the desktop. I might think that it's compiz, but the rest of the effects are ok :S I don't have the exact sequence to repeat this error, it seems to be random :S Do you know what could it be?

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  • A more concise example that illustrates that type inference can be very costly?

    - by mrrusof
    It was brought to my attention that the cost of type inference in a functional language like OCaml can be very high. The claim is that there is a sequence of expressions such that for each expression the length of the corresponding type is exponential on the length of the expression. I devised the sequence below. My question is: do you know of a sequence with more concise expressions that achieves the same types? # fun a -> a;; - : 'a -> 'a = <fun> # fun b a -> b a;; - : ('a -> 'b) -> 'a -> 'b = <fun> # fun c b a -> c b (b a);; - : (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'a -> 'c = <fun> # fun d c b a -> d c b (c b (b a));; - : ((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'a -> 'd = <fun> # fun e d c b a -> e d c b (d c b (c b (b a)));; - : (((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'd -> 'e) -> ((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'a -> 'e = <fun> # fun f e d c b a -> f e d c b (e d c b (d c b (c b (b a))));; - : ((((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'd -> 'e) -> ((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'e -> 'f) -> (((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'd -> 'e) -> ((('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'c -> 'd) -> (('a -> 'b) -> 'b -> 'c) -> ('a -> 'b) -> 'a -> 'f = <fun>

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  • Tutorial: Linux Boot Camp: How Linux Boots (part 1)

    Booting. Sometimes it seems like it takes forever. What's the computer doing all that time? How do you find out? The Linux boot sequence is surprisingly simple, and the best part is that almost all of it is controlled by shell scripts you can read -- and even edit yourself.

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  • Why do we need a format for binary executable files

    - by user3671483
    When binary files (i.e. executables) are saved they usually have a format (e.g. ELF or .out) where we have a header containing pointers to where data or code is stored inside the file. But why don't we store the binary files directly in the form of sequence of machine instructions.Why do we need to store data separately from the code?Secondly when the assembler creates a binary file is the file is among the above formats?

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  • User login cycles

    - by Doug Brown
    Just install 12.04-64bit and while I can login using the guest login, I cannot with my user login: it just cycles back to the login screen. I have performed the sequence of apt-get update/upgrade and install of the nvidia-current driver, but got back that it was already in use. The password appears to be recognized, as wrong one results in an error. Have also tried switching to the 2D Unity, without other results.

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  • A lot of 408 errors in apache logs - how to prevent them?

    - by Robert Grezan
    I see a lot of 408 errors in my apache2 logs. I increased RequestReadTimeout and KeepAliveTimout but errors are still there. The errors look like this: xx.xx.xx.xx - - [05/Dec/2012:19:33:56 +0100] "-" 408 4561 "-" "-" xx.xx.xx.xx - - [05/Dec/2012:19:33:56 +0100] "-" 408 4561 "-" "-" I heard that these errors are related to Chrome optimization and some users did reported our site returning 408 internal error. It is interesting that we get two 408 error from same IP in sequence then it that IP start working.

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  • How to perform Cross Join with Linq

    - by berthin
    Cross join consists to perform a Cartesian product of two sets or sequences. The following example shows a simple Cartesian product of the sets A and B: A (a1, a2) B (b1, b2) => C (a1 b1,            a1 b2,            a2 b1,            a2, b2 ) is the Cartesian product's result. Linq to Sql allows using Cross join operations. Cross join is not equijoin, means that no predicate expression of equality in the Join clause of the query. To define a cross join query, you can use multiple from clauses. Note that there's no explicit operator for the cross join. In the following example, the query must join a sequence of Product with a sequence of Pricing Rules: 1: //Fill the data source 2: var products = new List<Product> 3: { 4: new Product{ProductID="P01",ProductName="Amaryl"}, 5: new Product {ProductID="P02", ProductName="acetaminophen"} 6: }; 7:  8: var pricingRules = new List<PricingRule> 9: { 10: new PricingRule {RuleID="R_1", RuleType="Free goods"}, 11: new PricingRule {RuleID="R_2", RuleType="Discount"}, 12: new PricingRule {RuleID="R_3", RuleType="Discount"} 13: }; 14: 15: //cross join query 16: var crossJoin = from p in products 17: from r in pricingRules 18: select new { ProductID = p.ProductID, RuleID = r.RuleID };   Below the definition of the two entities using in the above example.   1: public class Product 2: { 3: public string ProductID { get; set; } 4: public string ProductName { get; set; } 5: } 1: public class PricingRule 2: { 3: public string RuleID { get; set; } 4: public string RuleType { get; set; } 5: }   Doing this: 1: foreach (var result in crossJoin) 2: { 3: Console.WriteLine("({0} , {1})", result.ProductID, result.RuleID); 4: }   The output should be similar on this:   ( P01   -    R_1 )   ( P01   -    R_2 )   ( P01   -    R_3 )   ( P02   -    R_1 )   ( P02   -    R_2 )   ( P02   -    R_3) Conclusion Cross join operation is useful when performing a Cartesian product of two sequences object. However, it can produce very large result sets that may caused a problem of performance. So use with precautions :)

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  • Hows to set Skype shortcut for opening existing instance?

    - by Koffeehaus
    I'm using Linux for about two years now, but due to my Windows legacy I like keeping shortcuts on my desktop instead of dockies, panel shortcuts, etc. If Skype is already running, pressing the shortcut starts a new sequence rather than opening an existing one. This is kinda cool as you can have two accounts running. But I only have one. So, my question is whether it is possible to tweak Skype into opening an already existent instance when pressing the shortcut?

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  • Window Functions in SQL Server

    When SQL Server introduced Window Functions in SQL Server 2005, it was done in a rather tentative way, with only a handful of functions being introduced. This was frustrating, as they remove the last excuse for cursor-based operations by providing aggregations over a partition of the result set, and imposing an ordered sequence over a partition. Now, with SQL Server 2012, we are soon to enjoy a full range of Window Functions. They are going to make for some much simpler SQL queries.

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  • Information About Joomla Templates

    JOOMLA template is a sequence of files within the content management system of JOOMLA that manage the content presentation. It is not a website, it is considered as the basic foundation design to view the JOOMLA website.

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  • Information About Joomla Templates

    JOOMLA template is a sequence of files within the content management system of JOOMLA that manage the content presentation. It is not a website, it is considered as the basic foundation design to view the JOOMLA website.

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  • Row Number Transformation

    The Row Number Transformation calculates a row number for each row, and adds this as a new output column to the data flow. The column number is a sequential number, based on a seed value. Each row receives the next number in the sequence, based on the defined increment value. Develop seamlessly between Management Studio and Visual StudioSQL Connect is a Visual Studio add-in that makes it easy to keep your database and Visual Studio project in sync.

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  • Why does Ubuntu 12.04 dual boot fail?

    - by Tranas
    Fresh install of XP followed by a fresh install of Ubuntu 12.04 results in the following error: error: unknown filesystem. grub rescue and the machine will not boot. Prior to the 12.04 install, XP worked fine. During the 12.04 install, all partitions and free space was visible, and the install seemed to complete without issues until the error message. Although I can fix the MBR via recovery console in XP and allow the machine to boot to windows, why is GRUB/Ubuntu trashing the boot sequence?

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  • SEO - What is That? - Why You Need to Do It!

    In this article I try to explain the differences between Internet Marketing and SEO or Search Engine Optimization in a simple form so it is easily understood. I think the importance of SEO is quite often overlooked for the easier and much emphasized way of marketing and that is email and lead generation marketing using a sequence of letters and auto responders. There is such a high failure rate in marketing today and I think part of that could be related to the form of marketing one is relying on.

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  • Unable to connect java webservie to android

    - by nag prakash
    This is my android activity. Please help me out. I will send the project completely if you can drop your mail id. package prakash.ws.connectsql; import org.ksoap2.SoapEnvelope; import org.ksoap2.serialization.SoapObject; import org.ksoap2.serialization.SoapPrimitive; import org.ksoap2.serialization.SoapSerializationEnvelope; import org.ksoap2.transport.AndroidHttpTransport; import android.os.Bundle; import android.app.Activity; import android.widget.EditText; import android.widget.TextView; public class MainActivity extends Activity { private static final String Soap_Action="http://testws.ws.prakash/testws"; private static final String Method_Name="testws"; private static final String Name_Space="http://testws.ws.prakash/"; private static final String URI="http://localhost:8045/testws/services/Testws?wsdl"; EditText ET; TextView Tv; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Packeting the request SoapObject request=new SoapObject(Name_Space,Method_Name); // pass the parameters to the method.If it has one request.addProperty("name", ET.getText().toString()); //passing the entire request to the envelope SoapSerializationEnvelope soapEnvelope=new SoapSerializationEnvelope(SoapEnvelope.VER11); soapEnvelope.setOutputSoapObject(request); //transporting envelope AndroidHttpTransport aht=new AndroidHttpTransport(URI); try{ aht.call(Soap_Action, soapEnvelope); @SuppressWarnings("deprecation") SoapPrimitive resultString=(SoapPrimitive) soapEnvelope.getResult(); Tv.setText(resultString.toString()); }catch(Exception e) { Tv.setText("error"); } } } This XML file does not appear to have any style information associated with it. The document tree is shown below. <wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:ns1="http://org.apache.axis2/xsd" xmlns:ns="http://testws.ws.prakash" xmlns:wsaw="http://www.w3.org/2006/05/addressing/wsdl" xmlns:http="http://schemas.xmlsoap.org/wsdl/http/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:mime="http://schemas.xmlsoap.org/wsdl/mime/" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/" targetNamespace="http://testws.ws.prakash"> <wsdl:documentation>Please Type your service description here</wsdl:documentation> <wsdl:types> <xs:schema attributeFormDefault="qualified" elementFormDefault="qualified" targetNamespace="http://testws.ws.prakash"> <xs:element name="testws"> <xs:complexType> <xs:sequence> <xs:element minOccurs="0" name="name" nillable="true" type="xs:string"/> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="testwsResponse"> <xs:complexType> <xs:sequence> <xs:element minOccurs="0" name="return" nillable="true" type="xs:string"/> </xs:sequence> </xs:complexType> </xs:element> </xs:schema> </wsdl:types> <wsdl:message name="testwsRequest"> <wsdl:part name="parameters" element="ns:testws"/> </wsdl:message> <wsdl:message name="testwsResponse"> <wsdl:part name="parameters" element="ns:testwsResponse"/> </wsdl:message> <wsdl:portType name="TestwsPortType"> <wsdl:operation name="testws"> <wsdl:input message="ns:testwsRequest" wsaw:Action="urn:testws"/> <wsdl:output message="ns:testwsResponse" wsaw:Action="urn:testwsResponse"/> </wsdl:operation> </wsdl:portType> <wsdl:binding name="TestwsSoap11Binding" type="ns:TestwsPortType"> <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document"/> <wsdl:operation name="testws"> <soap:operation soapAction="urn:testws" style="document"/> <wsdl:input> <soap:body use="literal"/> </wsdl:input> <wsdl:output> <soap:body use="literal"/> </wsdl:output> </wsdl:operation> </wsdl:binding> <wsdl:binding name="TestwsSoap12Binding" type="ns:TestwsPortType"> <soap12:binding transport="http://schemas.xmlsoap.org/soap/http" style="document"/> <wsdl:operation name="testws"> <soap12:operation soapAction="urn:testws" style="document"/> <wsdl:input> <soap12:body use="literal"/> </wsdl:input> <wsdl:output> <soap12:body use="literal"/> </wsdl:output> </wsdl:operation> </wsdl:binding> <wsdl:binding name="TestwsHttpBinding" type="ns:TestwsPortType"> <http:binding verb="POST"/> <wsdl:operation name="testws"> <http:operation location="testws"/> <wsdl:input> <mime:content type="text/xml" part="parameters"/> </wsdl:input> <wsdl:output> <mime:content type="text/xml" part="parameters"/> </wsdl:output> </wsdl:operation> </wsdl:binding> <wsdl:service name="Testws"> <wsdl:port name="TestwsHttpSoap11Endpoint" binding="ns:TestwsSoap11Binding"> <soap:address location="http://localhost:8045/testws/services/Testws.TestwsHttpSoap11Endpoint/"/> </wsdl:port> <wsdl:port name="TestwsHttpSoap12Endpoint" binding="ns:TestwsSoap12Binding"> <soap12:address location="http://localhost:8045/testws/services/Testws.TestwsHttpSoap12Endpoint/"/> </wsdl:port> <wsdl:port name="TestwsHttpEndpoint" binding="ns:TestwsHttpBinding"> <http:address location="http://localhost:8045/testws/services/Testws.TestwsHttpEndpoint/"/> </wsdl:port> </wsdl:service> </wsdl:definitions> this web service is running fine in the server. Manifest File I have added the internet Permission. Now this is the error in the logcat. 07-04 21:31:00.757: E/dalvikvm(375): Could not find class 'org.ksoap2.serialization.SoapObject', referenced from method prakash.ws.connectsql.MainActivity.onCreate 07-04 21:31:00.757: W/dalvikvm(375): VFY: unable to resolve new-instance 481 (Lorg/ksoap2/serialization/SoapObject;) in Lprakash/ws/connectsql/MainActivity; 07-04 21:31:00.757: D/dalvikvm(375): VFY: replacing opcode 0x22 at 0x0008 07-04 21:31:00.757: D/dalvikvm(375): VFY: dead code 0x000a-004e in Lprakash/ws/connectsql/MainActivity;.onCreate (Landroid/os/Bundle;)V 07-04 21:31:00.937: D/AndroidRuntime(375): Shutting down VM 07-04 21:31:00.937: W/dalvikvm(375): threadid=1: thread exiting with uncaught exception (group=0x40015560) 07-04 21:31:00.957: E/AndroidRuntime(375): FATAL EXCEPTION: main 07-04 21:31:00.957: E/AndroidRuntime(375): java.lang.NoClassDefFoundError: org.ksoap2.serialization.SoapObject 07-04 21:31:00.957: E/AndroidRuntime(375): at prakash.ws.connectsql.MainActivity.onCreate(MainActivity.java:30) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.os.Handler.dispatchMessage(Handler.java:99) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.os.Looper.loop(Looper.java:123) 07-04 21:31:00.957: E/AndroidRuntime(375): at android.app.ActivityThread.main(ActivityThread.java:3683) 07-04 21:31:00.957: E/AndroidRuntime(375): at java.lang.reflect.Method.invokeNative(Native Method) 07-04 21:31:00.957: E/AndroidRuntime(375): at java.lang.reflect.Method.invoke(Method.java:507) 07-04 21:31:00.957: E/AndroidRuntime(375): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 07-04 21:31:00.957: E/AndroidRuntime(375): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 07-04 21:31:00.957: E/AndroidRuntime(375): at dalvik.system.NativeStart.main(Native Method) 07-04 21:31:05.307: I/Process(375): Sending signal. PID: 375 SIG: 9

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