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• Significant amount of the time, I can't think of a reason to have an object instead of a static class. Do objects have more benefits than I think?

  - by Prog

  I understand the concept of an object, and as a Java programmer I feel the OO paradigm comes rather naturally to me in practice. However recently I found myself thinking: Wait a second, what are actually the practical benefits of using an object over using a static class (with proper encapsulation and OO practices)? I could think of two benefits of using an object (both significant and powerful): Polymorphism: allows you to swap functionality dynamically and flexibly during runtime. Also allows to add new functionality 'parts' and alternatives to the system easily. For example if there's a Car class designed to work with Engine objects, and you want to add a new Engine to the system that the Car can use, you can create a new Engine subclass and simply pass an object of this class into the Car object, without having to change anything about Car. And you can decide to do so during runtime. Being able to 'pass functionality around': you can pass an object around the system dynamically. But are there any more advantages to objects over static classes? Often when I add new 'parts' to a system, I do so by creating a new class and instantiating objects from it. But recently when I stopped and thought about it, I realized that a static class would do just the same as an object, in a lot of the places where I normally use an object. For example, I'm working on adding a save/load-file mechanism to my app. With an object, the calling line of code will look like this: Thing thing = fileLoader.load(file); With a static class, it would look like this: Thing thing = FileLoader.load(file); What's the difference? Fairly often I just can't think of a reason to instantiate an object when a plain-old static-class would act just the same. But in OO systems, static classes are fairly rare. So I must be missing something. Are there any more advantages to objects other from the two that I listed? Please explain.

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• Static vs. dynamic memory allocation - lots of constant objects, only small part of them used at runtime

  - by k29

  Here are two options: Option 1: enum QuizCategory { CATEGORY_1(new MyCollection<Question>() .add(Question.QUESTION_A) .add(Question.QUESTION_B) .add...), CATEGORY_2(new MyCollection<Question>() .add(Question.QUESTION_B) .add(Question.QUESTION_C) .add...), ... ; public MyCollection<Question> collection; private QuizCategory(MyCollection<Question> collection) { this.collection = collection; } public Question getRandom() { return collection.getRandomQuestion(); } } Option 2: enum QuizCategory2 { CATEGORY_1 { @Override protected MyCollection<Question> populateWithQuestions() { return new MyCollection<Question>() .add(Question.QUESTION_A) .add(Question.QUESTION_B) .add...; } }, CATEGORY_2 { @Override protected MyCollection<Question> populateWithQuestions() { return new MyCollection<Question>() .add(Question.QUESTION_B) .add(Question.QUESTION_C) .add...; } }; public Question getRandom() { MyCollection<Question> collection = populateWithQuestions(); return collection.getRandomQuestion(); } protected abstract MyCollection<Question> populateWithQuestions(); } There will be around 1000 categories, each containing 10 - 300 questions (100 on average). At runtime typically only 10 categories and 30 questions will be used. Each question is itself an enum constant (with its fields and methods). I'm trying to decide between those two options in the mobile application context. I haven't done any measurements since I have yet to write the questions and would like to gather more information before committing to one or another option. As far as I understand: (a) Option 1 will perform better since there will be no need to populate the collection and then garbage-collect the questions; (b) Option 1 will require extra memory: 1000 categories x 100 questions x 4 bytes for each reference = 400 Kb, which is not significant. So I'm leaning to Option 1, but just wondered if I'm correct in my assumptions and not missing something important? Perhaps someone has faced a similar dilemma? Or perhaps it doesn't actually matter that much?

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• Trying to implement pre/post method code: better to use methods or a parent class?

  - by Will

  I'm finding it difficult to frame this question so ... I want to execute code both before and after a method runs in PHP. There are, as far as I know, two ways to implement this: Method One: pre and post methods class Model { function find($id) { $this->_precode(); // ... do stuff $this->post_code(); } } Add the calls to _precode() and _postcode() to each method where I need this functionality. Method Two: __call and method naming class Model extends PrePost { function prepost_find($id) { // ... do stuff ... } } class PrePost { function __call($method,$param) { $method = "prepost_$method"; // .. precode here .. $result = $this->$method($param); // .. postcode here .. } } This relies on naming a method in a specific way in the inheriting class. Is there a preferred way of doing this? The call method can be made to only handle its specific cases and even defer to a child class's call if there is one. I'm not looking for opinions; I'm looking to find out if there are valid reasons to choose one way over another.

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• How can we add arch specific conflicts tag when building .deb package?

  - by Sphopale

  We are trying to build multi-arch supported i386 .deb package. There are two .deb packages build on i386 X1 & X2 (X2 is a subset of X1 binaries). X1 <- X2 conflict each other when installing . Only one .deb package can be installed at any instance. We similarly have binaries on xa64 arch. Again on xa64, there are two .deb packages X1 & X2 (X2 is a subset of X1 binaries). X1 <- X2 conflict each other when installing . Only one .deb package can be installed at any instance. In case of multi-arch i386 .deb package,i386 .deb packages (X1 & X2) can be installed on xa64 along side with 64bit (X1 & X2) However I see that when installing X1:i386 & X1:amd64 can co-exist However, it throws conflict error when trying to install X1:i386 & X2:amd64 In short, Can we mark package to conflict based on arch Conflict: X2:i386 X1:i386 package should only conflict with X2:i386 & allow other packages to co-exist X1:amd64 package should only conflict with X2:amd64 & allow other packages to co-exist X1:i386 can co-exist with X1:amd64 OR X2:amd64 X2:i386 can co-exist with X1:amd64 OR X2:amd64 Thanks for your reply

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• 2012 EC Election Results

  - by heathervc

  The 2012 Fall Executive Committee Election process is now complete. The ballot closed at midnight pacific time on Monday, 29 October.  Congratulations to Cinterion Wireless Modules GmbH, Credit Suisse, Fujitsu Limited, Hewlett-Packard (all four candidates were ratified),  and CloudBees and London Java Community (two elected candidates) as the new and re-elected merged EC Members. For more information regarding the merged EC, please refer to JSR 355 and the JCP 2.9 Process Document. Ratified Seats: Cinterion Wireless Modules GmbH, Credit Suisse, Fujitsu Limited and Hewlett-Packard Open Election Seats: CloudBees and London Java Community Newly elected EC Members take their seats on Tuesday, 13 November 2012. Detailed Election Results:Number of Eligible Voters: 1131 Percent of Eligible Members Casting Votes: 23.70% Ratified Seats: Candidate Yes Votes (%) No Votes (%) Abstentions Cinterion Wireless Modules GmbH 156 (76) 48 (24) 64 Credit Suisse 205 (85) 35 (15) 28 Fujitsu Limited 195 (85) 35 (15) 38 Hewlett-Packard 182 (81) 44 (19) 42 Open Election Seats: The top two candidates have been elected. Candidate Votes (%) Cisco Systems 37 (7) CloudBees 101 (20) Giuseppe Dell'Abate 6 (1) Liferay, Inc. 35 (7) London Java Community 164 (33) MoroccoJUG 46 (9) North Sixty-One Ltd 26 (5) Software AG 19 (4) ZeroTurnaround 64 (13) None of the above 5 (1) For more information about the candidates who ran for the 2012 Executive Committee Election, please visit the 2012 Executive Committee Elections Nominees page.

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• I need a form to tie MySQL Records together (i.e., many-to-many relationships).

  - by John R

  I need a HTML-based form to tie database records together. The user scenario that I envision is somthing like this: A super-user does a search of the database and is delivered a table of records based on that search; each record is numbered with the database-record id. There would also be two text fields next to each record. These text fields would allow: the user to make a reference from one record to another. For example, a user could enter into record id #457 that there is a correlation with record ID #242. The user would also describe the type of relationship it is. This could be with a simple integer that represents the type of relationship between the two records. When the super-user hits the submit button, all of these relationships are saved in a mySqljoin table. One option is to give me advice on how to implement and code this myself in PHP. However, before I reinvent the wheel, another option is to lead me to a free script that does something similar.

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• SQL RDBMS : one query or multiple calls

  - by None None

  After looking around the internet, I decided to create DAOs that returned objects (POJOs) to the calling business logic function/method. For example: a Customer object with a Address reference would be split in the RDBMS into two tables; Customer and ADDRESS. The CustomerDAO would be in charge of joining the data from the two tables and create both an Address POJO and Customer POJO adding the address to the customer object. Finally return the fulll Customer POJO. Simple, however, now i am at a point where i need to join three or four tables and each representing an attribute or list of attributes for the resulting POJO. The sql will include a group by but i will still result with multiple rows for the same pojo, because some of the tables are joining a one to many relationship. My app code will now have to loop through all the rows trying to figure out if the rows are the same with different attributes or if the record should be a new POJO. Should I continue to create my daos using this technique or break up my Pojo creation into multiple db calls to make the code easier to understand and maintain?

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• How do I fix the Dash search not being able to find "additional drivers" nor "update"?

  - by Dronz

  I am a fairly new user of Ubuntu, and currently have two 12.04 installations, one of which seems to work ok but I have two problems. The problem I'm asking about in this question, is that the Dash search seems unable to find things, such as "additional drivers" or "update". On my working machine, searching for "additional drivers" there finds an icon for the driver program, but on the problem machine, it gives "Sorry, there is nothing that matches your search." Dash also only shows sections for Recent Files, and Downloads, on that machine. The account I'm running is an admin account. This installation also has a stuck Ubuntu Software Center (it loads and hangs) as in threads like this one. I don't think I've done very much to this computer that could cause a problem. I installed g++ and Wt to do some programming. The biggest change I can remember is uninstalling the newfangled scrollbars with "sudo apt-get remove liboverlay-scrollbar3-0.2-0", but re-installing that module seems to have no effect on these issues. Anyone have any ideas? Both machines have been updated with all recommended updates and say they are up to date.

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• I am being paid very little(imo), how can I change this? [migrated]

  - by LagWagon

  I am a web developer with about 4 years of relevant work experience in my field. Recently, I went from making $30/hr working from home contracting for large companies to a full time job that only pays 40k/yr. The company I work for now is great, nice people, but a little behind the times. I joined on with very little experience in SQL development but they put me in charge of querying the DB and making reports right away, so I had to go in head first and pick up that skill right away. Which is great, I'm happy I learned more of that, and really make good time when doing SQL now. However, I'm now doing most of their advanced SQL stuff. The day I started, another employee who was running a MVC project based in Yii (which is the sole item that makes this company software) put in his two weeks. Two weeks later, I'm the only one who knows how to use, access, modify, or update this project. Its quite a large responsibility for an "entry level dev", no? I am doing highly advanced jQuery for them to modernize their forms, webpages, amongst other things, a skill that I would bet on few Entry levels being able to do as well as me. I may be wrong, but I feel that what I'm making now is not acceptable. We don't have reviews, ever, so I can't just wait for that.. so I was wondering.. do I sound justified in wanting to be paid more, and how can I make this happen?

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• Arguments for discouraging satellite sites?

  - by Jjdelc

  I am working with a client who's read about satellite sites on a SEP book and has been building hundreds of keyword reach domains (buytoyotacorona1989cheap.com, brandnewsuvinred.com) with specific content about such domains. They all link to a main domain (CompanyName.com) where most of the information is either repeated(from other sites) or new. I told him to drop all the other domains and only focus on building good content for the main site as it is too difficult to maintain so many websites, plus they might look like link farms to Google. He told me to make a Google search for "Buy Toyota cheap " and two of his websites were listed among top 10. So it's seem to be doing some good, but I get the feeling that what he is doing is wrong. What other arguments are there to discourage this practice? or is he doing the right thing? My arguments have helped him to decide go down from hundreds to close to one hundred (because cost of maintainance) but I believe he should only have one or two sites. PS: The business is not actually about cars.

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• Will these optimizations to my Ruby implementation of diff improve performance in a Rails app?

  - by grg-n-sox

  <tl;dr> In source version control diff patch generation, would it be worth it to use the optimizations listed at the very bottom of this writing (see <optimizations>) in my Ruby implementation of diff for making diff patches? </tl;dr> <introduction> I am programming something I have never done before and there might already be tools out there to do the exact thing I am programming but at this point I am having too much fun to care so I am still going to do it from scratch, even if there is a tool for this. So anyways, I am working on a Ruby on Rails app and need a certain feature. Basically I want each entry in a table of mine, let's say for example a table of video games, to have a stored chunk of text that represents a review or something of the sort for that table entry. However, I want this text to be both editable by any registered user and also keep track of different submissions in a version control system. The simplest solution I could think of is just implement a solution that keeps track of the text body and the diff patch history of different versions of the text body as objects in Ruby and then serialize it, preferably in human readable form (so I'll most likely use YAML for this) for editing if needed due to corruption by a software bug or a mistake is made by an admin doing some version editing. So at first I just tried to dive in head first into this feature to find that the problem of generating a diff patch is more difficult that I thought to do efficiently. So I did some research and came across some ideas. Some I have implemented already and some I have not. However, it all pretty much revolves around the longest common subsequence problem, as you would already know if you have already done anything with diff or diff-like features, and optimization the function that solves it. Currently I have it so it truncates the compared versions of the text body from the beginning and end until non-matching lines are found. Then it solves the problem using a comparison matrix, but instead of incrementing the value stored in a cell when it finds a matching line like in most longest common subsequence algorithms I have seen examples of, I increment when I have a non-matching line so as to calculate edit distance instead of longest common subsequence. Although as far as I can tell between the two approaches, they are essentially two sides of the same coin so either could be used to derive an answer. It then back-traces through the comparison matrix and notes when there was an incrementation and in which adjacent cell (West, Northwest, or North) to determine that line's diff entry and assumes all other lines to be unchanged. Normally I would leave it at that, but since this is going into a Rails environment and not just some stand-alone Ruby script, I started getting worried about needing to optimize at least enough so if a spammer that somehow knew how I implemented the version control system and knew my worst case scenario entry still wouldn't be able to hit the server that bad. After some searching and reading of research papers and articles through the internet, I've come across several that seem decent but all seem to have pros and cons and I am having a hard time deciding how well in this situation that the pros and cons balance out. So are the ones listed here worth it? I have listed them with known pros and cons. </introduction> <optimizations> Chop the compared sequences into multiple chucks of subsequences by splitting where lines are unchanged, and then truncating each section of unchanged lines at the beginning and end of each section. Then solve the edit distance of each subsequence. Pro: Changes the time increase as the changed area gets bigger from a quadratic increase to something more similar to a linear increase. Con: Figuring out where to split already seems like you have to solve edit distance except now you don't care how it is changed. Would be fine if this was solvable by a process closer to solving hamming distance but a single insertion would throw this off. Use a cryptographic hash function to both convert all sequence elements into integers and ensure uniqueness. Then solve the edit distance comparing the hash integers instead of the sequence elements themselves. Pro: The operation of comparing two integers is faster than the operation of comparing two strings, so a slight performance gain is received after every comparison, which can be a lot overall. Con: Using a cryptographic hash function takes time to convert all the sequence elements and may end up costing more time to do the conversion that you gain back from the integer comparisons. You could use the built in hash function for a string but that will not guarantee uniqueness. Use lazy evaluation to only calculate the three center-most diagonals of the comparison matrix and then only calculate additional diagonals as needed. And then also use this approach to possibly remove the need on some comparisons to compare all three adjacent cells as desribed here. Pro: Can turn an algorithm that always takes O(n * m) time and make it so only worst case scenario is that time, best case becomes practically linear, and average case is somewhere between the two. Con: It is an algorithm I've only seen implemented in functional programming languages and I am having a difficult time comprehending how to convert this into Ruby based on how it is described at the site linked to above. Make a C module and do the hard work at the native level in C and just make a Ruby wrapper for it so Ruby can make all the calls to it that it needs. Pro: I have to imagine that evaluating something like this in could be a LOT faster. Con: I have no idea how Rails handles apps with ruby code that has C extensions and it hurts the portability of the app. This is an optimization for after the solving of edit distance, but idea is to store additional combined diffs with the ones produced by each version to make a delta-tree data structure with the most recently made diff as the root node of the tree so getting to any version takes worst case time of O(log n) instead of O(n). Pro: Would make going back to an old version a lot faster. Con: It would mean every new commit, the delta-tree would get a new root node that will cost time to reorganize the delta-tree for an operation that will be carried out a lot more often than going back a version, not to mention the unlikelihood it will be an old version. </optimizations> So are these things worth the effort?

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• g++ SSE intrinsics dilemma - value from intrinsic "saturates"

  - by Sriram

  Hi, I wrote a simple program to implement SSE intrinsics for computing the inner product of two large (100000 or more elements) vectors. The program compares the execution time for both, inner product computed the conventional way and using intrinsics. Everything works out fine, until I insert (just for the fun of it) an inner loop before the statement that computes the inner product. Before I go further, here is the code: //this is a sample Intrinsics program to compute inner product of two vectors and compare Intrinsics with traditional method of doing things. #include <iostream> #include <iomanip> #include <xmmintrin.h> #include <stdio.h> #include <time.h> #include <stdlib.h> using namespace std; typedef float v4sf __attribute__ ((vector_size(16))); double innerProduct(float* arr1, int len1, float* arr2, int len2) { //assume len1 = len2. float result = 0.0; for(int i = 0; i < len1; i++) { for(int j = 0; j < len1; j++) { result += (arr1[i] * arr2[i]); } } //float y = 1.23e+09; //cout << "y = " << y << endl; return result; } double sse_v4sf_innerProduct(float* arr1, int len1, float* arr2, int len2) { //assume that len1 = len2. if(len1 != len2) { cout << "Lengths not equal." << endl; exit(1); } /*steps: * 1. load a long-type (4 float) into a v4sf type data from both arrays. * 2. multiply the two. * 3. multiply the same and store result. * 4. add this to previous results. */ v4sf arr1Data, arr2Data, prevSums, multVal, xyz; //__builtin_ia32_xorps(prevSums, prevSums); //making it equal zero. //can explicitly load 0 into prevSums using loadps or storeps (Check). float temp[4] = {0.0, 0.0, 0.0, 0.0}; prevSums = __builtin_ia32_loadups(temp); float result = 0.0; for(int i = 0; i < (len1 - 3); i += 4) { for(int j = 0; j < len1; j++) { arr1Data = __builtin_ia32_loadups(&arr1[i]); arr2Data = __builtin_ia32_loadups(&arr2[i]); //store the contents of two arrays. multVal = __builtin_ia32_mulps(arr1Data, arr2Data); //multiply. xyz = __builtin_ia32_addps(multVal, prevSums); prevSums = xyz; } } //prevSums will hold the sums of 4 32-bit floating point values taken at a time. Individual entries in prevSums also need to be added. __builtin_ia32_storeups(temp, prevSums); //store prevSums into temp. cout << "Values of temp:" << endl; for(int i = 0; i < 4; i++) cout << temp[i] << endl; result += temp[0] + temp[1] + temp[2] + temp[3]; return result; } int main() { clock_t begin, end; int length = 100000; float *arr1, *arr2; double result_Conventional, result_Intrinsic; // printStats("Allocating memory."); arr1 = new float[length]; arr2 = new float[length]; // printStats("End allocation."); srand(time(NULL)); //init random seed. // printStats("Initializing array1 and array2"); begin = clock(); for(int i = 0; i < length; i++) { // for(int j = 0; j < length; j++) { // arr1[i] = rand() % 10 + 1; arr1[i] = 2.5; // arr2[i] = rand() % 10 - 1; arr2[i] = 2.5; // } } end = clock(); cout << "Time to initialize array1 and array2 = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; // printStats("Finished initialization."); // printStats("Begin inner product conventionally."); begin = clock(); result_Conventional = innerProduct(arr1, length, arr2, length); end = clock(); cout << "Time to compute inner product conventionally = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; // printStats("End inner product conventionally."); // printStats("Begin inner product using Intrinsics."); begin = clock(); result_Intrinsic = sse_v4sf_innerProduct(arr1, length, arr2, length); end = clock(); cout << "Time to compute inner product with intrinsics = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; //printStats("End inner product using Intrinsics."); cout << "Results: " << endl; cout << " result_Conventional = " << result_Conventional << endl; cout << " result_Intrinsics = " << result_Intrinsic << endl; return 0; } I use the following g++ invocation to build this: g++ -W -Wall -O2 -pedantic -march=i386 -msse intrinsics_SSE_innerProduct.C -o innerProduct Each of the loops above, in both the functions, runs a total of N^2 times. However, given that arr1 and arr2 (the two floating point vectors) are loaded with a value 2.5, the length of the array is 100,000, the result in both cases should be 6.25e+10. The results I get are: Results: result_Conventional = 6.25e+10 result_Intrinsics = 5.36871e+08 This is not all. It seems that the value returned from the function that uses intrinsics "saturates" at the value above. I tried putting other values for the elements of the array and different sizes too. But it seems that any value above 1.0 for the array contents and any size above 1000 meets with the same value we see above. Initially, I thought it might be because all operations within SSE are in floating point, but floating point should be able to store a number that is of the order of e+08. I am trying to see where I could be going wrong but cannot seem to figure it out. I am using g++ version: g++ (GCC) 4.4.1 20090725 (Red Hat 4.4.1-2). Any help on this is most welcome. Thanks, Sriram.

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• Cumulative +1/-1 Cointoss crashes on 1000 iterations. Please advise; c++ boost random libraries

  - by user1731972

  following some former advice Multithreaded application, am I doing it right? I think I have a threadsafe number generator using boost, but my program crashes when I input 1000 iterations. The output .csv file when graphed looks right, but I'm not sure why it's crashing. It's using _beginthread, and everyone is telling me I should use the more (convoluted) _beingthreadex, which I'm not familiar with. If someone could recommend an example, I would greatly appreciate it. Also... someone pointed out I should be applying a second parameter to my _beginthread for the array counting start positions, but I have no idea how to pass more than one parameter, other than attempting to use a structure, and I've read structure's and _beginthread don't get along (although, I could just use the boost threads...) #include <process.h> #include <windows.h> #include <iostream> #include <fstream> #include <time.h> #include <random> #include <boost/random.hpp> //for srand48_r(time(NULL), &randBuffer); which doesn't work #include <stdio.h> #include <stdlib.h> //#include <thread> using namespace std; using namespace boost; using namespace boost::random; void myThread0 (void *dummy ); void myThread1 (void *dummy ); void myThread2 (void *dummy ); void myThread3 (void *dummy ); //for random seeds void initialize(); //from http://stackoverflow.com/questions/7114043/random-number-generation-in-c11-how-to-generate-how-do-they-work uniform_int_distribution<> two(1,2); typedef std::mt19937 MyRNG; // the Mersenne Twister with a popular choice of parameters uint32_t seed_val; // populate somehow MyRNG rng1; // e.g. keep one global instance (per thread) MyRNG rng2; // e.g. keep one global instance (per thread) MyRNG rng3; // e.g. keep one global instance (per thread) MyRNG rng4; // e.g. keep one global instance (per thread) //only needed for shared variables //CRITICAL_SECTION cs1,cs2,cs3,cs4; // global int main() { ofstream myfile; myfile.open ("coinToss.csv"); int rNum; long numRuns; long count = 0; int divisor = 1; float fHolder = 0; long counter = 0; float percent = 0.0; //? //unsigned threadID; //HANDLE hThread; initialize(); HANDLE hThread[4]; const int size = 100000; int array[size]; printf ("Runs (uses multiple of 100,000) "); cin >> numRuns; for (int a = 0; a < numRuns; a++) { hThread[0] = (HANDLE)_beginthread( myThread0, 0, (void*)(array) ); hThread[1] = (HANDLE)_beginthread( myThread1, 0, (void*)(array) ); hThread[2] = (HANDLE)_beginthread( myThread2, 0, (void*)(array) ); hThread[3] = (HANDLE)_beginthread( myThread3, 0, (void*)(array) ); //waits for threads to finish before continuing WaitForMultipleObjects(4, hThread, TRUE, INFINITE); //closes handles I guess? CloseHandle( hThread[0] ); CloseHandle( hThread[1] ); CloseHandle( hThread[2] ); CloseHandle( hThread[3] ); //dump array into calculations //average array into fHolder //this could be split into threads as well for (int p = 0; p < size; p++) { counter += array[p] == 2 ? 1 : -1; //cout << array[p] << endl; //cout << counter << endl; } //this fHolder calculation didn't work //fHolder = counter / size; //so I had to use this cout << counter << endl; fHolder = counter; fHolder = fHolder / size; myfile << fHolder << endl; } } void initialize() { //seed value needs to be supplied //rng1.seed(seed_val*1); rng1.seed((unsigned int)time(NULL)); rng2.seed(((unsigned int)time(NULL))*2); rng3.seed(((unsigned int)time(NULL))*3); rng4.seed(((unsigned int)time(NULL))*4); }; void myThread0 (void *param) { //EnterCriticalSection(&cs1); //aquire the critical section object int *i = (int *)param; for (int x = 0; x < 25000; x++) { //doesn't work, part of merssene twister //i[x] = next(); i[x] = two(rng1); //original srand //i[x] = rand() % 2 + 1; //doesn't work for some reason. //uint_dist2(rng); //i[x] = qrand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs1); // release the critical section object } void myThread1 (void *param) { //EnterCriticalSection(&cs2); //aquire the critical section object int *i = (int *)param; for (int x = 25000; x < 50000; x++) { //param[x] = rand() % 2 + 1; i[x] = two(rng2); //i[x] = rand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs2); // release the critical section object } void myThread2 (void *param) { //EnterCriticalSection(&cs3); //aquire the critical section object int *i = (int *)param; for (int x = 50000; x < 75000; x++) { i[x] = two(rng3); //i[x] = rand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs3); // release the critical section object } void myThread3 (void *param) { //EnterCriticalSection(&cs4); //aquire the critical section object int *i = (int *)param; for (int x = 75000; x < 100000; x++) { i[x] = two(rng4); //i[x] = rand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs4); // release the critical section object }

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• How to get full query string parameters not UrlDecoded

  - by developerit

  Introduction While developing Developer IT’s website, we came across a problem when the user search keywords containing special character like the plus ‘+’ char. We found it while looking for C++ in our search engine. The request parameter output in ASP.NET was “c “. I found it strange that it removed the ‘++’ and replaced it with a space… Analysis After a bit of Googling and Reflection, it turns out that ASP.NET calls UrlDecode on each parameters retreived by the Request(“item”) method. The Request.Params property is affected by this two since it mashes all QueryString, Forms and other collections into a single one. Workaround Finally, I solve the puzzle usign the Request.RawUrl property and parsing it with the same RegEx I use in my url re-writter. The RawUrl not affected by anything. As its name say it, it’s raw. Published on http://www.developerit.com/

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• C# development with Mono and MonoDevelop

  - by developerit

  In the past two years, I have been developing .NET from my MacBook by running Windows XP into VM Ware and more recently into Virtual Box from OS X. This way, I could install Visual Studio and be able to work seamlessly. But, this way of working has a major down side: it kills the battery of my laptop… I can easiely last for 3 hours if I stay in OS X, but can only last 45 min when XP is running. Recently, I gave MonoDevelop a try for developing Developer IT‘s tools and web site. While being way less complete then Visual Studio, it provides essentials tools when it comes to developping software. It works well with solutions and projects files created from Visual Studio, it has Intellisence (word completion), it can compile your code and can even target your .NET app to linux or unix. This tools can save me a lot of time and batteries! Although I could not only work with MonoDevelop, I find it way better than a simple text editor like Smultron. Thanks to Novell, we can now bring Microsoft technology to OS X.

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• Parallelism in .NET – Part 12, More on Task Decomposition

  - by Reed

  Many tasks can be decomposed using a Data Decomposition approach, but often, this is not appropriate.  Frequently, decomposing the problem into distinctive tasks that must be performed is a more natural abstraction. However, as I mentioned in Part 1, Task Decomposition tends to be a bit more difficult than data decomposition, and can require a bit more effort.  Before we being parallelizing our algorithm based on the tasks being performed, we need to decompose our problem, and take special care of certain considerations such as ordering and grouping of tasks. Up to this point in this series, I’ve focused on parallelization techniques which are most appropriate when a problem space can be decomposed by data.  Using PLINQ and the Parallel class, I’ve shown how problem spaces where there is a collection of data, and each element needs to be processed, can potentially be parallelized. However, there are many other routines where this is not appropriate.  Often, instead of working on a collection of data, there is a single piece of data which must be processed using an algorithm or series of algorithms.  Here, there is no collection of data, but there may still be opportunities for parallelism. As I mentioned before, in cases like this, the approach is to look at your overall routine, and decompose your problem space based on tasks.  The idea here is to look for discrete “tasks,” individual pieces of work which can be conceptually thought of as a single operation. Let’s revisit the example I used in Part 1, an application startup path.  Say we want our program, at startup, to do a bunch of individual actions, or “tasks”.  The following is our list of duties we must perform right at startup: Display a splash screen Request a license from our license manager Check for an update to the software from our web server If an update is available, download it Setup our menu structure based on our current license Open and display our main, welcome Window Hide the splash screen The first step in Task Decomposition is breaking up the problem space into discrete tasks. This, naturally, can be abstracted as seven discrete tasks.  In the serial version of our program, if we were to diagram this, the general process would appear as: These tasks, obviously, provide some opportunities for parallelism.  Before we can parallelize this routine, we need to analyze these tasks, and find any dependencies between tasks.  In this case, our dependencies include: The splash screen must be displayed first, and as quickly as possible. We can’t download an update before we see whether one exists. Our menu structure depends on our license, so we must check for the license before setting up the menus. Since our welcome screen will notify the user of an update, we can’t show it until we’ve downloaded the update. Since our welcome screen includes menus that are customized based off the licensing, we can’t display it until we’ve received a license. We can’t hide the splash until our welcome screen is displayed. By listing our dependencies, we start to see the natural ordering that must occur for the tasks to be processed correctly. The second step in Task Decomposition is determining the dependencies between tasks, and ordering tasks based on their dependencies. Looking at these tasks, and looking at all the dependencies, we quickly see that even a simple decomposition such as this one can get quite complicated.  In order to simplify the problem of defining the dependencies, it’s often a useful practice to group our tasks into larger, discrete tasks.  The goal when grouping tasks is that you want to make each task “group” have as few dependencies as possible to other tasks or groups, and then work out the dependencies within that group.  Typically, this works best when any external dependency is based on the “last” task within the group when it’s ordered, although that is not a firm requirement.  This process is often called Grouping Tasks.  In our case, we can easily group together tasks, effectively turning this into four discrete task groups: 1. Show our splash screen – This needs to be left as its own task.  First, multiple things depend on this task, mainly because we want this to start before any other action, and start as quickly as possible. 2. Check for Update and Download the Update if it Exists - These two tasks logically group together.  We know we only download an update if the update exists, so that naturally follows.  This task has one dependency as an input, and other tasks only rely on the final task within this group. 3. Request a License, and then Setup the Menus – Here, we can group these two tasks together.  Although we mentioned that our welcome screen depends on the license returned, it also depends on setting up the menu, which is the final task here.  Setting up our menus cannot happen until after our license is requested.  By grouping these together, we further reduce our problem space. 4. Display welcome and hide splash - Finally, we can display our welcome window and hide our splash screen.  This task group depends on all three previous task groups – it cannot happen until all three of the previous groups have completed. By grouping the tasks together, we reduce our problem space, and can naturally see a pattern for how this process can be parallelized.  The diagram below shows one approach: The orange boxes show each task group, with each task represented within.  We can, now, effectively take these tasks, and run a large portion of this process in parallel, including the portions which may be the most time consuming.  We’ve now created two parallel paths which our process execution can follow, hopefully speeding up the application startup time dramatically. The main point to remember here is that, when decomposing your problem space by tasks, you need to: Define each discrete action as an individual Task Discover dependencies between your tasks Group tasks based on their dependencies Order the tasks and groups of tasks

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• Database model for keeping track of likes/shares/comments on blog posts over time

  - by gage

  My goal is to keep track of the popular posts on different blog sites based on social network activity at any given time. The goal is not to simply get the most popular now, but instead find posts that are popular compared to other posts on the same blog. For example, I follow a tech blog, a sports blog, and a gossip blog. The tech blog gets waaay more readership than the other two blogs, so in raw numbers every post on the tech blog will always out number views on the other two. So lets say the average tech blog post gets 500 facebook likes and the other two get an average of 50 likes per post. Then when there is a sports blog post that has 200 fb likes and a gossip blog post with 300 while the tech blog posts today have 500 likes I want to highlight the sports and gossip blog posts (more likes than average vs tech blog with more # of likes but just average for the blog) The approach I am thinking of taking is to make an entry in a database for each blog post. Every x minutes (say every 15 minutes) I will check how many likes/shares/comments an entry has received on all the social networks (facebook, twitter, google+, linkeIn). So over time there will be a history of likes for each blog post, i.e post 1234 after 15 min: 10 fb likes, 4 tweets, 6 g+ after 30 min: 15 fb likes, 15 tweets, 10 g+ ... ... after 48 hours: 200 fb likes, 25 tweets, 15 g+ By keeping a history like this for each blog post I can know the average number of likes/shares/tweets at any give time interval. So for example the average number of fb likes for all blog posts 48hrs after posting is 50, and a particular post has 200 I can mark that as a popular post and feature/highlight it. A consideration in the design is to be able to easily query the values (likes/shares) for a specific time-frame, i.e. fb likes after 30min or tweets after 24 hrs in-order to compute averages with which to compare against (or should averages be stored in it's own table?) If this approach is flawed or could use improvement please let me know, but it is not my main question. My main question is what should a database scheme for storing this info look like? Assuming that the above approach is taken I am trying to figure out what a database schema for storing the likes over time would look like. I am brand new to databases, in doing some basic reading I see that it is advisable to make a 3NF database. I have come up with the following possible schema. Schema 1 DB Popular Posts Table: Post post_id ( primary key(pk) ) url title Table: Social Activity activity_id (pk) url (fk) type (i.e. facebook,twitter,g+) value timestamp This was my initial instinct (base on my very limited db knowledge). As far as I under stand this schema would be 3NF? I searched for designs of similar database model, and found this question on stackoverflow, http://stackoverflow.com/questions/11216080/data-structure-for-storing-height-and-weight-etc-over-time-for-multiple-users . The scenario in that question is similar (recording weight/height of users overtime). Taking the accepted answer for that question and applying it to my model results in something like: Schema 2 (same as above, but break down the social activity into 2 tables) DB Popular Posts Table: Post post_id (pk) url title Table: Social Measurement measurement_id (pk) post_id (fk) timestamp Table: Social stat stat_id (pk) measurement_id (fk) type (i.e. facebook,twitter,g+) value The advantage I see in schema 2 is that I will likely want to access all the values for a given time, i.e. when making a measurement at 30min after a post is published I will simultaneous check number of fb likes, fb shares, fb comments, tweets, g+, linkedIn. So with this schema it may be easier get get all stats for a measurement_id corresponding to a certain time, i.e. all social stats for post 1234 at time x. Another thought I had is since it doesn't make sense to compare number of fb likes with number of tweets or g+ shares, maybe it makes sense to separate each social measurement into it's own table? Schema 3 DB Popular Posts Table: Post post_id (pk) url title Table: fb_likes fb_like_id (pk) post_id (fk) timestamp value Table: fb_shares fb_shares_id (pk) post_id (fk) timestamp value Table: tweets tweets__id (pk) post_id (fk) timestamp value Table: google_plus google_plus_id (pk) post_id (fk) timestamp value As you can see I am generally lost/unsure of what approach to take. I'm sure this typical type of database problem (storing measurements overtime, i.e temperature statistic) that must have a common solution. Is there a design pattern/model for this, does it have a name? I tried searching for "database periodic data collection" or "database measurements over time" but didn't find anything specific. What would be an appropriate model to solve the needs of this problem?

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• SQL SERVER – When are Statistics Updated – What triggers Statistics to Update

  - by pinaldave

  If you are an SQL Server Consultant/Trainer involved with Performance Tuning and Query Optimization, I am sure you have faced the following questions many times. When is statistics updated? What is the interval of Statistics update? What is the algorithm behind update statistics? These are the puzzling questions and more. I searched the Internet as well many official MS documents in order to find answers. All of them have provided almost similar algorithm. However, at many places, I have seen a bit of variation in algorithm as well. I have finally compiled the list of various algorithms and decided to share what was the most common “factor” in all of them. I would like to ask for your suggestions as whether following the details, when Statistics is updated, are accurate or not. I will update this blog post with accurate information after receiving your ideas. The answer I have found here is when statistics are expired and not when they are automatically updated. I need your help here to answer when they are updated. Permanent table If the table has no rows, statistics is updated when there is a single change in table. If the number of rows in a table is less than 500, statistics is updated for every 500 changes in table. If the number of rows in table is more than 500, statistics is updated for every 500+20% of rows changes in table. Temporary table If the table has no rows, statistics is updated when there is a single change in table. If the number of rows in table is less than 6, statistics is updated for every 6 changes in table. If the number of rows in table is less than 500, statistics is updated for every 500 changes in table. If the number of rows in table is more than 500, statistics is updated for every 500+20% of rows changes in table. Table variable There is no statistics for Table Variables. If you want to read further about statistics, I suggest that you read the white paper Statistics Used by the Query Optimizer in Microsoft SQL Server 2008. Let me know your opinions about statistics, as well as if there is any update in the above algorithm. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics

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• Deciding which technology to use is a big decision when no technology is an obvious choice

  Deciding which technology to use in a new venture or project is a big decision for any company when no technology is an obvious choice. It is always best to analyze the current requirements of the project, and also evaluate the existing technology climate so that the correct technology based on the situation at the time is selected. When evaluation the requirements of a new project it is best to be open to as many technologies as possible initially so a company can be sure that the right decision gets made. Another important aspect of the technology decision is what can the current network and  hardware environment handle, and what would be needed to be adjusted if a specific technology was selected. For example if the current network operating system is Linux then VB6 would force  a huge change in the current computing environment. However if the current network operation system was windows based then very little change would be needed to allow for VB6 if any change had to be done at all. Finally and most importantly an analysis should be done regarding the current technical employees pertaining to their skills and aspirations. For example if you have a team of Java programmers then forcing them to build something in C# might not be an ideal situation. However having a team of VB.net developers who want to develop something in C# would be a better situation based on this example because they are already failure with the .Net Framework and have a desire to use the new technology. In addition to this analysis the cost associated with building and maintaining the project is also a key factor. If two languages are ideal for a project but one technology will increase the budget or timeline by 50% then it might not be the best choice in that situation. An ideal situation for developing in C# applications would be a project that is built on existing Microsoft technologies. An example of this would be a company who uses Windows 2008 Server as their network operating system, Windows XP Pro as their main operation system, Microsoft SQL Server 2008 as their primary database, and has a team of developers experience in the .net framework. In the above situation Java would be a poor technology decision based on their current computing environment and potential lack of Java development by the company’s developers. It would take the developers longer to develop the application due the fact that they would have to first learn the language and then become comfortable with the language. Although these barriers do exist, it does not mean that it is not due able if the company and developers were committed to the project.

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• It’s nice to be important, but it’s more important to be nice

  - by BuckWoody

  I’ve been a little “preachy” lately, telling you that you should let people finish their sentences, and always check a problem out before you tell a user that their issue is “impossible”. Well, I’ll round that out with one more tip today. Keep in mind that all of these things are actions I’ve been guilty of, hopefully in the past. I’m kind of a “work in progress”. And yes, I know these tips are coming from someone who picks on people in presentations, but that is of course done in fun, and (hopefully) with the audience’s knowledge.   (No, this isn’t aimed at any one person or event in particular – I just see it happen a lot)   I’ve seen, unfortunately over and over, someone in authority react badly to someone who is incorrect, or at least perceived to be incorrect. This might manifest itself in a comment, post, question or whatever, but the point is that I’ve seen really intelligent people literally attack someone they view as getting something wrong. Don’t misunderstand me; if someone posts that you should always drop a production database in the middle of the day I think you should certainly speak up and mention that this might be a bad idea!  No, I’m talking about generalizations or even incorrect statements done in good faith. Let me explain with an example.   Suppose someone makes the statement: “If you don’t have enough space on your system, you can just use a DBCC command to shrink the database”. Let’s take two responses to this statement.   Response One: “That’s insane. Everyone knows that shrinking a database is a stupid idea, you’re just going to fragment your indexes all over the place.” Response Two: “That’s an interesting take – in my experience and from what I’ve read here (someurl.com) I think this might not be a universal best practice.”   Of course, both responses let the person making the statement and those reading it know that you don’t agree, and that it’s probably wrong. But the person you responded to and the general audience hearing you (or reading your response) might form two different opinions of you.   The first response says to me “this person really needs to be right, and takes arguments personally. They aren’t thinking of the other person at all, or the folks reading or hearing the exchange. They turned an incorrect technical statement into a personal attack. They haven’t left the other party any room to ‘save face’, and they have potentially turned what could be a positive learning experience for everyone into a negative. Also, they sound more than just a little arrogant.”   The second response says to me “this person has left room for everyone to save face, has presented evidence to the contrary and is thinking about moving the ball forward and getting it right rather than attacking someone for getting it wrong.” It’s the idea of questioning a statement rather than attacking a person.   Perhaps you have a different take. Maybe you think the “direct” approach is best – and maybe that’s worked for you. Something to consider is what you’ve really accomplished while using that first method. Sure, the info you provide is correct, and perhaps someone out there won’t shrink a database because of your response – but perhaps you’ve turned a lot more people off, and now they won’t listen to your other valuable information. You’ll be an expert, but another one of the nameless, arrogant jerks in technology. And I don’t think anyone likes to be thought of that way.   OK, I’ll get down off of the high-horse now. And I’ll keep the title of this entry (said to me by my grandmother when I was a little kid) in mind when I dismount. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• BizTalk Server 2009 - Architecture Options

  - by StuartBrierley

  I recently needed to put forward a proposal for a BizTalk 2009 implementation and as a part of this needed to describe some of the basic architecture options available for consideration.  While I already had an idea of the type of environment that I would be looking to recommend, I felt that presenting a range of options while trying to explain some of the strengths and weaknesses of those options was a good place to start.  These outline architecture options should be equally valid for any version of BizTalk Server from 2004, through 2006 and R2, up to 2009.   The following diagram shows a crude representation of the common implementation options to consider when designing a BizTalk environment.         Each of these options provides differing levels of resilience in the case of failure or disaster, with the later options also providing more scope for performance tuning and scalability.   Some of the options presented above make use of clustering. Clustering may best be described as a technology that automatically allows one physical server to take over the tasks and responsibilities of another physical server that has failed. Given that all computer hardware and software will eventually fail, the goal of clustering is to ensure that mission-critical applications will have little or no downtime when such a failure occurs. Clustering can also be configured to provide load balancing, which should generally lead to performance gains and increased capacity and throughput.   (A) Single Servers   This option is the most basic BizTalk implementation that should be considered. It involves the deployment of a single BizTalk server in conjunction with a single SQL server. This configuration does not provide for any resilience in the case of the failure of either server. It is however the cheapest and easiest to implement option of those available.   Using a single BizTalk server does not provide for the level of performance tuning that is otherwise available when using more than one BizTalk server in a cluster.   The common edition of BizTalk used in single server implementations is the standard edition. It should be noted however that if future demand requires increased capacity for a solution, this BizTalk edition is limited to scaling up the implementation and not scaling out the number of servers in use. Any need to scale out the solution would require an upgrade to the enterprise edition of BizTalk.   (B) Single BizTalk Server with Clustered SQL Servers   This option uses a single BizTalk server with a cluster of SQL servers. By utilising clustered SQL servers we can ensure that there is some resilience to the implementation in respect of the databases that BizTalk relies on to operate. The clustering of two SQL servers is possible with the standard edition but to go beyond this would require the enterprise level edition. While this option offers improved resilience over option (A) it does still present a potential single point of failure at the BizTalk server.   Using a single BizTalk server does not provide for the level of performance tuning that is otherwise available when using more than one BizTalk server in a cluster.   The common edition of BizTalk used in single server implementations is the standard edition. It should be noted however that if future demand requires increased capacity for a solution, this BizTalk edition is limited to scaling up the implementation and not scaling out the number of servers in use. You are also unable to take advantage of multiple message boxes, which would allow us to balance the SQL load in the event of any bottlenecks in this area of the implementation. Any need to scale out the solution would require an upgrade to the enterprise edition of BizTalk.   (C) Clustered BizTalk Servers with Clustered SQL Servers   This option makes use of a cluster of BizTalk servers with a cluster of SQL servers to offer high availability and resilience in the case of failure of either of the server types involved. Clustering of BizTalk is only available with the enterprise edition of the product. Clustering of two SQL servers is possible with the standard edition but to go beyond this would require the enterprise level edition.    The use of a BizTalk cluster also provides for the ability to balance load across the servers and gives more scope for performance tuning any implemented solutions. It is also possible to add more BizTalk servers to an existing cluster, giving scope for scaling out the solution as future demand requires.   This might be seen as the middle cost option, providing a good level of protection in the case of failure, a decent level of future proofing, but at a higher cost than the single BizTalk server implementations.   (D) Clustered BizTalk Servers with Clustered SQL Servers – with disaster recovery/service continuity   This option is similar to that offered by (C) and makes use of a cluster of BizTalk servers with a cluster of SQL servers to offer high availability and resilience in case of failure of either of the server types involved. Clustering of BizTalk is only available with the enterprise edition of the product. Clustering of two SQL servers is possible with the standard edition but to go beyond this would require the enterprise level edition.    As with (C) the use of a BizTalk cluster also provides for the ability to balance load across the servers and gives more scope for performance tuning the implemented solution. It is also possible to add more BizTalk servers to an existing cluster, giving scope for scaling the solution out as future demand requires.   In this scenario however, we would be including some form of disaster recovery or service continuity. An example of this would be making use of multiple sites, with the BizTalk server cluster operating across sites to offer resilience in case of the loss of one or more sites. In this scenario there are options available for the SQL implementation depending on the network implementation; making use of either one cluster per site or a single SQL cluster across the network. A multi-site SQL implementation would require some form of data replication across the sites involved.   This is obviously an expensive and complex option, but does provide an extraordinary amount of protection in the case of failure.

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• It’s nice to be important, but it’s more important to be nice

  - by BuckWoody

  I’ve been a little “preachy” lately, telling you that you should let people finish their sentences, and always check a problem out before you tell a user that their issue is “impossible”. Well, I’ll round that out with one more tip today. Keep in mind that all of these things are actions I’ve been guilty of, hopefully in the past. I’m kind of a “work in progress”. And yes, I know these tips are coming from someone who picks on people in presentations, but that is of course done in fun, and (hopefully) with the audience’s knowledge.   (No, this isn’t aimed at any one person or event in particular – I just see it happen a lot)   I’ve seen, unfortunately over and over, someone in authority react badly to someone who is incorrect, or at least perceived to be incorrect. This might manifest itself in a comment, post, question or whatever, but the point is that I’ve seen really intelligent people literally attack someone they view as getting something wrong. Don’t misunderstand me; if someone posts that you should always drop a production database in the middle of the day I think you should certainly speak up and mention that this might be a bad idea!  No, I’m talking about generalizations or even incorrect statements done in good faith. Let me explain with an example.   Suppose someone makes the statement: “If you don’t have enough space on your system, you can just use a DBCC command to shrink the database”. Let’s take two responses to this statement.   Response One: “That’s insane. Everyone knows that shrinking a database is a stupid idea, you’re just going to fragment your indexes all over the place.” Response Two: “That’s an interesting take – in my experience and from what I’ve read here (someurl.com) I think this might not be a universal best practice.”   Of course, both responses let the person making the statement and those reading it know that you don’t agree, and that it’s probably wrong. But the person you responded to and the general audience hearing you (or reading your response) might form two different opinions of you.   The first response says to me “this person really needs to be right, and takes arguments personally. They aren’t thinking of the other person at all, or the folks reading or hearing the exchange. They turned an incorrect technical statement into a personal attack. They haven’t left the other party any room to ‘save face’, and they have potentially turned what could be a positive learning experience for everyone into a negative. Also, they sound more than just a little arrogant.”   The second response says to me “this person has left room for everyone to save face, has presented evidence to the contrary and is thinking about moving the ball forward and getting it right rather than attacking someone for getting it wrong.” It’s the idea of questioning a statement rather than attacking a person.   Perhaps you have a different take. Maybe you think the “direct” approach is best – and maybe that’s worked for you. Something to consider is what you’ve really accomplished while using that first method. Sure, the info you provide is correct, and perhaps someone out there won’t shrink a database because of your response – but perhaps you’ve turned a lot more people off, and now they won’t listen to your other valuable information. You’ll be an expert, but another one of the nameless, arrogant jerks in technology. And I don’t think anyone likes to be thought of that way.   OK, I’ll get down off of the high-horse now. And I’ll keep the title of this entry (said to me by my grandmother when I was a little kid) in mind when I dismount. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Management and Monitoring Tools for Windows Azure

  - by BuckWoody

  With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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• Using HTML 5 SessionState to save rendered Page Content

  - by Rick Strahl

  HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• SSH new connection begins to hang (not reject or terminate) after a day or so on Ubuntu 13.04 server

  - by kross

  Recently we upgraded the server from 12.04 LTS server to 13.04. All was well, including after a reboot. With all packages updated we began to see a strange issue, ssh works for a day or so (unclear on timing) then a later request for SSH hangs (cannot ctrl+c, nothing). It is up and serving webserver traffic etc. Port 22 is open (ips etc altered slightly for posting): nmap -T4 -A x.acme.com Starting Nmap 6.40 ( http://nmap.org ) at 2013-09-12 16:01 CDT Nmap scan report for x.acme.com (69.137.56.18) Host is up (0.026s latency). rDNS record for 69.137.56.18: c-69-137-56-18.hsd1.tn.provider.net Not shown: 998 filtered ports PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 6.1p1 Debian 4 (protocol 2.0) | ssh-hostkey: 1024 54:d3:e3:38:44:f4:20:a4:e7:42:49:d0:a7:f1:3e:21 (DSA) | 2048 dc:21:77:3b:f4:4e:74:d0:87:33:14:40:04:68:33:a6 (RSA) |_256 45:69:10:79:5a:9f:0b:f0:66:15:39:87:b9:a1:37:f7 (ECDSA) 80/tcp open http Jetty 7.6.2.v20120308 | http-title: Log in as a Bamboo user - Atlassian Bamboo |_Requested resource was http://x.acme.com/userlogin!default.action;jsessionid=19v135zn8cl1tgso28fse4d50?os_destination=%2Fstart.action Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel Service detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 12.89 seconds Here is the ssh -vvv: ssh -vvv x.acme.com OpenSSH_5.9p1, OpenSSL 0.9.8x 10 May 2012 debug1: Reading configuration data /Users/tfergeson/.ssh/config debug1: Reading configuration data /etc/ssh_config debug1: /etc/ssh_config line 20: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to x.acme.com [69.137.56.18] port 22. debug1: Connection established. debug3: Incorrect RSA1 identifier debug3: Could not load "/Users/tfergeson/.ssh/id_rsa" as a RSA1 public key debug1: identity file /Users/tfergeson/.ssh/id_rsa type 1 debug1: identity file /Users/tfergeson/.ssh/id_rsa-cert type -1 debug1: identity file /Users/tfergeson/.ssh/id_dsa type -1 debug1: identity file /Users/tfergeson/.ssh/id_dsa-cert type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_6.1p1 Debian-4 debug1: match: OpenSSH_6.1p1 Debian-4 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.9 debug2: fd 3 setting O_NONBLOCK debug3: load_hostkeys: loading entries for host "x.acme.com" from file "/Users/tfergeson/.ssh/known_hosts" debug3: load_hostkeys: found key type RSA in file /Users/tfergeson/.ssh/known_hosts:10 debug3: load_hostkeys: loaded 1 keys debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],ssh-rsa debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: [email protected],[email protected],ssh-rsa,[email protected],[email protected],ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,[email protected],zlib debug2: kex_parse_kexinit: none,[email protected],zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256 debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,[email protected] debug2: kex_parse_kexinit: none,[email protected] debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5 debug1: kex: server->client aes128-ctr hmac-md5 none debug2: mac_setup: found hmac-md5 debug1: kex: client->server aes128-ctr hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug2: dh_gen_key: priv key bits set: 130/256 debug2: bits set: 503/1024 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Server host key: RSA dc:21:77:3b:f4:4e:74:d0:87:33:14:40:04:68:33:a6 debug3: load_hostkeys: loading entries for host "x.acme.com" from file "/Users/tfergeson/.ssh/known_hosts" debug3: load_hostkeys: found key type RSA in file /Users/tfergeson/.ssh/known_hosts:10 debug3: load_hostkeys: loaded 1 keys debug3: load_hostkeys: loading entries for host "69.137.56.18" from file "/Users/tfergeson/.ssh/known_hosts" debug3: load_hostkeys: found key type RSA in file /Users/tfergeson/.ssh/known_hosts:6 debug3: load_hostkeys: loaded 1 keys debug1: Host 'x.acme.com' is known and matches the RSA host key. debug1: Found key in /Users/tfergeson/.ssh/known_hosts:10 debug2: bits set: 493/1024 debug1: ssh_rsa_verify: signature correct debug2: kex_derive_keys debug2: set_newkeys: mode 1 debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug2: set_newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: /Users/tfergeson/.ssh/id_rsa (0x7ff189c1d7d0) debug2: key: /Users/tfergeson/.ssh/id_dsa (0x0) debug1: Authentications that can continue: publickey debug3: start over, passed a different list publickey debug3: preferred publickey,keyboard-interactive,password debug3: authmethod_lookup publickey debug3: remaining preferred: keyboard-interactive,password debug3: authmethod_is_enabled publickey debug1: Next authentication method: publickey debug1: Offering RSA public key: /Users/tfergeson/.ssh/id_rsa debug3: send_pubkey_test debug2: we sent a publickey packet, wait for reply debug1: Server accepts key: pkalg ssh-rsa blen 277 debug2: input_userauth_pk_ok: fp 3c:e5:29:6c:9d:27:d1:7d:e8:09:a2:e8:8e:6e:af:6f debug3: sign_and_send_pubkey: RSA 3c:e5:29:6c:9d:27:d1:7d:e8:09:a2:e8:8e:6e:af:6f debug1: read PEM private key done: type RSA debug1: Authentication succeeded (publickey). Authenticated to x.acme.com ([69.137.56.18]:22). debug1: channel 0: new [client-session] debug3: ssh_session2_open: channel_new: 0 debug2: channel 0: send open debug1: Requesting [email protected] debug1: Entering interactive session. debug2: callback start debug2: client_session2_setup: id 0 debug2: fd 3 setting TCP_NODELAY debug2: channel 0: request pty-req confirm 1 debug1: Sending environment. debug3: Ignored env ATLAS_OPTS debug3: Ignored env rvm_bin_path debug3: Ignored env TERM_PROGRAM debug3: Ignored env GEM_HOME debug3: Ignored env SHELL debug3: Ignored env TERM debug3: Ignored env CLICOLOR debug3: Ignored env IRBRC debug3: Ignored env TMPDIR debug3: Ignored env Apple_PubSub_Socket_Render debug3: Ignored env TERM_PROGRAM_VERSION debug3: Ignored env MY_RUBY_HOME debug3: Ignored env TERM_SESSION_ID debug3: Ignored env USER debug3: Ignored env COMMAND_MODE debug3: Ignored env rvm_path debug3: Ignored env COM_GOOGLE_CHROME_FRAMEWORK_SERVICE_PROCESS/USERS/tfergeson/LIBRARY/APPLICATION_SUPPORT/GOOGLE/CHROME_SOCKET debug3: Ignored env JPDA_ADDRESS debug3: Ignored env APDK_HOME debug3: Ignored env SSH_AUTH_SOCK debug3: Ignored env Apple_Ubiquity_Message debug3: Ignored env __CF_USER_TEXT_ENCODING debug3: Ignored env rvm_sticky_flag debug3: Ignored env MAVEN_OPTS debug3: Ignored env LSCOLORS debug3: Ignored env rvm_prefix debug3: Ignored env PATH debug3: Ignored env PWD debug3: Ignored env JAVA_HOME debug1: Sending env LANG = en_US.UTF-8 debug2: channel 0: request env confirm 0 debug3: Ignored env JPDA_TRANSPORT debug3: Ignored env rvm_version debug3: Ignored env M2_HOME debug3: Ignored env HOME debug3: Ignored env SHLVL debug3: Ignored env rvm_ruby_string debug3: Ignored env LOGNAME debug3: Ignored env M2_REPO debug3: Ignored env GEM_PATH debug3: Ignored env AWS_RDS_HOME debug3: Ignored env rvm_delete_flag debug3: Ignored env EC2_PRIVATE_KEY debug3: Ignored env RUBY_VERSION debug3: Ignored env SECURITYSESSIONID debug3: Ignored env EC2_CERT debug3: Ignored env _ debug2: channel 0: request shell confirm 1 debug2: callback done debug2: channel 0: open confirm rwindow 0 rmax 32768 I can hard reboot (only mac monitors at that location) and it will again be accessible. This now happens every single time. It is imperative that I get it sorted. The strange thing is that it behaves initially then starts to hang after several hours. I perused logs previously and nothing stood out. From the auth.log, I can see that it has allowed me in, but still I get nothing back on the client side: Sep 20 12:47:50 cbear sshd[25376]: Accepted publickey for tfergeson from 10.1.10.14 port 54631 ssh2 Sep 20 12:47:50 cbear sshd[25376]: pam_unix(sshd:session): session opened for user tfergeson by (uid=0) UPDATES: Still occurring even after setting UseDNS no and commenting out #session optional pam_mail.so standard noenv This does not appear to be a network/dns related issue, as all services running on the machine are as responsive and accessible as ever, with the exception of sshd. Any thoughts on where to start?

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