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• Code golf - hex to (raw) binary conversion

  - by Alnitak

  In response to this question asking about hex to (raw) binary conversion, a comment suggested that it could be solved in "5-10 lines of C, or any other language." I'm sure that for (some) scripting languages that could be achieved, and would like to see how. Can we prove that comment true, for C, too? NB: this doesn't mean hex to ASCII binary - specifically the output should be a raw octet stream corresponding to the input ASCII hex. Also, the input parser should skip/ignore white space. edit (by Brian Campbell) May I propose the following rules, for consistency? Feel free to edit or delete these if you don't think these are helpful, but I think that since there has been some discussion of how certain cases should work, some clarification would be helpful. The program must read from stdin and write to stdout (we could also allow reading from and writing to files passed in on the command line, but I can't imagine that would be shorter in any language than stdin and stdout) The program must use only packages included with your base, standard language distribution. In the case of C/C++, this means their respective standard libraries, and not POSIX. The program must compile or run without any special options passed to the compiler or interpreter (so, 'gcc myprog.c' or 'python myprog.py' or 'ruby myprog.rb' are OK, while 'ruby -rscanf myprog.rb' is not allowed; requiring/importing modules counts against your character count). The program should read integer bytes represented by pairs of adjacent hexadecimal digits (upper, lower, or mixed case), optionally separated by whitespace, and write the corresponding bytes to output. Each pair of hexadecimal digits is written with most significant nibble first. The behavior of the program on invalid input (characters besides [a-fA-F \t\r\n], spaces separating the two characters in an individual byte, an odd number of hex digits in the input) is undefined; any behavior (other than actively damaging the user's computer or something) on bad input is acceptable (throwing an error, stopping output, ignoring bad characters, treating a single character as the value of one byte, are all OK) The program may write no additional bytes to output. Code is scored by fewest total bytes in the source file. (Or, if we wanted to be more true to the original challenge, the score would be based on lowest number of lines of code; I would impose an 80 character limit per line in that case, since otherwise you'd get a bunch of ties for 1 line).

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• Parse lines of integers in C

  - by Jérôme

  This is a classical problem, but I can not find a simple solution. I have an input file like: 1 3 9 13 23 25 34 36 38 40 52 54 59 2 3 9 14 23 26 34 36 39 40 52 55 59 63 67 76 85 86 90 93 99 108 114 2 4 9 15 23 27 34 36 63 67 76 85 86 90 93 99 108 115 1 25 34 36 38 41 52 54 59 63 67 76 85 86 90 93 98 107 113 2 3 9 16 24 28 2 3 10 14 23 26 34 36 39 41 52 55 59 63 67 76 Lines of different number of integers separated by a space. I would like to parse them in an array, and separate each line with a marker, let say -1. The difficulty is that I must handle integers and line returns. Here my existing code, it loops upon the scanf loop (because scanf can not begin at a given position). #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { if (argc != 4) { fprintf(stderr, "Usage: %s <data file> <nb transactions> <nb items>\n", argv[0]); return 1; } FILE * file; file = fopen (argv[1],"r"); if (file==NULL) { fprintf(stderr, "Error: can not open %s\n", argv[1]); fclose(file); return 1; } int nb_trans = atoi(argv[2]); int nb_items = atoi(argv[3]); int *bdd = malloc(sizeof(int) * (nb_trans + nb_items)); char line[1024]; int i = 0; while ( fgets(line, 1024, file) ) { int item; while ( sscanf (line, "%d ", &item )){ printf("%s %d %d\n", line, i, item); bdd[i++] = item; } bdd[i++] = -1; } for ( i = 0; i < nb_trans + nb_items; i++ ) { printf("%d ", bdd[i]); } printf("\n"); }

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• How to perform add/update of a model object that contains EntitySet

  - by David Liddle

  I have a similar concept to the SO questions/tags scenario however am trying to decide the best way of implementation. Tables Questions, QuestionTags and Tags Questions QuestionTags Tags --------- ------------ ---- QID QID TID QName TID TName When adding/updating a question I have 2 textboxes. The important part is a single textbox that allows users to enter in multiple Tags separated by spaces. I am using Linq2Sql so the Questions model has an EntitySet of QuestionTags with then link to Tags. My question is regarding the adding/updating of Questions (part 1), and also how to best show QuestionTags for a Question (part 2). Part 1 Before performing an add/update, my service layer needs to deal with 3 scenarios before passing to their respective repositories. Insert Tags that do not already exist Insert/Update Question Insert QuestionTags - when updating need to remove existing QuestionTags Here is my code below however started to get into a bit of a muddle. I've created extension methods on my repositories to get Tags WithNames etc. public void Add(Question q, string tags) { var tagList = tags.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries).ToList(); using (DB.TransactionScope ts = new DB.TransactionScope()) { var existingTags = TagsRepository.Get() .WithName(tagList) .ToList(); var newTags = (from t in tagList select new Tag { TName = t }).Except(existingTags, new TagsComparer()).ToList(); TagsRepository.Add(newTags); //need to insert QuestionTags QuestionsRepository.Add(q); ts.Complete(); } } Part 2 My second question is, when displaying a list of Questions how is it best to show their QuestionTags? For example, I have an Index view that shows a list of Questions in a table. One of the columns shows an image and when the user hovers over it shows the list of Tags. My current implementation is to create a custom ViewModel and show a List of QuestionIndexViewModel in the View. QuestionIndexViewModel { Question Question { get; set; } string Tags { get; set; } } However, this seems a bit clumsy and quite a few DB calls. public ViewResult Index() { var model= new List<QuestionIndexViewModel>(); //make a call to get a list of questions //foreach question make a call to get their QuestionTags, //to be able to get their Tag names and then join them //to form a single string. return View(model); } Also, just for test purposes using SQL Profiler, I decided to iterate through the QuestionTags entity set of a Question in my ViewModel however nothing was picked up in Profiler? What would be the reason for this?

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• Grid sorting with persistent master sort

  - by MikeWyatt

  I have a UI with a grid. Each record in the grid is sorted by a "master" sort column, let's call it a page number. Each record is a story in a magazine. I want the user to be able to drag and drop a record to a new position in the grid and automatically update the page number field to reflect the updated position. Easy enough, right? Now imagine that I also want to have the grid sortable by any other column (story title, section, author name, etc.). How does the drag and drop operation work now? Revert to page number sort during or after the drag and drop operation? This could confuse the user (why did my sort just change?). It would also result in arbitrary row positioning. Would the story now be before the row that was after it when the user dropped it? Or, would it be after the row that was before it? Those rows may now be widely separated after the master order sort. Disable the drag and drop feature if the grid isn't currently sorted by the page number? This would be easy, but the user might wonder why he can't drag and drop at certain times. Knowing to first sort by page number may not be very intuitive. Let the user rearrange his rows, but not make any changes to the page number? Require the user to enter a "Arrange Stories" mode, in which the grid sort is temporarily switched to page number and drag and drop is enabled? They would then exit the mode, and the previous sort would be reapplied. The big difference between this and the second option is that it would be more explicit than simply clicking on a column header. Any other ideas, or reasons why one of the above is the way to go? EDIT I'd like to point out that any of the above is technically possible, and easy to implement. My question is design-related. What is the most intuitive way to solve this problem, from the user's perspective?

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• C++ Class Access Specifier Verbosity

  - by PolyTex

  A "traditional" C++ class (just some random declarations) might resemble the following: class Foo { public: Foo(); explicit Foo(const std::string&); ~Foo(); enum FooState { Idle, Busy, Unknown }; FooState GetState() const; bool GetBar() const; void SetBaz(int); private: struct FooPartialImpl; void HelperFunction1(); void HelperFunction2(); void HelperFunction3(); FooPartialImpl* m_impl; // smart ptr FooState m_state; bool m_bar; int m_baz; }; I always found this type of access level specification ugly and difficult to follow if the original programmer didn't organize his "access regions" neatly. Taking a look at the same snippet in a Java/C# style, we get: class Foo { public: Foo(); public: explicit Foo(const std::string&); public: ~Foo(); public: enum FooState { Idle, Busy, Unknown }; public: FooState GetState() const; public: bool GetBar() const; public: void SetBaz(int); private: struct FooPartialImpl; private: void HelperFunction1(); private: void HelperFunction2(); private: void HelperFunction3(); private: FooPartialImpl* m_impl; // smart ptr private: FooState m_state; private: bool m_bar; private: int m_baz; }; In my opinion, this is much easier to read in a header because the access specifier is right next to the target, and not a bunch of lines away. I found this especially true when working with header-only template code that wasn't separated into the usual "*.hpp/*.inl" pair. In that scenario, the size of the function implementations overpowered this small but important information. My question is simple and stems from the fact that I've never seen anyone else actively do this in their C++ code. Assuming that I don't have a "Class View" capable IDE, are there any obvious drawbacks to using this level of verbosity? Any other style recommendations are welcome!

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• Where do you put your unit test?

  - by soulmerge

  I have found several conventions to housekeeping unit tests in a project and I'm not sure which approach would be suitable for our next PHP project. I am trying to find the best convention to encourage easy development and accessibility of the tests when reviewing the source code. I would be very interested in your experience/opinion regarding each: One folder for productive code, another for unit tests: This separates unit tests from the logic files of the project. This separation of concerns is as much a nuisance as it is an advantage: Someone looking into the source code of the project will - so I suppose - either browse the implementation or the unit tests (or more commonly: the implementation only). The advantage of unit tests being another viewpoint to your classes is lost - those two viewpoints are just too far apart IMO. Annotated test methods: Any modern unit testing framework I know allows developers to create dedicated test methods, annotating them (@test) and embedding them in the project code. The big drawback I see here is that the project files get cluttered. Even if these methods are separated using a comment header (like UNIT TESTS below this line) it just bloats the class unnecessarily. Test files within the same folders as the implementation files: Our file naming convention dictates that PHP files containing classes (one class per file) should end with .class.php. I could imagine that putting unit tests regarding a class file into another one ending on .test.php would render the tests much more present to other developers without tainting the class. Although it bloats the project folders, instead of the implementation files, this is my favorite so far, but I have my doubts: I would think others have come up with this already, and discarded this option for some reason (i.e. I have not seen a java project with the files Foo.java and FooTest.java within the same folder.) Maybe it's because java developers make heavier use of IDEs that allow them easier access to the tests, whereas in PHP no big editors have emerged (like eclipse for java) - many devs I know use vim/emacs or similar editors with little support for PHP development per se. What is your experience with any of these unit test placements? Do you have another convention I haven't listed here? Or am I just overrating unit test accessibility to reviewers?

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• Strange behaviour on postback in ASP.NET

  - by C-King

  I'm working on a website with a login form. To log in, a postback is used to an OnClick handler in the codebehind. Somehow, the value returned from the Text-property of the username and password textboxes is ten times the value I entered, separated by commas. I checked my entire code for double ID's (which seems to be the most common problem causing this behaviour), but I found each ID defined only once. In the ASPX file I have this: <asp:Label ID="lblFeedback" ForeColor="Red" Font-Bold="true" runat="server" Visible="false" /><br /> <asp:Panel ID="pnlLogin" runat="server"> <table style="border-style: none;"> <tr> <td> <asp:Label ID="lblUsername" AssociatedControlID="txtUsername" runat="server" /> </td> <td> <asp:TextBox ID="txtUsername" runat="server" /><br /> </td> </tr> <tr> <td> <asp:Label ID="lblPassword" AssociatedControlID="txtPassword" runat="server" /> </td> <td> <asp:TextBox ID="txtPassword" runat="server" TextMode="password" /><br /> </td> </tr> <tr> <td> </td> <td> <asp:Button ID="btnLogin" OnClick="btnLogin_Click" runat="server" /> </td> </tr> </table> </asp:Panel> The OnClick handler in the Codebehind: protected void btnLogin_Click(object sender, EventArgs e) { string username = Util.Escape(txtUsername.Text); string password = Util.Escape(txtPassword.Text); WebsiteUser user = WebsiteUser.Create(username, password); if (user != null) { //Set some session variables and redirect to user profile } else { lblFeedback.Text = Localizer.Translate("INVALID_LOGIN"); lblFeedback.ForeColor = Color.Red; lblFeedback.Visible = true; pnlLogin.Visible = true; } } The website is running on ASP.NET 2.0 on ISS 5.1 (Win XP Pro)

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• How would you structure your entity model for storing arbitrary key/value data with different data t

  - by Nathan Ridley

  I keep coming across scenarios where it will be useful to store a set of arbitrary data in a table using a per-row key/value model, rather than a rigid column/field model. The problem is, I want to store the values with their correct data type rather than converting everything to a string. This means I have to choose either a single table with multiple nullable columns, one for each data type, or a set of value tables, one for each data type. I'm also unsure as to whether I should use full third normal form and separate the keys into a separate table, referencing them via a foreign key from the value table(s), or if it would be better to keep things simple and store the string keys in the value table(s) and accept the duplication of strings. Old/bad: This solution makes adding additional values a pain in a fluid environment because the table needs to be modified regularly. MyTable ============================ ID Key1 Key2 Key3 int int string date ---------------------------- 1 Value1 Value2 Value3 2 Value4 Value5 Value6 Single Table Solution This solution allows simplicity via a single table. The querying code still needs to check for nulls to determine which data type the field is storing. A check constraint is probably also required to ensure only one of the value fields contains non-nulll data. DataValues ============================================================= ID RecordID Key IntValue StringValue DateValue int int string int string date ------------------------------------------------------------- 1 1 Key1 Value1 NULL NULL 2 1 Key2 NULL Value2 NULL 3 1 Key3 NULL NULL Value3 4 2 Key1 Value4 NULL NULL 5 2 Key2 NULL Value5 NULL 6 2 Key3 NULL NULL Value6 Multiple-Table Solution This solution allows for more concise purposing of each table, though the code needs to know the data type in advance as it needs to query a different table for each data type. Indexing is probably simpler and more efficient because there are less columns that need indexing. IntegerValues =============================== ID RecordID Key Value int int string int ------------------------------- 1 1 Key1 Value1 2 2 Key1 Value4 StringValues =============================== ID RecordID Key Value int int string string ------------------------------- 1 1 Key2 Value2 2 2 Key2 Value5 DateValues =============================== ID RecordID Key Value int int string date ------------------------------- 1 1 Key3 Value3 2 2 Key3 Value6 How do you approach this problem? Which solution is better? Also, should the key column be separated into a separate table and referenced via a foreign key or be should it be kept in the value table and bulk updated if for some reason the key name changes?

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• Is it any loose coupling mechanism in Objective-C + Cocoa like C# delegates or C++Qt signals+slots?

  - by Eye of Hell

  Hello. For a large programs, the standard way to chalenge a complexity is to divide a program code into small objects. Most of the actual programming languages offer this functionality via classes, so is Objective-C. But after source code is separated into small object, the second challenge is to somehow connect them with each over. Standard approaches, supported by most languages are compositon (one object is a member field of another), inheritance, templates (generics) and callbacks. More cryptic techniques include method-level delagates (C#) and signals+slots (C++Qt). I like the delegates / signals idea, since while connecting two objects i can connect individual methods with each over, without objects knowing anything of each over. For C#, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); object1.SomethingHappened += object2.HandleSomething; In this code, is object1 calls it's SomethingHappened delegate (like a normal method call) the HandleSomething method of object2 will be called. For C++Qt, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); connect( object1, SIGNAL(SomethingHappened()), object2, SLOT(HandleSomething()) ); The result will be exactly the same. This technique has some advantages and disadvantages, but generally i like it more than interfaces since if program code base grows i can change connections and add new ones without creating tons of interfaces. After examination of Objective-C i havn't found any way to use this technique i like :(. It seems that Objective-C supports message passing perfectly well, but it requres for object1 to have a pointer to object2 in order to pass it a message. If some object needs to be connected to lots of other objects, in Objective-C i will be forced to give him pointers to each of the objects it must be connected. So, the question :). Is it any approach in Objective-C programming that will closely resemble delegate / signal+slot types of connection, not a 'give first object an entire pointer to second object so it can pass a message to it'. Method-level connections are a bit more preferable to me than object-level connection ^_^.

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• Convert string from getline into a number

  - by haskellguy

  I am trying to create a 2D array with vectors. I have a file that has for each line a set of numbers. So what I did I implemented a split function that every time I have a new number (separated by \t) it splits that and add it to the vector vector<double> &split(const string &s, char delim, vector<double> &elems) { stringstream ss(s); string item; while (getline(ss, item, delim)) { cout << item << endl; double number = atof(item.c_str()); cout << number; elems.push_back(number); } return elems; } vector<double> split(const string &s, char delim) { vector<double> elems; split(s, delim, elems); return elems; } After that I simply iterate through it. int main() { ifstream file("./data/file.txt"); string row; vector< vector<double> > matrix; int line_count = -1; while (getline(file, row)) { line_count++; if (line_count <= 4) continue; vector<double> cols = split(row, '\t'); matrix.push_back(cols); } ... } Now my issues is in this bit here: while (getline(ss, item, delim)) { cout << item << endl; double number = atof(item.c_str()); cout << number; Where item.c_str() is converted to a 0. Shouldn't that be still a string having the same value as item? It works on a separate example if I do straight from string to c_string, but when I use this getline I end up in this error situation, hints?

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• organizing unit test

  - by soulmerge

  I have found several conventions to housekeeping unit tests in a project and I'm not sure which approach would be suitable for our next PHP project. I am trying to find the best convention to encourage easy development and accessibility of the tests when reviewing the source code. I would be very interested in your experience/opinion regarding each: One folder for productive code, another for unit tests: This separates unit tests from the logic files of the project. This separation of concerns is as much a nuisance as it is an advantage: Someone looking into the source code of the project will - so I suppose - either browse the implementation or the unit tests (or more commonly: the implementation only). The advantage of unit tests being another viewpoint to your classes is lost - those two viewpoints are just too far apart IMO. Annotated test methods: Any modern unit testing framework I know allows developers to create dedicated test methods, annotating them (@test) and embedding them in the project code. The big drawback I see here is that the project files get cluttered. Even if these methods are separated using a comment header (like UNIT TESTS below this line) it just bloats the class unnecessarily. Test files within the same folders as the implementation files: Our file naming convention dictates that PHP files containing classes (one class per file) should end with .class.php. I could imagine that putting unit tests regarding a class file into another one ending on .test.php would render the tests much more present to other developers without tainting the class. Although it bloats the project folders, instead of the implementation files, this is my favorite so far, but I have my doubts: I would think others have come up with this already, and discarded this option for some reason (i.e. I have not seen a java project with the files Foo.java and FooTest.java within the same folder.) Maybe it's because java developers make heavier use of IDEs that allow them easier access to the tests, whereas in PHP no big editors have emerged (like eclipse for java) - many devs I know use vim/emacs or similar editors with little support for PHP development per se. What is your experience with any of these unit test placements? Do you have another convention I haven't listed here? Or am I just overrating unit test accessibility to reviewing developers?

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• How can I link two Java serialised objects back together?

  - by Kidburla

  Sometimes (quite a lot, actually) we get a situation in Java where two objects are pointing to the same thing. Now if we serialise these separately it is quite appropriate that the serialised forms have separate copies of the object as it should be possible to open one without the other. However if we now deserialise them both, we find that they are still separated. Is there any way to link them back together? Example follows. public class Example { private static class ContainerClass implements java.io.Serializable { private ReferencedClass obj; public ReferencedClass get() { return obj; } public void set(ReferencedClass obj) { this.obj = obj; } } private static class ReferencedClass implements java.io.Serializable { private int i = 0; public int get() { return i; } public void set(int i) { this.i = i; } } public static void main(String[] args) throws Exception { //Initialise the classes ContainerClass test1 = new ContainerClass(); ContainerClass test2 = new ContainerClass(); ReferencedClass ref = new ReferencedClass(); //Make both container class point to the same reference test1.set(ref); test2.set(ref); //This does what we expect: setting the integer in one (way of accessing the) referenced class sets it in the other one test1.get().set(1234); System.out.println(Integer.toString(test2.get().get())); //Now serialise the container classes java.io.ObjectOutputStream os = new java.io.ObjectOutputStream(new java.io.FileOutputStream("C:\\Users\\Public\\test1.ser")); os.writeObject(test1); os.close(); os = new java.io.ObjectOutputStream(new java.io.FileOutputStream("C:\\Users\\Public\\test2.ser")); os.writeObject(test2); os.close(); //And deserialise them java.io.ObjectInputStream is = new java.io.ObjectInputStream(new java.io.FileInputStream("C:\\Users\\Public\\test1.ser")); ContainerClass test3 = (ContainerClass)is.readObject(); is.close(); is = new java.io.ObjectInputStream(new java.io.FileInputStream("C:\\Users\\Public\\test2.ser")); ContainerClass test4 = (ContainerClass)is.readObject(); is.close(); //We expect the same thing as before, and would expect a result of 4321, but this doesn't happen as the referenced objects are now separate instances test3.get().set(4321); System.out.println(Integer.toString(test4.get().get())); } }

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• factory class, wrong number of arguments being passed to subclass constructor

  - by Hugh Bothwell

  I was looking at Python: Exception in the separated module works wrong which uses a multi-purpose GnuLibError class to 'stand in' for a variety of different errors. Each sub-error has its own ID number and error format string. I figured it would be better written as a hierarchy of Exception classes, and set out to do so: class GNULibError(Exception): sub_exceptions = 0 # patched with dict of subclasses once subclasses are created err_num = 0 err_format = None def __new__(cls, *args): print("new {}".format(cls)) # DEBUG if len(args) and args[0] in GNULibError.sub_exceptions: print(" factory -> {} {}".format(GNULibError.sub_exceptions[args[0]], args[1:])) # DEBUG return super(GNULibError, cls).__new__(GNULibError.sub_exceptions[args[0]], *(args[1:])) else: print(" plain {} {}".format(cls, args)) # DEBUG return super(GNULibError, cls).__new__(cls, *args) def __init__(self, *args): cls = type(self) print("init {} {}".format(cls, args)) # DEBUG self.args = args if cls.err_format is None: self.message = str(args) else: self.message = "[GNU Error {}] ".format(cls.err_num) + cls.err_format.format(*args) def __str__(self): return self.message def __repr__(self): return '{}{}'.format(type(self).__name__, self.args) class GNULibError_Directory(GNULibError): err_num = 1 err_format = "destination directory does not exist: {}" class GNULibError_Config(GNULibError): err_num = 2 err_format = "configure file does not exist: {}" class GNULibError_Module(GNULibError): err_num = 3 err_format = "selected module does not exist: {}" class GNULibError_Cache(GNULibError): err_num = 4 err_format = "{} is expected to contain gl_M4_BASE({})" class GNULibError_Sourcebase(GNULibError): err_num = 5 err_format = "missing sourcebase argument: {}" class GNULibError_Docbase(GNULibError): err_num = 6 err_format = "missing docbase argument: {}" class GNULibError_Testbase(GNULibError): err_num = 7 err_format = "missing testsbase argument: {}" class GNULibError_Libname(GNULibError): err_num = 8 err_format = "missing libname argument: {}" # patch master class with subclass reference # (TO DO: auto-detect all available subclasses instead of hardcoding them) GNULibError.sub_exceptions = { 1: GNULibError_Directory, 2: GNULibError_Config, 3: GNULibError_Module, 4: GNULibError_Cache, 5: GNULibError_Sourcebase, 6: GNULibError_Docbase, 7: GNULibError_Testbase, 8: GNULibError_Libname } This starts out with GNULibError as a factory class - if you call it with an error number belonging to a recognized subclass, it returns an object belonging to that subclass, otherwise it returns itself as a default error type. Based on this code, the following should be exactly equivalent (but aren't): e = GNULibError(3, 'missing.lib') f = GNULibError_Module('missing.lib') print e # -> '[GNU Error 3] selected module does not exist: 3' print f # -> '[GNU Error 3] selected module does not exist: missing.lib' I added some strategic print statements, and the error seems to be in GNULibError.__new__: >>> e = GNULibError(3, 'missing.lib') new <class '__main__.GNULibError'> factory -> <class '__main__.GNULibError_Module'> ('missing.lib',) # good... init <class '__main__.GNULibError_Module'> (3, 'missing.lib') # NO! ^ why? I call the subclass constructor as subclass.__new__(*args[1:]) - this should drop the 3, the subclass type ID - and yet its __init__ is still getting the 3 anyway! How can I trim the argument list that gets passed to subclass.__init__?

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• Efficient method of finding database rows that have *one or more* qualities from a list of seven qualities

  - by hithere

  Hello! For this question, I'm looking to see if anyone has a better idea of how to implement what I'm currently planning on implementing (below): I'm keeping track of a set of images, using a database. Each image is represented by one row. I want to be able to search for images, using a number of different search parameters. One of these parameters involves a search-by-color option. (The rest of the search stuff is currently working fine.) Images in this database can contain up to seven colors: -Red -Orange -Yellow -Green -Blue -Indigo -Violet Here are some example user queries: "I want an image that contains red." "I want an image that contains red and blue." "I want an image that contains yellow and violet." "I want an image that contains red, orange, yellow, green, blue, indigo and violet." And so on. Users make this selection through the use of checkboxes in an html form. They can check zero checkboxes, all seven, and anything in between. I'm curious to hear what people think would be the most efficient way to perform this database search. I have two possible options right now, but I feel like there must be something better that I'm not thinking of. (Option 1) -For each row, simply have seven additional fields in the database, one for each color. Each field holds a 1 or 0 (true/false) value, and I SELECT based on whatever the user has checked off. (I didn't like this solution so much, because it seemed kind of wasteful to add seven additional fields...especially since most pictures in this table will only have 3-4 colors max, though some could have up to 7. So that means I'm storing a lot of zeros.) Also, if I added more searchable colors later on (which I don't think I will, but it's always possible), I'd have to add more fields. (Option 2) -For each image row, I could have a "colors" text field that stores space-separated color names (or numbers for the sake of compactness). Then I could do a fulltext match against search through the fields, selecting rows that contain "red yellow green" (or "1 3 4"). But I kind of didn't want to do fulltext searching because I already allow a keyword search, and I didn't really want to do two fulltext searches per image search. Plus, if the database gets big, fulltext stuff might slow down. Any better options that I didn't think of? Thanks! Side Note: I'm using PHP to work with a MySQL database.

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• C++ class is not recognizing string data type

  - by reallythecrash

  I'm working on a program from my C++ textbook, and this this the first time I've really run into trouble. I just can't seem to see what is wrong here. Visual Studio is telling me Error: identifier "string" is undefined. I separated the program into three files. A header file for the class specification, a .cpp file for the class implementation and the main program file. These are the instructions from my book: Write a class named Car that has the following member variables: year. An int that holds the car's model year. make. A string that holds the make of the car. speed. An int that holds the car's current speed. In addition, the class should have the following member functions. Constructor. The constructor should accept the car's year and make as arguments and assign these values to the object's year and make member variables. The constructor should initialize the speed member variable to 0. Accessors. Appropriate accessor functions should be created to allow values to be retrieved from an object's year, make and speed member variables. There are more instructions, but they are not necessary to get this part to work. Here is my source code: // File Car.h -- Car class specification file #ifndef CAR_H #define CAR_H class Car { private: int year; string make; int speed; public: Car(int, string); int getYear(); string getMake(); int getSpeed(); }; #endif // File Car.cpp -- Car class function implementation file #include "Car.h" // Default Constructor Car::Car(int inputYear, string inputMake) { year = inputYear; make = inputMake; speed = 0; } // Accessors int Car::getYear() { return year; } string Car::getMake() { return make; } int Car::getSpeed() { return speed; } // Main program #include <iostream> #include <string> #include "Car.h" using namespace std; int main() { } I haven't written anything in the main program yet, because I can't get the class to compile. I've only linked the header file to the main program. Thanks in advance to all who take the time to investigate this problem for me.

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• Displaying an image on a LED matrix with a Netduino

  - by Bertrand Le Roy

  In the previous post, we’ve been flipping bits manually on three ports of the Netduino to simulate the data, clock and latch pins that a shift register expected. We did all that in order to control one line of a LED matrix and create a simple Knight Rider effect. It was rightly pointed out in the comments that the Netduino has built-in knowledge of the sort of serial protocol that this shift register understands through a feature called SPI. That will of course make our code a whole lot simpler, but it will also make it a whole lot faster: writing to the Netduino ports is actually not that fast, whereas SPI is very, very fast. Unfortunately, the Netduino documentation for SPI is severely lacking. Instead, we’ve been reliably using the documentation for the Fez, another .NET microcontroller. To send data through SPI, we’ll just need  to move a few wires around and update the code. SPI uses pin D11 for writing, pin D12 for reading (which we won’t do) and pin D13 for the clock. The latch pin is a parameter that can be set by the user. This is very close to the wiring we had before (data on D11, clock on D12 and latch on D13). We just have to move the latch from D13 to D10, and the clock from D12 to D13. The code that controls the shift register has slimmed down considerably with that change. Here is the new version, which I invite you to compare with what we had before: public class ShiftRegister74HC595 { protected SPI Spi; public ShiftRegister74HC595(Cpu.Pin latchPin) : this(latchPin, SPI.SPI_module.SPI1) { } public ShiftRegister74HC595(Cpu.Pin latchPin, SPI.SPI_module spiModule) { var spiConfig = new SPI.Configuration( SPI_mod: spiModule, ChipSelect_Port: latchPin, ChipSelect_ActiveState: false, ChipSelect_SetupTime: 0, ChipSelect_HoldTime: 0, Clock_IdleState: false, Clock_Edge: true, Clock_RateKHz: 1000 ); Spi = new SPI(spiConfig); } public void Write(byte buffer) { Spi.Write(new[] {buffer}); } } All we have to do here is configure SPI. The write method couldn’t be any simpler. Everything is now handled in hardware by the Netduino. We set the frequency to 1MHz, which is largely sufficient for what we’ll be doing, but it could potentially go much higher. The shift register addresses the columns of the matrix. The rows are directly wired to ports D0 to D7 of the Netduino. The code writes to only one of those eight lines at a time, which will make it fast enough. The way an image is displayed is that we light the lines one after the other so fast that persistence of vision will give the illusion of a stable image: foreach (var bitmap in matrix.MatrixBitmap) { matrix.OnRow(row, bitmap, true); matrix.OnRow(row, bitmap, false); row++; } Now there is a twist here: we need to run this code as fast as possible in order to display the image with as little flicker as possible, but we’ll eventually have other things to do. In other words, we need the code driving the display to run in the background, except when we want to change what’s being displayed. Fortunately, the .NET Micro Framework supports multithreading. In our implementation, we’ve added an Initialize method that spins a new thread that is tied to the specific instance of the matrix it’s being called on. public LedMatrix Initialize() { DisplayThread = new Thread(() => DoDisplay(this)); DisplayThread.Start(); return this; } I quite like this way to spin a thread. As you may know, there is another, built-in way to contextualize a thread by passing an object into the Start method. For the method to work, the thread must have been constructed with a ParameterizedThreadStart delegate, which takes one parameter of type object. I like to use object as little as possible, so instead I’m constructing a closure with a Lambda, currying it with the current instance. This way, everything remains strongly-typed and there’s no casting to do. Note that this method would extend perfectly to several parameters. Of note as well is the return value of Initialize, a common technique to add some fluency to the API and enabling the matrix to be instantiated and initialized in a single line: using (var matrix = new LedMS88SR74HC595().Initialize()) The “using” in the previous line is because we have implemented IDisposable so that the matrix kills the thread and clears the display when the user code is done with it: public void Dispose() { Clear(); DisplayThread.Abort(); } Thanks to the multi-threaded version of the matrix driver class, we can treat the display as a simple bitmap with a very synchronous programming model: matrix.Set(someimage); while (button.Read()) { Thread.Sleep(10); } Here, the call into Set returns immediately and from the moment the bitmap is set, the background display thread will constantly continue refreshing no matter what happens in the main thread. That enables us to wait or read a button’s port on the main thread knowing that the current image will continue displaying unperturbed and without requiring manual refreshing. We’ve effectively hidden the implementation of the display behind a convenient, synchronous-looking API. Pretty neat, eh? Before I wrap up this post, I want to talk about one small caveat of using SPI rather than driving the shift register directly: when we got to the point where we could actually display images, we noticed that they were a mirror image of what we were sending in. Oh noes! Well, the reason for it is that SPI is sending the bits in a big-endian fashion, in other words backwards. Now sure you could fix that in software by writing some bit-level code to reverse the bits we’re sending in, but there is a far more efficient solution than that. We are doing hardware here, so we can simply reverse the order in which the outputs of the shift register are connected to the columns of the matrix. That’s switching 8 wires around once, as compared to doing bit operations every time we send a line to display. All right, so bringing it all together, here is the code we need to write to display two images in succession, separated by a press on the board’s button: var button = new InputPort(Pins.ONBOARD_SW1, false, Port.ResistorMode.Disabled); using (var matrix = new LedMS88SR74HC595().Initialize()) { // Oh, prototype is so sad! var sad = new byte[] { 0x66, 0x24, 0x00, 0x18, 0x00, 0x3C, 0x42, 0x81 }; DisplayAndWait(sad, matrix, button); // Let's make it smile! var smile = new byte[] { 0x42, 0x18, 0x18, 0x81, 0x7E, 0x3C, 0x18, 0x00 }; DisplayAndWait(smile, matrix, button); } And here is a video of the prototype running: The prototype in action I’ve added an artificial delay between the display of each row of the matrix to clearly show what’s otherwise happening very fast. This way, you can clearly see each of the two images being displayed line by line. Next time, we’ll do no hardware changes, focusing instead on building a nice programming model for the matrix, with sprites, text and hardware scrolling. Fun stuff. By the way, can any of my reader guess where we’re going with all that? The code for this prototype can be downloaded here: http://weblogs.asp.net/blogs/bleroy/Samples/NetduinoLedMatrixDriver.zip

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• Creating packages in code - Package Configurations

  Continuing my theme of building various types of packages in code, this example shows how to building a package with package configurations. Incidentally it shows you how to add a variable, and a connection too. It covers the five most common configurations: Configuration File Indirect Configuration File SQL Server Indirect SQL Server Environment Variable  For a general overview try the SQL Server Books Online Package Configurations topic. The sample uses a a simple helper function ApplyConfig to create or update a configuration, although in the example we will only ever create. The most useful knowledge is the configuration string (Configuration.ConfigurationString) that you need to set. Configuration Type Configuration String Description Configuration File The full path and file name of an XML configuration file. The file can contain one or more configuration and includes the target path and new value to set. Indirect Configuration File An environment variable the value of which contains full path and file name of an XML configuration file as per the Configuration File type described above. SQL Server A three part configuration string, with each part being quote delimited and separated by a semi-colon. -- The first part is the connection manager name. The connection tells you which server and database to look for the configuration table. -- The second part is the name of the configuration table. The table is of a standard format, use the Package Configuration Wizard to help create an example, or see the sample script files below. The table contains one or more rows or configuration items each with a target path and new value. -- The third and final part is the optional filter name. A configuration table can contain multiple configurations, and the filter is  literal value that can be used to group items together and act as a filter clause when configurations are being read. If you do not need a filter, just leave the value empty. Indirect SQL Server An environment variable the value of which is the three part configuration string as per the SQL Server type described above. Environment Variable An environment variable the value of which is the value to set in the package. This is slightly different to the other examples as the configuration definition in the package also includes the target information. In our ApplyConfig function this is the only example that actually supplies a target value for the Configuration.PackagePath property. The path is an XPath style path for the target property, \Package.Variables[User::Variable].Properties[Value], the equivalent of which can be seen in the screenshot below, with the object being our variable called Variable, and the property to set is the Value property of that variable object. The configurations as seen when opening the generated package in BIDS: The sample code creates the package, adds a variable and connection manager, enables configurations, and then adds our example configurations. The package is then saved to disk, useful for checking the package and testing, before finally executing, just to prove it is valid. There are some external resources used here, namely some environment variables and a table, see below for more details. namespace Konesans.Dts.Samples { using System; using Microsoft.SqlServer.Dts.Runtime; public class PackageConfigurations { public void CreatePackage() { // Create a new package Package package = new Package(); package.Name = "ConfigurationSample"; // Add a variable, the target for our configurations package.Variables.Add("Variable", false, "User", 0); // Add a connection, for SQL configurations // Add the SQL OLE-DB connection ConnectionManager connectionManagerOleDb = package.Connections.Add("OLEDB"); connectionManagerOleDb.Name = "SQLConnection"; connectionManagerOleDb.ConnectionString = "Provider=SQLOLEDB.1;Data Source=(local);Initial Catalog=master;Integrated Security=SSPI;"; // Add our example configurations, first must enable package setting package.EnableConfigurations = true; // Direct configuration file, see sample file this.ApplyConfig(package, "Configuration File", DTSConfigurationType.ConfigFile, "C:\\Temp\\XmlConfig.dtsConfig", string.Empty); // Indirect configuration file, the emvironment variable XmlConfigFileEnvironmentVariable // contains the path to the configuration file, e.g. C:\Temp\XmlConfig.dtsConfig this.ApplyConfig(package, "Indirect Configuration File", DTSConfigurationType.IConfigFile, "XmlConfigFileEnvironmentVariable", string.Empty); // Direct SQL Server configuration, uses the SQLConnection package connection to read // configurations from the [dbo].[SSIS Configurations] table, with a filter of "SampleFilter" this.ApplyConfig(package, "SQL Server", DTSConfigurationType.SqlServer, "\"SQLConnection\";\"[dbo].[SSIS Configurations]\";\"SampleFilter\";", string.Empty); // Indirect SQL Server configuration, the environment variable "SQLServerEnvironmentVariable" // contains the configuration string e.g. "SQLConnection";"[dbo].[SSIS Configurations]";"SampleFilter"; this.ApplyConfig(package, "Indirect SQL Server", DTSConfigurationType.ISqlServer, "SQLServerEnvironmentVariable", string.Empty); // Direct environment variable, the value of the EnvironmentVariable environment variable is // applied to the target property, the value of the "User::Variable" package variable this.ApplyConfig(package, "EnvironmentVariable", DTSConfigurationType.EnvVariable, "EnvironmentVariable", "\\Package.Variables[User::Variable].Properties[Value]"); #if DEBUG // Save package to disk, DEBUG only new Application().SaveToXml(String.Format(@"C:\Temp\{0}.dtsx", package.Name), package, null); Console.WriteLine(@"C:\Temp\{0}.dtsx", package.Name); #endif // Execute package package.Execute(); // Basic check for warnings foreach (DtsWarning warning in package.Warnings) { Console.WriteLine("WarningCode : {0}", warning.WarningCode); Console.WriteLine(" SubComponent : {0}", warning.SubComponent); Console.WriteLine(" Description : {0}", warning.Description); Console.WriteLine(); } // Basic check for errors foreach (DtsError error in package.Errors) { Console.WriteLine("ErrorCode : {0}", error.ErrorCode); Console.WriteLine(" SubComponent : {0}", error.SubComponent); Console.WriteLine(" Description : {0}", error.Description); Console.WriteLine(); } package.Dispose(); } /// <summary> /// Add or update an package configuration. /// </summary> /// <param name="package">The package.</param> /// <param name="name">The configuration name.</param> /// <param name="type">The type of configuration</param> /// <param name="setting">The configuration setting.</param> /// <param name="target">The target of the configuration, leave blank if not required.</param> internal void ApplyConfig(Package package, string name, DTSConfigurationType type, string setting, string target) { Configurations configurations = package.Configurations; Configuration configuration; if (configurations.Contains(name)) { configuration = configurations[name]; } else { configuration = configurations.Add(); } configuration.Name = name; configuration.ConfigurationType = type; configuration.ConfigurationString = setting; configuration.PackagePath = target; } } } The following table lists the environment variables required for the full example to work along with some sample values. Variable Sample value EnvironmentVariable 1 SQLServerEnvironmentVariable "SQLConnection";"[dbo].[SSIS Configurations]";"SampleFilter"; XmlConfigFileEnvironmentVariable C:\Temp\XmlConfig.dtsConfig Sample code, package and configuration file. ConfigurationApplication.cs ConfigurationSample.dtsx XmlConfig.dtsConfig

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• Java Logger API

  - by Koppar

  This is a more like a tip rather than technical write up and serves as a quick intro for newbies. The logger API helps to diagnose application level or JDK level issues at runtime. There are 7 levels which decide the detailing in logging (SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST). Its best to start with highest level and as we narrow down, use more detailed logging for a specific area. SEVERE is the highest and FINEST is the lowest. This may not make sense until we understand some jargon. The Logger class provides the ability to stream messages to an output stream in a format that can be controlled by the user. What this translates to is, I can create a logger with this simple invocation and use it add debug messages in my class: import java.util.logging.*; private static final Logger focusLog = Logger.getLogger("java.awt.focus.KeyboardFocusManager"); if (focusLog.isLoggable(Level.FINEST)) { focusLog.log(Level.FINEST, "Calling peer setCurrentFocusOwner}); LogManager acts like a book keeper and all the getLogger calls are forwarded to LogManager. The LogManager itself is a singleton class object which gets statically initialized on JVM start up. More on this later. If there is no existing logger with the given name, a new one is created. If there is one (and not yet GC’ed), then the existing Logger object is returned. By default, a root logger is created on JVM start up. All anonymous loggers are made as the children of the root logger. Named loggers have the hierarchy as per their name resolutions. Eg: java.awt.focus is the parent logger for java.awt.focus.KeyboardFocusManager etc. Before logging any message, the logger checks for the log level specified. If null is specified, the log level of the parent logger will be set. However, if the log level is off, no log messages would be written, irrespective of the parent’s log level. All the messages that are posted to the Logger are handled as a LogRecord object.i.e. FocusLog.log would create a new LogRecord object with the log level and message as its data members). The level of logging and thread number are also tracked. LogRecord is passed on to all the registered Handlers. Handler is basically a means to output the messages. The output may be redirected to either a log file or console or a network logging service. The Handler classes use the LogManager properties to set filters and formatters. During initialization or JVM start up, LogManager looks for logging.properties file in jre/lib and sets the properties if the file is provided. An alternate location for properties file can also be specified by setting java.util.logging.config.file system property. This can be set in Java Control Panel ? Java ? Runtime parameters as -Djava.util.logging.config.file = <mylogfile> or passed as a command line parameter java -Djava.util.logging.config.file = C:/Sunita/myLog The redirection of logging depends on what is specified rather registered as a handler with JVM in the properties file. java.util.logging.ConsoleHandler sends the output to system.err and java.util.logging.FileHandler sends the output to file. File name of the log file can also be specified. If you prefer XML format output, in the configuration file, set java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter and if you prefer simple text, set set java.util.logging.FileHandler.formatter =java.util.logging.SimpleFormatter Below is the default logging Configuration file: ############################################################ # Default Logging Configuration File # You can use a different file by specifying a filename # with the java.util.logging.config.file system property. # For example java -Djava.util.logging.config.file=myfile ############################################################ ############################################################ # Global properties ############################################################ # "handlers" specifies a comma separated list of log Handler # classes. These handlers will be installed during VM startup. # Note that these classes must be on the system classpath. # By default we only configure a ConsoleHandler, which will only # show messages at the INFO and above levels. handlers= java.util.logging.ConsoleHandler # To also add the FileHandler, use the following line instead. #handlers= java.util.logging.FileHandler, java.util.logging.ConsoleHandler # Default global logging level. # This specifies which kinds of events are logged across # all loggers. For any given facility this global level # can be overriden by a facility specific level # Note that the ConsoleHandler also has a separate level # setting to limit messages printed to the console. .level= INFO ############################################################ # Handler specific properties. # Describes specific configuration info for Handlers. ############################################################ # default file output is in user's home directory. java.util.logging.FileHandler.pattern = %h/java%u.log java.util.logging.FileHandler.limit = 50000 java.util.logging.FileHandler.count = 1 java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter # Limit the message that are printed on the console to INFO and above. java.util.logging.ConsoleHandler.level = INFO java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter ############################################################ # Facility specific properties. # Provides extra control for each logger. ############################################################ # For example, set the com.xyz.foo logger to only log SEVERE # messages: com.xyz.foo.level = SEVERE Since I primarily use this method to track focus issues, here is how I get detailed awt focus related logging. Just set the logger name to java.awt.focus.level=FINEST and change the default log level to FINEST. Below is a basic sample program. The sample programs are from http://www2.cs.uic.edu/~sloan/CLASSES/java/ and have been modified to illustrate the logging API. By changing the .level property in the logging.properties file, one can control the output written to the logs. To play around with the example, try changing the levels in the logging.properties file and notice the difference in messages going to the log file. Example --------KeyboardReader.java------------------------------------------------------------------------------------- import java.io.*; import java.util.*; import java.util.logging.*; public class KeyboardReader { private static final Logger mylog = Logger.getLogger("samples.input"); public static void main (String[] args) throws java.io.IOException { String s1; String s2; double num1, num2, product; // set up the buffered reader to read from the keyboard BufferedReader br = new BufferedReader (new InputStreamReader (System.in)); System.out.println ("Enter a line of input"); s1 = br.readLine(); if (mylog.isLoggable(Level.SEVERE)) { mylog.log (Level.SEVERE,"The line entered is " + s1); } if (mylog.isLoggable(Level.INFO)) { mylog.log (Level.INFO,"The line has " + s1.length() + " characters"); } if (mylog.isLoggable(Level.FINE)) { mylog.log (Level.FINE,"Breaking the line into tokens we get:"); } int numTokens = 0; StringTokenizer st = new StringTokenizer (s1); while (st.hasMoreTokens()) { s2 = st.nextToken(); numTokens++; if (mylog.isLoggable(Level.FINEST)) { mylog.log (Level.FINEST, " Token " + numTokens + " is: " + s2); } } } } ----------MyFileReader.java---------------------------------------------------------------------------------------- import java.io.*; import java.util.*; import java.util.logging.*; public class MyFileReader extends KeyboardReader { private static final Logger mylog = Logger.getLogger("samples.input.file"); public static void main (String[] args) throws java.io.IOException { String s1; String s2; // set up the buffered reader to read from the keyboard BufferedReader br = new BufferedReader (new FileReader ("MyFileReader.txt")); s1 = br.readLine(); if (mylog.isLoggable(Level.SEVERE)) { mylog.log (Level.SEVERE,"ATTN The line is " + s1); } if (mylog.isLoggable(Level.INFO)) { mylog.log (Level.INFO, "The line has " + s1.length() + " characters"); } if (mylog.isLoggable(Level.FINE)) { mylog.log (Level.FINE,"Breaking the line into tokens we get:"); } int numTokens = 0; StringTokenizer st = new StringTokenizer (s1); while (st.hasMoreTokens()) { s2 = st.nextToken(); numTokens++; if (mylog.isLoggable(Level.FINEST)) { mylog.log (Level.FINEST,"Breaking the line into tokens we get:"); mylog.log (Level.FINEST," Token " + numTokens + " is: " + s2); } } //end of while } // end of main } // end of class ----------MyFileReader.txt------------------------------------------------------------------------------------------ My first logging example -------logging.properties------------------------------------------------------------------------------------------- handlers= java.util.logging.ConsoleHandler, java.util.logging.FileHandler .level= FINEST java.util.logging.FileHandler.pattern = java%u.log java.util.logging.FileHandler.limit = 50000 java.util.logging.FileHandler.count = 1 java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter java.util.logging.ConsoleHandler.level = FINEST java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter java.awt.focus.level=ALL ------Output log------------------------------------------------------------------------------------------- May 21, 2012 11:44:55 AM MyFileReader main SEVERE: ATTN The line is My first logging example May 21, 2012 11:44:55 AM MyFileReader main INFO: The line has 24 characters May 21, 2012 11:44:55 AM MyFileReader main FINE: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 1 is: My May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 2 is: first May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 3 is: logging May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 4 is: example Invocation command: "C:\Program Files (x86)\Java\jdk1.6.0_29\bin\java.exe" -Djava.util.logging.config.file=logging.properties MyFileReader References Further technical details are available here: http://docs.oracle.com/javase/1.4.2/docs/guide/util/logging/overview.html#1.0 http://docs.oracle.com/javase/1.4.2/docs/api/java/util/logging/package-summary.html http://www2.cs.uic.edu/~sloan/CLASSES/java/

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• BNF – how to read syntax?

  - by Piotr Rodak

  A few days ago I read post of Jen McCown (blog) about her idea of blogging about random articles from Books Online. I think this is a great idea, even if Jen says that it’s not exciting or sexy. I noticed that many of the questions that appear on forums and other media arise from pure fact that people asking questions didn’t bother to read and understand the manual – Books Online. Jen came up with a brilliant, concise acronym that describes very well the category of posts about Books Online – RTFM365. I take liberty of tagging this post with the same acronym. I often come across questions of type – ‘Hey, i am trying to create a table, but I am getting an error’. The error often says that the syntax is invalid. 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT DEFAULT Guid_Default NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); 5 The answer is usually(1), ‘Ok, let me check it out.. Ah yes – you have to put name of the DEFAULT constraint before the type of constraint: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); Why many people stumble on syntax errors? Is the syntax poorly documented? No, the issue is, that correct syntax of the CREATE TABLE statement is documented very well in Books Online and is.. intimidating. Many people can be taken aback by the rather complex block of code that describes all intricacies of the statement. However, I don’t know better way of defining syntax of the statement or command. The notation that is used to describe syntax in Books Online is a form of Backus-Naur notatiion, called BNF for short sometimes. This is a notation that was invented around 50 years ago, and some say that even earlier, around 400 BC – would you believe? Originally it was used to define syntax of, rather ancient now, ALGOL programming language (in 1950’s, not in ancient India). If you look closer at the definition of the BNF, it turns out that the principles of this syntax are pretty simple. Here are a few bullet points: italic_text is a placeholder for your identifier <italic_text_in_angle_brackets> is a definition which is described further. [everything in square brackets] is optional {everything in curly brackets} is obligatory everything | separated | by | operator is an alternative ::= “assigns” definition to an identifier Yes, it looks like these six simple points give you the key to understand even the most complicated syntax definitions in Books Online. Books Online contain an article about syntax conventions – have you ever read it? Let’s have a look at fragment of the CREATE TABLE statement: 1 CREATE TABLE 2 [ database_name . [ schema_name ] . | schema_name . ] table_name 3 ( { <column_definition> | <computed_column_definition> 4 | <column_set_definition> } 5 [ <table_constraint> ] [ ,...n ] ) 6 [ ON { partition_scheme_name ( partition_column_name ) | filegroup 7 | "default" } ] 8 [ { TEXTIMAGE_ON { filegroup | "default" } ] 9 [ FILESTREAM_ON { partition_scheme_name | filegroup 10 | "default" } ] 11 [ WITH ( <table_option> [ ,...n ] ) ] 12 [ ; ] Let’s look at line 2 of the above snippet: This line uses rules 3 and 5 from the list. So you know that you can create table which has specified one of the following. just name – table will be created in default user schema schema name and table name – table will be created in specified schema database name, schema name and table name – table will be created in specified database, in specified schema database name, .., table name – table will be created in specified database, in default schema of the user. Note that this single line of the notation describes each of the naming schemes in deterministic way. The ‘optionality’ of the schema_name element is nested within database_name.. section. You can use either database_name and optional schema name, or just schema name – this is specified by the pipe character ‘|’. The error that user gets with execution of the first script fragment in this post is as follows: Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'DEFAULT'. Ok, let’s have a look how to find out the correct syntax. Line number 3 of the BNF fragment above contains reference to <column_definition>. Since column_definition is in angle brackets, we know that this is a reference to notion described further in the code. And indeed, the very next fragment of BNF contains syntax of the column definition. 1 <column_definition> ::= 2 column_name <data_type> 3 [ FILESTREAM ] 4 [ COLLATE collation_name ] 5 [ NULL | NOT NULL ] 6 [ 7 [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] 8 | [ IDENTITY [ ( seed ,increment ) ] [ NOT FOR REPLICATION ] 9 ] 10 [ ROWGUIDCOL ] [ <column_constraint> [ ...n ] ] 11 [ SPARSE ] Look at line 7 in the above fragment. It says, that the column can have a DEFAULT constraint which, if you want to name it, has to be prepended with [CONSTRAINT constraint_name] sequence. The name of the constraint is optional, but I strongly recommend you to make the effort of coming up with some meaningful name yourself. So the correct syntax of the CREATE TABLE statement from the beginning of the article is like this: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); That is practically everything you should know about BNF. I encourage you to study the syntax definitions for various statements and commands in Books Online, you can find really interesting things hidden there. Technorati Tags: SQL Server,t-sql,BNF,syntax   (1) No, my answer usually is a question – ‘What error message? What does it say?’. You’d be surprised to know how many people think I can go through time and space and look at their screen at the moment they received the error.

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• Preserving Permalinks

  - by Daniel Moth

  One of the things that gets me on a rant is websites that break permalinks. If you have posted something somewhere and there is a public URL pointing to it, that URL should never ever return a 404. You are breaking all websites that ever linked to you and you are breaking all search engine links to your content (that others will try and follow). It is a pet peeve of mine. So when I had to move my blog, obviously I would preserve the root URL (www.danielmoth.com/Blog/), but I also wanted to preserve every URL my blog has generated over the years. To be clear, our focus here is on the URL formatting, not the content migration which I'll talk about in my next post. In this post, I'll describe my solution first and then what it solves. 1. The IIS7 Rewrite Module and web.config There are a few ways you can map an old URL to a new one (so when requests to the old URL come in, they get redirected to the new one). The new blog engine I use (dasBlog) has built-in functionality to do that (Scott refers to it here). Instead, the way I chose to address the issue was to use the IIS7 rewrite module. The IIS7 rewrite module allows redirecting URLs based on pattern matching, regular expressions and, of course, hardcoded full URLs for things that don't fall into any pattern. You can configure it visually from IIS Manager using a handy dialog that allows testing patterns against input URLs. Here is what mine looked like after configuring a few rules: To learn more about this technology check out this video, the reference page and this overview blog post; all 3 pages have a collection of related resources at the bottom worth checking out too. All the visual configuration ends up in a web.config file at the root folder of your website. If you are on a shared hosting service, probably the only way you can use the Rewrite Module is by directly editing the web.config file. Next, I'll describe the URLs I had to map and how that manifested itself in the web.config file. What I did was create the rules locally using the GUI, and then took the generated web.config file and uploaded it to my live site. You can view my web.config here. 2. Monthly Archives Observe the difference between the way the two blog engines generate this type of URL Blogger: /Blog/2004_07_01_mothblog_archive.html dasBlog: /Blog/default,month,2004-07.aspx In my web.config file, the rule that deals with this is the one named "monthlyarchive_redirect". 3. Categories Observe the difference between the way the two blog engines generate this type of URL Blogger: /Blog/labels/Personal.html dasBlog: /Blog/CategoryView,category,Personal.aspx In my web.config file the rule that deals with this is the one named "category_redirect". 4. Posts Observe the difference between the way the two blog engines generate this type of URL Blogger: /Blog/2004/07/hello-world.html dasBlog: /Blog/Hello-World.aspx In my web.config file the rule that deals with this is the one named "post_redirect". Note: The decision is taken to use dasBlog URLs that do not include the date info (see the description of my Appearance settings). If we included the date info then it would have to include the day part, which blogger did not generate. This makes it impossible to redirect correctly and to have a single permalink for blog posts moving forward. An implication of this decision, is that no two blog posts can have the same title. The tool I will describe in my next post (inelegantly) deals with duplicates, but not with triplicates or higher. 5. Unhandled by a generic rule Unfortunately, the two blog engines use different rules for generating URLs for blog posts. Most of the time the conversion is as simple as the example of the previous section where a post titled "Hello World" generates a URL with the words separated by a hyphen. Some times that is not the case, for example: /Blog/2006/05/medc-wrap-up.html /Blog/MEDC-Wrapup.aspx or /Blog/2005/01/best-of-moth-2004.html /Blog/Best-Of-The-Moth-2004.aspx or /Blog/2004/11/more-windows-mobile-2005-details.html /Blog/More-Windows-Mobile-2005-Details-Emerge.aspx In short, blogger does not add words to the title beyond ~39 characters, it drops some words from the title generation (e.g. a, an, on, the), and it preserve hyphens that appear in the title. For this reason, we need to detect these and explicitly list them for redirects (no regular expression can help here because the full set of rules is not listed anywhere). In my web.config file the rule that deals with this is the one named "Redirect rule1 for FullRedirects" combined with the rewriteMap named "StaticRedirects". Note: The tool I describe in my next post will detect all the URLs that need to be explicitly redirected and will list them in a file ready for you to copy them to your web.config rewriteMap. 6. C# code doing the same as the web.config I wrote some naive code that does the same thing as the web.config: given a string it will return a new string converted according to the 3 rules above. It does not take into account the 4th case where an explicit hard-coded conversion is needed (the tool I present in the next post does take that into account). static string REGEX_post_redirect = "[0-9]{4}/[0-9]{2}/([0-9a-z-]+).html"; static string REGEX_category_redirect = "labels/([_0-9a-z-% ]+).html"; static string REGEX_monthlyarchive_redirect = "([0-9]{4})_([0-9]{2})_[0-9]{2}_mothblog_archive.html"; static string Redirect(string oldUrl) { GroupCollection g; if (RunRegExOnIt(oldUrl, REGEX_post_redirect, 2, out g)) return string.Concat(g[1].Value, ".aspx"); if (RunRegExOnIt(oldUrl, REGEX_category_redirect, 2, out g)) return string.Concat("CategoryView,category,", g[1].Value, ".aspx"); if (RunRegExOnIt(oldUrl, REGEX_monthlyarchive_redirect, 3, out g)) return string.Concat("default,month,", g[1].Value, "-", g[2], ".aspx"); return string.Empty; } static bool RunRegExOnIt(string toRegEx, string pattern, int groupCount, out GroupCollection g) { if (pattern.Length == 0) { g = null; return false; } g = new Regex(pattern, RegexOptions.IgnoreCase | RegexOptions.Compiled).Match(toRegEx).Groups; return (g.Count == groupCount); } Comments about this post welcome at the original blog.

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• How to get SQL Railroad Diagrams from MSDN BNF syntax notation.

  - by Phil Factor

  pre {margin-bottom:.0001pt; font-size:8.0pt; font-family:"Courier New"; margin-left: 0cm; margin-right: 0cm; margin-top: 0cm; } On SQL Server Books-On-Line, in the Transact-SQL Reference (database Engine), every SQL Statement has its syntax represented in  ‘Backus–Naur Form’ notation (BNF)  syntax. For a programmer in a hurry, this should be ideal because It is the only quick way to understand and appreciate all the permutations of the syntax. It is a great feature once you get your eye in. It isn’t the only way to get the information;  You can, of course, reverse-engineer an understanding of the syntax from the examples, but your understanding won’t be complete, and you’ll have wasted time doing it. BNF is a good start in representing the syntax:  Oracle and SQLite go one step further, and have proper railroad diagrams for their syntax, which is a far more accessible way of doing it. There are three problems with the BNF on MSDN. Firstly, it is isn’t a standard version of  BNF, but an ancient fork from EBNF, inherited from Sybase. Secondly, it is excruciatingly difficult to understand, and thirdly it has a number of syntactic and semantic errors. The page describing DML triggers, for example, currently has the absurd BNF error that makes it state that all statements in the body of the trigger must be separated by commas.  There are a few other detail problems too. Here is the offending syntax for a DML trigger, pasted from MSDN. Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { sql_statement [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > }   <dml_trigger_option> ::=     [ ENCRYPTION ]     [ EXECUTE AS Clause ]   <method_specifier> ::=  This should, of course, be /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ CREATE TRIGGER [ schema_name . ]trigger_name ON { table | view } [ WITH <dml_trigger_option> [ ,...n ] ] { FOR | AFTER | INSTEAD OF } { [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } [ NOT FOR REPLICATION ] AS { {sql_statement [ ; ]} [ ...n ] | EXTERNAL NAME <method_specifier> [ ; ] }   <dml_trigger_option> ::=     [ ENCRYPTION ]     [ EXECUTE AS CLAUSE ]   <method_specifier> ::=     assembly_name.class_name.method_name I’d love to tell Microsoft when I spot errors like this so they can correct them but I can’t. Obviously, there is a mechanism on MSDN to get errors corrected by using comments, but that doesn’t work for me (*Error occurred while saving your data.”), and when I report that the comment system doesn’t work to MSDN, I get no reply. I’ve been trying to create railroad diagrams for all the important SQL Server SQL statements, as good as you’d find for Oracle, and have so far published the CREATE TABLE and ALTER TABLE railroad diagrams based on the BNF. Although I’ve been aware of them, I’ve never realised until recently how many errors there are. Then, Colin Daley created a translator for the SQL Server dialect of  BNF which outputs standard EBNF notation used by the W3C. The example MSDN BNF for the trigger would be rendered as … /* Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger) */ create_trigger ::= 'CREATE TRIGGER' ( schema_name '.' ) ? trigger_name 'ON' ( table | view ) ( 'WITH' dml_trigger_option ( ',' dml_trigger_option ) * ) ? ( 'FOR' | 'AFTER' | 'INSTEAD OF' ) ( ( 'INSERT' ) ? ( ',' ) ? ( 'UPDATE' ) ? ( ',' ) ? ( 'DELETE' ) ? ) ( 'NOT FOR REPLICATION' ) ? 'AS' ( ( sql_statement ( ';' ) ? ) + | 'EXTERNAL NAME' method_specifier ( ';' ) ? )   dml_trigger_option ::= ( 'ENCRYPTION' ) ? ( 'EXECUTE AS CLAUSE' ) ?   method_specifier ::= assembly_name '.' class_name '.' method_name Colin’s intention was to allow anyone to paste SQL Server’s BNF notation into his website-based parser, and from this generate classic railroad diagrams via Gunther Rademacher's Railroad Diagram Generator.  Colin's application does this for you: you're not aware that you are moving to a different site.  Because Colin's 'translator' it is a parser, it will pick up syntax errors. Once you’ve fixed the syntax errors, you will get the syntax in the form of a human-readable railroad diagram and, in this form, the semantic mistakes become flamingly obvious. Gunter’s Railroad Diagram Generator is brilliant. To be able, after correcting the MSDN dialect of BNF, to generate a standard EBNF, and from thence to create railroad diagrams for SQL Server’s syntax that are as good as Oracle’s, is a great boon, and many thanks to Colin for the idea. Here is the result of the W3C EBNF from Colin’s application then being run through the Railroad diagram generator. create_trigger: dml_trigger_option: method_specifier:   Now that’s much better, you’ll agree. This is pretty easy to understand, and at this point any error is immediately obvious. This should be seriously useful, and it is to me. However  there is that snag. The BNF is generally incorrect, and you can’t expect the average visitor to mess about with it. The answer is, of course, to correct the BNF on MSDN and maybe even add railroad diagrams for the syntax. Stop giggling! I agree it won’t happen. In the meantime, we need to collaboratively store and publish these corrected syntaxes ourselves as we do them. How? GitHub?  SQL Server Central?  Simple-Talk? What should those of us who use the system  do with our corrected EBNF so that anyone can use them without hassle?

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• April 2013 Release of the Ajax Control Toolkit

  - by Stephen.Walther

  I’m excited to announce the April 2013 release of the Ajax Control Toolkit. For this release, we focused on improving two controls: the AjaxFileUpload and the MaskedEdit controls. You can download the latest release from CodePlex at http://AjaxControlToolkit.CodePlex.com or, better yet, you can execute the following NuGet command within Visual Studio 2010/2012: There are three builds of the Ajax Control Toolkit: .NET 3.5, .NET 4.0, and .NET 4.5. A Better AjaxFileUpload Control We completely rewrote the AjaxFileUpload control for this release. We had two primary goals. First, we wanted to support uploading really large files. In particular, we wanted to support uploading multi-gigabyte files such as video files or application files. Second, we wanted to support showing upload progress on as many browsers as possible. The previous version of the AjaxFileUpload could show upload progress when used with Google Chrome or Mozilla Firefox but not when used with Apple Safari or Microsoft Internet Explorer. The new version of the AjaxFileUpload control shows upload progress when used with any browser. Using the AjaxFileUpload Control Let me walk-through using the AjaxFileUpload in the most basic scenario. And then, in following sections, I can explain some of its more advanced features. Here’s how you can declare the AjaxFileUpload control in a page: <ajaxToolkit:ToolkitScriptManager runat="server" /> <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" AllowedFileTypes="mp4" OnUploadComplete="AjaxFileUpload1_UploadComplete" runat="server" /> The exact appearance of the AjaxFileUpload control depends on the features that a browser supports. In the case of Google Chrome, which supports drag-and-drop upload, here’s what the AjaxFileUpload looks like: Notice that the page above includes two Ajax Control Toolkit controls: the AjaxFileUpload and the ToolkitScriptManager control. You always need to include the ToolkitScriptManager with any page which uses Ajax Control Toolkit controls. The AjaxFileUpload control declared in the page above includes an event handler for its UploadComplete event. This event handler is declared in the code-behind page like this: protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Save uploaded file to App_Data folder AjaxFileUpload1.SaveAs(MapPath("~/App_Data/" + e.FileName)); } This method saves the uploaded file to your website’s App_Data folder. I’m assuming that you have an App_Data folder in your project – if you don’t have one then you need to create one or you will get an error. There is one more thing that you must do in order to get the AjaxFileUpload control to work. The AjaxFileUpload control relies on an HTTP Handler named AjaxFileUploadHandler.axd. You need to declare this handler in your application’s root web.config file like this: <configuration> <system.web> <compilation debug="true" targetFramework="4.5" /> <httpRuntime targetFramework="4.5" maxRequestLength="42949672" /> <httpHandlers> <add verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </httpHandlers> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <handlers> <add name="AjaxFileUploadHandler" verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </handlers> <security> <requestFiltering> <requestLimits maxAllowedContentLength="4294967295"/> </requestFiltering> </security> </system.webServer> </configuration> Notice that the web.config file above also contains configuration settings for the maxRequestLength and maxAllowedContentLength. You need to assign large values to these configuration settings — as I did in the web.config file above — in order to accept large file uploads. Supporting Chunked File Uploads Because one of our primary goals with this release was support for large file uploads, we added support for client-side chunking. When you upload a file using a browser which fully supports the HTML5 File API — such as Google Chrome or Mozilla Firefox — then the file is uploaded in multiple chunks. You can see chunking in action by opening F12 Developer Tools in your browser and observing the Network tab: Notice that there is a crazy number of distinct post requests made (about 360 distinct requests for a 1 gigabyte file). Each post request looks like this: http://localhost:24338/AjaxFileUploadHandler.axd?contextKey={DA8BEDC8-B952-4d5d-8CC2-59FE922E2923}&fileId=B7CCE31C-6AB1-BB28-2940-49E0C9B81C64 &fileName=Sita_Sings_the_Blues_480p_2150kbps.mp4&chunked=true&firstChunk=false Each request posts another chunk of the file being uploaded. Notice that the request URL includes a chunked=true parameter which indicates that the browser is breaking the file being uploaded into multiple chunks. Showing Upload Progress on All Browsers The previous version of the AjaxFileUpload control could display upload progress only in the case of browsers which fully support the HTML5 File API. The new version of the AjaxFileUpload control can display upload progress in the case of all browsers. If a browser does not fully support the HTML5 File API then the browser polls the server every few seconds with an Ajax request to determine the percentage of the file that has been uploaded. This technique of displaying progress works with any browser which supports making Ajax requests. There is one catch. Be warned that this new feature only works with the .NET 4.0 and .NET 4.5 versions of the AjaxControlToolkit. To show upload progress, we are taking advantage of the new ASP.NET HttpRequest.GetBufferedInputStream() and HttpRequest.GetBufferlessInputStream() methods which are not supported by .NET 3.5. For example, here is what the Network tab looks like when you use the AjaxFileUpload with Microsoft Internet Explorer: Here’s what the requests in the Network tab look like: GET /WebForm1.aspx?contextKey={DA8BEDC8-B952-4d5d-8CC2-59FE922E2923}&poll=1&guid=9206FF94-76F9-B197-D1BC-EA9AD282806B HTTP/1.1 Notice that each request includes a poll=1 parameter. This parameter indicates that this is a polling request to get the size of the file buffered on the server. Here’s what the response body of a request looks like when about 20% of a file has been uploaded: Buffering to a Temporary File When you upload a file using the AjaxFileUpload control, the file upload is buffered to a temporary file located at Path.GetTempPath(). When you call the SaveAs() method, as we did in the sample page above, the temporary file is copied to a new file and then the temporary file is deleted. If you don’t call the SaveAs() method, then you must ensure that the temporary file gets deleted yourself. For example, if you want to save the file to a database then you will never call the SaveAs() method and you are responsible for deleting the file. The easiest way to delete the temporary file is to call the AjaxFileUploadEventArgs.DeleteTemporaryData() method in the UploadComplete handler: protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Save uploaded file to a database table e.DeleteTemporaryData(); } You also can call the static AjaxFileUpload.CleanAllTemporaryData() method to delete all temporary data and not only the temporary data related to the current file upload. For example, you might want to call this method on application start to ensure that all temporary data is removed whenever your application restarts. A Better MaskedEdit Extender This release of the Ajax Control Toolkit contains bug fixes for the top-voted issues related to the MaskedEdit control. We closed over 25 MaskedEdit issues. Here is a complete list of the issues addressed with this release: · 17302 MaskedEditExtender MaskType=Date, Mask=99/99/99 Undefined JS Error · 11758 MaskedEdit causes error in JScript when working with 2-digits year · 18810 Maskededitextender/validator Date validation issue · 23236 MaskEditValidator does not work with date input using format dd/mm/yyyy · 23042 Webkit based browsers (Safari, Chrome) and MaskedEditExtender · 26685 MaskedEditExtender@(ClearMaskOnLostFocus=false) adds a zero character when you each focused to target textbox · 16109 MaskedEditExtender: Negative amount, followed by decimal, sets value to positive · 11522 MaskEditExtender of AjaxtoolKit-1.0.10618.0 does not work properly for Hungarian Culture · 25988 MaskedEditExtender – CultureName (HU-hu) > DateSeparator · 23221 MaskedEditExtender date separator problem · 15233 Day and month swap in Dynamic user control · 15492 MaskedEditExtender with ClearMaskOnLostFocus and with MaskedEditValidator with ClientValidationFunction · 9389 MaskedEditValidator – when on no entry · 11392 MaskedEdit Number format messed up · 11819 MaskedEditExtender erases all values beyond first comma separtor · 13423 MaskedEdit(Extender/Validator) combo problem · 16111 MaskedEditValidator cannot validate date with DayMonthYear in UserDateFormat of MaskedEditExtender · 10901 MaskedEdit: The months and date fields swap values when you hit submit if UserDateFormat is set. · 15190 MaskedEditValidator can’t make use of MaskedEditExtender’s UserDateFormat property · 13898 MaskedEdit Extender with custom date type mask gives javascript error · 14692 MaskedEdit error in “yy/MM/dd” format. · 16186 MaskedEditExtender does not handle century properly in a date mask · 26456 MaskedEditBehavior. ConvFmtTime : function(input,loadFirst) fails if this._CultureAMPMPlaceholder == “” · 21474 Error on MaskedEditExtender working with number format · 23023 MaskedEditExtender’s ClearMaskOnLostFocus property causes problems for MaskedEditValidator when set to false · 13656 MaskedEditValidator Min/Max Date value issue Conclusion This latest release of the Ajax Control Toolkit required many hours of work by a team of talented developers. I want to thank the members of the Superexpert team for the long hours which they put into this release.

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• Recover Data Like a Forensics Expert Using an Ubuntu Live CD

  - by Trevor Bekolay

  There are lots of utilities to recover deleted files, but what if you can’t boot up your computer, or the whole drive has been formatted? We’ll show you some tools that will dig deep and recover the most elusive deleted files, or even whole hard drive partitions. We’ve shown you simple ways to recover accidentally deleted files, even a simple method that can be done from an Ubuntu Live CD, but for hard disks that have been heavily corrupted, those methods aren’t going to cut it. In this article, we’ll examine four tools that can recover data from the most messed up hard drives, regardless of whether they were formatted for a Windows, Linux, or Mac computer, or even if the partition table is wiped out entirely. Note: These tools cannot recover data that has been overwritten on a hard disk. Whether a deleted file has been overwritten depends on many factors – the quicker you realize that you want to recover a file, the more likely you will be able to do so. Our setup To show these tools, we’ve set up a small 1 GB hard drive, with half of the space partitioned as ext2, a file system used in Linux, and half the space partitioned as FAT32, a file system used in older Windows systems. We stored ten random pictures on each hard drive. We then wiped the partition table from the hard drive by deleting the partitions in GParted. Is our data lost forever? Installing the tools All of the tools we’re going to use are in Ubuntu’s universe repository. To enable the repository, open Synaptic Package Manager by clicking on System in the top-left, then Administration > Synaptic Package Manager. Click on Settings > Repositories and add a check in the box labelled “Community-maintained Open Source software (universe)”. Click Close, and then in the main Synaptic Package Manager window, click the Reload button. Once the package list has reloaded, and the search index rebuilt, search for and mark for installation one or all of the following packages: testdisk, foremost, and scalpel. Testdisk includes TestDisk, which can recover lost partitions and repair boot sectors, and PhotoRec, which can recover many different types of files from tons of different file systems. Foremost, originally developed by the US Air Force Office of Special Investigations, recovers files based on their headers and other internal structures. Foremost operates on hard drives or drive image files generated by various tools. Finally, scalpel performs the same functions as foremost, but is focused on enhanced performance and lower memory usage. Scalpel may run better if you have an older machine with less RAM. Recover hard drive partitions If you can’t mount your hard drive, then its partition table might be corrupted. Before you start trying to recover your important files, it may be possible to recover one or more partitions on your drive, recovering all of your files with one step. Testdisk is the tool for the job. Start it by opening a terminal (Applications > Accessories > Terminal) and typing in: sudo testdisk If you’d like, you can create a log file, though it won’t affect how much data you recover. Once you make your choice, you’re greeted with a list of the storage media on your machine. You should be able to identify the hard drive you want to recover partitions from by its size and label. TestDisk asks you select the type of partition table to search for. In most cases (ext2/3, NTFS, FAT32, etc.) you should select Intel and press Enter. Highlight Analyse and press enter. In our case, our small hard drive has previously been formatted as NTFS. Amazingly, TestDisk finds this partition, though it is unable to recover it. It also finds the two partitions we just deleted. We are able to change their attributes, or add more partitions, but we’ll just recover them by pressing Enter. If TestDisk hasn’t found all of your partitions, you can try doing a deeper search by selecting that option with the left and right arrow keys. We only had these two partitions, so we’ll recover them by selecting Write and pressing Enter. Testdisk informs us that we will have to reboot. Note: If your Ubuntu Live CD is not persistent, then when you reboot you will have to reinstall any tools that you installed earlier. After restarting, both of our partitions are back to their original states, pictures and all. Recover files of certain types For the following examples, we deleted the 10 pictures from both partitions and then reformatted them. PhotoRec Of the three tools we’ll show, PhotoRec is the most user-friendly, despite being a console-based utility. To start recovering files, open a terminal (Applications > Accessories > Terminal) and type in: sudo photorec To begin, you are asked to select a storage device to search. You should be able to identify the right device by its size and label. Select the right device, and then hit Enter. PhotoRec asks you select the type of partition to search. In most cases (ext2/3, NTFS, FAT, etc.) you should select Intel and press Enter. You are given a list of the partitions on your selected hard drive. If you want to recover all of the files on a partition, then select Search and hit enter. However, this process can be very slow, and in our case we only want to search for pictures files, so instead we use the right arrow key to select File Opt and press Enter. PhotoRec can recover many different types of files, and deselecting each one would take a long time. Instead, we press “s” to clear all of the selections, and then find the appropriate file types – jpg, gif, and png – and select them by pressing the right arrow key. Once we’ve selected these three, we press “b” to save these selections. Press enter to return to the list of hard drive partitions. We want to search both of our partitions, so we highlight “No partition” and “Search” and then press Enter. PhotoRec prompts for a location to store the recovered files. If you have a different healthy hard drive, then we recommend storing the recovered files there. Since we’re not recovering very much, we’ll store it on the Ubuntu Live CD’s desktop. Note: Do not recover files to the hard drive you’re recovering from. PhotoRec is able to recover the 20 pictures from the partitions on our hard drive! A quick look in the recup_dir.1 directory that it creates confirms that PhotoRec has recovered all of our pictures, save for the file names. Foremost Foremost is a command-line program with no interactive interface like PhotoRec, but offers a number of command-line options to get as much data out of your had drive as possible. For a full list of options that can be tweaked via the command line, open up a terminal (Applications > Accessories > Terminal) and type in: foremost –h In our case, the command line options that we are going to use are: -t, a comma-separated list of types of files to search for. In our case, this is “jpeg,png,gif”. -v, enabling verbose-mode, giving us more information about what foremost is doing. -o, the output folder to store recovered files in. In our case, we created a directory called “foremost” on the desktop. -i, the input that will be searched for files. This can be a disk image in several different formats; however, we will use a hard disk, /dev/sda. Our foremost invocation is: sudo foremost –t jpeg,png,gif –o foremost –v –i /dev/sda Your invocation will differ depending on what you’re searching for and where you’re searching for it. Foremost is able to recover 17 of the 20 files stored on the hard drive. Looking at the files, we can confirm that these files were recovered relatively well, though we can see some errors in the thumbnail for 00622449.jpg. Part of this may be due to the ext2 filesystem. Foremost recommends using the –d command-line option for Linux file systems like ext2. We’ll run foremost again, adding the –d command-line option to our foremost invocation: sudo foremost –t jpeg,png,gif –d –o foremost –v –i /dev/sda This time, foremost is able to recover all 20 images! A final look at the pictures reveals that the pictures were recovered with no problems. Scalpel Scalpel is another powerful program that, like Foremost, is heavily configurable. Unlike Foremost, Scalpel requires you to edit a configuration file before attempting any data recovery. Any text editor will do, but we’ll use gedit to change the configuration file. In a terminal window (Applications > Accessories > Terminal), type in: sudo gedit /etc/scalpel/scalpel.conf scalpel.conf contains information about a number of different file types. Scroll through this file and uncomment lines that start with a file type that you want to recover (i.e. remove the “#” character at the start of those lines). Save the file and close it. Return to the terminal window. Scalpel also has a ton of command-line options that can help you search quickly and effectively; however, we’ll just define the input device (/dev/sda) and the output folder (a folder called “scalpel” that we created on the desktop). Our invocation is: sudo scalpel /dev/sda –o scalpel Scalpel is able to recover 18 of our 20 files. A quick look at the files scalpel recovered reveals that most of our files were recovered successfully, though there were some problems (e.g. 00000012.jpg). Conclusion In our quick toy example, TestDisk was able to recover two deleted partitions, and PhotoRec and Foremost were able to recover all 20 deleted images. Scalpel recovered most of the files, but it’s very likely that playing with the command-line options for scalpel would have enabled us to recover all 20 images. These tools are lifesavers when something goes wrong with your hard drive. If your data is on the hard drive somewhere, then one of these tools will track it down! Similar Articles Productive Geek Tips Recover Deleted Files on an NTFS Hard Drive from a Ubuntu Live CDUse an Ubuntu Live CD to Securely Wipe Your PC’s Hard DriveReset Your Ubuntu Password Easily from the Live CDBackup Your Windows Live Writer SettingsAdding extra Repositories on Ubuntu TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Awe inspiring, inter-galactic theme (Win 7) Case Study – How to Optimize Popular Wordpress Sites Restore Hidden Updates in Windows 7 & Vista Iceland an Insurance Job? Find Downloads and Add-ins for Outlook Recycle !

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• bluetooth not working on Ubuntu 13.10

  - by iacopo

  I upgrated ubuntu from 13.4 to 13.10 and my bluetooth stopped working. When I open bluetooth I'm able to put it ON but the visibility doesn't show anything and didn't detect any device. when I: dmesg | grep Blue [ 2.046249] usb 3-1: Product: Bluetooth V2.0 Dongle [ 2.046252] usb 3-1: Manufacturer: Bluetooth v2.0 [ 15.255710] Bluetooth: Core ver 2.16 [ 15.255748] Bluetooth: HCI device and connection manager initialized [ 15.255759] Bluetooth: HCI socket layer initialized [ 15.255765] Bluetooth: L2CAP socket layer initialized [ 15.255776] Bluetooth: SCO socket layer initialized [ 20.110379] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [ 20.110386] Bluetooth: BNEP filters: protocol multicast [ 20.110400] Bluetooth: BNEP socket layer initialized [ 20.120635] Bluetooth: RFCOMM TTY layer initialized [ 20.120656] Bluetooth: RFCOMM socket layer initialized [ 20.120660] Bluetooth: RFCOMM ver 1.11 when I digit: lsusb Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 002: ID 0bc2:2300 Seagate RSS LLC Expansion Portable Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 006 Device 002: ID 0e6a:6001 Megawin Technology Co., Ltd GEMBIRD Flexible keyboard KB-109F-B-DE Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 005 Device 002: ID 13ee:0001 MosArt Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 002: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode) Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub when I: hciconfig -a hci0: Type: BR/EDR Bus: USB BD Address: 00:1B:10:00:2A:EC ACL MTU: 1017:8 SCO MTU: 64:0 DOWN RX bytes:457 acl:0 sco:0 events:16 errors:0 TX bytes:68 acl:0 sco:0 commands:16 errors:0 Features: 0xff 0xff 0x8d 0xfe 0x9b 0xf9 0x00 0x80 Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 Link policy: Link mode: SLAVE ACCEPT when I digit: rfkill list 0: phy0: Wireless LAN Soft blocked: yes Hard blocked: no 1: hci0: Bluetooth Soft blocked: no Hard blocked: no when I digit: sudo gedit /etc/bluetooth/main.conf [General] # List of plugins that should not be loaded on bluetoothd startup #DisablePlugins = network,input # Default adaper name # %h - substituted for hostname # %d - substituted for adapter id Name = %h-%d # Default device class. Only the major and minor device class bits are # considered. Class = 0x000100 # How long to stay in discoverable mode before going back to non-discoverable # The value is in seconds. Default is 180, i.e. 3 minutes. # 0 = disable timer, i.e. stay discoverable forever DiscoverableTimeout = 0 # How long to stay in pairable mode before going back to non-discoverable # The value is in seconds. Default is 0. # 0 = disable timer, i.e. stay pairable forever PairableTimeout = 0 # Use some other page timeout than the controller default one # which is 16384 (10 seconds). PageTimeout = 8192 # Automatic connection for bonded devices driven by platform/user events. # If a platform plugin uses this mechanism, automatic connections will be # enabled during the interval defined below. Initially, this feature # intends to be used to establish connections to ATT channels. AutoConnectTimeout = 60 # What value should be assumed for the adapter Powered property when # SetProperty(Powered, ...) hasn't been called yet. Defaults to true InitiallyPowered = true # Remember the previously stored Powered state when initializing adapters RememberPowered = false # Use vendor id source (assigner), vendor, product and version information for # DID profile support. The values are separated by ":" and assigner, VID, PID # and version. # Possible vendor id source values: bluetooth, usb (defaults to usb) #DeviceID = bluetooth:1234:5678:abcd # Do reverse service discovery for previously unknown devices that connect to # us. This option is really only needed for qualification since the BITE tester # doesn't like us doing reverse SDP for some test cases (though there could in # theory be other useful purposes for this too). Defaults to true. ReverseServiceDiscovery = true # Enable name resolving after inquiry. Set it to 'false' if you don't need # remote devices name and want shorter discovery cycle. Defaults to 'true'. NameResolving = true # Enable runtime persistency of debug link keys. Default is false which # makes debug link keys valid only for the duration of the connection # that they were created for. DebugKeys = false # Enable the GATT functionality. Default is false EnableGatt = false when I digit: dmesg | grep Bluetooth [ 2.013041] usb 3-1: Product: Bluetooth V2.0 Dongle [ 2.013049] usb 3-1: Manufacturer: Bluetooth v2.0 [ 13.798293] Bluetooth: Core ver 2.16 [ 13.798338] Bluetooth: HCI device and connection manager initialized [ 13.798352] Bluetooth: HCI socket layer initialized [ 13.798357] Bluetooth: L2CAP socket layer initialized [ 13.798368] Bluetooth: SCO socket layer initialized [ 20.184162] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [ 20.184173] Bluetooth: BNEP filters: protocol multicast [ 20.184197] Bluetooth: BNEP socket layer initialized [ 20.238947] Bluetooth: RFCOMM TTY layer initialized [ 20.238983] Bluetooth: RFCOMM socket layer initialized [ 20.239018] Bluetooth: RFCOMM ver 1.11 When I digit: uname -a Linux casa-desktop 3.11.0-13-generic #20-Ubuntu SMP Wed Oct 23 07:38:26 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux When I digit: lsmod Module Size Used by parport_pc 32701 0 rfcomm 69070 4 bnep 19564 2 ppdev 17671 0 ip6t_REJECT 12910 1 xt_hl 12521 6 ip6t_rt 13507 3 nf_conntrack_ipv6 18938 9 nf_defrag_ipv6 34616 1 nf_conntrack_ipv6 ipt_REJECT 12541 1 xt_LOG 17718 8 xt_limit 12711 11 xt_tcpudp 12884 32 xt_addrtype 12635 4 nf_conntrack_ipv4 15012 9 nf_defrag_ipv4 12729 1 nf_conntrack_ipv4 xt_conntrack 12760 18 ip6table_filter 12815 1 ip6_tables 27025 1 ip6table_filter nf_conntrack_netbios_ns 12665 0 nf_conntrack_broadcast 12589 1 nf_conntrack_netbios_ns nf_nat_ftp 12741 0 nf_nat 26653 1 nf_nat_ftp kvm_amd 59958 0 nf_conntrack_ftp 18608 1 nf_nat_ftp kvm 431315 1 kvm_amd nf_conntrack 91736 8 nf_nat_ftp,nf_conntrack_netbios_ns,nf_nat,xt_conntrack,nf_conntrack_broadcast,nf_conntrack_ftp,nf_conntrack_ipv4,nf_conntrack_ipv6 iptable_filter 12810 1 crct10dif_pclmul 14289 0 crc32_pclmul 13113 0 ip_tables 27239 1 iptable_filter snd_hda_codec_realtek 55704 1 ghash_clmulni_intel 13259 0 aesni_intel 55624 0 aes_x86_64 17131 1 aesni_intel snd_hda_codec_hdmi 41117 1 x_tables 34059 13 ip6table_filter,xt_hl,ip_tables,xt_tcpudp,xt_limit,xt_conntrack,xt_LOG,iptable_filter,ip6t_rt,ipt_REJECT,ip6_tables,xt_addrtype,ip6t_REJECT lrw 13257 1 aesni_intel snd_hda_intel 48171 5 gf128mul 14951 1 lrw glue_helper 13990 1 aesni_intel ablk_helper 13597 1 aesni_intel joydev 17377 0 cryptd 20329 3 ghash_clmulni_intel,aesni_intel,ablk_helper snd_hda_codec 188738 3 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel arc4 12608 2 snd_hwdep 13602 1 snd_hda_codec rt2800pci 18690 0 snd_pcm 102033 3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel radeon 1402449 3 rt2800lib 79963 1 rt2800pci btusb 28267 0 rt2x00pci 13287 1 rt2800pci rt2x00mmio 13603 1 rt2800pci snd_page_alloc 18710 2 snd_pcm,snd_hda_intel rt2x00lib 55238 4 rt2x00pci,rt2800lib,rt2800pci,rt2x00mmio snd_seq_midi 13324 0 mac80211 596969 3 rt2x00lib,rt2x00pci,rt2800lib snd_seq_midi_event 14899 1 snd_seq_midi ttm 83995 1 radeon snd_rawmidi 30095 1 snd_seq_midi cfg80211 479757 2 mac80211,rt2x00lib drm_kms_helper 52651 1 radeon snd_seq 61560 2 snd_seq_midi_event,snd_seq_midi bluetooth 371880 12 bnep,btusb,rfcomm microcode 23518 0 eeprom_93cx6 13344 1 rt2800pci snd_seq_device 14497 3 snd_seq,snd_rawmidi,snd_seq_midi crc_ccitt 12707 1 rt2800lib snd_timer 29433 2 snd_pcm,snd_seq snd 69141 21 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_seq_device,snd_seq_midi psmouse 97626 0 drm 296739 5 ttm,drm_kms_helper,radeon k10temp 13126 0 soundcore 12680 1 snd serio_raw 13413 0 i2c_algo_bit 13413 1 radeon i2c_piix4 22106 0 video 19318 0 mac_hid 13205 0 lp 17759 0 parport 42299 3 lp,ppdev,parport_pc hid_generic 12548 0 usbhid 53014 0 hid 105818 2 hid_generic,usbhid pata_acpi 13038 0 usb_storage 62062 1 r8169 67341 0 sdhci_pci 18985 0 sdhci 42630 1 sdhci_pci mii 13934 1 r8169 pata_atiixp 13242 0 ohci_pci 13561 0 ahci 25819 2 libahci 31898 1 ahci Someone can help me?

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• The Proper Use of the VM Role in Windows Azure

  - by BuckWoody

  At the Professional Developer’s Conference (PDC) in 2010 we announced an addition to the Computational Roles in Windows Azure, called the VM Role. This new feature allows a great deal of control over the applications you write, but some have confused it with our full infrastructure offering in Windows Hyper-V. There is a proper architecture pattern for both of them. Virtualization Virtualization is the process of taking all of the hardware of a physical computer and replicating it in software alone. This means that a single computer can “host” or run several “virtual” computers. These virtual computers can run anywhere - including at a vendor’s location. Some companies refer to this as Cloud Computing since the hardware is operated and maintained elsewhere. IaaS The more detailed definition of this type of computing is called Infrastructure as a Service (Iaas) since it removes the need for you to maintain hardware at your organization. The operating system, drivers, and all the other software required to run an application are still under your control and your responsibility to license, patch, and scale. Microsoft has an offering in this space called Hyper-V, that runs on the Windows operating system. Combined with a hardware hosting vendor and the System Center software to create and deploy Virtual Machines (a process referred to as provisioning), you can create a Cloud environment with full control over all aspects of the machine, including multiple operating systems if you like. Hosting machines and provisioning them at your own buildings is sometimes called a Private Cloud, and hosting them somewhere else is often called a Public Cloud. State-ful and Stateless Programming This paradigm does not create a new, scalable way of computing. It simply moves the hardware away. The reason is that when you limit the Cloud efforts to a Virtual Machine, you are in effect limiting the computing resources to what that single system can provide. This is because much of the software developed in this environment maintains “state” - and that requires a little explanation. “State-ful programming” means that all parts of the computing environment stay connected to each other throughout a compute cycle. The system expects the memory, CPU, storage and network to remain in the same state from the beginning of the process to the end. You can think of this as a telephone conversation - you expect that the other person picks up the phone, listens to you, and talks back all in a single unit of time. In “Stateless” computing the system is designed to allow the different parts of the code to run independently of each other. You can think of this like an e-mail exchange. You compose an e-mail from your system (it has the state when you’re doing that) and then you walk away for a bit to make some coffee. A few minutes later you click the “send” button (the network has the state) and you go to a meeting. The server receives the message and stores it on a mail program’s database (the mail server has the state now) and continues working on other mail. Finally, the other party logs on to their mail client and reads the mail (the other user has the state) and responds to it and so on. These events might be separated by milliseconds or even days, but the system continues to operate. The entire process doesn’t maintain the state, each component does. This is the exact concept behind coding for Windows Azure. The stateless programming model allows amazing rates of scale, since the message (think of the e-mail) can be broken apart by multiple programs and worked on in parallel (like when the e-mail goes to hundreds of users), and only the order of re-assembling the work is important to consider. For the exact same reason, if the system makes copies of those running programs as Windows Azure does, you have built-in redundancy and recovery. It’s just built into the design. The Difference Between Infrastructure Designs and Platform Designs When you simply take a physical server running software and virtualize it either privately or publicly, you haven’t done anything to allow the code to scale or have recovery. That all has to be handled by adding more code and more Virtual Machines that have a slight lag in maintaining the running state of the system. Add more machines and you get more lag, so the scale is limited. This is the primary limitation with IaaS. It’s also not as easy to deploy these VM’s, and more importantly, you’re often charged on a longer basis to remove them. your agility in IaaS is more limited. Windows Azure is a Platform - meaning that you get objects you can code against. The code you write runs on multiple nodes with multiple copies, and it all works because of the magic of Stateless programming. you don’t worry, or even care, about what is running underneath. It could be Windows (and it is in fact a type of Windows Server), Linux, or anything else - but that' isn’t what you want to manage, monitor, maintain or license. You don’t want to deploy an operating system - you want to deploy an application. You want your code to run, and you don’t care how it does that. Another benefit to PaaS is that you can ask for hundreds or thousands of new nodes of computing power - there’s no provisioning, it just happens. And you can stop using them quicker - and the base code for your application does not have to change to make this happen. Windows Azure Roles and Their Use If you need your code to have a user interface, in Visual Studio you add a Web Role to your project, and if the code needs to do work that doesn’t involve a user interface you can add a Worker Role. They are just containers that act a certain way. I’ll provide more detail on those later. Note: That’s a general description, so it’s not entirely accurate, but it’s accurate enough for this discussion. So now we’re back to that VM Role. Because of the name, some have mistakenly thought that you can take a Virtual Machine running, say Linux, and deploy it to Windows Azure using this Role. But you can’t. That’s not what it is designed for at all. If you do need that kind of deployment, you should look into Hyper-V and System Center to create the Private or Public Infrastructure as a Service. What the VM Role is actually designed to do is to allow you to have a great deal of control over the system where your code will run. Let’s take an example. You’ve heard about Windows Azure, and Platform programming. You’re convinced it’s the right way to code. But you have a lot of things you’ve written in another way at your company. Re-writing all of your code to take advantage of Windows Azure will take a long time. Or perhaps you have a certain version of Apache Web Server that you need for your code to work. In both cases, you think you can (or already have) code the the software to be “Stateless”, you just need more control over the place where the code runs. That’s the place where a VM Role makes sense. Recap Virtualizing servers alone has limitations of scale, availability and recovery. Microsoft’s offering in this area is Hyper-V and System Center, not the VM Role. The VM Role is still used for running Stateless code, just like the Web and Worker Roles, with the exception that it allows you more control over the environment of where that code runs.

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