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  • Compiz stop working

    - by Aikanáro
    I'm on a laptop sony vaio, vng-nw330f with ubuntu 11.10. One day I used my computer normally, I shutdown and the other day when I turn on it again, all was different. Compiz effects is not working at all, it doesn't matter what plugin (from ccsm) i enable or disable, nothings happens, nothings changes. I tried next commands: unity --reset unity --reset-icons sudo rm -rf .config .gnome .gnome2 .gnome2_private .compiz .icons .fonts .nautilus .themes .qt .local (from my home directory) gconftool-2 --recursive-unset /apps/compiz-1 I try reinstalling compiz (I remove compiz from software center and installed it again). I have just a couple of weeks using ubuntu, I'm not sure if exist a desktop call it unity 3d, but I think that it's missing. I want the graphics interface of ubuntu 11.10 by default.

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  • Persisting NLP parsed data

    - by tjb1982
    I've recently started experimenting with NLP using Stanford's CoreNLP, and I'm wondering what are some of the standard ways to store NLP parsed data for something like a text mining application? One way I thought might be interesting is to store the children as an adjacency list and make good use of recursive queries (postgres supports this and I've found it works really well). Something like this: Component ( id, POS, parent_id ) Word ( id, raw, lemma, POS, NER ) CW_Map ( component_id, word_id, position int ) But I assume there are probably many standard ways to do this depending on what kind of analysis is being done that have been adopted by people working in the field over the years. So what are the standard persistence strategies for NLP parsed data and how are they used?

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  • Reuseable Platform For Custom Board Game

    - by George Bailey
    Is there a generic platform to allow me to customize the rules to a board game. The board game uses a square grid, similar to Checkers or Chess. I was hoping to take some of the work out of creating this computer opponent, by reusing what is already written. I would think that there would be a pre-written routine for deciding which moves would lead to the best outcome, and all that I would need to program is the pieces, legal moves, what layout constitutes a win/lose or draw, and perhaps some kind of scoring for value of pieces. I have seen chess programs that appear to use a recursive routine, so they think anywhere from 2 to 20 moves ahead to create varying degrees of difficulty. I have noticed this on chess.com. The game I am programming will not be as complex. Is there a platform designed to be re-used for different grid/piece based games. JavaScript would be preferable, but Java or Perl would be acceptable.

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  • Automatically analyze excel files

    - by dole doug
    I have to replicate a manual generation of a large number of excel files. I started to manually track the relations between cells ( files, formulas, etc). I also had a talk with the person which generates those files. For now I have a general understanding about how the excel files are generated, but "devil is in the details". I assume that I can write a script which will generate the hierarchy between cells and files, but this might require the same effort as manually noticing the relations. Also, I'm afraid that I'm not too experienced and my app is more prone to error approach than a manual analyze. How to handle this problem? Do you know about an open source project which analyze the excel files in a recursive mode following the formulas ?

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  • Dans Guardian install

    - by Matt
    I'm trying to install Dans Guardian on a virtual machine. The instructions ask me to run the ./configure script and then execute the command make install. The configure script runs fine but the make install throws errors. Making all in src make[2]: Entering directory `/webmin/dansguardian-2.10/src' g++ -DHAVE_CONFIG_H -I. -I.. -D__CONFFILE='"/usr/local/etc/dansguardian/dansguardian.conf"' -D__LOGLOCATION='"/usr/local/var/log/dansguardian/"' -D__PIDDIR='"/usr/local/var/run"' -D__PROXYUSER='"nobody"' -D__PROXYGROUP='"nobody"' -D__CONFDIR='"/usr/local/etc/dansguardian"' -g -O2 -MT dansguardian-fancy.o -MD -MP -MF .deps/dansguardian-fancy.Tpo -c -o dansguardian-fancy.o `test -f 'downloadmanagers/fancy.cpp' || echo './'`downloadmanagers/fancy.cpp downloadmanagers/fancy.cpp: In member function âstd::string fancydm::timestring(int)â: downloadmanagers/fancy.cpp:507:72: error: âsnprintfâ was not declared in this scope make[2]: *** [dansguardian-fancy.o] Error 1 make[2]: Leaving directory `/webmin/dansguardian-2.10/src' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/webmin/dansguardian-2.10' make: *** [all] Error 2 I'm running 12.04 LTS server x64

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  • Zoom out recursively for all the folders

    - by Chaitanya
    I want to reduce the icons size in all the folders. In ubuntu 11.10, version, there is an option to decrease icons size and I changed there, and all the icons size is reduced recursively. I am using 11.10 version now. Here, whichever folder I open every time I need to zoom out.(I want zoom out). If I have 20 recursive folders, I open each and every folder and right click there and zoom out. Do we have any global command or grapical tool to reduce the icons size in all the folders. I was told that unity will do this work but I am confused how to use it. If unity is the only solution, please guide me where to change the size. Thanks a ton, Thanks, Chaitanya.

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  • Drawing Flowchart for function calculate a number in the Fibonacci Series

    - by truongvan
    I'm trying make Flowchart for function calculate a number in the Fibonacci Series. But It looks like not right. I don't how draw the recursive function. Please help me how to fix it. My flowchart: DIA This is my code: #include <iostream> using namespace std; long long Fibonacci(int input); int main() { cout << "Input Fibonacci Index number: "; int Index = 0; cin >> Index; cout << Fibonacci(i) << endl; return 0; } long long Fibonacci(int input) { if (input < 2) return input; else { return Fibonacci(input - 1) + Fibonacci(input - 2); } }

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  • yield – Just yet another sexy c# keyword?

    - by George Mamaladze
    yield (see NSDN c# reference) operator came I guess with .NET 2.0 and I my feeling is that it’s not as wide used as it could (or should) be.   I am not going to talk here about necessarity and advantages of using iterator pattern when accessing custom sequences (just google it).   Let’s look at it from the clean code point of view. Let's see if it really helps us to keep our code understandable, reusable and testable.   Let’s say we want to iterate a tree and do something with it’s nodes, for instance calculate a sum of their values. So the most elegant way would be to build a recursive method performing a classic depth traversal returning the sum.           private int CalculateTreeSum(Node top)         {             int sumOfChildNodes = 0;             foreach (Node childNode in top.ChildNodes)             {                 sumOfChildNodes += CalculateTreeSum(childNode);             }             return top.Value + sumOfChildNodes;         }     “Do One Thing” Nevertheless it violates one of the most important rules “Do One Thing”. Our  method CalculateTreeSum does two things at the same time. It travels inside the tree and performs some computation – in this case calculates sum. Doing two things in one method is definitely a bad thing because of several reasons: ·          Understandability: Readability / refactoring ·          Reuseability: when overriding - no chance to override computation without copying iteration code and vice versa. ·          Testability: you are not able to test computation without constructing the tree and you are not able to test correctness of tree iteration.   I want to spend some more words on this last issue. How do you test the method CalculateTreeSum when it contains two in one: computation & iteration? The only chance is to construct a test tree and assert the result of the method call, in our case the sum against our expectation. And if the test fails you do not know wether was the computation algorithm wrong or was that the iteration? At the end to top it all off I tell you: according to Murphy’s Law the iteration will have a bug as well as the calculation. Both bugs in a combination will cause the sum to be accidentally exactly the same you expect and the test will PASS. J   Ok let’s use yield! That’s why it is generally a very good idea not to mix but isolate “things”. Ok let’s use yield!           private int CalculateTreeSumClean(Node top)         {             IEnumerable<Node> treeNodes = GetTreeNodes(top);             return CalculateSum(treeNodes);         }             private int CalculateSum(IEnumerable<Node> nodes)         {             int sumOfNodes = 0;             foreach (Node node in nodes)             {                 sumOfNodes += node.Value;             }             return sumOfNodes;         }           private IEnumerable<Node> GetTreeNodes(Node top)         {             yield return top;             foreach (Node childNode in top.ChildNodes)             {                 foreach (Node currentNode in GetTreeNodes(childNode))                 {                     yield return currentNode;                 }             }         }   Two methods does not know anything about each other. One contains calculation logic another jut the iteration logic. You can relpace the tree iteration algorithm from depth traversal to breath trevaersal or use stack or visitor pattern instead of recursion. This will not influence your calculation logic. And vice versa you can relace the sum with product or do whatever you want with node values, the calculateion algorithm is not aware of beeng working on some tree or graph.  How about not using yield? Now let’s ask the question – what if we do not have yield operator? The brief look at the generated code gives us an answer. The compiler generates a 150 lines long class to implement the iteration logic.       [CompilerGenerated]     private sealed class <GetTreeNodes>d__0 : IEnumerable<Node>, IEnumerable, IEnumerator<Node>, IEnumerator, IDisposable     {         ...        150 Lines of generated code        ...     }   Often we compromise code readability, cleanness, testability, etc. – to reduce number of classes, code lines, keystrokes and mouse clicks. This is the human nature - we are lazy. Knowing and using such a sexy construct like yield, allows us to be lazy, write very few lines of code and at the same time stay clean and do one thing in a method. That's why I generally welcome using staff like that.   Note: The above used recursive depth traversal algorithm is possibly the compact one but not the best one from the performance and memory utilization point of view. It was taken to emphasize on other primary aspects of this post.

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  • After how much line of code a function should be break down?

    - by Sumeet
    While working on existing code base, I usually come across procedures that contain Abusive use of IF and Switch statements. The procedures consist of overwhelming code, which I think require re-factoring badly. The situation gets worse when I identify that some of these are recursive as well. But this is always a matter of debate as the code is working fine and no one wants to wake up the dragon. But, everyone accepts it is very expensive code to manage. I am wondering if are any recommendations to determine if a particular Method is a culprit and needs a revisit/rewrite , so that it can broken down or polymophized in an effective manner. Are there any Metrics (like no. of lines in procedure) that can be used to identify such segment of code. The checklist or advice to convince everyone, will be great!

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  • 12c - Utl_Call_Stack...

    - by noreply(at)blogger.com (Thomas Kyte)
    Over the next couple of months, I'll be writing about some cool new little features of Oracle Database 12c - things that might not make the front page of Oracle.com.  I'm going to start with a new package - UTL_CALL_STACK.In the past, developers have had access to three functions to try to figure out "where the heck am I in my code", they were:dbms_utility.format_call_stackdbms_utility.format_error_backtracedbms_utility.format_error_stackNow these routines, while useful, were of somewhat limited use.  Let's look at the format_call_stack routine for a reason why.  Here is a procedure that will just print out the current call stack for us:ops$tkyte%ORA12CR1> create or replace  2  procedure Print_Call_Stack  3  is  4  begin  5    DBMS_Output.Put_Line(DBMS_Utility.Format_Call_Stack());  6  end;  7  /Procedure created.Now, if we have a package - with nested functions and even duplicated function names:ops$tkyte%ORA12CR1> create or replace  2  package body Pkg is  3    procedure p  4    is  5      procedure q  6      is  7        procedure r  8        is  9          procedure p is 10          begin 11            Print_Call_Stack(); 12            raise program_error; 13          end p; 14        begin 15          p(); 16        end r; 17      begin 18        r(); 19      end q; 20    begin 21      q(); 22    end p; 23  end Pkg; 24  /Package body created.When we execute the procedure PKG.P - we'll see as a result:ops$tkyte%ORA12CR1> exec pkg.p----- PL/SQL Call Stack -----  object      line  object  handle    number  name0x6e891528         4  procedure OPS$TKYTE.PRINT_CALL_STACK0x6ec4a7c0        10  package body OPS$TKYTE.PKG0x6ec4a7c0        14  package body OPS$TKYTE.PKG0x6ec4a7c0        17  package body OPS$TKYTE.PKG0x6ec4a7c0        20  package body OPS$TKYTE.PKG0x76439070         1  anonymous blockBEGIN pkg.p; END;*ERROR at line 1:ORA-06501: PL/SQL: program errorORA-06512: at "OPS$TKYTE.PKG", line 11ORA-06512: at "OPS$TKYTE.PKG", line 14ORA-06512: at "OPS$TKYTE.PKG", line 17ORA-06512: at "OPS$TKYTE.PKG", line 20ORA-06512: at line 1The bit in red above is the output from format_call_stack whereas the bit in black is the error message returned to the client application (it would also be available to you via the format_error_backtrace API call). As you can see - it contains useful information but to use it you would need to parse it - and that can be trickier than it seems.  The format of those strings is not set in stone, they have changed over the years (I wrote the "who_am_i", "who_called_me" functions, I did that by parsing these strings - trust me, they change over time!).Starting in 12c - we'll have structured access to the call stack and a series of API calls to interrogate this structure.  I'm going to rewrite the print_call_stack function as follows:ops$tkyte%ORA12CR1> create or replace 2  procedure Print_Call_Stack  3  as  4    Depth pls_integer := UTL_Call_Stack.Dynamic_Depth();  5    6    procedure headers  7    is  8    begin  9        dbms_output.put_line( 'Lexical   Depth   Line    Name' ); 10        dbms_output.put_line( 'Depth             Number      ' ); 11        dbms_output.put_line( '-------   -----   ----    ----' ); 12    end headers; 13    procedure print 14    is 15    begin 16        headers; 17        for j in reverse 1..Depth loop 18          DBMS_Output.Put_Line( 19            rpad( utl_call_stack.lexical_depth(j), 10 ) || 20                    rpad( j, 7) || 21            rpad( To_Char(UTL_Call_Stack.Unit_Line(j), '99'), 9 ) || 22            UTL_Call_Stack.Concatenate_Subprogram 23                       (UTL_Call_Stack.Subprogram(j))); 24        end loop; 25    end; 26  begin 27    print; 28  end; 29  /Here we are able to figure out what 'depth' we are in the code (utl_call_stack.dynamic_depth) and then walk up the stack using a loop.  We will print out the lexical_depth, along with the line number within the unit we were executing plus - the unit name.  And not just any unit name, but the fully qualified, all of the way down to the subprogram name within a package.  Not only that - but down to the subprogram name within a subprogram name within a subprogram name.  For example - running the PKG.P procedure again results in:ops$tkyte%ORA12CR1> exec pkg.pLexical   Depth   Line    NameDepth             Number-------   -----   ----    ----1         6       20      PKG.P2         5       17      PKG.P.Q3         4       14      PKG.P.Q.R4         3       10      PKG.P.Q.R.P0         2       26      PRINT_CALL_STACK1         1       17      PRINT_CALL_STACK.PRINTBEGIN pkg.p; END;*ERROR at line 1:ORA-06501: PL/SQL: program errorORA-06512: at "OPS$TKYTE.PKG", line 11ORA-06512: at "OPS$TKYTE.PKG", line 14ORA-06512: at "OPS$TKYTE.PKG", line 17ORA-06512: at "OPS$TKYTE.PKG", line 20ORA-06512: at line 1This time - we get much more than just a line number and a package name as we did previously with format_call_stack.  We not only got the line number and package (unit) name - we got the names of the subprograms - we can see that P called Q called R called P as nested subprograms.  Also note that we can see a 'truer' calling level with the lexical depth, we can see we "stepped" out of the package to call print_call_stack and that in turn called another nested subprogram.This new package will be a nice addition to everyone's error logging packages.  Of course there are other functions in there to get owner names, the edition in effect when the code was executed and more. See UTL_CALL_STACK for all of the details.

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  • How to upgrade a particular package dependencies only?

    - by zerkms
    Let's say I have a package A which has Depends: B (>= 1.0.0) in its control file. The B was installed as an A dependency some time ago with 1.0.0 version. Now B was updated in the repository to the 1.0.42 version and I'd like to upgrade it. What I don't like to do: apt-get install B since it will mark B as "manually installed" (not sure how to name it correctly) package and it won't be removed with autoremove if I decide to stop using A ever. So is there an analogue of apt-get upgrade that only upgrades a particular package and its dependencies (probably recursive, it doesn't matter in my case since B doesn't depend on anything else) only?

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  • Persisting natural language processing parsed data

    - by tjb1982
    I've recently started experimenting with natural language processing (NLP) using Stanford's CoreNLP, and I'm wondering what are some of the standard ways to store NLP parsed data for something like a text mining application? One way I thought might be interesting is to store the children as an adjacency list and make good use of recursive queries (Postgres supports this and I've found it works really well). But I assume there are probably many standard ways to do this depending on what kind of analysis is being done that have been adopted by people working in the field over the years. So what are the standard persistence strategies for NLP parsed data and how are they used?

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  • Trace code pascal [on hold]

    - by mghaffari
    I haven't worked with Pascal so far, and my problem is understanding the recursive aspects that prm assignment operators and how the final (correct) value is derived. Would someone please explain that line for me. Program test(output); FUNCTION prm(az:integer) : real; begin if az = 1 then prm := sqrt(12) else prm := sqrt(12*prm(az-1)); end; begin writeln(prm(30):0:2); end.

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  • Tree position terminology/naming

    - by wst
    This is a naming things question. I am processing trees (XML documents), and there are often special rules applied to nodes based on structure. It's been very difficult coming up with concise naming conventions for some cases, namely for nodes in the first position among their siblings, along with some recursive relationship: Given an arbitrary node, I want to describe its first child, and then that node's first child, and so on recursively. Given another arbitrary node, I want to describe its parent if the parent is first among its siblings, and that parent's parent if it's first, and so on recursively. Is there existing terminology to describe these tree positions? How would you name a variable or function that captures one of these cases so that it's intuitive to an unfamiliar developer trying to understand an algorithm?

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  • Nashorn in the Twitterverse, Continued

    - by jlaskey
    After doing the Twitter example, it seemed reasonable to try graphing the result with JavaFX.  At this time the Nashorn project doesn't have an JavaFX shell, so we have to go through some hoops to create an JavaFX application.  I thought showing you some of those hoops might give you some idea about what you can do mixing Nashorn and Java (we'll add a JavaFX shell to the todo list.) First, let's look at the meat of the application.  Here is the repackaged version of the original twitter example. var twitter4j      = Packages.twitter4j; var TwitterFactory = twitter4j.TwitterFactory; var Query          = twitter4j.Query; function getTrendingData() {     var twitter = new TwitterFactory().instance;     var query   = new Query("nashorn OR nashornjs");     query.since("2012-11-21");     query.count = 100;     var data = {};     do {         var result = twitter.search(query);         var tweets = result.tweets;         for each (tweet in tweets) {             var date = tweet.createdAt;             var key = (1900 + date.year) + "/" +                       (1 + date.month) + "/" +                       date.date;             data[key] = (data[key] || 0) + 1;         }     } while (query = result.nextQuery());     return data; } Instead of just printing out tweets, getTrendingData tallies "tweets per date" during the sample period (since "2012-11-21", the date "New Project: Nashorn" was posted.)   getTrendingData then returns the resulting tally object. Next, use JavaFX BarChart to display that data. var javafx         = Packages.javafx; var Stage          = javafx.stage.Stage var Scene          = javafx.scene.Scene; var Group          = javafx.scene.Group; var Chart          = javafx.scene.chart.Chart; var FXCollections  = javafx.collections.FXCollections; var ObservableList = javafx.collections.ObservableList; var CategoryAxis   = javafx.scene.chart.CategoryAxis; var NumberAxis     = javafx.scene.chart.NumberAxis; var BarChart       = javafx.scene.chart.BarChart; var XYChart        = javafx.scene.chart.XYChart; var Series         = XYChart.Series; var Data           = XYChart.Data; function graph(stage, data) {     var root = new Group();     stage.scene = new Scene(root);     var dates = Object.keys(data);     var xAxis = new CategoryAxis();     xAxis.categories = FXCollections.observableArrayList(dates);     var yAxis = new NumberAxis("Tweets", 0.0, 200.0, 50.0);     var series = FXCollections.observableArrayList();     for (var date in data) {         series.add(new Data(date, data[date]));     }     var tweets = new Series("Tweets", series);     var barChartData = FXCollections.observableArrayList(tweets);     var chart = new BarChart(xAxis, yAxis, barChartData, 25.0);     root.children.add(chart); } I should point out that there is a lot of subtlety going on in the background.  For example; stage.scene = new Scene(root) is equivalent to stage.setScene(new Scene(root)). If Nashorn can't find a property (scene), then it searches (via Dynalink) for the Java Beans equivalent (setScene.)  Also note, that Nashorn is magically handling the generic class FXCollections.  Finally,  with the call to observableArrayList(dates), Nashorn is automatically converting the JavaScript array dates to a Java collection.  It really is hard to identify which objects are JavaScript and which are Java.  Does it really matter? Okay, with the meat out of the way, let's talk about the hoops. When working with JavaFX, you start with a main subclass of javafx.application.Application.  This class handles the initialization of the JavaFX libraries and the event processing.  This is what I used for this example; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import javafx.application.Application; import javafx.stage.Stage; import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; import javax.script.ScriptException; public class TrendingMain extends Application { private static final ScriptEngineManager MANAGER = new ScriptEngineManager(); private final ScriptEngine engine = MANAGER.getEngineByName("nashorn"); private Trending trending; public static void main(String[] args) { launch(args); } @Override public void start(Stage stage) throws Exception { trending = (Trending) load("Trending.js"); trending.start(stage); } @Override public void stop() throws Exception { trending.stop(); } private Object load(String script) throws IOException, ScriptException { try (final InputStream is = TrendingMain.class.getResourceAsStream(script)) { return engine.eval(new InputStreamReader(is, "utf-8")); } } } To initialize Nashorn, we use JSR-223's javax.script.  private static final ScriptEngineManager MANAGER = new ScriptEngineManager(); private final ScriptEngine engine = MANAGER.getEngineByName("nashorn"); This code sets up an instance of the Nashorn engine for evaluating scripts. The  load method reads a script into memory and then gets engine to eval that script.  Note, that load also returns the result of the eval. Now for the fun part.  There are several different approaches we could use to communicate between the Java main and the script.  In this example we'll use a Java interface.  The JavaFX main needs to do at least start and stop, so the following will suffice as an interface; public interface Trending {     public void start(Stage stage) throws Exception;     public void stop() throws Exception; } At the end of the example's script we add; (function newTrending() {     return new Packages.Trending() {         start: function(stage) {             var data = getTrendingData();             graph(stage, data);             stage.show();         },         stop: function() {         }     } })(); which instantiates a new subclass instance of Trending and overrides the start and stop methods.  The result of this function call is what is returned to main via the eval. trending = (Trending) load("Trending.js"); To recap, the script Trending.js contains functions getTrendingData, graph and newTrending, plus the call at the end to newTrending.  Back in the Java code, we cast the result of the eval (call to newTrending) to Trending, thus, we end up with an object that we can then use to call back into the script.  trending.start(stage); Voila. ?

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  • Efficient way to calculate "vision cones" on 2D tile map?

    - by OverMachoGrande
    I'm trying to calculate which tiles a particular unit can "see" if facing a certain direction on a tile map (within a certain range and angle of facing). The easiest way would be to draw a certain number of tiles outward and raycast to each tile. However, I'm hoping for something slightly more efficient. A picture says a thousand words: The red dot is the unit (who's facing upwards). My goal is to calculate the yellow tiles. The green blocks are walls (walls are between tiles, and it's easy to check if you can pass between two tiles). The blue line represents something like the "raycasting" method I was talking about, but I'd rather not have to do this. EDIT: Units can only be facing north/south/east/west (0, 90, 180, or 270 degrees) and FoV is always 90 degrees. Should simplify some calculations. I'm thinking there's some sort of recursive-ish/stack-based/queue-based algorithm, but I can't quite figure it out. Thanks!

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  • What has 'rm -r ~' done to my home directory?

    - by GUI Junkie
    gedit creates hidden backup files ending with '~'. I wanted to do a recursive cleanup of my directory tree. The command rm *~ will delete all local files ending with '~' I thought rm -r *~ . would delete all files in the whole tree, but I typo-ed rm -r ~. There was a message some directory could not be deleted and I quit the command. The question is: What have I been deleting? I did notice that my Filezilla configuration was gone. Does this command delete all hidden directories from the home dir?

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  • Why do I get this error trying to compile libxml2?

    - by bfaskiplar
    Although, I installed libxml2 once and reinstalled it for a few times. I cannot compile c-source code because compiler cannot find where the header file is. I am able to locate where it is (in the folder where I downloaded the tar.gz package) but I had a feeling in my guts that this package isn't installed correctly because when I tried to sudo make install, it says /bin/bash: /home/bfaskiplar/Downloads/tar.gz: No such file or directory make[2]: *** [install-libLTLIBRARIES] Error 127 make[2]: Leaving directory `/home/bfaskiplar/Downloads/tar.gz packages/libxml2-2.8.0' make[1]: *** [install-am] Error 2 make[1]: Leaving directory `/home/bfaskiplar/Downloads/tar.gz packages/libxml2-2.8.0' make: *** [install-recursive] Error 1 that's why I installed synaptic package manager and reinstalled it, but in this case, isn't it supposed to put header files in default directory where gcc normally searches in currently, I am able to compile it with -I option, but I wonder why do I have to copy headers manually even if I used synaptic for installation and why I am getting Error 1 and Error 2 when trying to install the package manually. thanks in advance

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  • Generating CMakeLists.txt

    - by vanna
    I got a bunch of C++ sources files and headers. They may use external libraries such as Boost e.g. I am interested in the process of building binaries for Windows and *nix. Makefiles (*nix) and .vcproj (Windows) call compilers with some specifications such as the order of compilation, compilation options and stuff. CMakeLists.txt can be used by CMake to build either makefiles or .vcproj and use very helpful commands such as recursive search of files, automatic linkage with known libraries, installers, variables that can be used in source files... Is there any existing tool that would generate a CMakeLists.txt from specified options ? Options could be like : scan this folder and make a library out of it, then scan this other folder and make an executable and automatically link both with Boost as well along with a user friendly installer with generated INSTALL.txt and README.txt. Something very powerful like that.

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  • Zen and the Art of File and Folder Organization

    - by Mark Virtue
    Is your desk a paragon of neatness, or does it look like a paper-bomb has gone off? If you’ve been putting off getting organized because the task is too huge or daunting, or you don’t know where to start, we’ve got 40 tips to get you on the path to zen mastery of your filing system. For all those readers who would like to get their files and folders organized, or, if they’re already organized, better organized—we have compiled a complete guide to getting organized and staying organized, a comprehensive article that will hopefully cover every possible tip you could want. Signs that Your Computer is Poorly Organized If your computer is a mess, you’re probably already aware of it.  But just in case you’re not, here are some tell-tale signs: Your Desktop has over 40 icons on it “My Documents” contains over 300 files and 60 folders, including MP3s and digital photos You use the Windows’ built-in search facility whenever you need to find a file You can’t find programs in the out-of-control list of programs in your Start Menu You save all your Word documents in one folder, all your spreadsheets in a second folder, etc Any given file that you’re looking for may be in any one of four different sets of folders But before we start, here are some quick notes: We’re going to assume you know what files and folders are, and how to create, save, rename, copy and delete them The organization principles described in this article apply equally to all computer systems.  However, the screenshots here will reflect how things look on Windows (usually Windows 7).  We will also mention some useful features of Windows that can help you get organized. Everyone has their own favorite methodology of organizing and filing, and it’s all too easy to get into “My Way is Better than Your Way” arguments.  The reality is that there is no perfect way of getting things organized.  When I wrote this article, I tried to keep a generalist and objective viewpoint.  I consider myself to be unusually well organized (to the point of obsession, truth be told), and I’ve had 25 years experience in collecting and organizing files on computers.  So I’ve got a lot to say on the subject.  But the tips I have described here are only one way of doing it.  Hopefully some of these tips will work for you too, but please don’t read this as any sort of “right” way to do it. At the end of the article we’ll be asking you, the reader, for your own organization tips. Why Bother Organizing At All? For some, the answer to this question is self-evident. And yet, in this era of powerful desktop search software (the search capabilities built into the Windows Vista and Windows 7 Start Menus, and third-party programs like Google Desktop Search), the question does need to be asked, and answered. I have a friend who puts every file he ever creates, receives or downloads into his My Documents folder and doesn’t bother filing them into subfolders at all.  He relies on the search functionality built into his Windows operating system to help him find whatever he’s looking for.  And he always finds it.  He’s a Search Samurai.  For him, filing is a waste of valuable time that could be spent enjoying life! It’s tempting to follow suit.  On the face of it, why would anyone bother to take the time to organize their hard disk when such excellent search software is available?  Well, if all you ever want to do with the files you own is to locate and open them individually (for listening, editing, etc), then there’s no reason to ever bother doing one scrap of organization.  But consider these common tasks that are not achievable with desktop search software: Find files manually.  Often it’s not convenient, speedy or even possible to utilize your desktop search software to find what you want.  It doesn’t work 100% of the time, or you may not even have it installed.  Sometimes its just plain faster to go straight to the file you want, if you know it’s in a particular sub-folder, rather than trawling through hundreds of search results. Find groups of similar files (e.g. all your “work” files, all the photos of your Europe holiday in 2008, all your music videos, all the MP3s from Dark Side of the Moon, all your letters you wrote to your wife, all your tax returns).  Clever naming of the files will only get you so far.  Sometimes it’s the date the file was created that’s important, other times it’s the file format, and other times it’s the purpose of the file.  How do you name a collection of files so that they’re easy to isolate based on any of the above criteria?  Short answer, you can’t. Move files to a new computer.  It’s time to upgrade your computer.  How do you quickly grab all the files that are important to you?  Or you decide to have two computers now – one for home and one for work.  How do you quickly isolate only the work-related files to move them to the work computer? Synchronize files to other computers.  If you have more than one computer, and you need to mirror some of your files onto the other computer (e.g. your music collection), then you need a way to quickly determine which files are to be synced and which are not.  Surely you don’t want to synchronize everything? Choose which files to back up.  If your backup regime calls for multiple backups, or requires speedy backups, then you’ll need to be able to specify which files are to be backed up, and which are not.  This is not possible if they’re all in the same folder. Finally, if you’re simply someone who takes pleasure in being organized, tidy and ordered (me! me!), then you don’t even need a reason.  Being disorganized is simply unthinkable. Tips on Getting Organized Here we present our 40 best tips on how to get organized.  Or, if you’re already organized, to get better organized. Tip #1.  Choose Your Organization System Carefully The reason that most people are not organized is that it takes time.  And the first thing that takes time is deciding upon a system of organization.  This is always a matter of personal preference, and is not something that a geek on a website can tell you.  You should always choose your own system, based on how your own brain is organized (which makes the assumption that your brain is, in fact, organized). We can’t instruct you, but we can make suggestions: You may want to start off with a system based on the users of the computer.  i.e. “My Files”, “My Wife’s Files”, My Son’s Files”, etc.  Inside “My Files”, you might then break it down into “Personal” and “Business”.  You may then realize that there are overlaps.  For example, everyone may want to share access to the music library, or the photos from the school play.  So you may create another folder called “Family”, for the “common” files. You may decide that the highest-level breakdown of your files is based on the “source” of each file.  In other words, who created the files.  You could have “Files created by ME (business or personal)”, “Files created by people I know (family, friends, etc)”, and finally “Files created by the rest of the world (MP3 music files, downloaded or ripped movies or TV shows, software installation files, gorgeous desktop wallpaper images you’ve collected, etc).”  This system happens to be the one I use myself.  See below:  Mark is for files created by meVC is for files created by my company (Virtual Creations)Others is for files created by my friends and familyData is the rest of the worldAlso, Settings is where I store the configuration files and other program data files for my installed software (more on this in tip #34, below). Each folder will present its own particular set of requirements for further sub-organization.  For example, you may decide to organize your music collection into sub-folders based on the artist’s name, while your digital photos might get organized based on the date they were taken.  It can be different for every sub-folder! Another strategy would be based on “currentness”.  Files you have yet to open and look at live in one folder.  Ones that have been looked at but not yet filed live in another place.  Current, active projects live in yet another place.  All other files (your “archive”, if you like) would live in a fourth folder. (And of course, within that last folder you’d need to create a further sub-system based on one of the previous bullet points). Put some thought into this – changing it when it proves incomplete can be a big hassle!  Before you go to the trouble of implementing any system you come up with, examine a wide cross-section of the files you own and see if they will all be able to find a nice logical place to sit within your system. Tip #2.  When You Decide on Your System, Stick to It! There’s nothing more pointless than going to all the trouble of creating a system and filing all your files, and then whenever you create, receive or download a new file, you simply dump it onto your Desktop.  You need to be disciplined – forever!  Every new file you get, spend those extra few seconds to file it where it belongs!  Otherwise, in just a month or two, you’ll be worse off than before – half your files will be organized and half will be disorganized – and you won’t know which is which! Tip #3.  Choose the Root Folder of Your Structure Carefully Every data file (document, photo, music file, etc) that you create, own or is important to you, no matter where it came from, should be found within one single folder, and that one single folder should be located at the root of your C: drive (as a sub-folder of C:\).  In other words, do not base your folder structure in standard folders like “My Documents”.  If you do, then you’re leaving it up to the operating system engineers to decide what folder structure is best for you.  And every operating system has a different system!  In Windows 7 your files are found in C:\Users\YourName, whilst on Windows XP it was C:\Documents and Settings\YourName\My Documents.  In UNIX systems it’s often /home/YourName. These standard default folders tend to fill up with junk files and folders that are not at all important to you.  “My Documents” is the worst offender.  Every second piece of software you install, it seems, likes to create its own folder in the “My Documents” folder.  These folders usually don’t fit within your organizational structure, so don’t use them!  In fact, don’t even use the “My Documents” folder at all.  Allow it to fill up with junk, and then simply ignore it.  It sounds heretical, but: Don’t ever visit your “My Documents” folder!  Remove your icons/links to “My Documents” and replace them with links to the folders you created and you care about! Create your own file system from scratch!  Probably the best place to put it would be on your D: drive – if you have one.  This way, all your files live on one drive, while all the operating system and software component files live on the C: drive – simply and elegantly separated.  The benefits of that are profound.  Not only are there obvious organizational benefits (see tip #10, below), but when it comes to migrate your data to a new computer, you can (sometimes) simply unplug your D: drive and plug it in as the D: drive of your new computer (this implies that the D: drive is actually a separate physical disk, and not a partition on the same disk as C:).  You also get a slight speed improvement (again, only if your C: and D: drives are on separate physical disks). Warning:  From tip #12, below, you will see that it’s actually a good idea to have exactly the same file system structure – including the drive it’s filed on – on all of the computers you own.  So if you decide to use the D: drive as the storage system for your own files, make sure you are able to use the D: drive on all the computers you own.  If you can’t ensure that, then you can still use a clever geeky trick to store your files on the D: drive, but still access them all via the C: drive (see tip #17, below). If you only have one hard disk (C:), then create a dedicated folder that will contain all your files – something like C:\Files.  The name of the folder is not important, but make it a single, brief word. There are several reasons for this: When creating a backup regime, it’s easy to decide what files should be backed up – they’re all in the one folder! If you ever decide to trade in your computer for a new one, you know exactly which files to migrate You will always know where to begin a search for any file If you synchronize files with other computers, it makes your synchronization routines very simple.   It also causes all your shortcuts to continue to work on the other machines (more about this in tip #24, below). Once you’ve decided where your files should go, then put all your files in there – Everything!  Completely disregard the standard, default folders that are created for you by the operating system (“My Music”, “My Pictures”, etc).  In fact, you can actually relocate many of those folders into your own structure (more about that below, in tip #6). The more completely you get all your data files (documents, photos, music, etc) and all your configuration settings into that one folder, then the easier it will be to perform all of the above tasks. Once this has been done, and all your files live in one folder, all the other folders in C:\ can be thought of as “operating system” folders, and therefore of little day-to-day interest for us. Here’s a screenshot of a nicely organized C: drive, where all user files are located within the \Files folder:   Tip #4.  Use Sub-Folders This would be our simplest and most obvious tip.  It almost goes without saying.  Any organizational system you decide upon (see tip #1) will require that you create sub-folders for your files.  Get used to creating folders on a regular basis. Tip #5.  Don’t be Shy About Depth Create as many levels of sub-folders as you need.  Don’t be scared to do so.  Every time you notice an opportunity to group a set of related files into a sub-folder, do so.  Examples might include:  All the MP3s from one music CD, all the photos from one holiday, or all the documents from one client. It’s perfectly okay to put files into a folder called C:\Files\Me\From Others\Services\WestCo Bank\Statements\2009.  That’s only seven levels deep.  Ten levels is not uncommon.  Of course, it’s possible to take this too far.  If you notice yourself creating a sub-folder to hold only one file, then you’ve probably become a little over-zealous.  On the other hand, if you simply create a structure with only two levels (for example C:\Files\Work) then you really haven’t achieved any level of organization at all (unless you own only six files!).  Your “Work” folder will have become a dumping ground, just like your Desktop was, with most likely hundreds of files in it. Tip #6.  Move the Standard User Folders into Your Own Folder Structure Most operating systems, including Windows, create a set of standard folders for each of its users.  These folders then become the default location for files such as documents, music files, digital photos and downloaded Internet files.  In Windows 7, the full list is shown below: Some of these folders you may never use nor care about (for example, the Favorites folder, if you’re not using Internet Explorer as your browser).  Those ones you can leave where they are.  But you may be using some of the other folders to store files that are important to you.  Even if you’re not using them, Windows will still often treat them as the default storage location for many types of files.  When you go to save a standard file type, it can become annoying to be automatically prompted to save it in a folder that’s not part of your own file structure. But there’s a simple solution:  Move the folders you care about into your own folder structure!  If you do, then the next time you go to save a file of the corresponding type, Windows will prompt you to save it in the new, moved location. Moving the folders is easy.  Simply drag-and-drop them to the new location.  Here’s a screenshot of the default My Music folder being moved to my custom personal folder (Mark): Tip #7.  Name Files and Folders Intelligently This is another one that almost goes without saying, but we’ll say it anyway:  Do not allow files to be created that have meaningless names like Document1.doc, or folders called New Folder (2).  Take that extra 20 seconds and come up with a meaningful name for the file/folder – one that accurately divulges its contents without repeating the entire contents in the name. Tip #8.  Watch Out for Long Filenames Another way to tell if you have not yet created enough depth to your folder hierarchy is that your files often require really long names.  If you need to call a file Johnson Sales Figures March 2009.xls (which might happen to live in the same folder as Abercrombie Budget Report 2008.xls), then you might want to create some sub-folders so that the first file could be simply called March.xls, and living in the Clients\Johnson\Sales Figures\2009 folder. A well-placed file needs only a brief filename! Tip #9.  Use Shortcuts!  Everywhere! This is probably the single most useful and important tip we can offer.  A shortcut allows a file to be in two places at once. Why would you want that?  Well, the file and folder structure of every popular operating system on the market today is hierarchical.  This means that all objects (files and folders) always live within exactly one parent folder.  It’s a bit like a tree.  A tree has branches (folders) and leaves (files).  Each leaf, and each branch, is supported by exactly one parent branch, all the way back to the root of the tree (which, incidentally, is exactly why C:\ is called the “root folder” of the C: drive). That hard disks are structured this way may seem obvious and even necessary, but it’s only one way of organizing data.  There are others:  Relational databases, for example, organize structured data entirely differently.  The main limitation of hierarchical filing structures is that a file can only ever be in one branch of the tree – in only one folder – at a time.  Why is this a problem?  Well, there are two main reasons why this limitation is a problem for computer users: The “correct” place for a file, according to our organizational rationale, is very often a very inconvenient place for that file to be located.  Just because it’s correctly filed doesn’t mean it’s easy to get to.  Your file may be “correctly” buried six levels deep in your sub-folder structure, but you may need regular and speedy access to this file every day.  You could always move it to a more convenient location, but that would mean that you would need to re-file back to its “correct” location it every time you’d finished working on it.  Most unsatisfactory. A file may simply “belong” in two or more different locations within your file structure.  For example, say you’re an accountant and you have just completed the 2009 tax return for John Smith.  It might make sense to you to call this file 2009 Tax Return.doc and file it under Clients\John Smith.  But it may also be important to you to have the 2009 tax returns from all your clients together in the one place.  So you might also want to call the file John Smith.doc and file it under Tax Returns\2009.  The problem is, in a purely hierarchical filing system, you can’t put it in both places.  Grrrrr! Fortunately, Windows (and most other operating systems) offers a way for you to do exactly that:  It’s called a “shortcut” (also known as an “alias” on Macs and a “symbolic link” on UNIX systems).  Shortcuts allow a file to exist in one place, and an icon that represents the file to be created and put anywhere else you please.  In fact, you can create a dozen such icons and scatter them all over your hard disk.  Double-clicking on one of these icons/shortcuts opens up the original file, just as if you had double-clicked on the original file itself. Consider the following two icons: The one on the left is the actual Word document, while the one on the right is a shortcut that represents the Word document.  Double-clicking on either icon will open the same file.  There are two main visual differences between the icons: The shortcut will have a small arrow in the lower-left-hand corner (on Windows, anyway) The shortcut is allowed to have a name that does not include the file extension (the “.docx” part, in this case) You can delete the shortcut at any time without losing any actual data.  The original is still intact.  All you lose is the ability to get to that data from wherever the shortcut was. So why are shortcuts so great?  Because they allow us to easily overcome the main limitation of hierarchical file systems, and put a file in two (or more) places at the same time.  You will always have files that don’t play nice with your organizational rationale, and can’t be filed in only one place.  They demand to exist in two places.  Shortcuts allow this!  Furthermore, they allow you to collect your most often-opened files and folders together in one spot for convenient access.  The cool part is that the original files stay where they are, safe forever in their perfectly organized location. So your collection of most often-opened files can – and should – become a collection of shortcuts! If you’re still not convinced of the utility of shortcuts, consider the following well-known areas of a typical Windows computer: The Start Menu (and all the programs that live within it) The Quick Launch bar (or the Superbar in Windows 7) The “Favorite folders” area in the top-left corner of the Windows Explorer window (in Windows Vista or Windows 7) Your Internet Explorer Favorites or Firefox Bookmarks Each item in each of these areas is a shortcut!  Each of those areas exist for one purpose only:  For convenience – to provide you with a collection of the files and folders you access most often. It should be easy to see by now that shortcuts are designed for one single purpose:  To make accessing your files more convenient.  Each time you double-click on a shortcut, you are saved the hassle of locating the file (or folder, or program, or drive, or control panel icon) that it represents. Shortcuts allow us to invent a golden rule of file and folder organization: “Only ever have one copy of a file – never have two copies of the same file.  Use a shortcut instead” (this rule doesn’t apply to copies created for backup purposes, of course!) There are also lesser rules, like “don’t move a file into your work area – create a shortcut there instead”, and “any time you find yourself frustrated with how long it takes to locate a file, create a shortcut to it and place that shortcut in a convenient location.” So how to we create these massively useful shortcuts?  There are two main ways: “Copy” the original file or folder (click on it and type Ctrl-C, or right-click on it and select Copy):  Then right-click in an empty area of the destination folder (the place where you want the shortcut to go) and select Paste shortcut: Right-drag (drag with the right mouse button) the file from the source folder to the destination folder.  When you let go of the mouse button at the destination folder, a menu pops up: Select Create shortcuts here. Note that when shortcuts are created, they are often named something like Shortcut to Budget Detail.doc (windows XP) or Budget Detail – Shortcut.doc (Windows 7).   If you don’t like those extra words, you can easily rename the shortcuts after they’re created, or you can configure Windows to never insert the extra words in the first place (see our article on how to do this). And of course, you can create shortcuts to folders too, not just to files! Bottom line: Whenever you have a file that you’d like to access from somewhere else (whether it’s convenience you’re after, or because the file simply belongs in two places), create a shortcut to the original file in the new location. Tip #10.  Separate Application Files from Data Files Any digital organization guru will drum this rule into you.  Application files are the components of the software you’ve installed (e.g. Microsoft Word, Adobe Photoshop or Internet Explorer).  Data files are the files that you’ve created for yourself using that software (e.g. Word Documents, digital photos, emails or playlists). Software gets installed, uninstalled and upgraded all the time.  Hopefully you always have the original installation media (or downloaded set-up file) kept somewhere safe, and can thus reinstall your software at any time.  This means that the software component files are of little importance.  Whereas the files you have created with that software is, by definition, important.  It’s a good rule to always separate unimportant files from important files. So when your software prompts you to save a file you’ve just created, take a moment and check out where it’s suggesting that you save the file.  If it’s suggesting that you save the file into the same folder as the software itself, then definitely don’t follow that suggestion.  File it in your own folder!  In fact, see if you can find the program’s configuration option that determines where files are saved by default (if it has one), and change it. Tip #11.  Organize Files Based on Purpose, Not on File Type If you have, for example a folder called Work\Clients\Johnson, and within that folder you have two sub-folders, Word Documents and Spreadsheets (in other words, you’re separating “.doc” files from “.xls” files), then chances are that you’re not optimally organized.  It makes little sense to organize your files based on the program that created them.  Instead, create your sub-folders based on the purpose of the file.  For example, it would make more sense to create sub-folders called Correspondence and Financials.  It may well be that all the files in a given sub-folder are of the same file-type, but this should be more of a coincidence and less of a design feature of your organization system. Tip #12.  Maintain the Same Folder Structure on All Your Computers In other words, whatever organizational system you create, apply it to every computer that you can.  There are several benefits to this: There’s less to remember.  No matter where you are, you always know where to look for your files If you copy or synchronize files from one computer to another, then setting up the synchronization job becomes very simple Shortcuts can be copied or moved from one computer to another with ease (assuming the original files are also copied/moved).  There’s no need to find the target of the shortcut all over again on the second computer Ditto for linked files (e.g Word documents that link to data in a separate Excel file), playlists, and any files that reference the exact file locations of other files. This applies even to the drive that your files are stored on.  If your files are stored on C: on one computer, make sure they’re stored on C: on all your computers.  Otherwise all your shortcuts, playlists and linked files will stop working! Tip #13.  Create an “Inbox” Folder Create yourself a folder where you store all files that you’re currently working on, or that you haven’t gotten around to filing yet.  You can think of this folder as your “to-do” list.  You can call it “Inbox” (making it the same metaphor as your email system), or “Work”, or “To-Do”, or “Scratch”, or whatever name makes sense to you.  It doesn’t matter what you call it – just make sure you have one! Once you have finished working on a file, you then move it from the “Inbox” to its correct location within your organizational structure. You may want to use your Desktop as this “Inbox” folder.  Rightly or wrongly, most people do.  It’s not a bad place to put such files, but be careful:  If you do decide that your Desktop represents your “to-do” list, then make sure that no other files find their way there.  In other words, make sure that your “Inbox”, wherever it is, Desktop or otherwise, is kept free of junk – stray files that don’t belong there. So where should you put this folder, which, almost by definition, lives outside the structure of the rest of your filing system?  Well, first and foremost, it has to be somewhere handy.  This will be one of your most-visited folders, so convenience is key.  Putting it on the Desktop is a great option – especially if you don’t have any other folders on your Desktop:  the folder then becomes supremely easy to find in Windows Explorer: You would then create shortcuts to this folder in convenient spots all over your computer (“Favorite Links”, “Quick Launch”, etc). Tip #14.  Ensure You have Only One “Inbox” Folder Once you’ve created your “Inbox” folder, don’t use any other folder location as your “to-do list”.  Throw every incoming or created file into the Inbox folder as you create/receive it.  This keeps the rest of your computer pristine and free of randomly created or downloaded junk.  The last thing you want to be doing is checking multiple folders to see all your current tasks and projects.  Gather them all together into one folder. Here are some tips to help ensure you only have one Inbox: Set the default “save” location of all your programs to this folder. Set the default “download” location for your browser to this folder. If this folder is not your desktop (recommended) then also see if you can make a point of not putting “to-do” files on your desktop.  This keeps your desktop uncluttered and Zen-like: (the Inbox folder is in the bottom-right corner) Tip #15.  Be Vigilant about Clearing Your “Inbox” Folder This is one of the keys to staying organized.  If you let your “Inbox” overflow (i.e. allow there to be more than, say, 30 files or folders in there), then you’re probably going to start feeling like you’re overwhelmed:  You’re not keeping up with your to-do list.  Once your Inbox gets beyond a certain point (around 30 files, studies have shown), then you’ll simply start to avoid it.  You may continue to put files in there, but you’ll be scared to look at it, fearing the “out of control” feeling that all overworked, chaotic or just plain disorganized people regularly feel. So, here’s what you can do: Visit your Inbox/to-do folder regularly (at least five times per day). Scan the folder regularly for files that you have completed working on and are ready for filing.  File them immediately. Make it a source of pride to keep the number of files in this folder as small as possible.  If you value peace of mind, then make the emptiness of this folder one of your highest (computer) priorities If you know that a particular file has been in the folder for more than, say, six weeks, then admit that you’re not actually going to get around to processing it, and move it to its final resting place. Tip #16.  File Everything Immediately, and Use Shortcuts for Your Active Projects As soon as you create, receive or download a new file, store it away in its “correct” folder immediately.  Then, whenever you need to work on it (possibly straight away), create a shortcut to it in your “Inbox” (“to-do”) folder or your desktop.  That way, all your files are always in their “correct” locations, yet you still have immediate, convenient access to your current, active files.  When you finish working on a file, simply delete the shortcut. Ideally, your “Inbox” folder – and your Desktop – should contain no actual files or folders.  They should simply contain shortcuts. Tip #17.  Use Directory Symbolic Links (or Junctions) to Maintain One Unified Folder Structure Using this tip, we can get around a potential hiccup that we can run into when creating our organizational structure – the issue of having more than one drive on our computer (C:, D:, etc).  We might have files we need to store on the D: drive for space reasons, and yet want to base our organized folder structure on the C: drive (or vice-versa). Your chosen organizational structure may dictate that all your files must be accessed from the C: drive (for example, the root folder of all your files may be something like C:\Files).  And yet you may still have a D: drive and wish to take advantage of the hundreds of spare Gigabytes that it offers.  Did you know that it’s actually possible to store your files on the D: drive and yet access them as if they were on the C: drive?  And no, we’re not talking about shortcuts here (although the concept is very similar). By using the shell command mklink, you can essentially take a folder that lives on one drive and create an alias for it on a different drive (you can do lots more than that with mklink – for a full rundown on this programs capabilities, see our dedicated article).  These aliases are called directory symbolic links (and used to be known as junctions).  You can think of them as “virtual” folders.  They function exactly like regular folders, except they’re physically located somewhere else. For example, you may decide that your entire D: drive contains your complete organizational file structure, but that you need to reference all those files as if they were on the C: drive, under C:\Files.  If that was the case you could create C:\Files as a directory symbolic link – a link to D:, as follows: mklink /d c:\files d:\ Or it may be that the only files you wish to store on the D: drive are your movie collection.  You could locate all your movie files in the root of your D: drive, and then link it to C:\Files\Media\Movies, as follows: mklink /d c:\files\media\movies d:\ (Needless to say, you must run these commands from a command prompt – click the Start button, type cmd and press Enter) Tip #18. Customize Your Folder Icons This is not strictly speaking an organizational tip, but having unique icons for each folder does allow you to more quickly visually identify which folder is which, and thus saves you time when you’re finding files.  An example is below (from my folder that contains all files downloaded from the Internet): To learn how to change your folder icons, please refer to our dedicated article on the subject. Tip #19.  Tidy Your Start Menu The Windows Start Menu is usually one of the messiest parts of any Windows computer.  Every program you install seems to adopt a completely different approach to placing icons in this menu.  Some simply put a single program icon.  Others create a folder based on the name of the software.  And others create a folder based on the name of the software manufacturer.  It’s chaos, and can make it hard to find the software you want to run. Thankfully we can avoid this chaos with useful operating system features like Quick Launch, the Superbar or pinned start menu items. Even so, it would make a lot of sense to get into the guts of the Start Menu itself and give it a good once-over.  All you really need to decide is how you’re going to organize your applications.  A structure based on the purpose of the application is an obvious candidate.  Below is an example of one such structure: In this structure, Utilities means software whose job it is to keep the computer itself running smoothly (configuration tools, backup software, Zip programs, etc).  Applications refers to any productivity software that doesn’t fit under the headings Multimedia, Graphics, Internet, etc. In case you’re not aware, every icon in your Start Menu is a shortcut and can be manipulated like any other shortcut (copied, moved, deleted, etc). With the Windows Start Menu (all version of Windows), Microsoft has decided that there be two parallel folder structures to store your Start Menu shortcuts.  One for you (the logged-in user of the computer) and one for all users of the computer.  Having two parallel structures can often be redundant:  If you are the only user of the computer, then having two parallel structures is totally redundant.  Even if you have several users that regularly log into the computer, most of your installed software will need to be made available to all users, and should thus be moved out of the “just you” version of the Start Menu and into the “all users” area. To take control of your Start Menu, so you can start organizing it, you’ll need to know how to access the actual folders and shortcut files that make up the Start Menu (both versions of it).  To find these folders and files, click the Start button and then right-click on the All Programs text (Windows XP users should right-click on the Start button itself): The Open option refers to the “just you” version of the Start Menu, while the Open All Users option refers to the “all users” version.  Click on the one you want to organize. A Windows Explorer window then opens with your chosen version of the Start Menu selected.  From there it’s easy.  Double-click on the Programs folder and you’ll see all your folders and shortcuts.  Now you can delete/rename/move until it’s just the way you want it. Note:  When you’re reorganizing your Start Menu, you may want to have two Explorer windows open at the same time – one showing the “just you” version and one showing the “all users” version.  You can drag-and-drop between the windows. Tip #20.  Keep Your Start Menu Tidy Once you have a perfectly organized Start Menu, try to be a little vigilant about keeping it that way.  Every time you install a new piece of software, the icons that get created will almost certainly violate your organizational structure. So to keep your Start Menu pristine and organized, make sure you do the following whenever you install a new piece of software: Check whether the software was installed into the “just you” area of the Start Menu, or the “all users” area, and then move it to the correct area. Remove all the unnecessary icons (like the “Read me” icon, the “Help” icon (you can always open the help from within the software itself when it’s running), the “Uninstall” icon, the link(s)to the manufacturer’s website, etc) Rename the main icon(s) of the software to something brief that makes sense to you.  For example, you might like to rename Microsoft Office Word 2010 to simply Word Move the icon(s) into the correct folder based on your Start Menu organizational structure And don’t forget:  when you uninstall a piece of software, the software’s uninstall routine is no longer going to be able to remove the software’s icon from the Start Menu (because you moved and/or renamed it), so you’ll need to remove that icon manually. Tip #21.  Tidy C:\ The root of your C: drive (C:\) is a common dumping ground for files and folders – both by the users of your computer and by the software that you install on your computer.  It can become a mess. There’s almost no software these days that requires itself to be installed in C:\.  99% of the time it can and should be installed into C:\Program Files.  And as for your own files, well, it’s clear that they can (and almost always should) be stored somewhere else. In an ideal world, your C:\ folder should look like this (on Windows 7): Note that there are some system files and folders in C:\ that are usually and deliberately “hidden” (such as the Windows virtual memory file pagefile.sys, the boot loader file bootmgr, and the System Volume Information folder).  Hiding these files and folders is a good idea, as they need to stay where they are and are almost never needed to be opened or even seen by you, the user.  Hiding them prevents you from accidentally messing with them, and enhances your sense of order and well-being when you look at your C: drive folder. Tip #22.  Tidy Your Desktop The Desktop is probably the most abused part of a Windows computer (from an organization point of view).  It usually serves as a dumping ground for all incoming files, as well as holding icons to oft-used applications, plus some regularly opened files and folders.  It often ends up becoming an uncontrolled mess.  See if you can avoid this.  Here’s why… Application icons (Word, Internet Explorer, etc) are often found on the Desktop, but it’s unlikely that this is the optimum place for them.  The “Quick Launch” bar (or the Superbar in Windows 7) is always visible and so represents a perfect location to put your icons.  You’ll only be able to see the icons on your Desktop when all your programs are minimized.  It might be time to get your application icons off your desktop… You may have decided that the Inbox/To-do folder on your computer (see tip #13, above) should be your Desktop.  If so, then enough said.  Simply be vigilant about clearing it and preventing it from being polluted by junk files (see tip #15, above).  On the other hand, if your Desktop is not acting as your “Inbox” folder, then there’s no reason for it to have any data files or folders on it at all, except perhaps a couple of shortcuts to often-opened files and folders (either ongoing or current projects).  Everything else should be moved to your “Inbox” folder. In an ideal world, it might look like this: Tip #23.  Move Permanent Items on Your Desktop Away from the Top-Left Corner When files/folders are dragged onto your desktop in a Windows Explorer window, or when shortcuts are created on your Desktop from Internet Explorer, those icons are always placed in the top-left corner – or as close as they can get.  If you have other files, folders or shortcuts that you keep on the Desktop permanently, then it’s a good idea to separate these permanent icons from the transient ones, so that you can quickly identify which ones the transients are.  An easy way to do this is to move all your permanent icons to the right-hand side of your Desktop.  That should keep them separated from incoming items. Tip #24.  Synchronize If you have more than one computer, you’ll almost certainly want to share files between them.  If the computers are permanently attached to the same local network, then there’s no need to store multiple copies of any one file or folder – shortcuts will suffice.  However, if the computers are not always on the same network, then you will at some point need to copy files between them.  For files that need to permanently live on both computers, the ideal way to do this is to synchronize the files, as opposed to simply copying them. We only have room here to write a brief summary of synchronization, not a full article.  In short, there are several different types of synchronization: Where the contents of one folder are accessible anywhere, such as with Dropbox Where the contents of any number of folders are accessible anywhere, such as with Windows Live Mesh Where any files or folders from anywhere on your computer are synchronized with exactly one other computer, such as with the Windows “Briefcase”, Microsoft SyncToy, or (much more powerful, yet still free) SyncBack from 2BrightSparks.  This only works when both computers are on the same local network, at least temporarily. A great advantage of synchronization solutions is that once you’ve got it configured the way you want it, then the sync process happens automatically, every time.  Click a button (or schedule it to happen automatically) and all your files are automagically put where they’re supposed to be. If you maintain the same file and folder structure on both computers, then you can also sync files depend upon the correct location of other files, like shortcuts, playlists and office documents that link to other office documents, and the synchronized files still work on the other computer! Tip #25.  Hide Files You Never Need to See If you have your files well organized, you will often be able to tell if a file is out of place just by glancing at the contents of a folder (for example, it should be pretty obvious if you look in a folder that contains all the MP3s from one music CD and see a Word document in there).  This is a good thing – it allows you to determine if there are files out of place with a quick glance.  Yet sometimes there are files in a folder that seem out of place but actually need to be there, such as the “folder art” JPEGs in music folders, and various files in the root of the C: drive.  If such files never need to be opened by you, then a good idea is to simply hide them.  Then, the next time you glance at the folder, you won’t have to remember whether that file was supposed to be there or not, because you won’t see it at all! To hide a file, simply right-click on it and choose Properties: Then simply tick the Hidden tick-box:   Tip #26.  Keep Every Setup File These days most software is downloaded from the Internet.  Whenever you download a piece of software, keep it.  You’ll never know when you need to reinstall the software. Further, keep with it an Internet shortcut that links back to the website where you originally downloaded it, in case you ever need to check for updates. See tip #33 below for a full description of the excellence of organizing your setup files. Tip #27.  Try to Minimize the Number of Folders that Contain Both Files and Sub-folders Some of the folders in your organizational structure will contain only files.  Others will contain only sub-folders.  And you will also have some folders that contain both files and sub-folders.  You will notice slight improvements in how long it takes you to locate a file if you try to avoid this third type of folder.  It’s not always possible, of course – you’ll always have some of these folders, but see if you can avoid it. One way of doing this is to take all the leftover files that didn’t end up getting stored in a sub-folder and create a special “Miscellaneous” or “Other” folder for them. Tip #28.  Starting a Filename with an Underscore Brings it to the Top of a List Further to the previous tip, if you name that “Miscellaneous” or “Other” folder in such a way that its name begins with an underscore “_”, then it will appear at the top of the list of files/folders. The screenshot below is an example of this.  Each folder in the list contains a set of digital photos.  The folder at the top of the list, _Misc, contains random photos that didn’t deserve their own dedicated folder: Tip #29.  Clean Up those CD-ROMs and (shudder!) Floppy Disks Have you got a pile of CD-ROMs stacked on a shelf of your office?  Old photos, or files you archived off onto CD-ROM (or even worse, floppy disks!) because you didn’t have enough disk space at the time?  In the meantime have you upgraded your computer and now have 500 Gigabytes of space you don’t know what to do with?  If so, isn’t it time you tidied up that stack of disks and filed them into your gorgeous new folder structure? So what are you waiting for?  Bite the bullet, copy them all back onto your computer, file them in their appropriate folders, and then back the whole lot up onto a shiny new 1000Gig external hard drive! Useful Folders to Create This next section suggests some useful folders that you might want to create within your folder structure.  I’ve personally found them to be indispensable. The first three are all about convenience – handy folders to create and then put somewhere that you can always access instantly.  For each one, it’s not so important where the actual folder is located, but it’s very important where you put the shortcut(s) to the folder.  You might want to locate the shortcuts: On your Desktop In your “Quick Launch” area (or pinned to your Windows 7 Superbar) In your Windows Explorer “Favorite Links” area Tip #30.  Create an “Inbox” (“To-Do”) Folder This has already been mentioned in depth (see tip #13), but we wanted to reiterate its importance here.  This folder contains all the recently created, received or downloaded files that you have not yet had a chance to file away properly, and it also may contain files that you have yet to process.  In effect, it becomes a sort of “to-do list”.  It doesn’t have to be called “Inbox” – you can call it whatever you want. Tip #31.  Create a Folder where Your Current Projects are Collected Rather than going hunting for them all the time, or dumping them all on your desktop, create a special folder where you put links (or work folders) for each of the projects you’re currently working on. You can locate this folder in your “Inbox” folder, on your desktop, or anywhere at all – just so long as there’s a way of getting to it quickly, such as putting a link to it in Windows Explorer’s “Favorite Links” area: Tip #32.  Create a Folder for Files and Folders that You Regularly Open You will always have a few files that you open regularly, whether it be a spreadsheet of your current accounts, or a favorite playlist.  These are not necessarily “current projects”, rather they’re simply files that you always find yourself opening.  Typically such files would be located on your desktop (or even better, shortcuts to those files).  Why not collect all such shortcuts together and put them in their own special folder? As with the “Current Projects” folder (above), you would want to locate that folder somewhere convenient.  Below is an example of a folder called “Quick links”, with about seven files (shortcuts) in it, that is accessible through the Windows Quick Launch bar: See tip #37 below for a full explanation of the power of the Quick Launch bar. Tip #33.  Create a “Set-ups” Folder A typical computer has dozens of applications installed on it.  For each piece of software, there are often many different pieces of information you need to keep track of, including: The original installation setup file(s).  This can be anything from a simple 100Kb setup.exe file you downloaded from a website, all the way up to a 4Gig ISO file that you copied from a DVD-ROM that you purchased. The home page of the software manufacturer (in case you need to look up something on their support pages, their forum or their online help) The page containing the download link for your actual file (in case you need to re-download it, or download an upgraded version) The serial number Your proof-of-purchase documentation Any other template files, plug-ins, themes, etc that also need to get installed For each piece of software, it’s a great idea to gather all of these files together and put them in a single folder.  The folder can be the name of the software (plus possibly a very brief description of what it’s for – in case you can’t remember what the software does based in its name).  Then you would gather all of these folders together into one place, and call it something like “Software” or “Setups”. If you have enough of these folders (I have several hundred, being a geek, collected over 20 years), then you may want to further categorize them.  My own categorization structure is based on “platform” (operating system): The last seven folders each represents one platform/operating system, while _Operating Systems contains set-up files for installing the operating systems themselves.  _Hardware contains ROMs for hardware I own, such as routers. Within the Windows folder (above), you can see the beginnings of the vast library of software I’ve compiled over the years: An example of a typical application folder looks like this: Tip #34.  Have a “Settings” Folder We all know that our documents are important.  So are our photos and music files.  We save all of these files into folders, and then locate them afterwards and double-click on them to open them.  But there are many files that are important to us that can’t be saved into folders, and then searched for and double-clicked later on.  These files certainly contain important information that we need, but are often created internally by an application, and saved wherever that application feels is appropriate. A good example of this is the “PST” file that Outlook creates for us and uses to store all our emails, contacts, appointments and so forth.  Another example would be the collection of Bookmarks that Firefox stores on your behalf. And yet another example would be the customized settings and configuration files of our all our software.  Granted, most Windows programs store their configuration in the Registry, but there are still many programs that use configuration files to store their settings. Imagine if you lost all of the above files!  And yet, when people are backing up their computers, they typically only back up the files they know about – those that are stored in the “My Documents” folder, etc.  If they had a hard disk failure or their computer was lost or stolen, their backup files would not include some of the most vital files they owned.  Also, when migrating to a new computer, it’s vital to ensure that these files make the journey. It can be a very useful idea to create yourself a folder to store all your “settings” – files that are important to you but which you never actually search for by name and double-click on to open them.  Otherwise, next time you go to set up a new computer just the way you want it, you’ll need to spend hours recreating the configuration of your previous computer! So how to we get our important files into this folder?  Well, we have a few options: Some programs (such as Outlook and its PST files) allow you to place these files wherever you want.  If you delve into the program’s options, you will find a setting somewhere that controls the location of the important settings files (or “personal storage” – PST – when it comes to Outlook) Some programs do not allow you to change such locations in any easy way, but if you get into the Registry, you can sometimes find a registry key that refers to the location of the file(s).  Simply move the file into your Settings folder and adjust the registry key to refer to the new location. Some programs stubbornly refuse to allow their settings files to be placed anywhere other then where they stipulate.  When faced with programs like these, you have three choices:  (1) You can ignore those files, (2) You can copy the files into your Settings folder (let’s face it – settings don’t change very often), or (3) you can use synchronization software, such as the Windows Briefcase, to make synchronized copies of all your files in your Settings folder.  All you then have to do is to remember to run your sync software periodically (perhaps just before you run your backup software!). There are some other things you may decide to locate inside this new “Settings” folder: Exports of registry keys (from the many applications that store their configurations in the Registry).  This is useful for backup purposes or for migrating to a new computer Notes you’ve made about all the specific customizations you have made to a particular piece of software (so that you’ll know how to do it all again on your next computer) Shortcuts to webpages that detail how to tweak certain aspects of your operating system or applications so they are just the way you like them (such as how to remove the words “Shortcut to” from the beginning of newly created shortcuts).  In other words, you’d want to create shortcuts to half the pages on the How-To Geek website! Here’s an example of a “Settings” folder: Windows Features that Help with Organization This section details some of the features of Microsoft Windows that are a boon to anyone hoping to stay optimally organized. Tip #35.  Use the “Favorite Links” Area to Access Oft-Used Folders Once you’ve created your great new filing system, work out which folders you access most regularly, or which serve as great starting points for locating the rest of the files in your folder structure, and then put links to those folders in your “Favorite Links” area of the left-hand side of the Windows Explorer window (simply called “Favorites” in Windows 7):   Some ideas for folders you might want to add there include: Your “Inbox” folder (or whatever you’ve called it) – most important! The base of your filing structure (e.g. C:\Files) A folder containing shortcuts to often-accessed folders on other computers around the network (shown above as Network Folders) A folder containing shortcuts to your current projects (unless that folder is in your “Inbox” folder) Getting folders into this area is very simple – just locate the folder you’re interested in and drag it there! Tip #36.  Customize the Places Bar in the File/Open and File/Save Boxes Consider the screenshot below: The highlighted icons (collectively known as the “Places Bar”) can be customized to refer to any folder location you want, allowing instant access to any part of your organizational structure. Note:  These File/Open and File/Save boxes have been superseded by new versions that use the Windows Vista/Windows 7 “Favorite Links”, but the older versions (shown above) are still used by a surprisingly large number of applications. The easiest way to customize these icons is to use the Group Policy Editor, but not everyone has access to this program.  If you do, open it up and navigate to: User Configuration > Administrative Templates > Windows Components > Windows Explorer > Common Open File Dialog If you don’t have access to the Group Policy Editor, then you’ll need to get into the Registry.  Navigate to: HKEY_CURRENT_USER \ Software \ Microsoft  \ Windows \ CurrentVersion \ Policies \ comdlg32 \ Placesbar It should then be easy to make the desired changes.  Log off and log on again to allow the changes to take effect. Tip #37.  Use the Quick Launch Bar as a Application and File Launcher That Quick Launch bar (to the right of the Start button) is a lot more useful than people give it credit for.  Most people simply have half a dozen icons in it, and use it to start just those programs.  But it can actually be used to instantly access just about anything in your filing system: For complete instructions on how to set this up, visit our dedicated article on this topic. Tip #38.  Put a Shortcut to Windows Explorer into Your Quick Launch Bar This is only necessary in Windows Vista and Windows XP.  The Microsoft boffins finally got wise and added it to the Windows 7 Superbar by default. Windows Explorer – the program used for managing your files and folders – is one of the most useful programs in Windows.  Anyone who considers themselves serious about being organized needs instant access to this program at any time.  A great place to create a shortcut to this program is in the Windows XP and Windows Vista “Quick Launch” bar: To get it there, locate it in your Start Menu (usually under “Accessories”) and then right-drag it down into your Quick Launch bar (and create a copy). Tip #39.  Customize the Starting Folder for Your Windows 7 Explorer Superbar Icon If you’re on Windows 7, your Superbar will include a Windows Explorer icon.  Clicking on the icon will launch Windows Explorer (of course), and will start you off in your “Libraries” folder.  Libraries may be fine as a starting point, but if you have created yourself an “Inbox” folder, then it would probably make more sense to start off in this folder every time you launch Windows Explorer. To change this default/starting folder location, then first right-click the Explorer icon in the Superbar, and then right-click Properties:Then, in Target field of the Windows Explorer Properties box that appears, type %windir%\explorer.exe followed by the path of the folder you wish to start in.  For example: %windir%\explorer.exe C:\Files If that folder happened to be on the Desktop (and called, say, “Inbox”), then you would use the following cleverness: %windir%\explorer.exe shell:desktop\Inbox Then click OK and test it out. Tip #40.  Ummmmm…. No, that’s it.  I can’t think of another one.  That’s all of the tips I can come up with.  I only created this one because 40 is such a nice round number… Case Study – An Organized PC To finish off the article, I have included a few screenshots of my (main) computer (running Vista).  The aim here is twofold: To give you a sense of what it looks like when the above, sometimes abstract, tips are applied to a real-life computer, and To offer some ideas about folders and structure that you may want to steal to use on your own PC. Let’s start with the C: drive itself.  Very minimal.  All my files are contained within C:\Files.  I’ll confine the rest of the case study to this folder: That folder contains the following: Mark: My personal files VC: My business (Virtual Creations, Australia) Others contains files created by friends and family Data contains files from the rest of the world (can be thought of as “public” files, usually downloaded from the Net) Settings is described above in tip #34 The Data folder contains the following sub-folders: Audio:  Radio plays, audio books, podcasts, etc Development:  Programmer and developer resources, sample source code, etc (see below) Humour:  Jokes, funnies (those emails that we all receive) Movies:  Downloaded and ripped movies (all legal, of course!), their scripts, DVD covers, etc. Music:  (see below) Setups:  Installation files for software (explained in full in tip #33) System:  (see below) TV:  Downloaded TV shows Writings:  Books, instruction manuals, etc (see below) The Music folder contains the following sub-folders: Album covers:  JPEG scans Guitar tabs:  Text files of guitar sheet music Lists:  e.g. “Top 1000 songs of all time” Lyrics:  Text files MIDI:  Electronic music files MP3 (representing 99% of the Music folder):  MP3s, either ripped from CDs or downloaded, sorted by artist/album name Music Video:  Video clips Sheet Music:  usually PDFs The Data\Writings folder contains the following sub-folders: (all pretty self-explanatory) The Data\Development folder contains the following sub-folders: Again, all pretty self-explanatory (if you’re a geek) The Data\System folder contains the following sub-folders: These are usually themes, plug-ins and other downloadable program-specific resources. The Mark folder contains the following sub-folders: From Others:  Usually letters that other people (friends, family, etc) have written to me For Others:  Letters and other things I have created for other people Green Book:  None of your business Playlists:  M3U files that I have compiled of my favorite songs (plus one M3U playlist file for every album I own) Writing:  Fiction, philosophy and other musings of mine Mark Docs:  Shortcut to C:\Users\Mark Settings:  Shortcut to C:\Files\Settings\Mark The Others folder contains the following sub-folders: The VC (Virtual Creations, my business – I develop websites) folder contains the following sub-folders: And again, all of those are pretty self-explanatory. Conclusion These tips have saved my sanity and helped keep me a productive geek, but what about you? What tips and tricks do you have to keep your files organized?  Please share them with us in the comments.  Come on, don’t be shy… Similar Articles Productive Geek Tips Fix For When Windows Explorer in Vista Stops Showing File NamesWhy Did Windows Vista’s Music Folder Icon Turn Yellow?Print or Create a Text File List of the Contents in a Directory the Easy WayCustomize the Windows 7 or Vista Send To MenuAdd Copy To / Move To on Windows 7 or Vista Right-Click Menu 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 Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Track Daily Goals With 42Goals Video Toolbox is a Superb Online Video Editor Fun with 47 charts and graphs Tomorrow is Mother’s Day Check the Average Speed of YouTube Videos You’ve Watched OutlookStatView Scans and Displays General Usage Statistics

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  • Parallelism in .NET – Part 10, Cancellation in PLINQ and the Parallel class

    - by Reed
    Many routines are parallelized because they are long running processes.  When writing an algorithm that will run for a long period of time, its typically a good practice to allow that routine to be cancelled.  I previously discussed terminating a parallel loop from within, but have not demonstrated how a routine can be cancelled from the caller’s perspective.  Cancellation in PLINQ and the Task Parallel Library is handled through a new, unified cooperative cancellation model introduced with .NET 4.0. Cancellation in .NET 4 is based around a new, lightweight struct called CancellationToken.  A CancellationToken is a small, thread-safe value type which is generated via a CancellationTokenSource.  There are many goals which led to this design.  For our purposes, we will focus on a couple of specific design decisions: Cancellation is cooperative.  A calling method can request a cancellation, but it’s up to the processing routine to terminate – it is not forced. Cancellation is consistent.  A single method call requests a cancellation on every copied CancellationToken in the routine. Let’s begin by looking at how we can cancel a PLINQ query.  Supposed we wanted to provide the option to cancel our query from Part 6: double min = collection .AsParallel() .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } We would rewrite this to allow for cancellation by adding a call to ParallelEnumerable.WithCancellation as follows: var cts = new CancellationTokenSource(); // Pass cts here to a routine that could, // in parallel, request a cancellation try { double min = collection .AsParallel() .WithCancellation(cts.Token) .Min(item => item.PerformComputation()); } catch (OperationCanceledException e) { // Query was cancelled before it finished } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, if the user calls cts.Cancel() before the PLINQ query completes, the query will stop processing, and an OperationCanceledException will be raised.  Be aware, however, that cancellation will not be instantaneous.  When cts.Cancel() is called, the query will only stop after the current item.PerformComputation() elements all finish processing.  cts.Cancel() will prevent PLINQ from scheduling a new task for a new element, but will not stop items which are currently being processed.  This goes back to the first goal I mentioned – Cancellation is cooperative.  Here, we’re requesting the cancellation, but it’s up to PLINQ to terminate. If we wanted to allow cancellation to occur within our routine, we would need to change our routine to accept a CancellationToken, and modify it to handle this specific case: public void PerformComputation(CancellationToken token) { for (int i=0; i<this.iterations; ++i) { // Add a check to see if we've been canceled // If a cancel was requested, we'll throw here token.ThrowIfCancellationRequested(); // Do our processing now this.RunIteration(i); } } With this overload of PerformComputation, each internal iteration checks to see if a cancellation request was made, and will throw an OperationCanceledException at that point, instead of waiting until the method returns.  This is good, since it allows us, as developers, to plan for cancellation, and terminate our routine in a clean, safe state. This is handled by changing our PLINQ query to: try { double min = collection .AsParallel() .WithCancellation(cts.Token) .Min(item => item.PerformComputation(cts.Token)); } catch (OperationCanceledException e) { // Query was cancelled before it finished } PLINQ is very good about handling this exception, as well.  There is a very good chance that multiple items will raise this exception, since the entire purpose of PLINQ is to have multiple items be processed concurrently.  PLINQ will take all of the OperationCanceledException instances raised within these methods, and merge them into a single OperationCanceledException in the call stack.  This is done internally because we added the call to ParallelEnumerable.WithCancellation. If, however, a different exception is raised by any of the elements, the OperationCanceledException as well as the other Exception will be merged into a single AggregateException. The Task Parallel Library uses the same cancellation model, as well.  Here, we supply our CancellationToken as part of the configuration.  The ParallelOptions class contains a property for the CancellationToken.  This allows us to cancel a Parallel.For or Parallel.ForEach routine in a very similar manner to our PLINQ query.  As an example, we could rewrite our Parallel.ForEach loop from Part 2 to support cancellation by changing it to: try { var cts = new CancellationTokenSource(); var options = new ParallelOptions() { CancellationToken = cts.Token }; Parallel.ForEach(customers, options, customer => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // Check for cancellation here options.CancellationToken.ThrowIfCancellationRequested(); // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } }); } catch (OperationCanceledException e) { // The loop was cancelled } Notice that here we use the same approach taken in PLINQ.  The Task Parallel Library will automatically handle our cancellation in the same manner as PLINQ, providing a clean, unified model for cancellation of any parallel routine.  The TPL performs the same aggregation of the cancellation exceptions as PLINQ, as well, which is why a single exception handler for OperationCanceledException will cleanly handle this scenario.  This works because we’re using the same CancellationToken provided in the ParallelOptions.  If a different exception was thrown by one thread, or a CancellationToken from a different CancellationTokenSource was used to raise our exception, we would instead receive all of our individual exceptions merged into one AggregateException.

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  • WinInet Apps failing when Internet Explorer is set to Offline Mode

    - by Rick Strahl
    Ran into a nasty issue last week when all of a sudden many of my old applications that are using WinInet for HTTP access started failing. Specifically, the WinInet HttpSendRequest() call started failing with an error of 2, which when retrieving the error boils down to: WinInet Error 2: The system cannot find the file specified Now this error can pop up in many legitimate scenarios with WinInet such as when no Internet connection is available or the HTTP configuration (usually configured in Internet Explorer’s options) is misconfigured. The error typically means that the server in question cannot be found or more specifically an Internet connection can’t be established. In this case the problem started suddenly and was causing some of my own applications (old Visual FoxPro apps using my own wwHttp library) and all Adobe Air applications (which apparently uses WinInet for its basic HTTP stack) along with a few more oddball applications to fail instantly when trying to connect via HTTP. Most other applications – all of my installed browsers, email clients, various social network updaters all worked just fine. It seems it was only WinInet apps that were failing. Yet oddly Internet Explorer appeared to be working. So the problem seemed to be isolated to those ‘classic’ applications using WinInet. WinInet’s base configuration uses the Internet Explorer options dialog. To check this out I typically go to the Internet Explorer options and find the Connection tab, and check out the LAN Setup. Make sure there are no rogue proxy settings or configuration scripts that are invalid. Trying with Auto-configuration on and off also can often fix ‘real’ configuration errors. This time however this wasn’t a problem – nothing in the LAN configuration was set (all default). I also played with the Automatic detection of settings which also had no effect. I also tried to use Fiddler to see if that would tell me something. Fiddler has a few additional WinInet configuration options in its configuration. Running Fiddler and hitting an HTTP request using WinInet would never actually hit Fiddler – the failure would occur before WinInet ever fired up the HTTP connection to go through the Fiddler HTTP proxy. And the Culprit is: Internet Explorer’s Work Offline Option The culprit in this situation was Internet Explorer which at some point, unknown to me switched into Offline Mode and was then shut down: When this Offline mode is checked when IE is running *or* if IE gets shut down with this flag set, all applications using WinInet by default assume that it’s running in offline mode. Depending on your caching HTTP headers and whether the page was cached previously you may or may not get a response or an error. For an independent non-browser application this will be highly unpredictable and likely result in failures getting online – especially if the application forces requests to always reload by disabling HTTP caching (as I do on most of my dynamic HTTP clients). What makes this especially tricky is that even when IE is in offline mode in the browser, you can still browse around the Web *if* you have a connection. IE will try to load anything it has cached from the local cache, but as soon as you hit a URL that isn’t cached it will automatically try to access that URL and uncheck the Work Offline option. Conversely if you get knocked off the Internet and browse in IE 9, IE will automatically go into offline mode. I never explicitly set offline mode – it just automatically sets itself on and off depending on the connection. Problem is if you’re not using IE all the time (as I do – rarely and just for testing so usually a few commonly used URLs) and you left it in offline mode when you exit, offline mode stays set which results in the above head scratcher. Ack. This isn’t new behavior in IE 9 BTW – this behavior has always been there, but I think what’s different is that IE now automatically switches between online and offline modes without notifying you at all, so it’s hard to tell when you are offline. Fixing the Issue in your Code If you have an application that is using WinInet, there’s a WinInet option called INTERNET_OPTION_IGNORE_OFFLINE. I just checked this out in my own applications and Internet Explorer 9 and it works, but apparently it’s been broken for some older releases (I can’t confirm how far back though) – lots of posts seem to suggest the flag doesn’t work. However, in IE 9 at least it does seem to work if you call InternetSetOption before you call HttpOpenRequest with the Http Session handle. In FoxPro code I use: DECLARE INTEGER InternetSetOption ;    IN WININET.DLL ;    INTEGER HINTERNET,;    INTEGER dwFlags,;    INTEGER @dwValue,;    INTEGER cbSize lnOptionValue = 1   && BOOL TRUE pass by reference   *** Set needed SSL flags lnResult=InternetSetOption(this.hHttpSession,;    INTERNET_OPTION_IGNORE_OFFLINE ,;  && 77    @lnOptionValue ,4)   DECLARE INTEGER HttpOpenRequest ;    IN WININET.DLL ;    INTEGER hHTTPHandle,;    STRING lpzReqMethod,;    STRING lpzPage,;    STRING lpzVersion,;    STRING lpzReferer,;    STRING lpzAcceptTypes,;    INTEGER dwFlags,;    INTEGER dwContextw     hHTTPResult=HttpOpenRequest(THIS.hHttpsession,;    lcVerb,;    tcPage,;    NULL,NULL,NULL,;    INTERNET_FLAG_RELOAD + ;    IIF(THIS.lsecurelink,INTERNET_FLAG_SECURE,0) + ;    this.nHTTPServiceFlags,0) …  And this fixes the issue at least for IE 9… In my FoxPro wwHttp class I now call this by default to never get bitten by this again… This solves the problem permanently for my HTTP client. I never want to see offline operation in an HTTP client API – it’s just too unpredictable in handling errors and the last thing you want is getting unpredictably stale data. Problem solved but this behavior is – well ugly. But then that’s to be expected from an API that’s based on Internet Explorer, eh?© Rick Strahl, West Wind Technologies, 2005-2011Posted in HTTP  Windows  

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  • Plone: Creating new Page fails "AttributeError: 'str' object has no attribute 'dates'"

    - by paskster
    I just installed Plone on my Centos 5.5. I was able login via the admin-account and create new users. But when I try to create a new page I get the following error message: Traceback (innermost last): Module ZPublisher.Publish, line 127, in publish Module ZPublisher.mapply, line 77, in mapply Module ZPublisher.Publish, line 47, in call_object Module Products.CMFPlone.FactoryTool, line 446, in __call__ Module ZPublisher.mapply, line 77, in mapply Module ZPublisher.Publish, line 47, in call_object Module Products.CMFFormController.FSControllerPageTemplate, line 91, in __call__ Module Products.CMFFormController.BaseControllerPageTemplate, line 31, in _call Module Shared.DC.Scripts.Bindings, line 324, in __call__ Module Shared.DC.Scripts.Bindings, line 361, in _bindAndExec Module Products.CMFCore.FSPageTemplate, line 240, in _exec Module Products.CMFCore.FSPageTemplate, line 180, in pt_render Module Products.PageTemplates.PageTemplate, line 80, in pt_render Module zope.pagetemplate.pagetemplate, line 113, in pt_render Warning: Macro expansion failed Warning: <type 'exceptions.KeyError'>: 'macro' Module zope.tal.talinterpreter, line 271, in __call__ Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 888, in do_useMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 888, in do_useMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 954, in do_defineSlot Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 858, in do_defineMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 954, in do_defineSlot Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 946, in do_defineSlot Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 858, in do_defineMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 888, in do_useMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 852, in do_condition Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 954, in do_defineSlot Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 852, in do_condition Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 821, in do_loop_tal Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 522, in do_optTag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 821, in do_loop_tal Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 888, in do_useMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 888, in do_useMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 852, in do_condition Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 852, in do_condition Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 946, in do_defineSlot Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 533, in do_optTag_tal Module zope.tal.talinterpreter, line 518, in do_optTag Module zope.tal.talinterpreter, line 513, in no_tag Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 888, in do_useMacro Module zope.tal.talinterpreter, line 343, in interpret Module zope.tal.talinterpreter, line 583, in do_setLocal_tal Module zope.tales.tales, line 696, in evaluate URL: file:/usr/local/Plone/buildout-cache/eggs/Plone-4.0.2-py2.6.egg/Products/CMFPlone/skins/plone_templates/calendar_macros.pt Line 12, Column 4 Expression: <PythonExpr date_components_support_view.result(inputvalue, 0, starting_year, ending_year, future_years)> Names: {'container': <PloneSite at /reeple>, 'context': <ATDocument at /reeple/portal_factory/Document/document.2010-12-24.9331499294 used for /reeple>, 'default': <object object at 0x2ad1b9a18ae0>, 'here': <ATDocument at /reeple/portal_factory/Document/document.2010-12-24.9331499294 used for /reeple>, 'loop': {u'field': <Products.PageTemplates.Expressions.PathIterator object at 0x1bc9b9d0>, u'fieldset': <Products.PageTemplates.Expressions.PathIterator object at 0x1d396c90>}, 'nothing': None, 'options': {'args': (), 'state': <Products.CMFFormController.ControllerState.ControllerState object at 0x1ccdb2d0>}, 'repeat': <Products.PageTemplates.Expressions.SafeMapping object at 0x1d452ec0>, 'request': <HTTPRequest, URL=http://82.165.145.121:8081/reeple/portal_factory/Document/document.2010-12-24.9331499294/atct_edit>, 'root': <Application at >, 'template': <FSControllerPageTemplate at /reeple/atct_edit used for /reeple/portal_factory/Document/document.2010-12-24.9331499294>, 'traverse_subpath': [], 'user': <PloneUser 'pascalklein'>} Module Products.PageTemplates.ZRPythonExpr, line 49, in __call__ __traceback_info__: date_components_support_view.result(inputvalue, 0, starting_year, ending_year, future_years) Module PythonExpr, line 1, in <expression> Module plone.app.form.widgets.datecomponents, line 50, in result AttributeError: 'str' object has no attribute 'dates' Any suggestions? CentOS 5.5 has the Python Version 2.4. So I'm not sure if that causes the issue.

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  • SQL CLR Assembly Error 80131051 when late binding to a registered C# COM .dll

    - by Shanubus
    I must have hit an unusual one, because I can't find any reference to this specific failing anywhere... Scenario: I have a legacy SQL function used to transform(encrypt) data. This function is called from within many stored procedures used by multiple applications. I say this, because the obvious answer of 'just call it from your code' is not really an option (or at least one I'd prefer not explore). The legacy function used sp_OA with an ActiveX dll on SQL2000 to perform its work. The new function is targeted at SQL2008 x64. I am ditching the sp_OA call in favor of CLR assembly; and am getting rid of the ActiveX dll and using a COM+ .dll (3rd party) to perform the same work. This 3rd party COM+ is required to be used based on spec given to me, so can't get rid of this piece either. Problem: After multiple attempts at getting this to work I have eliminated the following approaches 1) Create a Sql Assembly to call the local COM+ directly -- Can't do this as it requires a reference to System.EnterpriseServices. Including this requires that a whole slew of unsupported assemblies be registered which I don't want. The COM+ requires it's methods to be accessed via an Interface, so my attempts at late binding to it directly have not been successful (late binding would allow me to drop the unsupported references). 2) Create a Sql Assembly which references a C# class library that then calls the COM+. -- Same issue as #1; since the referenced dll uses System.EnterpriseServices and will be added as a dependency when referenced in the Sql Assembly, again trying to load all the unsupported libraries 3) Create a Sql Assembly which late binds to an ActiveX COM dll that calls the COM+. -- Worked in my dev environment, but can't go to x64 in production with ActiveX dll's written in VB6 (not to mention I hate backtracking anyway)... again failure... I am now onto an approach that is almost working, with of course one last hangup. I now have -a Sql Assembly that late binds to a C# COM dll, eliminating the need for including System.EnterpriseServices and eliminating the need to reference the C# COM in the SqlAssembly itself. The C# COM does reference System.EnterpriseServices to call the COM+, but since I am late binding to it from the SqlAssembly, I bypass the need for Sql to actually load them as referenced assemblies. Works in debugger.. Works on my dev box when the SqlAssembly dll is referenced in a test console app and called directly Installs to Sql2008 just fine Executing the actual UDF works, but returns no data due to a failure reporting from the late bound dll! So the SqlAssembly is instanciated just fine. It actually fails on it's late binding to the C# COM, which is working from a test console app on the same machine. It appears to be a difference in behavior based on whether called from within the SQL UDF or not. Since it is working on the same box from my console app, I am assuming it's on the SQL side. My steps to install were. --Install the COM+ dll and ensure it can be called successfully (as from with in the console app) --Register the C# COM dll (which calls the COM+) and get it to the GAC (again proofed to be working from console app) --Create my Assymetric Key CREATE ASYMMETRIC KEY SqlCryptoKey FROM EXECUTABLE FILE = 'D:\SqlEx.dll' CREATE LOGIN SqlExLogin FROM ASYMMETRIC KEY SqlExKey GRANT UNSAFE ASSEMBLY TO SqlExLogin GO --Add the assembly CREATE ASSEMBLY SqlEx FROM 'D:\SqlEx.dll' WITH PERMISSION_SET = UNSAFE; GO --Create the function CREATE FUNCTION dbo.f_SqlEx( @clearText [nvarchar](512) ) RETURNS nvarchar(512) WITH EXECUTE AS CALLER AS EXTERNAL NAME SqlEx.[SqlEx.SqlEx].Ex GO With all that done, I can now call my function SELECT dbo.f_SqlEx('test') But get this error in the event log... Retrieving the COM class factory for component with CLSID {F69D6320-5884-323F-936A-7657946604BE} failed due to the following error: 80131051. I can't really provide direct code examples, due to internal security implications; but all the code itself seems to work, I am suspecting perms or something of the like... I just find it odd that I can't find any reference to error 80131051. If someone out there believe some 'indirect' code samples will help, I will be happy to provide. Any assistance is appreciated.

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  • The last MVVM you'll ever need?

    - by Nuri Halperin
    As my MVC projects mature and grow, the need to have some omnipresent, ambient model properties quickly emerge. The application no longer has only one dynamic pieced of data on the page: A sidebar with a shopping cart, some news flash on the side – pretty common stuff. The rub is that a controller is invoked in context of a single intended request. The rest of the data, even though it could be just as dynamic, is expected to appear on it's own. There are many solutions to this scenario. MVVM prescribes creating elaborate objects which expose your new data as a property on some uber-object with more properties exposing the "side show" ambient data. The reason I don't love this approach is because it forces fairly acute awareness of the view, and soon enough you have many MVVM objects laying around, and views have to start doing null-checks in order to ensure you really supplied all the values before binding to them. Ick. Just as unattractive is the ViewData dictionary. It's not strongly typed, and in both this and the MVVM approach someone has to populate these properties – n'est pas? Where does that live? With MVC2, we get the formerly-futures  feature Html.RenderAction(). The feature allows you plant a line in a view, of the format: <% Html.RenderAction("SessionInterest", "Session"); %> While this syntax looks very clean, I can't help being bothered by it. MVC was touting a very strong separation of concerns, the Model taking on the role of the business logic, the controller handling route and performing minimal view-choosing operations and the views strictly focused on rendering out angled-bracket tags. The RenderAction() syntax has the view calling some controller and invoking it inline with it's runtime rendering. This – to my taste – embeds too much  knowledge of controllers into the view's code – which was allegedly forbidden.  The one way flow "Controller Receive Data –> Controller invoke Model –> Controller select view –> Controller Hand data to view" now gets a "View calls controller and gets it's own data" which is not so one-way anymore. Ick. I toyed with some other solutions a bit, including some base controllers, special view classes etc. My current favorite though is making use of the ExpandoObject and dynamic features with C# 4.0. If you follow Phil Haack or read a bit from David Heyden you can see the general picture emerging. The game changer is that using the new dynamic syntax, one can sprout properties on an object and make use of them in the view. Well that beats having a bunch of uni-purpose MVVM's any day! Rather than statically exposed properties, we'll just use the capability of adding members at runtime. Armed with new ideas and syntax, I went to work: First, I created a factory method to enrich the focuse object: public static class ModelExtension { public static dynamic Decorate(this Controller controller, object mainValue) { dynamic result = new ExpandoObject(); result.Value = mainValue; result.SessionInterest = CodeCampBL.SessoinInterest(); result.TagUsage = CodeCampBL.TagUsage(); return result; } } This gives me a nice fluent way to have the controller add the rest of the ambient "side show" items (SessionInterest, TagUsage in this demo) and expose them all as the Model: public ActionResult Index() { var data = SyndicationBL.Refresh(TWEET_SOURCE_URL); dynamic result = this.Decorate(data); return View(result); } So now what remains is that my view knows to expect a dynamic object (rather than statically typed) so that the ASP.NET page compiler won't barf: <%@ Page Language="C#" Title="Ambient Demo" MasterPageFile="~/Views/Shared/Ambient.Master" Inherits="System.Web.Mvc.ViewPage<dynamic>" %> Notice the generic ViewPage<dynamic>. It doesn't work otherwise. In the page itself, Model.Value property contains the main data returned from the controller. The nice thing about this, is that the master page (Ambient.Master) also inherits from the generic ViewMasterPage<dynamic>. So rather than the page worrying about all this ambient stuff, the side bars and panels for ambient data all reside in a master page, and can be rendered using the RenderPartial() syntax: <% Html.RenderPartial("TagCloud", Model.SessionInterest as Dictionary<string, int>); %> Note here that a cast is necessary. This is because although dynamic is magic, it can't figure out what type this property is, and wants you to give it a type so its binder can figure out the right property to bind to at runtime. I use as, you can cast if you like. So there we go – no violation of MVC, no explosion of MVVM models and voila – right? Well, I could not let this go without a tweak or two more. The first thing to improve, is that some views may not need all the properties. In that case, it would be a waste of resources to populate every property. The solution to this is simple: rather than exposing properties, I change d the factory method to expose lambdas - Func<T> really. So only if and when a view accesses a member of the dynamic object does it load the data. public static class ModelExtension { // take two.. lazy loading! public static dynamic LazyDecorate(this Controller c, object mainValue) { dynamic result = new ExpandoObject(); result.Value = mainValue; result.SessionInterest = new Func<Dictionary<string, int>>(() => CodeCampBL.SessoinInterest()); result.TagUsage = new Func<Dictionary<string, int>>(() => CodeCampBL.TagUsage()); return result; } } Now that lazy loading is in place, there's really no reason not to hook up all and any possible ambient property. Go nuts! Add them all in – they won't get invoked unless used. This now requires changing the signature of usage on the ambient properties methods –adding some parenthesis to the master view: <% Html.RenderPartial("TagCloud", Model.SessionInterest() as Dictionary<string, int>); %> And, of course, the controller needs to call LazyDecorate() rather than the old Decorate(). The final touch is to introduce a convenience method to the my Controller class , so that the tedium of calling Decorate() everywhere goes away. This is done quite simply by adding a bunch of methods, matching View(object), View(string,object) signatures of the Controller class: public ActionResult Index() { var data = SyndicationBL.Refresh(TWEET_SOURCE_URL); return AmbientView(data); } //these methods can reside in a base controller for the solution: public ViewResult AmbientView(dynamic data) { dynamic result = ModelExtension.LazyDecorate(this, data); return View(result); } public ViewResult AmbientView(string viewName, dynamic data) { dynamic result = ModelExtension.LazyDecorate(this, data); return View(viewName, result); } The call to AmbientView now replaces any call the View() that requires the ambient data. DRY sattisfied, lazy loading and no need to replace core pieces of the MVC pipeline. I call this a good MVC day. Enjoy!

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