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• Excel Solver vs Solver Foundation

  - by JoshReuben

  I recently read a book http://www.amazon.com/Scientific-Engineering-Cookbook-Cookbooks-OReilly/dp/0596008791/ref=sr_1_1?ie=UTF8&s=books&qid=1296593374&sr=8-1 - the Excel Scientific and Engineering Cookbook.     The 2 main tools that this book leveraged were the Data Analysis Pack and Excel Solver. I had previously been aquanted with Microsoft Solver Foundation - this is a full fledged API for solving optimization problems, and went beyond being a mere Excel plugin - it exposed a C# programmatic interface for in process and a web service interface for out of process integration. were they the same? apparently not!   2 different solver frameworks for Excel: http://www.solver.com/index.html http://www.solverfoundation.com/ I contacted both vendors to get their perspectives.   Heres what the Excel Solver guys had to say:   "The Solver Foundation requires you to learn and use a very specific modeling language (OML). The Excel solver allows you to formulate your optimization problems without learning any new language simply by entering the formulas into cells on the Excel spreadsheet, something that nearly everyone is already familiar with doing.   The Excel Solver also allows you to seamlessly upgrade to products that combine Monte Carlo Simulation capabilities (our Risk Solver Premium and Risk Solver Platform products) which allow you to include uncertainty into your models when appropriate.   Our advanced Excel Solver Products also have a number of built in reporting tools for advanced analysis of the your model and it's results"           And Heres what the Microsoft Solver Foundation guys had to say:   "  With the release of Solver Foundation 3.0, Solver Foundation has the same kinds of solvers (plus a few more) than what is found in Excel Solver. I think there are two main differences:   1.      Problems are described differently. In Excel Solver the goals and constraints are specified inside the spreadsheet, in formulas. In Solver Foundation they are described either in .Net code that uses the Solver Foundation Services API, or using the OML modeling language in Excel. 2.      Solver Foundation’s primary strength is on solving large linear, mixed integer, and constraint models. That is, models that contain arbitrary nonlinear functions (such as trig functions, IF(), powers, etc) are handled a bit better by the Excel Solver at this point. "

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• SQL Saturday #162 Cambridge

  - by Most Valuable Yak (Rob Volk)

  Despite the efforts of American Airlines, this past weekend I attended the first SQL Saturday in the UK!  Hosted by the SQLCambs Chapter of PASS and organized by Mark (b|t) & Lorraine Broadbent, ably assisted by John Martin (b|t), Mark Pryce-Maher (b|t) and other folks whose names I've unfortunately forgotten, it was held at the Crowne Plaza Hotel, which is completely surrounded by Cambridge University. On Friday, they presented 3 pre-conference sessions given by the brilliant American Cloud & DBA Guru, Buck Woody (b|t), the brilliant Danish SQL Server Internals Guru, Mark Rasmussen (b|t), and the brilliant Scottish Business Intelligence Guru and recent Outstanding Pass Volunteer, Jen Stirrup (b|t).  While I would have loved to attend any of their pre-cons (having seen them present several times already), finances and American Airlines ultimately made that impossible.  But not to worry, I caught up with them during the regular sessions and at the speaker dinner.  And I got back the money they all owed me.  (Actually I owed Mark some money) The schedule was jam-packed even with only 4 tracks, there were 8 regular slots, a lunch session for sponsor presentations, and a 15 minute keynote given by Buck Woody, who besides giving an excellent history of SQL Server at Microsoft (and before), also explained the source of the "unknown contact" image that appears in Outlook.  Hint: it's not Buck himself. Amazingly, and against all better judgment, I even got to present at SQL Saturday 162!  I did a 5 minute Lightning Talk on Regular Expressions in SSMS.  I then did a regular 50 minute session on Constraints.  You can download the content for the regular session at that link, and for the regular expression presentation here. I had a great time and had a great audience for both of my sessions.  You would never have guessed this was the first event for the organizers, everything went very smoothly, especially for the number of attendees and the relative smallness of the space.  The event sponsors also deserve a lot of credit for making themselves fit in a small area and for staying through the entire event until the giveaways at the very end. Overall this was one of the best SQL Saturdays I've ever attended and I have to congratulate Mark B, Lorraine, John, Mark P-M, and all the volunteers and speakers for making this an astoundingly hard act to follow!  Well done!

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• VSDB to SSDT Part 1 : Converting projects and trimming excess files

  - by Etienne Giust

  Visual Studio 2012 introduces a change regarding Database Projects : they now use the SSDT technology, which means old VS2010 database projects (VSDB projects) need to be converted. Hopefully, VS2012 does that for you and it is quite painless, but in my case some unnecessary artifacts from the old project were left in place.  Also, when reopening the solution, database projects appeared unconverted even if I had converted them in the previous session and saved the solution.   Converting the project(s) When opening your Visual Studio 2010 solution with Visual Studio 2012, every standard project should be converted by default, but Visual Studio will ask you about your database projects : “Functional changes required Visual Studio will automatically make functional changes to the following projects in order to open them. The project behavior will change as a result. You will be able to open these projects in this version and Visual Studio 2010 SP1.” If you accept, your project is converted. And it should compile with no errors right away except if you have dependencies to dbschema files which are no longer supported.   The output of a SSDT project is a dacpac file which replaces the dbschema file you were accustomed to. References to dacpac files can be added to SSDT projects in the same fashion references to dbschema could be added to VSDB projects.   Cleaning up You will notice that your project file is now a sqlproj file but the old dbproj is still here. In fact at that point you can still reopen the solution in Visual Studio 2010 and everything should show up.   If like me you plan on using VS2012 exclusively, you can get rid of the following files which are still on your disk and in your source control : the dbproj and dbproj.vspscc files Properties/Database.sqlcmdvars Properties/Database.sqldeployment Properties/Database.sqlpermissions Properties/Database.sqlsettings   You might wonder where the information which used to be in the Properties files is now stored. Permissions : a Permissions.sql was created at the root level of your project. Note that when you create a new database project and import a database using the Schema Compare capabilities from Visual Studio, imported table and stored procedure definition files will hold the permission information (along with constraints and, indexes) SQLVars : they are defined inside the publish.xml files Deployment : they are also in the publish.xml files Settings : I was unable to find where those are now. I suppose they are not defined anymore   But Visual Studio still says my database projects should be converted ! I had this error upon closing and then re-opening the solution : my database projects would appear unconverted even though I did all the necessary steps previously.   Easy solution : remove those projects from the solution and add them again (the sqlproj files).   More For those who run into problems when converting from VSDB to SSDT, I suggest reading the following post : http://blogs.msdn.com/b/ssdt/archive/2011/11/21/top-vsdb-gt-ssdt-project-conversion-issues.aspx   Also interesting, is a side by side comparison of VSDB and SSDT project features : http://blogs.msdn.com/b/ssdt/archive/2011/11/21/sql-server-data-tools-ctp4-vs-vs2010-database-projects.aspx

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• Altering a Column Which has a Default Constraint

  - by Dinesh Asanka

  Setting up a default column is a common task for  developers.  But, are we naming those default constraints explicitly? In the below  table creation, for the column, sys_DateTime the default value Getdate() will be allocated. CREATE TABLE SampleTable (ID int identity(1,1), Sys_DateTime Datetime DEFAULT getdate() ) We can check the relevant information from the system catalogs from following query. SELECT sc.name TableName, dc.name DefaultName, dc.definition, OBJECT_NAME(dc.parent_object_id) TableName, dc.is_system_named  FROM sys.default_constraints dc INNER JOIN sys.columns sc ON dc.parent_object_id = sc.object_id AND dc.parent_column_id = sc.column_id and results would be: Most of the above columns are self-explanatory. The last column, is_system_named, is to identify whether the default name was given by the system. As you know, in the above case, since we didn’t provide  any default name, the  system will generate a default name for you. But the problem with these names is that they can differ from environment to environment.  If example if I create this table in different table the default name could be DF__SampleTab__Sys_D__7E6CC920 Now let us create another default and explicitly name it: CREATE TABLE SampleTable2 (ID int identity(1,1), Sys_DateTime Datetime )   ALTER TABLE SampleTable2 ADD CONSTRAINT DF_sys_DateTime_Getdate DEFAULT( Getdate()) FOR Sys_DateTime If we run the previous query again we will be returned the below output. And you can see that last created default name has 0 for is_system_named. Now let us say I want to change the data type of the sys_DateTime column to something else: ALTER TABLE SampleTable2 ALTER COLUMN Sys_DateTime Date This will generate the below error: Msg 5074, Level 16, State 1, Line 1 The object ‘DF_sys_DateTime_Getdate’ is dependent on column ‘Sys_DateTime’. Msg 4922, Level 16, State 9, Line 1 ALTER TABLE ALTER COLUMN Sys_DateTime failed because one or more objects access this column. This means, you need to drop the default constraint before altering it: ALTER TABLE [dbo].[SampleTable2] DROP CONSTRAINT [DF_sys_DateTime_Getdate] ALTER TABLE SampleTable2 ALTER COLUMN Sys_DateTime Date   ALTER TABLE [dbo].[SampleTable2] ADD CONSTRAINT [DF_sys_DateTime_Getdate] DEFAULT (getdate()) FOR [Sys_DateTime] If you have a system named default constraint that can differ from environment to environment and so you cannot drop it as before, you can use the below code template: DECLARE @defaultname VARCHAR(255) DECLARE @executesql VARCHAR(1000)   SELECT @defaultname = dc.name FROM sys.default_constraints dc INNER JOIN sys.columns sc ON dc.parent_object_id = sc.object_id AND dc.parent_column_id = sc.column_id WHERE OBJECT_NAME (parent_object_id) = 'SampleTable' AND sc.name ='Sys_DateTime' SET @executesql = 'ALTER TABLE SampleTable DROP CONSTRAINT ' + @defaultname EXEC( @executesql) ALTER TABLE SampleTable ALTER COLUMN Sys_DateTime Date ALTER TABLE [dbo].[SampleTable] ADD DEFAULT (Getdate()) FOR [Sys_DateTime]

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• Where would my different development rhythm be suitable for the work?

  - by DarenW

  Over the years I have worked on many projects, with some successful and a great benefit to the company, and some total failures with me getting fired or otherwise leaving. What is the difference? Naturally I prefer the former and wish to avoid the latter, so I'm pondering this issue. The key seems to be that my personal approach differs from the norm. I write code first, letting it be all spaghetti and chaos, using whatever tools "fit my hand" that I'm fluent in. I try to organize it, then give up and start over with a better design. I go through cycles, from thinking-design to coding-testing. This may seem to be the same as any other development process, Agile or whatever, cycling between design and coding, but there does seem to be a subtle difference: The methods (ideally) followed by most teams goes design, code; design, code; ... while I'm going code, design; code, design; (if that makes any sense.) Music analogy: some types of music have a strong downbeat while others have prominent syncopation. In practice, I just can't think in terms of UML, specifications and so on, but grok things only by attempting to code and debug and refactor ad-hoc. I need the grounding provided by coding in order to think constructively, then to offer any opinions, advice or solutions to the team and get real work done. In positions where I can initially hack up cowboy code without constraints of tool or language choices, I easily gain a "feel" for the data, requirements etc and eventually do good work. In formalized positions where paperwork and pure "design" comes first and only later any coding (even for small proof-of-concept projects), I am lost at sea and drown. Therefore, I'd like to know how to either 1) change my rhythm to match the more formalized methodology-oriented team ways of doing things, or 2) find positions at organizations where my sense of development rhythm is perfect for the work. It's probably unrealistic for a person to change their fundamental approach to things. So option 2) is preferred. So where I can I find such positions? How common is my approach and where is it seen as viable but different, and not dismissed as undisciplined or cowboy coder ways?

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• What source code organization approach helps improve modularity and API/Implementation separation?

  - by Berin Loritsch

  Few languages are as restrictive as Java with file naming standards and project structure. In that language, the file name must match the public class declared in the file, and the file must live in a directory structure matching the class package. I have mixed feelings about that approach. While I never have to guess where a file lives, there's still a lot of empty directories and artificial constraints. There's several languages that define everything about a class in one file, at least by convention. C#, Python (I think), Ruby, Erlang, etc. The commonality in most these languages is that they are object oriented, although that statement can probably be rebuffed (there is one non-OO language in the list already). Finally, there's quite a few languages mostly in the C family that have a separate header and implementation file. For C I think this makes sense, because it is one of the few ways to separate the API interface from implementations. With C it seems that feature is used to promote modularity. Yet, with C++ the way header and implementation files are split seems rather forced. You don't get the same clean API separation that you do with C, and you are forced to include some private details in the header you would rather keep only in the implementation. There's quite a few languages that have a concept that overlaps with interfaces like Java, C#, Go, etc. Some languages use what feels like a hack to provide the same concept like C# using pure virtual abstract classes. Still others don't really have an interface concept and rely on "duck" typing--for example Ruby. Ruby has modules, but those are more along the lines of mixing in behaviors to a class than they are for defining how to interact with a class. In OO terms, interfaces are a powerful way to provide separation between an API client and an API implementation. So to hurry up and ask the question, from a personal experience point of view: Does separation of header and implementation help you write more modular code, or does it get in the way? (it helps to specify the language you are referring to) Does the strict file name to class name scheme of Java help maintainability, or is it unnecessary structure for structure's sake? What would you propose to promote good API/Implementation separation and project maintenance, how would you prefer to do it?

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• Is there an appropriate coding style for implementing an algorithm during an interview?

  - by GlenPeterson

  I failed an interview question in C years ago about converting hex to decimal by not exploiting the ASCII table if (inputDigitByte > 9) hex = inputDigitByte - 'a'. The rise of Unicode has made this question pretty silly, but the point was that the interviewer valued raw execution speed above readability and error handling. They tell you to review algorithms textbooks to prepare for these interviews, yet these same textbooks tend to favor the implementation with the fewest lines of code, even if it has to rely on magic numbers (like "infinity") and a slower, more memory-intensive implementation (like a linked list instead of an array) to do that. I don't know what is right. Coding an algorithm within the space of an interview has at least 3 constraints: time to code, elegance/readability, and efficiency of execution. What trade-offs are appropriate for interview code? How much do you follow the textbook definition of an algorithm? Is it better to eliminate recursion, unroll loops, and use arrays for efficiency? Or is it better to use recursion and special values like "infinity" or Integer.MAX_VALUE to reduce the number of lines of code needed to write the algorithm? Interface: Make a very self-contained, bullet-proof interface, or sloppy and fast? On the one extreme, the array to be sorted might be a public static variable. On the other extreme, it might need to be passed to each method, allowing methods to be called individually from different threads for different purposes. Is it appropriate to use a linked-list data structure for items that are traversed in one direction vs. using arrays and doubling the size when the array is full? Implementing a singly-linked list during the interview is often much faster to code and easier remember for recursive algorithms like MergeSort. Thread safety - just document that it's unsafe, or say so verbally? How much should the interviewee be looking for opportunities for parallel processing? Is bit shifting appropriate? x / 2 or x >> 1 Polymorphism, type safety, and generics? Comments? Variable and method names: qs(a, p, q, r) vs: quickSort(theArray, minIdx, partIdx, maxIdx) How much should you use existing APIs? Obviously you can't use a java.util.HashMap to implement a hash-table, but what about using a java.util.List to accumulate your sorted results? Are there any guiding principals that would answer these and other questions, or is the guiding principal to ask the interviewer? Or maybe this should be the basis of a discussion while writing the code? If an interviewer can't or won't answer one of these questions, are there any tips for coaxing the information out of them?

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• How to port animation from one skeleton to another?

  - by shawn

  While I need to do this in a Blender3D modeler script, the math should be similar for other modelers or realtime engines. Blender3D specific terminology: Armature = skeleton EditBone = rest pose bone (stores the rest pose matrix) PoseBone = can store a different pose (animation matrix) for each frame of your animation I need to share animations (Blender Actions) between Armatures which have EditBones with same names and which have the same positions, but can have different (rest pose) angles and scales. Plus the Armatures might have different bone hierarchy (bone parenting/ no bone parenting). Why I need this: I've made an importer/exporter for a 3d format for a game. The format doesn't store enough info to connect/parent the bones, which makes posing/animating character models in a 3d modeller nearly impossible (original model files for the 3d modeler don't exist, this is for modding). As there are only 2 character skeleton types in the game, I decided to optionally allow to generate the bone from a hardcoded data in the model importer and undo that in the exporter. This allows to easily pose the model for checking weights, easily create weights, makes it easier for Blender to generate automatic weights and of course makes animating possible. This worked perfectly: the importer optionally generated the Armature itself and the exporter removed those changes, so the exported model works with existing animations in the game. But now I'm writing an importer and exporter for the game's animation format and here come the problems of: Trying to make original animations work in Blender with my "custom" (modified) Armature Trying to make animations created by using the "custom" (modified) Armature work with the original models in the game (and Blender). Constraints or bone snapping inside Blender won't work as they don't care that the bones have different angles in the rest pose, they will still face the same direction. It seems I just need to get the "difference" between the EditBone matrices of all EditBones for the two Armatures somehow and apply that difference to PoseBone matrices of all PoseBones, for all frames of my animation. I need to know how to get that difference and how to apply it. BTW, PoseBone matrices are relative to rest pose, they are by default [1.000000, 0.000000, 0.000000, 0.000000](matrix [row 0]) [0.000000, 1.000000, 0.000000, 0.000000](matrix [row 1]) [0.000000, 0.000000, 1.000000, 0.000000](matrix [row 2]) [0.000000, 0.000000, 0.000000, 1.000000](matrix [row 3]) So the question is: How to get the difference between two bone (EditBone) matrices to apply that difference to the animation matrices (PoseBone matrices)? Please be easy on the matrix math.

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• Exit Infragistics, Enter Telerik

  - by Anthony Trudeau

  Today I made the purchase of the Premium Collection of components from Telerik.  This follows an evaluation I’ve been doing to replace the Infragistics components we currently use for Windows Forms, ASP.NET MVC, and WPF. It was not a formal evaluation.  I had already decided to move the company away from Infragistics.  That decision was mostly born out of frustration with support over using the Infragistics components in my first production MVC application. One such issue was a simple scenario where you have a model that has a scalar property that can be one value out of a list.  The built-in combobox does this, but I was told by Infragistics support that they didn’t support it – and it took them several emails and days of waiting between responses to determine that.  I implemented this in Telerik in a minute not including the several minutes it took me to get a rudimentary understanding for the component and its API. Here’s the code using the built-in combobox:@Html.DropDownListFor(x => x.VendorId, new SelectList(ViewBag.Vendors, "VendorId", "VendorName", Model.VendorId), "Select Id") Here’s the code using the Telerik combobox:@(Html.Telerik().ComboBoxFor(model => model.VendorId) .AutoFill(true) .BindTo(new SelectList(ViewBag.Vendors, "VendorId", "VendorName", Model.VendorId)) )   I chose Telerik over other competitors based on the professional appearance of their website, and how easy it was to find information.  I’d like to say I had time to evaluate other Infragistics competitors.  Due to time constraints I had to make an initial decision based on superficial, but still important things. I picked Telerik with the plan to only look further at other companies if my evaluation didn’t meet my expectations.  Luckily they did, because I didn’t relish the thought of carving out more time to evaluate another set of components. Overall my experience with Telerik has been superior to Infragistics in every way.  The installation was easy using their control panel installer application.  Getting up to speed has been easy.  And the communication from Telerik has met my expectations.  And we’ll continue to be good as long as I don’t start getting email messages from a sales rep saying that they want to talk to me about training and consulting – I’m looking at you Infragistics.

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• Is reliance on parametrized queries the only way to protect against SQL injection?

  - by Chris Walton

  All I have seen on SQL injection attacks seems to suggest that parametrized queries, particularly ones in stored procedures, are the only way to protect against such attacks. While I was working (back in the Dark Ages) stored procedures were viewed as poor practice, mainly because they were seen as less maintainable; less testable; highly coupled; and locked a system into one vendor; (this question covers some other reasons). Although when I was working, projects were virtually unaware of the possibility of such attacks; various rules were adopted to secure the database against corruption of various sorts. These rules can be summarised as: No client/application had direct access to the database tables. All accesses to all tables were through views (and all the updates to the base tables were done through triggers). All data items had a domain specified. No data item was permitted to be nullable - this had implications that had the DBAs grinding their teeth on occasion; but was enforced. Roles and permissions were set up appropriately - for instance, a restricted role to give only views the right to change the data. So is a set of (enforced) rules such as this (though not necessarily this particular set) an appropriate alternative to parametrized queries in preventing SQL injection attacks? If not, why not? Can a database be secured against such attacks by database (only) specific measures? EDIT Emphasis of the question changed slightly, in the light of the initial responses received. Base question unchanged. EDIT2 The approach of relying on paramaterized queries seems to be only a peripheral step in defense against attacks on systems. It seems to me that more fundamental defenses are both desirable, and may render reliance on such queries not necessary, or less critical, even to defend specifically against injection attacks. The approach implicit in my question was based on "armouring" the database and I had no idea whether it was a viable option. Further research has suggested that there are such approaches. I have found the following sources that provide some pointers to this type of approach: http://database-programmer.blogspot.com http://thehelsinkideclaration.blogspot.com The principle features I have taken from these sources is: An extensive data dictionary, combined with an extensive security data dictionary Generation of triggers, queries and constraints from the data dictionary Minimize Code and maximize data While the answers I have had so far are very useful and point out difficulties arising from disregarding paramaterized queries, ultimately they do not answer my original question(s) (now emphasised in bold).

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• Canonicalization issue regarding academic URL vs. blog URL

  - by user5395

  I'm sorry if what I am about to write is long-winded. I only wish to be clear. I am an academic in the scientific community. I maintain a web site for my research, teaching, and other professional activities. Until recently, the content for this site was hosted in a directory on my university department's own server. The address is of the typical form (universityname).edu/~(myusername) I decided that I wanted to use WordPress in order to host and manage my page. So I set up a WordPress.com blog and then replaced the index.html file in (universityname).edu/~(myusername) with a new one consisting of a single frame, containing the WordPress.com blog. Now when a user visits (universityname).edu/~(myusername), he or she sees the blog instead. This has been pretty nice because, even when the user clicks on links between pages or posts in the blog, the only thing showing up in the address bar of the browser is www.(universityname).edu/~(myusername), because the blog is constrained to a frame. However, the effect of this change on the search side of things has not been so kind to me. Before, when someone searched for my name in Google, the first result was always (universityname).edu/~(myusername). This is the most desirable outcome, for professional reasons. (Having my academic URL come up first suggests that I am an accredited professional, and not just some crank with a blog!) But now, Google seems to have canonicalized my web presence under the blog's WordPress.com address. It has completely forgotten about my academic URL and considers the WordPress.com address to be the best address representing me on the web. Unfortunately, WordPress.com doesn't support the canonical tag, so I can't tell the blog to advertise itself as my academic URL in the header. (It doesn't seem to help at all that I have used the WordPress.com dashboard to turn on no-indexing of the blog.) One obvious solution would be to use the departmental server to host my content again, and use a local installation of the WordPress platform. For reasons beyond my control, the platform will not be deployed on the departmental server at this time. Another solution would be to use shared hosting with WordPress.org support, because the WordPress.org platform does support the canonical tag (albeit via a plug-in). But this seems to usually require purchasing a domain name and other fees, and there is no guarantee that Google will listen to the canonical tag (it might use whatever domain name I end up with instead). Is there a way I can more cleverly integrate the WordPress.com blog into a page hosted on my department's server? Is there some PHP code I can write to retrieve the blog's contents in a way that Google won't treat as a link / "perceive" the blog? Please note: I am a PHP novice at best. I just feel there should be a simpler solution to all this, within the constraints of what I have described above. Thanks!

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• Throwing exception from a property when my object state is invalid

  - by Rumi P.

  Microsoft guidelines say: "Avoid throwing exceptions from property getters", and I normally follow that. But my application uses Linq2SQL, and there is the case where my object can be in invalid state because somebody or something wrote nonsense into the database. Consider this toy example: [Table(Name="Rectangle")] public class Rectangle { [Column(Name="ID", IsPrimaryKey = true, IsDbGenerated = true)] public int ID {get; set;} [Column(Name="firstSide")] public double firstSide {get; set;} [Column(Name="secondSide")] public double secondSide {get; set;} public double sideRatio { get { return firstSide/secondSide; } } } Here, I could write code which ensures that my application never writes a Rectangle with a zero-length side into the database. But no matter how bulletproof I make my own code, somebody could open the database with a different application and create an invalid Rectangle, especially one with a 0 for secondSide. (For this example, please forget that it is possible to design the database in a way such that writing a side length of zero into the rectangle table is impossible; my domain model is very complex and there are constraints on model state which cannot be expressed in a relational database). So, the solution I am gravitating to is to change the getter to: get { if(firstSide > 0 && secondSide > 0) return firstSide/secondSide; else throw new System.InvalidOperationException("All rectangle sides should have a positive length"); } The reasoning behind not throwing exceptions from properties is that programmers should be able to use them without having to make precautions about catching and handling them them. But in this case, I think that it is OK to continue to use this property without such precautions: if the exception is thrown because my application wrote a non-zero rectangle side into the database, then this is a serious bug. It cannot and shouldn't be handled in the application, but there should be code which prevents it. It is good that the exception is visibly thrown, because that way the bug is caught. if the exception is thrown because a different application changed the data in the database, then handling it is outside of the scope of my application. So I can't do anything about it if I catch it. Is this a good enough reasoning to get over the "avoid" part of the guideline and throw the exception? Or should I turn it into a method after all? Note that in the real code, the properties which can have an invalid state feel less like the result of a calculation, so they are "natural" properties, not methods.

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• Is it ok to initialize an RB_ConstraintActor in PostBeginPlay?

  - by Almo

  I have a KActorSpawnable subclass that acts weird. In PostBeginPlay, I initialize an RB_ConstraintActor; the default is not to allow rotation. If I create one in the editor, it's fine, and won't rotate. If I spawn one, it rotates. Here's the class: class QuadForceKActor extends KActorSpawnable placeable; var(Behavior) bool bConstrainRotation; var(Behavior) bool bConstrainX; var(Behavior) bool bConstrainY; var(Behavior) bool bConstrainZ; var RB_ConstraintActor PhysicsConstraintActor; simulated event PostBeginPlay() { Super.PostBeginPlay(); PhysicsConstraintActor = Spawn(class'RB_ConstraintActorSpawnable', self, '', Location, rot(0, 0, 0)); if(bConstrainRotation) { PhysicsConstraintActor.ConstraintSetup.bSwingLimited = true; PhysicsConstraintActor.ConstraintSetup.bTwistLimited = true; } SetLinearConstraints(bConstrainX, bConstrainY, bConstrainZ); PhysicsConstraintActor.InitConstraint(self, None); } function SetLinearConstraints(bool InConstrainX, bool InConstrainY, bool InConstrainZ) { if(InConstrainX) { PhysicsConstraintActor.ConstraintSetup.LinearXSetup.bLimited = 1; } else { PhysicsConstraintActor.ConstraintSetup.LinearXSetup.bLimited = 0; } if(InConstrainY) { PhysicsConstraintActor.ConstraintSetup.LinearYSetup.bLimited = 1; } else { PhysicsConstraintActor.ConstraintSetup.LinearYSetup.bLimited = 0; } if(InConstrainZ) { PhysicsConstraintActor.ConstraintSetup.LinearZSetup.bLimited = 1; } else { PhysicsConstraintActor.ConstraintSetup.LinearZSetup.bLimited = 0; } } DefaultProperties { bConstrainRotation=true bConstrainX=false bConstrainY=false bConstrainZ=false bSafeBaseIfAsleep=false bNoEncroachCheck=false } Here's the code I use to spawn one. It's a subclass of the one above, but it doesn't reference the constraint at all. local QuadForceKCreateBlock BlockActor; BlockActor = spawn(class'QuadForceKCreateBlock', none, 'PowerCreate_Block', BlockLocation(), m_PreparedRotation, , false); BlockActor.SetDuration(m_BlockDuration); BlockActor.StaticMeshComponent.SetNotifyRigidBodyCollision(true); BlockActor.StaticMeshComponent.ScriptRigidBodyCollisionThreshold = 0.001; BlockActor.StaticMeshComponent.SetStaticMesh(m_ValidCreationBlock.StaticMesh); BlockActor.StaticMeshComponent.AddImpulse(m_InitialVelocity); I used to initialize an RB_ConstraintActor where I spawned it from the outside. This worked, which is why I'm pretty sure it has nothing to do with the other code in QuadForceKCreateBlock. I then added the internal constraint in QuadForceKActor for other purposes. When I realized I had two constraints on the CreateBlock doing the same thing, I removed the constraint code from the place where I spawn it. Then it started rotating. Is there a reason I should not be initializing an RB_ConstraintActor in PostBeginPlay? I feel like there's some basic thing about how the engine works that I'm missing.

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• Thoughts on schemas and schema proliferation

  - by jamiet

  In SQL Server 2005 Microsoft introduced user-schema separation and since then I have seen the use of schemas increase; whereas before I would typically see databases where all objects were in the [dbo] schema I now see databases that have multiple schemas, a database I saw recently had 31 (thirty one) of them. I can’t help but wonder whether this is a good thing or not – clearly 31 is an extreme case but I question whether multiple schemas create more problems than they solve? I have been involved in many discussions that go something like this: Developer #1> “I have a new function to add to the database and I’m not sure which schema to put it in” Developer #2> “What does it do?” Developer #1> “It provides data to a report in Reporting Services” Developer #2> “Ok, so put it in the [reports] schema” Developer #1> “Well I could, but the data will only be used by our Financial reporting folks so shouldn’t I put it in the [financial] schema?” Developer #2> “Maybe, yes” Developer #1> “Mind you, the data is supposed to be used for regulatory reporting to the FSA, should I put it in [regulatory]?” Developer #2> “Err….” You get the idea!!! The more schemas that exist in your database then the more chance that their supposed usages will overlap. I’m left wondering whether the use of schemas is actually necessary. I don’t view really see them as an aid to security because I generally believe that principles should be assigned permissions on objects as-needed on a case-by-case basis (and I have a stock SQL query that deciphers them all for me) so why bother using them at all? I can envisage a use where a database is used to house objects pertaining to many different business functions (which, in itself, is an ambiguous term) and in that circumstance perhaps a schema per business function would be appropriate; hence of late I have been loosely following this edict: If some objects in a database could be moved en masse to another database without the need to remove any foreign key constraints then those objects could legitimately exist in a dedicated schema. I am interested to know what other people’s thoughts are on this. If you would like to share then please do so in the comments. @Jamiet

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• How to handle this unfortunately non hypothetical situation with end-users?

  - by User Smith

  I work in a medium sized company but with a very small IT force. Last year (2011), I wrote an application that is very popular with a large group of end-users. We hit a deadline at the end of last year and some functionality (I will call funcA from now on) was not added into the application that was wanted at the very end. So, this application has been running in live/production since the end of 2011, I might add without issue. Yesterday, a whole group of end-users started complaining that funcA that was never in the application is no longer working. Our priority at this company is that if an application is broken it must be fixed first prior to prioritized projects. I have compared code and queries and there is no difference since 2011, which is proofA. I then was able to get one of the end-users to admit that it never worked proofB, but since then that end-user has went back and said that it was working previously......I believe the horde of end-users has assimilated her. I have also reviewed my notes for this project which has requirements and daily updates regarding the project which specifically states, "funcA not achieved due to time constraints", proofC. I have spoken with many of them and I can see where they could be confused as they are very far from a programming background, but I also know they are intelligent enough to act in a group in order to bypass project prioritization orders in order to get functionality that they want to make their job easier. The worst part is is that now group think is setting in and my boss and the head of IT is actually starting to believe them, even though there is no code or query changes. As far as reviewing the state of the logic it is very cut and dry to the point of if 1 = 1, funcA will not work. So, this is the end of the description of my scenario, but I am trying not to get severally dinged on my performance metrics due to this which would essentially have me moved to fixing a production problem that doesn't exist that will probably take over 1 month. I am looking for direct answers to this question. This question is not for rants, polling, or discussions as this is not the format for StackExchange. Please don't downvote me too terribly it is pretty common on this specific site of stack, I am looking for honest answers to this situation and I couldn't find a forum more appropriate.

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• Is code like this a "train wreck" (in violation of Law of Demeter)?

  - by Michael Kjörling

  Browsing through some code I've written, I came across the following construct which got me thinking. At a first glance, it seems clean enough. Yes, in the actual code the getLocation() method has a slightly more specific name which better describes exactly which location it gets. service.setLocation(this.configuration.getLocation().toString()); In this case, service is an instance variable of a known type, declared within the method. this.configuration comes from being passed in to the class constructor, and is an instance of a class implementing a specific interface (which mandates a public getLocation() method). Hence, the return type of the expression this.configuration.getLocation() is known; specifically in this case, it is a java.net.URL, whereas service.setLocation() wants a String. Since the two types String and URL are not directly compatible, some sort of conversion is required to fit the square peg in the round hole. However, according to the Law of Demeter as cited in Clean Code, a method f in class C should only call methods on C, objects created by or passed as arguments to f, and objects held in instance variables of C. Anything beyond that (the final toString() in my particular case above, unless you consider a temporary object created as a result of the method invocation itself, in which case the whole Law seems to be moot) is disallowed. Is there a valid reasoning why a call like the above, given the constraints listed, should be discouraged or even disallowed? Or am I just being overly nitpicky? If I were to implement a method URLToString() which simply calls toString() on a URL object (such as that returned by getLocation()) passed to it as a parameter, and returns the result, I could wrap the getLocation() call in it to achieve exactly the same result; effectively, I would just move the conversion one step outward. Would that somehow make it acceptable? (It seems to me, intuitively, that it should not make any difference either way, since all that does is move things around a little. However, going by the letter of the Law of Demeter as cited, it would be acceptable, since I would then be operating directly on a parameter to a function.) Would it make any difference if this was about something slightly more exotic than calling toString() on a standard type? When answering, do keep in mind that altering the behavior or API of the type that the service variable is of is not practical. Also, for the sake of argument, let's say that altering the return type of getLocation() is also impractical.

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• Data Model Dissonance

  - by Tony Davis

  So often at the start of the development of database applications, there is a premature rush to the keyboard. Unless, before we get there, we’ve mapped out and agreed the three data models, the Conceptual, the Logical and the Physical, then the inevitable refactoring will dog development work. It pays to get the data models sorted out up-front, however ‘agile’ you profess to be. The hardest model to get right, the most misunderstood, and the one most neglected by the various modeling tools, is the conceptual data model, and yet it is critical to all that follows. The conceptual model distils what the business understands about itself, and the way it operates. It represents the business rules that govern the required data, its constraints and its properties. The conceptual model uses the terminology of the business and defines the most important entities and their inter-relationships. Don’t assume that the organization’s understanding of these business rules is consistent or accurate. Too often, one department has a subtly different understanding of what an entity means and what it stores, from another. If our conceptual data model fails to resolve such inconsistencies, it will reduce data quality. If we don’t collect and measure the raw data in a consistent way across the whole business, how can we hope to perform meaningful aggregation? The conceptual data model has more to do with business than technology, and as such, developers often regard it as a worthy but rather arcane ceremony like saluting the flag or only eating fish on Friday. However, the consequences of getting it wrong have a direct and painful impact on many aspects of the project. If you adopt a silo-based (a.k.a. Domain driven) approach to development), you are still likely to suffer by starting with an incomplete knowledge of the domain. Even when you have surmounted these problems so that the data entities accurately reflect the business domain that the application represents, there are likely to be dire consequences from abandoning the goal of a shared, enterprise-wide understanding of the business. In reading this, you may recall experiences of the consequence of getting the conceptual data model wrong. I believe that Phil Factor, for example, witnessed the abandonment of a multi-million dollar banking project due to an inadequate conceptual analysis of how the bank defined a ‘customer’. We’d love to hear of any examples you know of development projects poleaxed by errors in the conceptual data model. Cheers, Tony

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• How can I be prepared to join a company?

  - by Aerovistae

  There's more to it than that, but this title was the best way I could think of to sum it up. I'm a senior in a good computer science program, and I'm graduating early. About to start interviews and all whatnot. I'm not a super-experienced programmer, not one of those people who started in middle school. I'm decent at this, but I'm not among the best, not nearly. I have to do an awful lot of googling. So today I'm meeting some fellow for lunch at a campus cafe to discuss some front-end details when this tall, good-looking guy begs pardon, says he's new to campus, says he's wondering if we know where he can go to sign up for recruiting developers. Quickly evolves into long conversation: he's the CEO of a seems-to-be-doing-well start-up. Hiring passionate interns and full-times. Sounds great! I take one look at his site on my own computer later, immediately spot a major bug. No idea how to fix it, but I see it. I go over to the page code, and good god. It's the standard amount of code you would expect from a full-scale web application, a couple dozen pages of HTML and scripts. I don't even know where to start reading it. I've built sites from scratch, but obviously never on that scale, nor have I ever worked on one of that scale. I have no idea which bit might generate the bug. But that sets me thinking: How could someone like me possibly settle into an environment like that? A start-up is a very high-pressure working environment. I don't know if I can work at that pace under those constraints-- I would hate to let people down. And with only 10 employees, it's not like anyone has much time to help you get your bearings. Somewhere in there is a question. Can you see it? I'm asking for general advice here. Maybe even anecdotal advice. Is joining a start-up right out of college a scary process? Am I overestimating what it would take to figure out the mass of code behind this site? What's the likelihood a decent but only moderately-experienced coder could earn his pay at such a place? For instance, I know nothing of server-side/back-end programming. Never touched it. That scares me.

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• Why can't the IT industry deliver large, faultless projects quickly as in other industries?

  - by MainMa

  After watching National Geographic's MegaStructures series, I was surprised how fast large projects are completed. Once the preliminary work (design, specifications, etc.) is done on paper, the realization itself of huge projects take just a few years or sometimes a few months. For example, Airbus A380 "formally launched on Dec. 19, 2000", and "in the Early March, 2005", the aircraft was already tested. The same goes for huge oil tankers, skyscrapers, etc. Comparing this to the delays in software industry, I can't help wondering why most IT projects are so slow, or more precisely, why they cannot be as fast and faultless, at the same scale, given enough people? Projects such as the Airbus A380 present both: Major unforeseen risks: while this is not the first aircraft built, it still pushes the limits if the technology and things which worked well for smaller airliners may not work for the larger one due to physical constraints; in the same way, new technologies are used which were not used yet, because for example they were not available in 1969 when Boeing 747 was done. Risks related to human resources and management in general: people quitting in the middle of the project, inability to reach a person because she's on vacation, ordinary human errors, etc. With those risks, people still achieve projects like those large airliners in a very short period of time, and despite the delivery delays, those projects are still hugely successful and of a high quality. When it comes to software development, the projects are hardly as large and complicated as an airliner (both technically and in terms of management), and have slightly less unforeseen risks from the real world. Still, most IT projects are slow and late, and adding more developers to the project is not a solution (going from a team of ten developer to two thousand will sometimes allow to deliver the project faster, sometimes not, and sometimes will only harm the project and increase the risk of not finishing it at all). Those which are still delivered may often contain a lot of bugs, requiring consecutive service packs and regular updates (imagine "installing updates" on every Airbus A380 twice per week to patch the bugs in the original product and prevent the aircraft from crashing). How can such differences be explained? Is it due exclusively to the fact that software development industry is too young to be able to manage thousands of people on a single project in order to deliver large scale, nearly faultless products very fast?

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• Oredev 2012: Summary and source code

  - by Laurent Bugnion

  This week, I had the pleasure to be invited to talk at Oredev, a really cool conference taking place in Malmo, Sweden. The whole event is awesome, including a very special dinner on Monday including sauna and swimming in a 6 degrees cold Baltic sea, and a reception with dinner at the town hall, including the mayor himself. Considering Malmo is a town of 300'000 inhabitants, it is a pretty nice occasion and the historical building itself is really worth seeing. For those interested, I placed my pictures on my Flickr account. I had a workshop on Tuesday morning about Windows 8 development with XAML/C#, and then a session on Wednesday about MVVM in Windows Phone 8 and Windows 8, of course using MVVM Light. I was very nervous because I reworked some of my demos as recently as this morning, in the wake of the Build conference last week and the release of both the Windows Phone SDK and MVVM Light V4.1. Everything went well however, and if I judge by the people I talked t after the talk, and Twitter, everything went pretty well. Before my talk on Tuesday, I had the pleasure to see a talk by Iris Classon (@irisclasson) on the challenges of being a "n00b" and a woman in software development. I especially appreciated her research and conclusions on the lack of women I our industry, a topic that is dear to my heart (because I want the best possible future for my two daughters, and also because I really enjoy working with women on projects, and getting a different insight on the art of software development. I really want to thank the excellent organization committee for their hard work and their fantastic welcome to Malmo. In particular Emily Holweck did a wonderful job and was super helpful throughout the preparation and the conference itself. I made a few pictures during my stay, all with the new Nokia Lumia 920, and hope you will enjoy them too. The source code and the slides… The source code is available for download from Skydrive. You will find the following: Windows 8 workshop slides. MVVM Applied slides Source code package with Win8Demo: The demo I built during the 4 hours workshop, with some light MVVM, web services (JSON), GridView, Design time data (Blend / Visual Studio designer), Bing maps integration, location sensor, Search pane integration. SemanticZoomSample: a sample I put together to demonstrate the SemanticZoom control, with two GridViews and of course full design time data for Blend work. Due to time constraints, I was not able to show this demo during the workshop, but I publish it anyway, hoping it will be useful to someone. PictureUploader: The demo I built during my 50 minutes session about MVVM Applied in Windows Phone 8 and Windows 8. Code sharing, design time data, MVVM Light are used in Windows Phone 8 and Windows 8 apps. And in video… You can also see the video of my MVVM talk thanks to the good services of the Oredev team! MVVM Applied in Windows Phone and Windows 8 from Øredev Conference on Vimeo.   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• Storing a looong lookup table

  - by inquisitive

  Background The product i am working on has a very long lookup-table. the table contains static data and cannot be auto generated. there are about 500 rows and 10 columns. columns have mostly integers and strings. to complicate the matters, there are actually two such tables. every row in table-1 maps to zero-or-more rows in table-2. we use an SQLite database with two tables. the product installer places the SQLite file in the installation directory. the application is written in dot-net and we use ADO to load the data once on startup. now, the lookup table grows. in each release a month, we add about 10 new entries existing entries are adjusted. every release we fine tune existing entries. The problem a team of (10) developers work on the lookup table. Code goes in the SVN, but the little devil the SQLite does not. this prevents multiple developers to work on it. we do take regular backups of the file, but proper versioning is not possible. we never know who did the breaking change. the worse thing is we dont know if there is any change at all. diff'ing databases is tedious if not impossible. the tables are expected to grow quite large in years to come and we would need developers to work in parallel on it. the data is business critical. we need to be able to audit changes made to it. Question What would be a solution for the problems outlines above? one idea was to transform the whole thing to XML and treat it like just another source file. that way SVN can do the versioning and we can work in parallel. but the data shows relational behavior. with XML we loose the unique and foreign-key constraints. also we cant query it with sql like ease. any help here will be appreciated.

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• Physics Engine [Collision Response, 2-dimensional] experts, help!! My stack is unstable!

  - by Register Sole

  Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based method with Projected-Gauss-Seidel (PGS) iterative solver as described by Erin Catto (mentioned in the reference of the paper as [Catt05]). So here's how it currently is: The simulation handles 2-dimensional rotating convex polygons. Detection is using separating-axis test, with a SKIN, meaning closest points between two polygons is detected and determined if their distance is less than SKIN. To resolve collision, simultaneous impulse-based method is used. It is solved using iterative solver (PGS-solver) as in Erin Catto's paper. Error-correction is implemented using Baumgarte's stabilization (you can refer to either paper for this) using J V = beta/dt*overlap, J is the Jacobian for the constraints, V the matrix containing the velocities of the bodies, beta an error-correction parameter that is better be < 1, dt the time-step taken by the engine, and overlap, the overlap between the bodies (true overlap, so SKIN is ignored). However, it is still less stable than I expected :s I tried to stack hexagons (or squares, doesn't really matter), and even with only 4 to 5 of them, they hardly stand still! Also note that I am not looking for a sleeping scheme. But I would settle if you have any explicit scheme to handle resting contacts. That said, I would be more than happy if you have a way of treating it generally (as continuous collision, instead of explicitly as a special state). Ideas I have: I would try adding a damping term (proportional to velocity) to the Baumgarte. Is this a good idea in general? If not I would not want to waste my time trying to tune the parameter hoping it magically works. Ideas I have tried: Using simultaneous position based error correction as described in the paper in section 5.3.2, turned out to be worse than the current scheme. If you want to know the parameters I used: Hexagons, side 50 (pixels) gravity 2400 (pixels/sec^2) time-step 1/60 (sec) beta 0.1 restitution 0 to 0.2 coeff. of friction 0.2 PGS iteration 10 initial separation 10 (pixels) mass 1 (unit is irrelevant for now, i modified velocity directly<-impulse method) inertia 1/1000 Thanks in advance! I really appreciate any help from you guys!! :)

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• MS NPS denying access, can't validate server certificate

  - by Fred Weston

  At my office we use a Cisco WLC2504 wireless controller and starting about a week ago we started having problems with users connecting to one of our secure wireless network. We are running AD on Windows Server 2008 R2 and use network policy server to control access to our wireless network. When I look at the logs in event viewer after a failed connection attempt I see an access reject message: Reason Code: 262 Reason: The supplied message is incomplete. The signature was not verified. Looking this up on Google I found this article: http://support.microsoft.com/kb/838502 I tried disabling server certificate validation on my computer and as soon as I did that I was able to connect to the network, so it seems that there is some sort of certificate validation issue. I'm not sure which certificate is unable to be validated or how to fix it. This used to work and stopped suddenly by itself so I am thinking a certificate may have expired. When I go to NPS Policies Network Policies My policy Constraints Auth methods Microsoft PEAP and view the properties, the certificae specified here expires in 2016, so doesn't seem as though this could be the problem. Any suggestions on how to troubleshoot this issue?

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• What good technology podcasts are out there?

  - by Michael Stum

  Yes, Podcasts, those nice little Audiobooks I can listen to on the way to work. With the current amount of Podcasts, it's like searching a needle in a haystack, except that the haystack happens to be the Internet and is filled with too many of these "Hot new Gadgets" stuff :( Now, even though I am mainly a .NET developer nowadays, maybe anyone knows some good Podcasts from people regarding the whole software lifecycle? Unit Testing, Continous Integration, Documentation, Deployment... So - what are you guys and gals listening to? Please note that the categorizations are somewhat subjective and may not be 100% accurate as many podcasts cover several areas. Categorization is made against what is considered the "main" area. General Software Engineering / Productivity Stack Overflow TekPub (Requires Paid Subscription) SE Radio 43 Folders Perspectives Dr. Dobb's (now a video feed) The Pragmatic Podcast (Inactive) IT Matters Agile Toolkit Podcast The Stack Trace (Inactive) Parleys Techzing The Startup Success Podcast Berkeley CS class lectures FOSS Weekly .NET / Visual Studio / Microsoft Herding Code Hanselminutes .NET Rocks! Deep Fried Bytes Alt.Net Podcast Polymorphic Podcast Sparkling Client (The Silverlight Podcast) dnrTV! Spaghetti Code ASP.NET Podcast Channel 9 Radio TFS PowerScripting Podcast The Thirsty Developer Elegant Code ConnectedShow Crafty Coders Coding QA jQuery yayQuery The official jQuery podcast Java / Groovy The Java Posse Grails Podcast Java Technology Insider Ruby / Rails Railscasts Rails Envy The Ruby on Rails Podcast Rubiverse Web Design / JavaScript / Ajax WebDevRadio Boagworld The Rissington podcast Ajaxian YUI Theater Unix / Linux / Mac / iPhone Mac Developer Network Hacker Public Radio Linux Outlaws Mac OS Ken LugRadio Linux radio show (Inactive) The Linux Action Show! Linux Kernel Mailing List (LKML) Summary Podcast Stanford's iPhone programming class SysAdmin, Security or Infrastructure RunAs Radio Security Now! Crypto-Gram Security Podcast Hak5 VMWare VMTN Windows Weekly PaulDotCom Security The Register - Semi-Coherent Computing FeatherCast General Tech / Business Tekzilla This Week in Tech The Guardian Tech Weekly PCMag Radio Podcast Entrepreneurship Corner Manager Tools Other / Misc. / Podcast Networks IT Conversations Retrobits Podcast No Agenda Netcast Cranky Geeks The Command Line Freelance Radio IBM developerWorks The Register - Open Season Drunk and Retired Technometria Sod This Radio4Nerds Hacker Medley

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• therubyracer on Ubuntu install issues with ruby-2.0.0-p247

  - by Victor S

  I can't seem to get therubyracer gem installed on ubuntu, i get the following errors, anyone can help? ERROR: Error installing therubyracer: ERROR: Failed to build gem native extension. /home/victorstan/.rvm/rubies/ruby-2.0.0-p247/bin/ruby extconf.rb checking for main() in -lpthread... yes creating Makefile make compiling constraints.cc compiling array.cc compiling value.cc compiling invocation.cc compiling primitive.cc compiling trycatch.cc compiling context.cc compiling exception.cc compiling template.cc compiling accessor.cc compiling object.cc compiling script.cc compiling external.cc compiling stack.cc compiling gc.cc compiling backref.cc compiling heap.cc compiling v8.cc compiling constants.cc compiling date.cc compiling function.cc compiling rr.cc compiling message.cc compiling init.cc compiling string.cc compiling handles.cc compiling signature.cc compiling locker.cc linking shared-object v8/init.so g++: /home/victorstan/.rvm/gems/ruby-2.0.0-p247@global/gems/libv8-3.11.8.17-x86_64-linux/vendor/v8/out/ia32.release/obj.target/tools/gyp/libv8_base.a: No such file or directory g++: /home/victorstan/.rvm/gems/ruby-2.0.0-p247@global/gems/libv8-3.11.8.17-x86_64-linux/vendor/v8/out/ia32.release/obj.target/tools/gyp/libv8_snapshot.a: No such file or directory make: *** [init.so] Error 1 Update It seems it's trying to use a 32 bit library instead of a 64 bit library, anyone else experience issue trying to install 64 bit applications and packages on Ubuntu, and it trying to install 32 bit version instead (even though the system is a 64 Linux)? Related: https://github.com/cowboyd/therubyracer/issues/262

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