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• How do I assign by "reference" to a class field in c#?

  - by Jamie

  I am trying to understand how to assign by "reference" to a class field in c#. I have the follwing example to consider: public class X { public X() { string example = "X"; new Y( ref example ); new Z( ref example ); System.Diagnostics.Debug.WriteLine( example ); } } public class Y { public Y( ref string example ) { example += " (Updated By Y)"; } } public class Z { private string _Example; public Z( ref string example ) { this._Example = example; this._Example += " (Updated By Z)"; } } var x = new X(); When running the above code the output is: X (Updated By Y) And not: X (Updated By Y) (Updated By Z) As I had hoped. It seems that assigning a "ref parameter" to a field loses the reference. Is there any way to keep hold of the reference when assigning to a field? Thanks.

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• Code Design question, circular reference across classes?

  - by dsollen

  I have no code here, as this is more of a design question (I assume this is still the best place to ask it). I have a very simple server in java which stores a mapping between certain values and UUID which are to be used by many systems across multiple platforms. It accepts a connection from a client and creates a clientSocket which stores the socket and all the other relevant data unique to that connection. Each clientSocket will run in their own thread and will block on the socket waiting for a read. I expect very little strain on this system, it will rarely get called, but when it does get a call it will need to respond quickly and due to the risk of it having a peak time with multiple calls coming in at once threaded is still better. Each thread has a reference to a Mapper class which stores the mapping of UUID which it's reporting to others (with proper synchronization of course). This all works until I have to add a new UUID to the list. When this happens I want to report to all clients that care about that particular UUID that a new one was added. I can't multicast (limitation of the system I'm running on) so I'm having each socket send the message to the client through the established socket. However, since each thread only knows about the socket it's waiting on I didn't have a clear method of looking up every thread/socket that cares about the data to inform them of the new UUID. Polling is out mostly because it seems a little too convoluted to try to maintain a list of newly added UUID. My solution as of now is to have the 'parent' class which creates the mapper class and spawns all the threads pass itself as an argument to the mapper. Then when the mapper creates a new UUID it can make a call to the parent class telling it to send out updates to all the other sockets that care about the change. I'm concerned that this may be a bad design due to the use of a circular reference; parent has a reference to mapper (to pass it to new ClientSocket threads) and mapper points to parent. It doesn't really feel like a bad design to me but I wanted to check since circular references are suppose to be bad. Note: I realize this means that the thread associated with whatever socket originally received the request that spawned the creation of a UUID is going to pay the 'cost' of outputting to all the other clients that care about the new UUID. I don't care about this; as I said I suspect the client to receive only intermittent messages. It's unlikely for one socket to receive multiple messages at one time, and there won't be that many sockets so it shouldn't take too long to send messages to each of them. Perhaps later I'll fix the fact that I'm saddling higher work load on whatever unfortunate thread gets the first request; but for now I think it's fine.

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• Will there ever be a version of Java which does not perform Type Erasure

  - by user63904

  Type erasure enables Java applications that use generics to maintain binary compatibility with Java libraries and applications that were created before generics Generics were introduced in Java 1.5, so presumably the statement "applications that were created before generics" is referring to Java 1.4? Given that Java 1.4 entered its End Of Life around 2006 and was officially End Of Life'd around 2008. Why is type erasure still being performed in Java 7, etc... Has the statement now become self referential i.e. Type erasure enables Java applications that use generics to maintain binary compatibility with Java libraries and applications that were created with Java versions that perform Type Erasure. Meaning therefore that there will never be a version of Java that doesn't perform Type Erasure.

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• reference list for non-IT driven algorithmic patterns

  - by Quicker

  I am looking for a reference list for non-IT driven algorithmic patterns (which still can be helped with IT implementations of IT). An Example List would be: name; short desc; reference Travelling Salesman; find the shortest possible route on a multiple target path; http://en.wikipedia.org/wiki/Travelling_salesman_problem Ressource Disposition (aka Regulation); Distribute a limited/exceeding input on a given number output receivers based on distribution rules; http://database-programmer.blogspot.de/2010/12/critical-analysis-of-algorithm-sproc.html If there is no such list, but you instantly think of something specific, please 'put it on the desk'. Maybe I can compile something out of the input I get here (actually I am very frustrated as I did not find any such list via research by myself). Details on Scoping: I found it very hard to formulate what I want in a way everything is out that I do not need (which may be the issue why I did not find anything at google). There is a database centric definition for what I am looking for in the section 'Processes' of the second example link. That somehow fits, but the database focus sort of drifts away from the pattern thinking, which I have in mind. So here are my own thoughts around what's in and what's out: I am NOT looking for a foundational algo ref list, which is implemented as basis for any programming language. Eg. the php reference describes substr and strlen. That implements algos, but is not what I am looking for. the problem the algo does address would even exist, if there were no computers (or other IT components) the main focus of the algo is NOT to help other algo's chances are high, that there are implementions of the solution or any workaround without any IT support out there in the world however the algo could be benefitialy implemented/fully supported by a software application = means: the problem of the algo has to be addressed anyway, but running an algo implementation with software automates the process (that is why I posted it on stackoverflow and not somewhere else) typically such algo implementations have more than one input field value and more than one output field value - which implies it could not be implemented as simple function (which is fixed to produce not more than one output value) in a normalized data model often times such algo implementation outputs span accross multiple rows (sometimes multiple tables), whereby the number of output rows depends on the input paraters and rows in the table(s) at start time - which implies that any algo implementation/procedure must interact with a database (read and/or write) I am mainly looking for patterns, not for specific implementations. Example: The Travelling Salesman assumes any coordinates, however it does not say: You need a table targets with fields x and y. - however sometimes descriptions are focussed on examples with specific implementations very much - no worries, as long as the pattern gets clear

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• How to get the field name of a java (weak) reference pointing to an object in an other class?

  - by Tom

  Imagine I have the following situation: Test1.java import java.lang.ref.WeakReference; public class Test1 { public WeakReference fieldName; public init() { fieldName = new WeakReference(this); Test2.setWeakRef(fieldName); } } Test2.java import java.lang.ref.WeakReference; public class Test2 { public static setWeakRef(WeakReference weakRef) { //at this point I got weakRef in an other class.. now, how do I get the field name this reference was created with? So that it returns exactly "fieldName", because that's the name I gave it in Test1.java? } } At the location of the comment I received the weak reference created in an other class. How would I retreive the field name that this weak reference was created with, in this case "fieldName"? Thanks in advance.

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• game programming career, vc++ reference and future of it [closed]

  - by Pappu Bacha

  1) I have quite a lot of interest in game programming and I (to my thought) am quite good at programming skills, I have developed some console based animations and text based animation games (like copter-it, snake, and a music visualization), should I invest in game programming? I have 2 years at college left. 2) If I am to pursue a career in game programming, and I select to go only with c++ and DirectX, is it enough? is assembly language necessary? 3) is Visual C++ or MFC dead? should I invest in it or not? 4) I am unable to find any reference book for Visual C++ 2008 or later (just like C++ the complete reference book) I need a book that covers the basic fundamentals and covers the most of the libraries etc.

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• Why subtract a value from itself (x - x) in Python?

  - by endolith

  In NumPy functions, there are often initial lines that do checking of variable types, forcing them to be certain types, etc. Can someone explain the point of these lines? What does subtracting a value from itself do? t,w = asarray(t), asarray(duty) w = asarray(w + (t-t)) t = asarray(t + (w-w))

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• Dynamic Code for type casting Generic Types 'generically' in C#

  - by Rick Strahl

  C# is a strongly typed language and while that's a fundamental feature of the language there are more and more situations where dynamic types make a lot of sense. I've written quite a bit about how I use dynamic for creating new type extensions: Dynamic Types and DynamicObject References in C# Creating a dynamic, extensible C# Expando Object Creating a dynamic DataReader for dynamic Property Access Today I want to point out an example of a much simpler usage for dynamic that I use occasionally to get around potential static typing issues in C# code especially those concerning generic types. TypeCasting Generics Generic types have been around since .NET 2.0 I've run into a number of situations in the past - especially with generic types that don't implement specific interfaces that can be cast to - where I've been unable to properly cast an object when it's passed to a method or assigned to a property. Granted often this can be a sign of bad design, but in at least some situations the code that needs to be integrated is not under my control so I have to make due with what's available or the parent object is too complex or intermingled to be easily refactored to a new usage scenario. Here's an example that I ran into in my own RazorHosting library - so I have really no excuse, but I also don't see another clean way around it in this case. A Generic Example Imagine I've implemented a generic type like this: public class RazorEngine<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase, new() You can now happily instantiate new generic versions of this type with custom template bases or even a non-generic version which is implemented like this: public class RazorEngine : RazorEngine<RazorTemplateBase> { public RazorEngine() : base() { } } To instantiate one: var engine = new RazorEngine<MyCustomRazorTemplate>(); Now imagine that the template class receives a reference to the engine when it's instantiated. This code is fired as part of the Engine pipeline when it gets ready to execute the template. It instantiates the template and assigns itself to the template: var template = new TBaseTemplateType() { Engine = this } The problem here is that possibly many variations of RazorEngine<T> can be passed. I can have RazorTemplateBase, RazorFolderHostTemplateBase, CustomRazorTemplateBase etc. as generic parameters and the Engine property has to reflect that somehow. So, how would I cast that? My first inclination was to use an interface on the engine class and then cast to the interface.  Generally that works, but unfortunately here the engine class is generic and has a few members that require the template type in the member signatures. So while I certainly can implement an interface: public interface IRazorEngine<TBaseTemplateType> it doesn't really help for passing this generically templated object to the template class - I still can't cast it if multiple differently typed versions of the generic type could be passed. I have the exact same issue in that I can't specify a 'generic' generic parameter, since there's no underlying base type that's common. In light of this I decided on using object and the following syntax for the property (and the same would be true for a method parameter): public class RazorTemplateBase :MarshalByRefObject,IDisposable { public object Engine {get;set; } } Now because the Engine property is a non-typed object, when I need to do something with this value, I still have no way to cast it explicitly. What I really would need is: public RazorEngine<> Engine { get; set; } but that's not possible. Dynamic to the Rescue Luckily with the dynamic type this sort of thing can be mitigated fairly easily. For example here's a method that uses the Engine property and uses the well known class interface by simply casting the plain object reference to dynamic and then firing away on the properties and methods of the base template class that are common to all templates:/// <summary> /// Allows rendering a dynamic template from a string template /// passing in a model. This is like rendering a partial /// but providing the input as a /// </summary> public virtual string RenderTemplate(string template,object model) { if (template == null) return string.Empty; // if there's no template markup if(!template.Contains("@")) return template; // use dynamic to get around generic type casting dynamic engine = Engine; string result = engine.RenderTemplate(template, model); if (result == null) throw new ApplicationException("RenderTemplate failed: " + engine.ErrorMessage); return result; } Prior to .NET 4.0  I would have had to use Reflection for this sort of thing which would have a been a heck of a lot more verbose, but dynamic makes this so much easier and cleaner and in this case at least the overhead is negliable since it's a single dynamic operation on an otherwise very complex operation call. Dynamic as  a Bailout Sometimes this sort of thing often reeks of a design flaw, and I agree that in hindsight this could have been designed differently. But as is often the case this particular scenario wasn't planned for originally and removing the generic signatures from the base type would break a ton of other code in the framework. Given the existing fairly complex engine design, refactoring an interface to remove generic types just to make this particular code work would have been overkill. Instead dynamic provides a nice and simple and relatively clean solution. Now if there were many other places where this occurs I would probably consider reworking the code to make this cleaner but given this isolated instance and relatively low profile operation use of dynamic seems a valid choice for me. This solution really works anywhere where you might end up with an inheritance structure that doesn't have a common base or interface that is sufficient. In the example above I know what I'm getting but there's no common base type that I can cast to. All that said, it's a good idea to think about use of dynamic before you rush in. In many situations there are alternatives that can still work with static typing. Dynamic definitely has some overhead compared to direct static access of objects, so if possible we should definitely stick to static typing. In the example above the application already uses dynamics extensively for dynamic page page templating and passing models around so introducing dynamics here has very little additional overhead. The operation itself also fires of a fairly resource heavy operation where the overhead of a couple of dynamic member accesses are not a performance issue. So, what's your experience with dynamic as a bailout mechanism? © Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Postfix : error: unsupported dictionary type: mysql

  - by flavio.troja

  I've a problem w/ postfix problem: # tail -f /var/log/mail.err Aug 20 17:57:50 myserver postfix/smtpd[8243]: error: unsupported dictionary type: mysql Aug 20 17:57:50 myserver postfix/smtpd[8243]: error: unsupported dictionary type: mysql Aug 20 17:58:05 myserver postfix/smtpd[8244]: error: unsupported dictionary type: mysql Aug 20 17:58:05 myserver postfix/smtpd[8244]: error: unsupported dictionary type: mysql Aug 20 18:00:38 myserver postfix/smtpd[8277]: error: unsupported dictionary type: mysql Aug 20 18:00:38 myserver postfix/smtpd[8277]: error: unsupported dictionary type: mysql Aug 20 18:03:32 myserver postfix/smtpd[8320]: error: unsupported dictionary type: mysql Aug 20 18:03:32 myserver postfix/smtpd[8320]: error: unsupported dictionary type: mysql Aug 20 18:03:33 myserver postfix/trivial-rewrite[8322]: error: unsupported dictionary type: mysql Aug 20 18:03:33 myserver postfix/trivial-rewrite[8322]: error: unsupported dictionary type: mysql idea?

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• SSIS Catalog: How to use environment in every type of package execution

  - by Kevin Shyr

  Here is a good blog on how to create a SSIS Catalog and setting up environments.  http://sqlblog.com/blogs/jamie_thomson/archive/2010/11/13/ssis-server-catalogs-environments-environment-variables-in-ssis-in-denali.aspx Here I will summarize 3 ways I know so far to execute a package while using variables set up in SSIS Catalog environment. First way, we have SSIS project having reference to environment, and having one of the project parameter using a value set up in the environment called "Development".  With this set up, you are limited to calling the packages by right-clicking on the packages in the SSIS catalog list and select Execute, but you are free to choose absolute or relative path of the environment. The following screenshot shows the 2 available paths to your SSIS environments.  Personally, I use absolute path because of Option 3, just to keep everything simple for myself. The second option is to call through SQL Job.  This does require you to configure your project to already reference an environment and use its variable.  When a job step is set up, the configuration part will require you to select that reference again.  This is more useful when you want to automate the same package that needs to be run in different environments. The third option is the most important to me as I have a SSIS framework that calls hundreds of packages.  The main part of the stored procedure is in this post (http://geekswithblogs.net/LifeLongTechie/archive/2012/11/14/time-to-stop-using-ldquoexecute-package-taskrdquondash-a-way-to.aspx).  But the top part had to be modified to include the logic to use environment reference. CREATE PROCEDURE [AUDIT].[LaunchPackageExecutionInSSISCatalog] @PackageName NVARCHAR(255) , @ProjectFolder NVARCHAR(255) , @ProjectName NVARCHAR(255) , @AuditKey INT , @DisableNotification BIT , @PackageExecutionLogID INT , @EnvironmentName NVARCHAR(128) = NULL , @Use32BitRunTime BIT = FALSE AS BEGIN TRY DECLARE @execution_id BIGINT = 0; -- Create a package execution IF @EnvironmentName IS NULL BEGIN   EXEC [SSISDB].[catalog].[create_execution]     @package_name=@PackageName,     @execution_id=@execution_id OUTPUT,     @folder_name=@ProjectFolder,     @project_name=@ProjectName,     @use32bitruntime=@Use32BitRunTime; END ELSE BEGIN   DECLARE @EnvironmentID AS INT   SELECT @EnvironmentID = [reference_id]    FROM SSISDB.[internal].[environment_references] WITH(NOLOCK)    WHERE [environment_name] = @EnvironmentName     AND [environment_folder_name] = @ProjectFolder      EXEC [SSISDB].[catalog].[create_execution]     @package_name=@PackageName,     @execution_id=@execution_id OUTPUT,     @folder_name=@ProjectFolder,     @project_name=@ProjectName,     @reference_id=@EnvironmentID,     @use32bitruntime=@Use32BitRunTime; END

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• Is it possible to create a "weak reference" in javascript?

  - by Stephen Cagle

  Is there any way in javascript to create a "weak reference" to another object? Here is the wiki page describing what a weak reference is. Here is another article that describes them in Java. Can anyone think of a way to implement this behavior in javascript?

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• Using a function with reference as a function with pointers?

  - by epatel

  Today I stumbled over a piece of code that looked horrifying to me. The pieces was chattered in different files, I have tried write the gist of it in a simple test case below. The code base is routinely scanned with FlexeLint on a daily basis, but this construct has been laying in the code since 2004. The thing is that a function implemented with a parameter passing using references is called as a function with a parameter passing using pointers...due to a function cast. The construct has worked since 2004 on Irix and now when porting it actually do work on Linux/gcc too. My question now. Is this a construct one can trust? I can understand if compiler constructors implement the reference passing as it was a pointer, but is it reliable? Are there hidden risks? Should I change the fref(..) to use pointers and risk braking anything in the process? What to you think? #include <iostream> using namespace std; // ---------------------------------------- // This will be passed as a reference in fref(..) struct string_struct { char str[256]; }; // ---------------------------------------- // Using pointer here! void fptr(const char *str) { cout << "fptr: " << str << endl; } // ---------------------------------------- // Using reference here! void fref(string_struct &str) { cout << "fref: " << str.str << endl; } // ---------------------------------------- // Cast to f(const char*) and call with pointer void ftest(void (*fin)()) { void (*fcall)(const char*) = (void(*)(const char*))fin; fcall("Hello!"); } // ---------------------------------------- // Let's go for a test int main() { ftest((void (*)())fptr); // test with fptr that's using pointer ftest((void (*)())fref); // test with fref that's using reference return 0; }

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• Customize Team Build 2010 – Part 16: Specify the relative reference path

  In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application Part 16: Specify the relative reference path As I have already blogged about, it is not intuitive how to specify the paths where the build server has to look for references that are stored in Source Control. It is a common practice to store 3rd party libraries in Source Control, so they are available to everyone, everyone uses the same version of the libraries and updating a library can be done centrally. In Team Build 2010 these paths are specified as a parameter for MSBuild. What we will do in this post is building the values for this parameter based on the values in an argument. You are now pretty aware how to customize the build template, so let’s do the modifications in another way. Instead of opening the xaml file in the workflow designer, we open it in the XML editor. You can open it in the XML Editor by either selecting the Open with menu (see the context menu), or by choosing the View code option. To add this functionality we need to: Specify a new argument Add the argument to the metadata Build the absolute paths for the references and add these paths to the MSBuild arguments 1. Specify a new argument Locate at the top of the document the Members (which are the arguments) of the XAML and add the following line <x:Property Name="ReferencePaths" Type="InArgument(s:String[])" /> 2. Add the argument to the metadata Then locate the line <mtbw:ProcessParameterMetadataCollection> and paste the following line <mtbw:ProcessParameterMetadata Category="Misc" Description="The list of reference paths, relative to the root path in the Workspace mapping." DisplayName="Reference paths" ParameterName="ReferencePaths" /> 3. Build the absolute paths for the references and add these paths to the MSBuild arguments Now locate the place where the assignments are done to the variables used in the agent. And add the following lines after the last Assign activity         <Sequence DisplayName="Initialize ReferencePath" sap:VirtualizedContainerService.HintSize="464,428">           <Sequence.Variables>             <Variable x:TypeArguments="x:String" Name="ReferencePathsArgument">               <Variable.Default>                 <Literal x:TypeArguments="x:String" Value="" />               </Variable.Default>             </Variable>           </Sequence.Variables>           <sap:WorkflowViewStateService.ViewState>             <scg:Dictionary x:TypeArguments="x:String, x:Object">               <x:Boolean x:Key="IsExpanded">True</x:Boolean>             </scg:Dictionary>           </sap:WorkflowViewStateService.ViewState>           <ForEach x:TypeArguments="x:String" DisplayName="Iterate through the paths" sap:VirtualizedContainerService.HintSize="287,206" mtbwt:BuildTrackingParticipant.Importance="Low" Values="[ReferencePaths]">             <ActivityAction x:TypeArguments="x:String">               <ActivityAction.Argument>                 <DelegateInArgument x:TypeArguments="x:String" Name="path" />               </ActivityAction.Argument>               <Assign x:TypeArguments="x:String" DisplayName="Build ReferencePath argument" sap:VirtualizedContainerService.HintSize="257,100" mtbwt:BuildTrackingParticipant.Importance="Low"  To="[ReferencePathsArgument]" Value="[If(String.IsNullOrEmpty(ReferencePathsArgument), &quot;&quot;, ReferencePathsArgument + &quot;;&quot;) + IO.Path.Combine(SourcesDirectory, path)]" />             </ActivityAction>           </ForEach>           <Assign DisplayName="Append the reference paths to the MSBuild Arguments" sap:VirtualizedContainerService.HintSize="287,58">             <Assign.To>               <OutArgument x:TypeArguments="x:String">[MSBuildArguments]</OutArgument>             </Assign.To>             <Assign.Value>               <InArgument x:TypeArguments="x:String">[String.Format("{0} /p:ReferencePath=""{1}""", MSBuildArguments, ReferencePathsArgument)]</InArgument>             </Assign.Value>           </Assign>         </Sequence> Now you can use the template to specify the paths relative to SourcesDirectory. You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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• SQL SERVER – OLEDB – Link Server – Wait Type – Day 23 of 28

  - by pinaldave

  When I decided to start writing about this wait type, the very first question that came to my mind was, “What does ‘OLEDB’ stand for?” A quick search on Wikipedia tells me that OLEDB means Object Linking and Embedding Database. (How many of you knew this?) Anyway, I found it very interesting that this wait type was in one of the top 10 wait types in many of the systems I have come across in my performance tuning experience. Books On-Line: ????OLEDB occurs when SQL Server calls the SQL Server Native Client OLE DB Provider. This wait type is not used for synchronization. Instead, it indicates the duration of calls to the OLE DB provider. OLEDB Explanation: This wait type primarily happens when Link Server or Remove Query has been executed. The most common case wherein this wait type is visible is during the execution of Linked Server. When SQL Server is retrieving data from the remote server, it uses OLEDB API to retrieve the data. It is possible that the remote system is not quick enough or the connection between them is not fast enough, leading SQL Server to wait for the result’s return from the remote (or external) server. This is the time OLEDB wait type occurs. Reducing OLEDB wait: Check the Link Server configuration. Checking Disk-Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) At this point in time, I am not able to think of any more ways on reducing this wait type. Do you have any opinion about this subject? Please share it here and I will share your comment with the rest of the Community, and of course, with due credit unto you. Please read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• How to use Object Type Converter

  - by arun.x.sridharan(at)oracle.com

  UseCase Description A person form where in user will enter String which has to be converted to Number while persisting. From the User Interface we might be getting a String value which has to be persisted in the database as a number in that scenario we can use converters to map the java object which is of type String to its database value which is a Number. For example , there is a 'Person' table in database which is used to store the user details passed from the User Interface. It has a 'Status' column which is of the value  Number. But from the User Interface String values (Active/InActive) are passed . For persisting the user details we can use Object type converter and provide the mappings for status column corresponding to the String values. Object type converter can be used if you wanted to have a mapping for a field for example when departmentName on the entity was of String value and mapped to dept_name field on the database table which is of the value NUMBER.   Implementation steps Sample EJB API for setting the value of status on Person Entity as a String     public void createPerson(String status,String firstName,String lastName) {                Person person = new Person();                // status will be set as a String value received from the User Interface         person.setStatus(status);                person.setFirstname(firstName);        person.setLastname(lastName);                persistPerson(person);         } In the sample code shown above status is passed as a String, this has to be converted to Number. The String value obtained will be set on Person object and persistPerson API will be called for creating a new person from the values passed from the User Interface.  Steps to configure Object type converter: 1. Navigate to Person Entity from persistence.xml and navigate to status field2. Click on Conversion tab and select Converted check box3. Select Object Type Converter radio button and set the Data Type Class to      java.math.BigDecimal and Object Type Class to java.lang.String4. Specify the conversion values for all the values that can be passed from the user interface  as shown below5. Set the Default Object value

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• How can I get type information at runtime from a DMP file in a Windbg extension?

  - by pj4533

  This is related to my previous question, regarding pulling objects from a dmp file. As I mentioned in the previous question, I can successfully pull object out of the dmp file by creating wrapper 'remote' objects. I have implemented several of these so far, and it seems to be working well. However I have run into a snag. In one case, a pointer is stored in a class, say of type 'SomeBaseClass', but that object is actually of the type 'SomeDerivedClass' which derives from 'SomeBaseClass'. For example it would be something like this: MyApplication!SomeObject +0x000 field1 : Ptr32 SomeBaseClass +0x004 field2 : Ptr32 SomeOtherClass +0x008 field3 : Ptr32 SomeOtherClass I need someway to find out what the ACTUAL type of 'field1' is. To be more specific, using example addresses: MyApplication!SomeObject +0x000 field1 : 0cae2e24 SomeBaseClass +0x004 field2 : 0x262c8d3c SomeOtherClass +0x008 field3 : 0x262c8d3c SomeOtherClass 0:000> dt SomeBaseClass 0cae2e24 MyApplication!SomeBaseClass +0x000 __VFN_table : 0x02de89e4 +0x038 basefield1 : (null) +0x03c basefield2 : 3 0:000> dt SomeDerivedClass 0cae2e24 MyApplication!SomeDerivedClass +0x000 __VFN_table : 0x02de89e4 +0x038 basefield1 : (null) +0x03c basefield2 : 3 +0x040 derivedfield1 : 357 +0x044 derivedfield2 : timecode_t When I am in WinDbg, I can do this: dt 0x02de89e4 And it will show the type: 0:000> dt 0x02de89e4 SomeDerivedClass::`vftable' Symbol not found. But how do get that inside an extension? Can I use SearchMemory() to look for 'SomeDerivedClass::`vftable'? If you follow my other question, I need this type information so I know what type of wrapper remote classes to create. I figure it might end up being some sort of case-statement, where I have to match a string to a type? I am ok with that, but I still don't know where I can get that string that represents the type of the object in question (ie SomeObject-field1 in the above example).

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• AutoMapper MappingFunction from Source Type of NameValueCollection

  - by REA_ANDREW

  I have had a situation arise today where I need to construct a complex type from a source of a NameValueCollection.  A little while back I submitted a patch for the Agatha Project to include REST (JSON and XML) support for the service contract.  I realized today that as useful as it is, it did not actually support true REST conformance, as REST should support GET so that you can use JSONP from JavaScript directly meaning you can query cross domain services.  My original implementation for POX and JSON used the POST method and this immediately rules out JSONP as from reading, JSONP only works with GET Requests. This then raised another issue.  The current operation contract of Agatha and one of its main benefits is that you can supply an array of Request objects in a single request, limiting the about of server requests you need to make.  Now, at the present time I am thinking that this will not be the case for the REST imlementation but will yield the benefits of the fact that : The same Request objects can be used for SOAP and RST (POX, JSON) The construct of the JavaScript functions will be simpler and more readable It will enable the use of JSONP for cross domain REST Services The current contract for the Agatha WcfRequestProcessor is at time of writing the following: [ServiceContract] public interface IWcfRequestProcessor { [OperationContract(Name = "ProcessRequests")] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [TransactionFlow(TransactionFlowOption.Allowed)] Response[] Process(params Request[] requests); [OperationContract(Name = "ProcessOneWayRequests", IsOneWay = true)] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] void ProcessOneWayRequests(params OneWayRequest[] requests); }   My current proposed solution, and at the very early stages of my concept is as follows: [ServiceContract] public interface IWcfRestJsonRequestProcessor { [OperationContract(Name="process")] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [TransactionFlow(TransactionFlowOption.Allowed)] [WebGet(UriTemplate = "process/{name}/{*parameters}", BodyStyle = WebMessageBodyStyle.WrappedResponse, ResponseFormat = WebMessageFormat.Json)] Response[] Process(string name, NameValueCollection parameters); [OperationContract(Name="processoneway",IsOneWay = true)] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [WebGet(UriTemplate = "process-one-way/{name}/{*parameters}", BodyStyle = WebMessageBodyStyle.WrappedResponse, ResponseFormat = WebMessageFormat.Json)] void ProcessOneWayRequests(string name, NameValueCollection parameters); }   Now this part I have not yet implemented, it is the preliminart step which I have developed which will allow me to take the name of the Request Type and the NameValueCollection and construct the complex type which is that of the Request which I can then supply to a nested instance of the original IWcfRequestProcessor  and work as it should normally.  To give an example of some of the urls which you I envisage with this method are: http://www.url.com/service.svc/json/process/getweather/?location=london http://www.url.com/service.svc/json/process/getproductsbycategory/?categoryid=1 http://www.url.om/service.svc/json/process/sayhello/?name=andy Another reason why my direction has gone to a single request for the REST implementation is because of restrictions which are imposed by browsers on the length of the url.  From what I have read this is on average 2000 characters.  I think that this is a very acceptable usage limit in the context of using 1 request, but I do not think this is acceptable for accommodating multiple requests chained together.  I would love to be corrected on that one, I really would but unfortunately from what I have read I have come to the conclusion that this is not the case. The mapping function So, as I say this is just the first pass I have made at this, and I am not overly happy with the try catch for detecting types without default constructors.  I know there is a better way but for the minute, it escapes me.  I would also like to know the correct way for adding mapping functions and not using the anonymous way that I have used.  To achieve this I have used recursion which I am sure is what other mapping function use. As you do have to go as deep as the complex type is. public static object RecurseType(NameValueCollection collection, Type type, string prefix) { try { var returnObject = Activator.CreateInstance(type); foreach (var property in type.GetProperties()) { foreach (var key in collection.AllKeys) { if (String.IsNullOrEmpty(prefix) || key.Length > prefix.Length) { var propertyNameToMatch = String.IsNullOrEmpty(prefix) ? key : key.Substring(property.Name.IndexOf(prefix) + prefix.Length + 1); if (property.Name == propertyNameToMatch) { property.SetValue(returnObject, Convert.ChangeType(collection.Get(key), property.PropertyType), null); } else if(property.GetValue(returnObject,null) == null) { property.SetValue(returnObject, RecurseType(collection, property.PropertyType, String.Concat(prefix, property.PropertyType.Name)), null); } } } } return returnObject; } catch (MissingMethodException) { //Quite a blunt way of dealing with Types without default constructor return null; } }   Another thing is performance, I have not measured this in anyway, it is as I say the first pass, so I hope this can be the start of a more perfected implementation.  I tested this out with a complex type of three levels, there is no intended logical meaning to the properties, they are simply for the purposes of example.  You could call this a spiking session, as from here on in, now I know what I am building I would take a more TDD approach.  OK, purists, why did I not do this from the start, well I didn’t, this was a brain dump and now I know what I am building I can. The console test and how I used with AutoMapper is as follows: static void Main(string[] args) { var collection = new NameValueCollection(); collection.Add("Name", "Andrew Rea"); collection.Add("Number", "1"); collection.Add("AddressLine1", "123 Street"); collection.Add("AddressNumber", "2"); collection.Add("AddressPostCodeCountry", "United Kingdom"); collection.Add("AddressPostCodeNumber", "3"); AutoMapper.Mapper.CreateMap<NameValueCollection, Person>() .ConvertUsing(x => { return(Person) RecurseType(x, typeof(Person), null); }); var person = AutoMapper.Mapper.Map<NameValueCollection, Person>(collection); Console.WriteLine(person.Name); Console.WriteLine(person.Number); Console.WriteLine(person.Address.Line1); Console.WriteLine(person.Address.Number); Console.WriteLine(person.Address.PostCode.Country); Console.WriteLine(person.Address.PostCode.Number); Console.ReadLine(); }   Notice the convention that I am using and that this method requires you do use.  Each property is prefixed with the constructed name of its parents combined.  This is the convention used by AutoMapper and it makes sense. I can also think of other uses for this including using with ASP.NET MVC ModelBinders for creating a complex type from the QueryString which is itself is a NameValueCollection. Hope this is of some help to people and I would welcome any code reviews you could give me. References: Agatha : http://code.google.com/p/agatha-rrsl/ AutoMapper : http://automapper.codeplex.com/   Cheers for now, Andrew   P.S. I will have the proposed solution for a more complete REST implementation for AGATHA very soon. 

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• Dynamic Type to do away with Reflection

  - by Rick Strahl

  The dynamic type in C# 4.0 is a welcome addition to the language. One thing I’ve been doing a lot with it is to remove explicit Reflection code that’s often necessary when you ‘dynamically’ need to walk and object hierarchy. In the past I’ve had a number of ReflectionUtils that used string based expressions to walk an object hierarchy. With the introduction of dynamic much of the ReflectionUtils code can be removed for cleaner code that runs considerably faster to boot. The old Way - Reflection Here’s a really contrived example, but assume for a second, you’d want to dynamically retrieve a Page.Request.Url.AbsoluteUrl based on a Page instance in an ASP.NET Web Page request. The strongly typed version looks like this: string path = Page.Request.Url.AbsolutePath; Now assume for a second that Page wasn’t available as a strongly typed instance and all you had was an object reference to start with and you couldn’t cast it (right I said this was contrived :-)) If you’re using raw Reflection code to retrieve this you’d end up writing 3 sets of Reflection calls using GetValue(). Here’s some internal code I use to retrieve Property values as part of ReflectionUtils: /// <summary> /// Retrieve a property value from an object dynamically. This is a simple version /// that uses Reflection calls directly. It doesn't support indexers. /// </summary> /// <param name="instance">Object to make the call on</param> /// <param name="property">Property to retrieve</param> /// <returns>Object - cast to proper type</returns> public static object GetProperty(object instance, string property) { return instance.GetType().GetProperty(property, ReflectionUtils.MemberAccess).GetValue(instance, null); } If you want more control over properties and support both fields and properties as well as array indexers a little more work is required: /// <summary> /// Parses Properties and Fields including Array and Collection references. /// Used internally for the 'Ex' Reflection methods. /// </summary> /// <param name="Parent"></param> /// <param name="Property"></param> /// <returns></returns> private static object GetPropertyInternal(object Parent, string Property) { if (Property == "this" || Property == "me") return Parent; object result = null; string pureProperty = Property; string indexes = null; bool isArrayOrCollection = false; // Deal with Array Property if (Property.IndexOf("[") > -1) { pureProperty = Property.Substring(0, Property.IndexOf("[")); indexes = Property.Substring(Property.IndexOf("[")); isArrayOrCollection = true; } // Get the member MemberInfo member = Parent.GetType().GetMember(pureProperty, ReflectionUtils.MemberAccess)[0]; if (member.MemberType == MemberTypes.Property) result = ((PropertyInfo)member).GetValue(Parent, null); else result = ((FieldInfo)member).GetValue(Parent); if (isArrayOrCollection) { indexes = indexes.Replace("[", string.Empty).Replace("]", string.Empty); if (result is Array) { int Index = -1; int.TryParse(indexes, out Index); result = CallMethod(result, "GetValue", Index); } else if (result is ICollection) { if (indexes.StartsWith("\"")) { // String Index indexes = indexes.Trim('\"'); result = CallMethod(result, "get_Item", indexes); } else { // assume numeric index int index = -1; int.TryParse(indexes, out index); result = CallMethod(result, "get_Item", index); } } } return result; } /// <summary> /// Returns a property or field value using a base object and sub members including . syntax. /// For example, you can access: oCustomer.oData.Company with (this,"oCustomer.oData.Company") /// This method also supports indexers in the Property value such as: /// Customer.DataSet.Tables["Customers"].Rows[0] /// </summary> /// <param name="Parent">Parent object to 'start' parsing from. Typically this will be the Page.</param> /// <param name="Property">The property to retrieve. Example: 'Customer.Entity.Company'</param> /// <returns></returns> public static object GetPropertyEx(object Parent, string Property) { Type type = Parent.GetType(); int at = Property.IndexOf("."); if (at < 0) { // Complex parse of the property return GetPropertyInternal(Parent, Property); } // Walk the . syntax - split into current object (Main) and further parsed objects (Subs) string main = Property.Substring(0, at); string subs = Property.Substring(at + 1); // Retrieve the next . section of the property object sub = GetPropertyInternal(Parent, main); // Now go parse the left over sections return GetPropertyEx(sub, subs); } As you can see there’s a fair bit of code involved into retrieving a property or field value reliably especially if you want to support array indexer syntax. This method is then used by a variety of routines to retrieve individual properties including one called GetPropertyEx() which can walk the dot syntax hierarchy easily. Anyway with ReflectionUtils I can  retrieve Page.Request.Url.AbsolutePath using code like this: string url = ReflectionUtils.GetPropertyEx(Page, "Request.Url.AbsolutePath") as string; This works fine, but is bulky to write and of course requires that I use my custom routines. It’s also quite slow as the code in GetPropertyEx does all sorts of string parsing to figure out which members to walk in the hierarchy. Enter dynamic – way easier! .NET 4.0’s dynamic type makes the above really easy. The following code is all that it takes: object objPage = Page; // force to object for contrivance :) dynamic page = objPage; // convert to dynamic from untyped object string scriptUrl = page.Request.Url.AbsolutePath; The dynamic type assignment in the first two lines turns the strongly typed Page object into a dynamic. The first assignment is just part of the contrived example to force the strongly typed Page reference into an untyped value to demonstrate the dynamic member access. The next line then just creates the dynamic type from the Page reference which allows you to access any public properties and methods easily. It also lets you access any child properties as dynamic types so when you look at Intellisense you’ll see something like this when typing Request.: In other words any dynamic value access on an object returns another dynamic object which is what allows the walking of the hierarchy chain. Note also that the result value doesn’t have to be explicitly cast as string in the code above – the compiler is perfectly happy without the cast in this case inferring the target type based on the type being assigned to. The dynamic conversion automatically handles the cast when making the final assignment which is nice making for natural syntnax that looks *exactly* like the fully typed syntax, but is completely dynamic. Note that you can also use indexers in the same natural syntax so the following also works on the dynamic page instance: string scriptUrl = page.Request.ServerVariables["SCRIPT_NAME"]; The dynamic type is going to make a lot of Reflection code go away as it’s simply so much nicer to be able to use natural syntax to write out code that previously required nasty Reflection syntax. Another interesting thing about the dynamic type is that it actually works considerably faster than Reflection. Check out the following methods that check performance: void Reflection() { Stopwatch stop = new Stopwatch(); stop.Start(); for (int i = 0; i < reps; i++) { // string url = ReflectionUtils.GetProperty(Page,"Title") as string;// "Request.Url.AbsolutePath") as string; string url = Page.GetType().GetProperty("Title", ReflectionUtils.MemberAccess).GetValue(Page, null) as string; } stop.Stop(); Response.Write("Reflection: " + stop.ElapsedMilliseconds.ToString()); } void Dynamic() { Stopwatch stop = new Stopwatch(); stop.Start(); dynamic page = Page; for (int i = 0; i < reps; i++) { string url = page.Title; //Request.Url.AbsolutePath; } stop.Stop(); Response.Write("Dynamic: " + stop.ElapsedMilliseconds.ToString()); } The dynamic code runs in 4-5 milliseconds while the Reflection code runs around 200+ milliseconds! There’s a bit of overhead in the first dynamic object call but subsequent calls are blazing fast and performance is actually much better than manual Reflection. Dynamic is definitely a huge win-win situation when you need dynamic access to objects at runtime.© Rick Strahl, West Wind Technologies, 2005-2010Posted in .NET  CSharp  

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• Combo/Input LOV displaying non-reference key value

  - by [email protected]

  Its a very common use-case of LOV that we want to diplay a non key value in the LOV but store the key value in the DB. I had to do the same in a sample application I was building. During implementation of this, I realized that there are multiple ways to achieve this.I am going to describe each of these below.Example : Lets take an example of our classic HR schema. I have 2 tables Employee and Department where Dno is the foreign key attribute in Employee that references Department table.I want to create a LOV for Deparment such that the List always displays Dname instead of Dno. However when I update it, it it should update the reference key Dno.To achieve this I had 3 alternative1) Approach 1 :Create a composite VO and add the attributes from Department into Employee using a join.Refer the blog http://andrejusb.blogspot.com/2009/11/defining-lov-on-reference-attribute-in.htmlPositives :1. Easy to implement and use.2. We can use this attribute directly in queries defined on new attribute i.e If i have to display this inside query panel.Negative : We have to create an additional Join on the VO.Ex:SELECT Employees.EMPLOYEE_ID,        Employees.FIRST_NAME,        Employees.LAST_NAME,        Employees.EMAIL,        Employees.PHONE_NUMBER,       Department.Dno,        Department.DnameFROM EMPLOYEES Employees, Department Department WHERE Employees.Dno = Department .Dno2) Approach 2 :

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• WPF: How do I get a reference to a styled window control in code behind?

  - by Brad

  I have a window defined with a style: <Window x:Class="winBorderless" x:Name="winBorderless" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Local="clr-namespace:WindowStyle" Style="{StaticResource Window_Cartesia}" WindowStartupLocation="CenterScreen" BorderThickness="1" BorderBrush="#FF9CAAC1" Margin="5" Title="[Document Title]"> and the style defined in an application level dictionary: <Style x:Key="Window_Cartesia" TargetType="{x:Type Window}"> <Setter Property="WindowStyle" Value="None"/> <Setter Property="AllowsTransparency" Value="True"/> <Setter Property="Background" Value="Transparent"/> <EventSetter Event="Loaded" Handler="Loaded"/> <EventSetter Event="PreviewKeyDown" Handler="Preview_KeyDown"/> <EventSetter Event="MouseMove" Handler="FullScreen_MouseMove"/> <Setter Property="Template"> In code behind I have a reference to the Window instance set: Win = DirectCast(sender, winBorderless) This allows access to the window properties as the EventSetters pass references to the various controls. However, it doesn't provide for access to the controls defined in the style through the window reference as they don't exist there. So, what is the best way to reference a control through code behind that is defined in the style. I'd prefer not to iterate the trees to find them but ya gotta do....

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• C# how to calculate hashcode from an object reference.

  - by Wayne

  Folks, here's a thorny problem for you! A part of the TickZoom system must collect instances of every type of object into a Dictionary< type. It is imperative that their equality and hash code be based on the instance of the object which means reference equality instead of value equality. The challenge is that some of the objects in the system have overridden Equals() and GetHashCode() for use as value equality and their internal values will change over time. That means that their Equals and GetHashCode are useless. How to solve this generically rather than intrusively? So far, We created a struct to wrap each object called ObjectHandle for hashing into the Dictionary. As you see below we implemented Equals() but the problem of how to calculate a hash code remains. public struct ObjectHandle : IEquatable<ObjectHandle>{ public object Object; public bool Equals(ObjectHandle other) { return object.ReferenceEquals(this.Object,other.Object); } } See? There is the method object.ReferenceEquals() which will compare reference equality without regard for any overridden Equals() implementation in the object. Now, how to calculate a matching GetHashCode() by only considering the reference without concern for any overridden GetHashCode() method? Ahh, I hope this give you an interesting puzzle. We're stuck over here. Sincerely, Wayne

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• Doctrine generate models - problem with relation type

  - by mrok

  I am trying generate doctrine models from yaml schema I have schema like that: Product: columns: id: type: integer(5) primary: true unsigned: true autoincrement: true activation_time: type: datetime notnull: true enduser_id: type: integer(5) unsigned: true notnull: true relations: Enduser: foreignType: one type: one foreignAlias: Product Hostid: columns: id: type: integer(5) primary: true unsigned: true autoincrement: true value: type: string(32) fixed: true notnull: true Order: columns: id: type: integer(5) primary: true autoincrement: true unsigned: true expire_date: type: datetime description: type: clob Enduser: columns: id: type: integer(5) primary: true unsigned: true autoincrement: true hostid_id: type: integer(5) unsigned: true notnull: true order_id: type: integer(5) unsigned: true notnull: true relations: Order: foreignAlias: Endusers Hostid: foreignAlias: Endusers and the problem is that models generated by doctrine generate-models-yaml are wrong in BaseEnduser $Product is defined as Doctrine_Collection $this-hasMany('Product', array( 'local' = 'id', 'foreign' = 'enduser_id')); instead just Product object what did I wrong? relation is defined as foreignType: one type: one

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• Reflect.Emit Dynamic Type Memory Blowup

  - by Firestrand

  Using C# 3.5 I am trying to generate dynamic types at runtime using reflection emit. I used the Dynamic Query Library sample from Microsoft to create a class generator. Everything works, my problem is that 100 generated types inflate the memory usage by approximately 25MB. This is a completely unacceptable memory profile as eventually I want to support having several hundred thousand types generated in memory. Memory profiling shows that the memory is apparently being held by various System.Reflection.Emit types and methods though I can't figure out why. I haven't found others talking about this problem so I am hoping someone in this community either knows what I am doing wrong or if this is expected behavior. Contrived Example below: using System; using System.Collections.Generic; using System.Text; using System.Reflection; using System.Reflection.Emit; namespace SmallRelfectExample { class Program { static void Main(string[] args) { int typeCount = 100; int propCount = 100; Random rand = new Random(); Type dynType = null; for (int i = 0; i < typeCount; i++) { List<DynamicProperty> dpl = new List<DynamicProperty>(propCount); for (int j = 0; j < propCount; j++) { dpl.Add(new DynamicProperty("Key" + rand.Next().ToString(), typeof(String))); } SlimClassFactory scf = new SlimClassFactory(); dynType = scf.CreateDynamicClass(dpl.ToArray(), i); //Optionally do something with the type here } Console.WriteLine("SmallRelfectExample: {0} Types generated.", typeCount); Console.ReadLine(); } } public class SlimClassFactory { private readonly ModuleBuilder module; public SlimClassFactory() { AssemblyName name = new AssemblyName("DynamicClasses"); AssemblyBuilder assembly = AppDomain.CurrentDomain.DefineDynamicAssembly(name, AssemblyBuilderAccess.Run); module = assembly.DefineDynamicModule("Module"); } public Type CreateDynamicClass(DynamicProperty[] properties, int Id) { string typeName = "DynamicClass" + Id.ToString(); TypeBuilder tb = module.DefineType(typeName, TypeAttributes.Class | TypeAttributes.Public, typeof(DynamicClass)); FieldInfo[] fields = GenerateProperties(tb, properties); GenerateEquals(tb, fields); GenerateGetHashCode(tb, fields); Type result = tb.CreateType(); return result; } static FieldInfo[] GenerateProperties(TypeBuilder tb, DynamicProperty[] properties) { FieldInfo[] fields = new FieldBuilder[properties.Length]; for (int i = 0; i < properties.Length; i++) { DynamicProperty dp = properties[i]; FieldBuilder fb = tb.DefineField("_" + dp.Name, dp.Type, FieldAttributes.Private); PropertyBuilder pb = tb.DefineProperty(dp.Name, PropertyAttributes.HasDefault, dp.Type, null); MethodBuilder mbGet = tb.DefineMethod("get_" + dp.Name, MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig, dp.Type, Type.EmptyTypes); ILGenerator genGet = mbGet.GetILGenerator(); genGet.Emit(OpCodes.Ldarg_0); genGet.Emit(OpCodes.Ldfld, fb); genGet.Emit(OpCodes.Ret); MethodBuilder mbSet = tb.DefineMethod("set_" + dp.Name, MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig, null, new Type[] { dp.Type }); ILGenerator genSet = mbSet.GetILGenerator(); genSet.Emit(OpCodes.Ldarg_0); genSet.Emit(OpCodes.Ldarg_1); genSet.Emit(OpCodes.Stfld, fb); genSet.Emit(OpCodes.Ret); pb.SetGetMethod(mbGet); pb.SetSetMethod(mbSet); fields[i] = fb; } return fields; } static void GenerateEquals(TypeBuilder tb, FieldInfo[] fields) { MethodBuilder mb = tb.DefineMethod("Equals", MethodAttributes.Public | MethodAttributes.ReuseSlot | MethodAttributes.Virtual | MethodAttributes.HideBySig, typeof(bool), new Type[] { typeof(object) }); ILGenerator gen = mb.GetILGenerator(); LocalBuilder other = gen.DeclareLocal(tb); Label next = gen.DefineLabel(); gen.Emit(OpCodes.Ldarg_1); gen.Emit(OpCodes.Isinst, tb); gen.Emit(OpCodes.Stloc, other); gen.Emit(OpCodes.Ldloc, other); gen.Emit(OpCodes.Brtrue_S, next); gen.Emit(OpCodes.Ldc_I4_0); gen.Emit(OpCodes.Ret); gen.MarkLabel(next); foreach (FieldInfo field in fields) { Type ft = field.FieldType; Type ct = typeof(EqualityComparer<>).MakeGenericType(ft); next = gen.DefineLabel(); gen.EmitCall(OpCodes.Call, ct.GetMethod("get_Default"), null); gen.Emit(OpCodes.Ldarg_0); gen.Emit(OpCodes.Ldfld, field); gen.Emit(OpCodes.Ldloc, other); gen.Emit(OpCodes.Ldfld, field); gen.EmitCall(OpCodes.Callvirt, ct.GetMethod("Equals", new Type[] { ft, ft }), null); gen.Emit(OpCodes.Brtrue_S, next); gen.Emit(OpCodes.Ldc_I4_0); gen.Emit(OpCodes.Ret); gen.MarkLabel(next); } gen.Emit(OpCodes.Ldc_I4_1); gen.Emit(OpCodes.Ret); } static void GenerateGetHashCode(TypeBuilder tb, FieldInfo[] fields) { MethodBuilder mb = tb.DefineMethod("GetHashCode", MethodAttributes.Public | MethodAttributes.ReuseSlot | MethodAttributes.Virtual | MethodAttributes.HideBySig, typeof(int), Type.EmptyTypes); ILGenerator gen = mb.GetILGenerator(); gen.Emit(OpCodes.Ldc_I4_0); foreach (FieldInfo field in fields) { Type ft = field.FieldType; Type ct = typeof(EqualityComparer<>).MakeGenericType(ft); gen.EmitCall(OpCodes.Call, ct.GetMethod("get_Default"), null); gen.Emit(OpCodes.Ldarg_0); gen.Emit(OpCodes.Ldfld, field); gen.EmitCall(OpCodes.Callvirt, ct.GetMethod("GetHashCode", new Type[] { ft }), null); gen.Emit(OpCodes.Xor); } gen.Emit(OpCodes.Ret); } } public abstract class DynamicClass { public override string ToString() { PropertyInfo[] props = GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public); StringBuilder sb = new StringBuilder(); sb.Append("{"); for (int i = 0; i < props.Length; i++) { if (i > 0) sb.Append(", "); sb.Append(props[i].Name); sb.Append("="); sb.Append(props[i].GetValue(this, null)); } sb.Append("}"); return sb.ToString(); } } public class DynamicProperty { private readonly string name; private readonly Type type; public DynamicProperty(string name, Type type) { if (name == null) throw new ArgumentNullException("name"); if (type == null) throw new ArgumentNullException("type"); this.name = name; this.type = type; } public string Name { get { return name; } } public Type Type { get { return type; } } } }

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• Webcast: Best Practices for Speeding Virtual Infrastructure Deployment with Oracle VM

  - by Honglin Su

  We announced Oracle VM Blade Cluster Reference Configuration last month, see the blog. The new Oracle VM blade cluster reference configuration can help reduce the time to deploy virtual infrastructure by up to 98 percent when compared to multi-vendor configurations. Customers and partners have shown lots of interests. Join Oracle's experts to learn the best practices for speeding virtual infrastructure deployment with Oracle VM, register the webcast (1/25/2011) here.   Virtualization has already been widely accepted as a means to increase IT flexibility and help IT services align better with changing business needs. The flexibility of a virtualized IT infrastructure enables new applications to be rapidly deployed, capacity to be easily scaled, and IT resources to be quickly redirected. The net result is that IT can bring greater value to the business, making virtualization an obvious win from a business perspective. However, building a virtualized infrastructure typically requires assembling and integrating multiple components (e.g. servers, storage, network, virtualization, and operating systems). This infrastructure must be deployed and tested before applications can even be installed. It can take weeks or months to plan, architect, configure, troubleshoot, and deploy a virtualized infrastructure. The process is not only time-consuming, but also error-prone, making it hard to achieve a timely and profitable return on investment.  Oracle is the only vendor that can offer a fully integrated virtualization infrastructure with all of the necessary hardware and software components. The Oracle VM blade cluster reference configuration is a single-vendor solution that addresses every layer of the virtualization stack with Oracle hardware and software components, see the figure below. It enables quick and easy deployment of the virtualized infrastructure using components that have been tested together and are all supported together by Oracle. To learn more about Oracle's virtualization offerings, visit http://oracle.com/virtualization.

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• Setting up a local AI server - easy with Solaris 11

  - by Stefan Hinker

  Many things are new in Solaris 11, Autoinstall is one of them.  If, like me, you've known Jumpstart for the last 2 centuries or so, you'll have to start from scratch.  Well, almost, as the concepts are similar, and it's not all that difficult.  Just new. I wanted to have an AI server that I could use for demo purposes, on the train if need be.  That answers the question of hardware requirements: portable.  But let's start at the beginning. First, you need an OS image, of course.  In the new world of Solaris 11, it is now called a repository.  The original can be downloaded from the Solaris 11 page at Oracle.   What you want is the "Oracle Solaris 11 11/11 Repository Image", which comes in two parts that can be combined using cat.  MD5 checksums for these (and all other downloads from that page) are available closer to the top of the page. With that, building the repository is quick and simple: # zfs create -o mountpoint=/export/repo rpool/ai/repo # zfs create rpool/ai/repo/s11 # mount -o ro -F hsfs /tmp/sol-11-1111-repo-full.iso /mnt # rsync -aP /mnt/repo /export/repo/s11 # umount /mnt # pkgrepo rebuild -s /export/repo/sol11/repo # zfs snapshot rpool/ai/repo/sol11@fcs # pkgrepo info -s /export/repo/sol11/repo PUBLISHER PACKAGES STATUS UPDATED solaris 4292 online 2012-03-12T20:47:15.378639Z That's all there's to it.  Let's make a snapshot, just to be on the safe side.  You never know when one will come in handy.  To use this repository, you could just add it as a file-based publisher: # pkg set-publisher -g file:///export/repo/sol11/repo solaris In case I'd want to access this repository through a (virtual) network, i'll now quickly activate the repository-service: # svccfg -s application/pkg/server \ setprop pkg/inst_root=/export/repo/sol11/repo # svccfg -s application/pkg/server setprop pkg/readonly=true # svcadm refresh application/pkg/server # svcadm enable application/pkg/server That's all you need - now point your browser to http://localhost/ to view your beautiful repository-server. Step 1 is done.  All of this, by the way, is nicely documented in the README file that's contained in the repository image. Of course, we already have updates to the original release.  You can find them in MOS in the Oracle Solaris 11 Support Repository Updates (SRU) Index.  You can simply add these to your existing repository or create separate repositories for each SRU.  The individual SRUs are self-sufficient and incremental - SRU4 includes all updates from SRU2 and SRU3.  With ZFS, you can also get both: A full repository with all updates and at the same time incremental ones up to each of the updates: # mount -o ro -F hsfs /tmp/sol-11-1111-sru4-05-incr-repo.iso /mnt # pkgrecv -s /mnt/repo -d /export/repo/sol11/repo '*' # umount /mnt # pkgrepo rebuild -s /export/repo/sol11/repo # zfs snapshot rpool/ai/repo/sol11@sru4 # zfs set snapdir=visible rpool/ai/repo/sol11 # svcadm restart svc:/application/pkg/server:default The normal repository is now updated to SRU4.  Thanks to the ZFS snapshots, there is also a valid repository of Solaris 11 11/11 without the update located at /export/repo/sol11/.zfs/snapshot/fcs . If you like, you can also create another repository service for each update, running on a separate port. But now lets continue with the AI server.  Just a little bit of reading in the dokumentation makes it clear that we will need to run a DHCP server for this.  Since I already have one active (for my SunRay installation) and since it's a good idea to have these kinds of services separate anyway, I decided to create this in a Zone.  So, let's create one first: # zfs create -o mountpoint=/export/install rpool/ai/install # zfs create -o mountpoint=/zones rpool/zones # zonecfg -z ai-server zonecfg:ai-server> create create: Using system default template 'SYSdefault' zonecfg:ai-server> set zonepath=/zones/ai-server zonecfg:ai-server> add dataset zonecfg:ai-server:dataset> set name=rpool/ai/install zonecfg:ai-server:dataset> set alias=install zonecfg:ai-server:dataset> end zonecfg:ai-server> commit zonecfg:ai-server> exit # zoneadm -z ai-server install # zoneadm -z ai-server boot ; zlogin -C ai-server Give it a hostname and IP address at first boot, and there's the Zone.  For a publisher for Solaris packages, it will be bound to the "System Publisher" from the Global Zone.  The /export/install filesystem, of course, is intended to be used by the AI server.  Let's configure it now: #zlogin ai-server root@ai-server:~# pkg install install/installadm root@ai-server:~# installadm create-service -n x86-fcs -a i386 \ -s pkg://solaris/install-image/[email protected],5.11-0.175.0.0.0.2.1482 \ -d /export/install/fcs -i 192.168.2.20 -c 3 With that, the core AI server is already done.  What happened here?  First, I installed the AI server software.  IPS makes that nice and easy.  If necessary, it'll also pull in the required DHCP-Server and anything else that might be missing.  Watch out for that DHCP server software.  In Solaris 11, there are two different versions.  There's the one you might know from Solaris 10 and earlier, and then there's a new one from ISC.  The latter is the one we need for AI.  The SMF service names of both are very similar.  The "old" one is "svc:/network/dhcp-server:default". The ISC-server comes with several SMF-services. We at least need "svc:/network/dhcp/server:ipv4".  The command "installadm create-service" creates the installation-service. It's called "x86-fcs", serves the "i386" architecture and gets its boot image from the repository of the system publisher, using version 5.11,5.11-0.175.0.0.0.2.1482, which is Solaris 11 11/11.  (The option "-a i386" in this example is optional, since the installserver itself runs on a x86 machine.) The boot-environment for clients is created in /export/install/fcs and the DHCP-server is configured for 3 IP-addresses starting at 192.168.2.20.  This configuration is stored in a very human readable form in /etc/inet/dhcpd4.conf.  An AI-service for SPARC systems could be created in the very same way, using "-a sparc" as the architecture option. Now we would be ready to register and install the first client.  It would be installed with the default "solaris-large-server" using the publisher "http://pkg.oracle.com/solaris/release" and would query it's configuration interactively at first boot.  This makes it very clear that an AI-server is really only a boot-server.  The true source of packets to install can be different.  Since I don't like these defaults for my demo setup, I did some extra config work for my clients. The configuration of a client is controlled by manifests and profiles.  The manifest controls which packets are installed and how the filesystems are layed out.  In that, it's very much like the old "rules.ok" file in Jumpstart.  Profiles contain additional configuration like root passwords, primary user account, IP addresses, keyboard layout etc.  Hence, profiles are very similar to the old sysid.cfg file. The easiest way to get your hands on a manifest is to ask the AI server we just created to give us it's default one.  Then modify that to our liking and give it back to the installserver to use: root@ai-server:~# mkdir -p /export/install/configs/manifests root@ai-server:~# cd /export/install/configs/manifests root@ai-server:~# installadm export -n x86-fcs -m orig_default \ -o orig_default.xml root@ai-server:~# cp orig_default.xml s11-fcs.small.local.xml root@ai-server:~# vi s11-fcs.small.local.xml root@ai-server:~# more s11-fcs.small.local.xml <!DOCTYPE auto_install SYSTEM "file:///usr/share/install/ai.dtd.1"> <auto_install> <ai_instance name="S11 Small fcs local"> <target> <logical> <zpool name="rpool" is_root="true"> <filesystem name="export" mountpoint="/export"/> <filesystem name="export/home"/> <be name="solaris"/> </zpool> </logical> </target> <software type="IPS"> <destination> <image> <!-- Specify locales to install --> <facet set="false">facet.locale.*</facet> <facet set="true">facet.locale.de</facet> <facet set="true">facet.locale.de_DE</facet> <facet set="true">facet.locale.en</facet> <facet set="true">facet.locale.en_US</facet> </image> </destination> <source> <publisher name="solaris"> <origin name="http://192.168.2.12/"/> </publisher> </source> <!-- By default the latest build available, in the specified IPS repository, is installed. If another build is required, the build number has to be appended to the 'entire' package in the following form: <name>pkg:/[email protected]#</name> --> <software_data action="install"> <name>pkg:/[email protected],5.11-0.175.0.0.0.2.0</name> <name>pkg:/group/system/solaris-small-server</name> </software_data> </software> </ai_instance> </auto_install> root@ai-server:~# installadm create-manifest -n x86-fcs -d \ -f ./s11-fcs.small.local.xml root@ai-server:~# installadm list -m -n x86-fcs Manifest Status Criteria -------- ------ -------- S11 Small fcs local Default None orig_default Inactive None The major points in this new manifest are: Install "solaris-small-server" Install a few locales less than the default.  I'm not that fluid in French or Japanese... Use my own package service as publisher, running on IP address 192.168.2.12 Install the initial release of Solaris 11:  pkg:/[email protected],5.11-0.175.0.0.0.2.0 Using a similar approach, I'll create a default profile interactively and use it as a template for a few customized building blocks, each defining a part of the overall system configuration.  The modular approach makes it easy to configure numerous clients later on: root@ai-server:~# mkdir -p /export/install/configs/profiles root@ai-server:~# cd /export/install/configs/profiles root@ai-server:~# sysconfig create-profile -o default.xml root@ai-server:~# cp default.xml general.xml; cp default.xml mars.xml root@ai-server:~# cp default.xml user.xml root@ai-server:~# vi general.xml mars.xml user.xml root@ai-server:~# more general.xml mars.xml user.xml :::::::::::::: general.xml :::::::::::::: <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type="profile" name="sysconfig"> <service version="1" type="service" name="system/timezone"> <instance enabled="true" name="default"> <property_group type="application" name="timezone"> <propval type="astring" name="localtime" value="Europe/Berlin"/> </property_group> </instance> </service> <service version="1" type="service" name="system/environment"> <instance enabled="true" name="init"> <property_group type="application" name="environment"> <propval type="astring" name="LANG" value="C"/> </property_group> </instance> </service> <service version="1" type="service" name="system/keymap"> <instance enabled="true" name="default"> <property_group type="system" name="keymap"> <propval type="astring" name="layout" value="US-English"/> </property_group> </instance> </service> <service version="1" type="service" name="system/console-login"> <instance enabled="true" name="default"> <property_group type="application" name="ttymon"> <propval type="astring" name="terminal_type" value="vt100"/> </property_group> </instance> </service> <service version="1" type="service" name="network/physical"> <instance enabled="true" name="default"> <property_group type="application" name="netcfg"> <propval type="astring" name="active_ncp" value="DefaultFixed"/> </property_group> </instance> </service> <service version="1" type="service" name="system/name-service/switch"> <property_group type="application" name="config"> <propval type="astring" name="default" value="files"/> <propval type="astring" name="host" value="files dns"/> <propval type="astring" name="printer" value="user files"/> </property_group> <instance enabled="true" name="default"/> </service> <service version="1" type="service" name="system/name-service/cache"> <instance enabled="true" name="default"/> </service> <service version="1" type="service" name="network/dns/client"> <property_group type="application" name="config"> <property type="net_address" name="nameserver"> <net_address_list> <value_node value="192.168.2.1"/> </net_address_list> </property> </property_group> <instance enabled="true" name="default"/> </service> </service_bundle> :::::::::::::: mars.xml :::::::::::::: <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type="profile" name="sysconfig"> <service version="1" type="service" name="network/install"> <instance enabled="true" name="default"> <property_group type="application" name="install_ipv4_interface"> <propval type="astring" name="address_type" value="static"/> <propval type="net_address_v4" name="static_address" value="192.168.2.100/24"/> <propval type="astring" name="name" value="net0/v4"/> <propval type="net_address_v4" name="default_route" value="192.168.2.1"/> </property_group> <property_group type="application" name="install_ipv6_interface"> <propval type="astring" name="stateful" value="yes"/> <propval type="astring" name="stateless" value="yes"/> <propval type="astring" name="address_type" value="addrconf"/> <propval type="astring" name="name" value="net0/v6"/> </property_group> </instance> </service> <service version="1" type="service" name="system/identity"> <instance enabled="true" name="node"> <property_group type="application" name="config"> <propval type="astring" name="nodename" value="mars"/> </property_group> </instance> </service> </service_bundle> :::::::::::::: user.xml :::::::::::::: <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type="profile" name="sysconfig"> <service version="1" type="service" name="system/config-user"> <instance enabled="true" name="default"> <property_group type="application" name="root_account"> <propval type="astring" name="login" value="root"/> <propval type="astring" name="password" value="noIWillNotTellYouMyPasswordNotEvenEncrypted"/> <propval type="astring" name="type" value="role"/> </property_group> <property_group type="application" name="user_account"> <propval type="astring" name="login" value="stefan"/> <propval type="astring" name="password" value="noIWillNotTellYouMyPasswordNotEvenEncrypted"/> <propval type="astring" name="type" value="normal"/> <propval type="astring" name="description" value="Stefan Hinker"/> <propval type="count" name="uid" value="12345"/> <propval type="count" name="gid" value="10"/> <propval type="astring" name="shell" value="/usr/bin/bash"/> <propval type="astring" name="roles" value="root"/> <propval type="astring" name="profiles" value="System Administrator"/> <propval type="astring" name="sudoers" value="ALL=(ALL) ALL"/> </property_group> </instance> </service> </service_bundle> root@ai-server:~# installadm create-profile -n x86-fcs -f general.xml root@ai-server:~# installadm create-profile -n x86-fcs -f user.xml root@ai-server:~# installadm create-profile -n x86-fcs -f mars.xml \ -c ipv4=192.168.2.100 root@ai-server:~# installadm list -p Service Name Profile ------------ ------- x86-fcs general.xml mars.xml user.xml root@ai-server:~# installadm list -n x86-fcs -p Profile Criteria ------- -------- general.xml None mars.xml ipv4 = 192.168.2.100 user.xml None Here's the idea behind these files: "general.xml" contains settings valid for all my clients.  Stuff like DNS servers, for example, which in my case will always be the same. "user.xml" only contains user definitions.  That is, a root password and a primary user.Both of these profiles will be valid for all clients (for now). "mars.xml" defines network settings for an individual client.  This profile is associated with an IP-Address.  For this to work, I'll have to tweak the DHCP-settings in the next step: root@ai-server:~# installadm create-client -e 08:00:27:AA:3D:B1 -n x86-fcs root@ai-server:~# vi /etc/inet/dhcpd4.conf root@ai-server:~# tail -5 /etc/inet/dhcpd4.conf host 080027AA3DB1 { hardware ethernet 08:00:27:AA:3D:B1; fixed-address 192.168.2.100; filename "01080027AA3DB1"; } This completes the client preparations.  I manually added the IP-Address for mars to /etc/inet/dhcpd4.conf.  This is needed for the "mars.xml" profile.  Disabling arbitrary DHCP-replies will shut up this DHCP server, making my life in a shared environment a lot more peaceful ;-)Now, I of course want this installation to be completely hands-off.  For this to work, I'll need to modify the grub boot menu for this client slightly.  You can find it in /etc/netboot.  "installadm create-client" will create a new boot menu for every client, identified by the client's MAC address.  The template for this can be found in a subdirectory with the name of the install service, /etc/netboot/x86-fcs in our case.  If you don't want to change this manually for every client, modify that template to your liking instead. root@ai-server:~# cd /etc/netboot root@ai-server:~# cp menu.lst.01080027AA3DB1 menu.lst.01080027AA3DB1.org root@ai-server:~# vi menu.lst.01080027AA3DB1 root@ai-server:~# diff menu.lst.01080027AA3DB1 menu.lst.01080027AA3DB1.org 1,2c1,2 < default=1 < timeout=10 --- > default=0 > timeout=30 root@ai-server:~# more menu.lst.01080027AA3DB1 default=1 timeout=10 min_mem64=0 title Oracle Solaris 11 11/11 Text Installer and command line kernel$ /x86-fcs/platform/i86pc/kernel/$ISADIR/unix -B install_media=htt p://$serverIP:5555//export/install/fcs,install_service=x86-fcs,install_svc_addre ss=$serverIP:5555 module$ /x86-fcs/platform/i86pc/$ISADIR/boot_archive title Oracle Solaris 11 11/11 Automated Install kernel$ /x86-fcs/platform/i86pc/kernel/$ISADIR/unix -B install=true,inst all_media=http://$serverIP:5555//export/install/fcs,install_service=x86-fcs,inst all_svc_address=$serverIP:5555,livemode=text module$ /x86-fcs/platform/i86pc/$ISADIR/boot_archive Now just boot the client off the network using PXE-boot.  For my demo purposes, that's a client from VirtualBox, of course.  That's all there's to it.  And despite the fact that this blog entry is a little longer - that wasn't that hard now, was it?

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