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  • I, Android

    - by andrewbrust
    I’m just back from the 2011 Consumer Electronics Show (CES).  I go to CES to get a sense of what Microsoft is doing in the consumer space, and how people are reacting to it.  When I first went to CES 2 years ago, Steve Ballmer announced the beta of Windows 7 at his keynote address, and the crowd went wild.  When I went again last year, everyone was hoping for a Windows tablet announcement at the Ballmer keynote.  Although they didn’t get one (unless you count the unreleased HP Slate running Windows 7), people continued to show anticipation around Project Natal (which became Xbox 360 Kinect) and around Windows Phone 7.  On the show floor last year, there were machines everywhere running Windows 7, including lots of netbooks.  Microsoft had a serious influence at the show both years. But this year, one brand, one product, one operating system evidenced itself over and over again: Android.  Whether in the multitude of tablet devices that were shown across the show, or the burgeoning number of smartphones shown (including all four forthcoming 4G-LTE handsets at Verizon Wireless’ booth) or the Google TV set top box from Logitech and the embedded implementation in new Sony TV models, Android was was there. There was excitement in the ubiquity of Android 2.2 (Froyo) and the emergence of Android 2.3 (Gingerbread).  There was anticipation around the tablet-optimized Android 3.0 (Honeycomb).  There were highly customized skins.  There was even an official CES Android app for navigating the exhibit halls and planning events.  Android was so ubiquitous, in fact, that it became surprising to find a device that was running anything else.  It was as if Android had become the de facto Original Equipment Manufacturing (OEM) operating system. Motorola’s booth was nothing less than an Android showcase.  And it was large, and it was packed.  Clearly Moto’s fortunes have improved dramatically in the last year and change.  The fact that the company morphed from being a core Windows Mobile OEM to an Android poster child seems non-coincidental to their improved fortunes. Even erstwhile WinMo OEMs who now do produce Windows Phone 7 devices were not pushing them.  Perhaps I missed them, but I couldn’t find WP7 handsets at Samsung’s booth, nor at LG’s.  And since the only carrier exhibiting at the show was Verizon Wireless, which doesn’t yet have WP7 devices, this left Microsoft’s booth as the only place to see the phones. Why is Android so popular with consumer electronics manufacturers in Japan, South Korea, China and Taiwan?  Yes, it’s free, but there’s more to it than that.  Android seems to have succeeded as an OEM OS because it’s directed at OEMs who are permitted to personalize it and extend it, and it provides enough base usability and touch-friendliness that OEMs want it.  In the process, it has become a de facto standard (which makes OEMs want it even more), and has done so in a remarkably short time: the OS was launched on a single phone in the US just 2 1/4 years ago. Despite its success and popularity, Apple’s iOS would never be used by OEMs, because it’s not meant to be embedded and customized, but rather to provide a fully finished experience.  Ironically, Windows Phone 7 is likewise disqualified from such embedded use.  Windows Mobile (6.x and earlier) may have been a candidate had it not atrophied so much in its final 5 years of life. What can Microsoft do?  It could start by developing a true touch-centric OS for tablets, whether that be within Windows 8, or derived from Windows Phone 7.  It would then need to deconstruct that finished product into components, via a new or altered version of Windows Embedded or Windows Embedded Compact.  And if Microsoft went that far, it would only make sense to work with its OEMs and mobile carriers to make certain they showcase their products using the OS at CES, and other consumer electronics venues, prominently. Mostly though, Microsoft would need to decide if it were really committed to putting sustained time, effort and money into a commodity product, especially given the far greater financial return that it now derives from its core Windows and Office franchises. Microsoft would need to see an OEM OS for what it is: a loss leader that helps build brand and platform momentum for up-level products.  Is that enough to make the investment worthwhile?  One thing is certain: if that question is not acknowledged and answered honestly, then any investment will be squandered.

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  • PowerShell &ndash; Recycle All IIS App Pools

    - by Lance Robinson
    With a little help from Shay Levy’s post on Stack Overflow and the MSDN documentation, I added this handy function to my profile to automatically recycle all IIS app pools.           function Recycle-AppPools {     param(     [string] $server = "3bhs001",     [int] $mode = 1, # ManagedPipelineModes: 0 = integrated, 1 = classic     )  $iis = [adsi]"IIS://$server/W3SVC/AppPools" $iis.psbase.children | %{ $pool = [adsi]($_.psbase.path);    if ($pool.AppPoolState -eq 2 -and $pool.ManagedPipelineMode -eq $mode) {    # AppPoolStates:  1 = starting, 2 = started, 3 = stopping, 4 = stopped               $pool.psbase.invoke("recycle")      }   }}

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  • Running ASP.Net MVC3 Alongside ASP.Net WebForms in the Same Project

    - by Sam Abraham
    I previously blogged on running ASP.Net MVC in an ASP.Net WebForms project. My reference at the time was a freely-available PDF document by Scott Guthrie which covered the setup process in good detail.   As I am preparing references to share with our audience at my upcoming talk at the Deerfield Beach Coders Café on March 1st (http://www.fladotnet.com/Reg.aspx?EventID=514), I found a nice blog post by Scott Hanselman on running both ASP.Net 4.0 WebForms along with ASP.Net MVC 3.0 in the same project. You can access this article here.   Moreover, Scott later followed-up with a blog showing how to leverage NuGet to automate the setup of ASP.Net MVC3 in an existing ASP.Net WebForms project.   One frequent question that usually comes up when discussing this side-by-side setup is the loss of the convenient Visual Studio Solution Explorer context menu which enable us to easily create controllers and views with a few mouse clicks.   A good suggestion brought up in the comments section of Scott’s article presented a good work-around to this problem: Manually add the MVC Visual Studio Project Type GUID in your .sln solution file ({E53F8FEA-EAE0-44A6-8774-FFD645390401}) which then brings back the MVC-specific context menu functionality in solution explorer of the hybrid project. (Thank James Raden!)

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  • How to clear the resent server name list in SQL Server Management Studio

    - by Pavan Kumar Pabothu
    If you are using SQL Server management Studio much the we can observer that the list of server names in the log in of it. As you can imagin a period of time after 6 month or 1 year you will see a long list of server names in the login dialog. How to clear this list...? I doesn't provide a mechanism to clean nor clear the list, so you'll have to do a little browsing through your file system. For SQl Server 2005 Management Studio, we should delete the below file C:\Documents and Settings\<user>\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\mru.dat. For SQl Server 2008 Management Studio, we should delete the below file C:\Documents and Settings\<user>\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\SQLStudio.bin. After deletion we can re-login the Management studio and can see the empty list.

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  • Unexpected issues with SessionPageStatePersiste

    - by geekrutherford
    Several iterations ago I implemented the SessionPageStatePersister in an application as a way to cut down on the size of the hidden ViewState input on aspx pages.   At first it seemed utterly fantasic. The size of the ViewState appeared to be drastically reduced and the application did not appear to peform any slower than baseline.   Enter the iFrame &amp; user control. I added a user control which pings the web server every 20 seconds in order to show updated application information to the user (new messages, reports, etc.) After releasing this nifty little control into the QA environment I quickly began receiving emails from testers about "post back" related error messages which mostly centered around invalid ViewState exceptions.   At first I dismissed it as something related to all of the AJAX requests happening on the page and considered turning off page event validation. However, upon further investigation I came across the following article:   Things That You Should Watch Out For When Using SessionPageStatePersister   In this article the author specifically states:   If you application uses frames than each frame request will create a new session view state item and as before it will remove items when reaching the maximum, you come into a situation that one of the frames will probably loose it session view state because other frames did post backs.   Oh snap! That is precisely what I am doing. That combined with multiple users on the application equals dropped ViewStates!   The temporary fix has been to disable the use of the SessionPageStatePersister in my application. This results in a bloated hidden ViewState input, but the web server is no longer tasked with maintaing/retreiving it and the app. no longer loses ViewState information.

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  • Select comma separated result from via comma separated parameter

    - by Rodney Vinyard
    Select comma separated result from via comma separated parameter PROCEDURE [dbo].[GetCommaSepStringsByCommaSepNumericIds] (@CommaSepNumericIds varchar(max))   AS   BEGIN   /* exec GetCommaSepStringsByCommaSepNumericIds '1xx1, 1xx2, 1xx3' */ DECLARE @returnCommaSepIds varchar(max); with cte as ( select distinct Left(qc.myString, 1) + '-' + substring(qc.myString, 2, 9) + '-' + substring(qc.myString, 11, 7) as myString from q_CoaRequestCompound qc               JOIN               dbo.SplitStringToNumberTable(@CommaSepNumericIds) AS s               ON               qc.q_CoaRequestId = s.ID where SUBSTRING(upper(myString), 1, 1) in('L', '?') ) SELECT @returnCommaSepIds = COALESCE(@returnCommaSepIds + ''',''', '''') + CAST(myString AS varchar(2x)) FROM cte;   set @returnCommaSepIds = @returnCommaSepIds + '''' SELECT @returnCommaSepIds   End   FUNCTION [dbo].[SplitStringToNumberTable] (        @commaSeparatedList varchar(max) ) RETURNS @outTable table (        ID int ) AS BEGIN        DECLARE @parsedItem varchar(10), @Pos int          SET @commaSeparatedList = LTRIM(RTRIM(@commaSeparatedList))+ ','        SET @commaSeparatedList = REPLACE(@commaSeparatedList, ' ', '')        SET @Pos = CHARINDEX(',', @commaSeparatedList, 1)          IF REPLACE(@commaSeparatedList, ',', '') <> ''        BEGIN               WHILE @Pos > 0               BEGIN                      SET @parsedItem = LTRIM(RTRIM(LEFT(@commaSeparatedList, @Pos - 1)))                      IF @parsedItem <> ''                            BEGIN                                   INSERT INTO @outTable(ID)                                   VALUES (CAST(@parsedItem AS int)) --Use Appropriate conversion                            END                            SET @commaSeparatedList = RIGHT(@commaSeparatedList, LEN(@commaSeparatedList) - @Pos)                            SET @Pos = CHARINDEX(',', @commaSeparatedList, 1)               END        END           RETURN END

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  • Learn to Take a Punch, Learn to Counter, Keep Moving Forward

    - by D'Arcy Lussier
    Originally posted on: http://geekswithblogs.net/dlussier/archive/2013/10/28/154483.aspxDuring a boxing workout a few months ago our trainer had us do something called “breadbaskets”. That’s where you hold your arms up and a partner punches you in your midsection – your breadbasket. I put my arms up, and braced for impact. The trainer came over, saw I was a bit nervous, and coached me through. I can see the fear in your eyes. Don’t be afraid to take the punch. Tighten your core, breathe through the hit. Don’t panic. Over the summer we’d do counter drills as well. This is where a partner throws a punch, you defend but also throw one back – a counter punch. You never just sit back and take a beating, you deflect the blow and come back with one more powerful. These lessons on fighting can apply to all aspects of our lives and any attempts at success that we have. I saw this image recently and agree with it 100%: Success is never a straight forward line. It’s messy, its wrought with failures, its learning over time and applying those life lessons. It’s learning how to take punches and lose your fear, its seeing a punch coming and countering it, but most of all its not giving up and continually moving forward. We do stairs at boxing, which is running up and down three flights of stairs. I’m not anywhere near incredible shape and after doing multiple stairs in a single workout you can feel gassed, tired, even discouraged after hitting the second floor and seeing everyone else running by you. I read a quote from Martin Luther King Jr. that I cling to throughout my day: You want to be successful? Take the punches, but learn how to take them. Counter them. and no matter what, always move forward.

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  • Part 1 Basic Webtrends REST Examples

    - by GeekAgilistMercenary
    In this entry I just want to cover some examples of how to connect to Webtrends DX Web Services.  The DX Web Services use REST as the architecture, providing simple URI based end points to connect to.  With the Webtrends SDK you can connect to these services with your account information.  Here are the basic steps to retrieve a profile list, the reports from one of those profiles, and then the report you want from that report list. First step is to create a Webtrends User. WebTrends.Sdk.Account.User webtrendsUser = new Account.User(); webtrendsUser.UserName = username; webtrendsUser.Password = password; webtrendsUser.AccountName = account; After you create the Webtrends User, simple request a profile list by getting list of ProfileDefinition Objects. List<WebTrends.Sdk.Profile.ProfileDefinition> profiles = WebTrends.Sdk.Factory.NavigationFactory.BuildListing(webtrendsUser); Next you will want to grab a report based on the profile you are in and your credentials. List<WebTrends.Sdk.Report.ReportDefinition> reports = WebTrends.Sdk.Factory.NavigationFactory.BuildListing(profiles[i], webtrendsUser); In the code above, i would equate to the specific profile you want from the retrieved list of profiles in the profiles list.  The common scenario is that one has pulled the profiles into a drop down, combo, or list box that the user can select.  Then when the user selects the specific profile that profile object can then be used to pull the List of ReportDefinitions. Once we have the report definitions, all sorts of criteria can be added together to query for a specific report.  This is also were things can get a little tricky.  For instance, take a look at the code below. WebTrends.Sdk.Factory.ReportFactory.CreateDimensionalReport( report.ID.ToString(), profiles[i].ID.ToString(), "2010m01", webtrendsUser); The CreateDimensionalReport takes 4 parameters for this particular overload.  The report ID, profile ID, the Webtrends Date Format, and the Webtrends User Object.  There are a number of other overloads available within this factory's method that allow for passing the specific REST URI, and other criteria to retrieve the report of your choice.  In the near future we will be adding some more to this method also, which will provide more flexibility without needing to use the full REST URI. I will have more on this, so all you Coders out there using Webtrends DX Services, I hope this is helpful!  Enjoy. Original Entry

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  • Deploying an SSL Application to Windows Azure &ndash; The Dark Secret

    - by ToStringTheory
    When working on an application that had been in production for some time, but was about to have a shopping cart added to it, the necessity for SSL certificates came up.  When ordering the certificates through the vendor, the certificate signing request (CSR) was generated through the providers (http://register.com) web interface, and within a day, we had our certificate. At first, I thought that the certification process would be the hard part…  Little did I know that my fun was just beginning… The Problem I’ll be honest, I had never really secured a site before with SSL.  This was a learning experience for me in the first place, but little did I know that I would be learning more than the simple procedure.  I understood a bit about SSL already, the mechanisms in how it works – the secure handshake, CA’s, chains, etc…  What I didn’t realize was the importance of the CSR in the whole process.  Apparently, when the CSR is created, a public key is created at the same time, as well as a private key that is stored locally on the PC that generated the request.  When the certificate comes back and you import it back into IIS (assuming you used IIS to generate the CSR), all of the information is combined together and the SSL certificate is added into your store. Since at the time the certificate had been ordered for our site, the selection to use the online interface to generate the CSR was chosen, the certificate came back to us in 5 separate files: A root certificate – (*.crt file) An intermediate certifcate – (*.crt file) Another intermediate certificate – (*.crt file) The SSL certificate for our site – (*.crt file) The private key for our certificate – (*.key file) Well, in case you don’t know much about Windows Azure and SSL certificates, the first thing you should learn is that certificates can only be uploaded to Azure if they are in a PFX package – securable by a password.  Also, in the case of our SSL certificate, you need to include the Private Key with the file.  As you can see, we didn’t have a PFX file to upload. If you don’t get the simple PFX from your hosting provider, but rather the multiple files, you will soon find out that the process has turned from something that should be simple – to one that borders on a circle of hell… Probably between the fifth and seventh somewhere… The Solution The solution is to take the files that make up the certificates chain and key, and combine them into a file that can be imported into your local computers store, as well as uploaded to Windows Azure.  I can not take the credit for this information, as I simply researched a while before finding out how to do this. Download the OpenSSL for Windows toolkit (Win32 OpenSSL v1.0.1c) Install the OpenSSL for Windows toolkit Download and move all of your certificate files to an easily accessible location (you'll be pointing to them in the command prompt, so I put them in a subdirectory of the OpenSSL installation) Open a command prompt Navigate to the folder where you installed OpenSSL Run the following command: openssl pkcs12 -export –out {outcert.pfx} –inkey {keyfile.key}      –in {sslcert.crt} –certfile {ca1.crt} –certfile (ca2.crt) From this command, you will get a file, outcert.pfx, with the sum total of your ssl certificate (sslcert.crt), private key {keyfile.key}, and as many CA/chain files as you need {ca1.crt, ca2.crt}. Taking this file, you can then import it into your own IIS in one operation, instead of importing each certificate individually.  You can also upload the PFX to Azure, and once you add the SSL certificate links to the cloud project in Visual Studio, your good to go! Conclusion When I first looked around for a solution to this problem, there were not many places online that had the information that I was looking for.  While what I ended up having to do may seem obvious, it isn’t for everyone, and I hope that this can at least help one developer out there solve the problem without hours of work!

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  • Commit Review Questions

    - by Wes McClure
    Note: in this article when I refer to a commit, I mean the commit you plan to share with the rest of the team, if you have local commits that you plan to amend/combine, I am referring to the final result. In time you will find these easier to do as you develop, however, all of these are valuable before checking in!  The pre commit review is a nice time to polish what might have been several hours of intense work, during which these things were the last things on your mind!  If you are concerned about losing your work in the process of responding to these questions, first do a check-in and amend it as you go (assuming you are using a tool such as git that supports this), rolling the result into one nice commit for everyone else.  Did you review your commit, change by change, with a diff utility? If not, this is a list of reasons why you might want to start! Did you test your changes? If the test is valuable to be automated, is it? If it’s a manual testing scenario, did you at least try the basics manually? Are the additions/changes formatted consistently with the rest of the project? Lots of automated tools can help here, don’t try to manually format the code, that’s a waste of time and as a human you will fail repeatedly. Are these consistent: tabs versus spaces, indentation, spacing, braces, line breaks, etc Resharper is a great example of a tool that can automate this for you (.net) Are naming conventions respected? Did you accidently use abbreviations, unless you have a good reason to use them? Does capitalization match the conventions in the project/language? Are files partitioned? Sometimes we add new code in existing files in a pinch, it’s a good idea to split these out if they don’t belong ie: are new classes defined in new files, if this is something your project values? Is there commented out code? If you are removing an existing feature, get rid of it, that is why we have VCS If it’s not done yet, then why are you checking it in? Perhaps a stash commit (git)? Did you leave debug or unnecessary changes? Do you understand all of the changes? http://geekswithblogs.net/wesm/archive/2012/04/11/programming-doesnrsquot-have-to-be-magic.aspx Are there spelling mistakes? Including your commit message! Is your commit message concise? Is there follow up work? Are there tasks you didn’t write down that you need to follow up with? Are readability or reorganization changes needed? This might be amended into the final commit, or it might be future work that needs added to the backlog. Are there other things your team values that you should review?

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  • Connect to running web role on Azure using Remote Desktop Connection and VS2012

    - by Magnus Karlsson
    We want to be able to collect IntelliTrace information from our running app and also use remote desktop to connect to the IIS and look around(probably debugging). 1. Create certificate 1.1 Right-click the cloud project (marked in red) and select “Configure remote desktop”. 1.2 In the drop down list of certificates, choose <create> at the bottom. 1.3. Follow the instructions, you can set it up with default values. 1.4 When done. Choose the certificate and click “Copy to File…” as seen in the left of the picture above. 1.5. Save the file with any name you want. Now we will save it to local storage to be able to import it to our solution through the azure configuration manager in step 3. 2. Save certificate to local storage Now we need to attach it to our local certificate storage to be able to reach it from our confiuguration manager in visual studio. Microsoft provides the following steps for doing this: http://support.microsoft.com/kb/232137 In order to view the Certificates store on the local computer, perform the following steps: Click Start, and then click Run. Type "MMC.EXE" (without the quotation marks) and click OK. Click Console in the new MMC you created, and then click Add/Remove Snap-in. In the new window, click Add. Highlight the Certificates snap-in, and then click Add. Choose the Computer option and click Next. Select Local Computer on the next screen, and then click OK. Click Close , and then click OK. You have now added the Certificates snap-in, which will allow you to work with any certificates in your computer's certificate store. You may want to save this MMC for later use. Now that you have access to the Certificates snap-in, you can import the server certificate into you computer's certificate store by following these steps: Open the Certificates (Local Computer) snap-in and navigate to Personal, and then Certificates. Note: Certificates may not be listed. If it is not, that is because there are no certificates installed. Right-click Certificates (or Personal if that option does not exist.) Choose All Tasks, and then click Import. When the wizard starts, click Next. Browse to the PFX file you created containing your server certificate and private key. Click Next. Enter the password you gave the PFX file when you created it. Be sure the Mark the key as exportable option is selected if you want to be able to export the key pair again from this computer. As an added security measure, you may want to leave this option unchecked to ensure that no one can make a backup of your private key. Click Next, and then choose the Certificate Store you want to save the certificate to. You should select Personal because it is a Web server certificate. If you included the certificates in the certification hierarchy, it will also be added to this store. Click Next. You should see a summary of screen showing what the wizard is about to do. If this information is correct, click Finish. You will now see the server certificate for your Web server in the list of Personal Certificates. It will be denoted by the common name of the server (found in the subject section of the certificate). Now that you have the certificate backup imported into the certificate store, you can enable Internet Information Services 5.0 to use that certificate (and the corresponding private key). To do this, perform the following steps: Open the Internet Services Manager (under Administrative Tools) and navigate to the Web site you want to enable secure communications (SSL/TLS) on. Right-click on the site and click Properties. You should now see the properties screen for the Web site. Click the Directory Security tab. Under the Secure Communications section, click Server Certificate. This will start the Web Site Certificate Wizard. Click Next. Choose the Assign an existing certificate option and click Next. You will now see a screen showing that contents of your computer's personal certificate store. Highlight your Web server certificate (denoted by the common name), and then click Next. You will now see a summary screen showing you all the details about the certificate you are installing. Be sure that this information is correct or you may have problems using SSL or TLS in HTTP communications. Click Next, and then click OK to exit the wizard. You should now have an SSL/TLS-enabled Web server. Be sure to protect your PFX files from any unwanted personnel. Image of a typical MMC.EXE with the certificates up.   3. Import the certificate to you visual studio project. 3.1 Now right click your equivalent to the MvcWebRole1 (as seen in the first picture under the red oval) and choose properties. 3.2 Choose Certificates. Right click the ellipsis to the right of the “thumbprint” and you should be able to select your newly created certificate here. After selecting it- save the file.   4. Upload the certificate to your Azure subscription. 4.1 Go to the azure management portal, click the services menu icon to the left and choose the service. Click Upload in the bottom menu.     5. Connect to server. Since I tried to use account settings(have to use another name) we have to set up a new name for the connection. No biggie. 5.1 Go to azure management portal, select your service and in the bottom menu, choose “REMOTE”. This will display the configuration for remote connection. It will actually change your ServiceConfiguration.cscfg file. After you change It here it might be good to choose download and replace the one in your project. Set a name that is not your windows azure account name and not Administrator. 5.2 Goto visual studio, click Server Explorer. Choose as selected in the picture below and click “COnnect using remote desktop”.   5.2 You will now be able to log in with the name and password set up in step 5.1. and voila! Windows server 2012, IIS and other nice stuff!   To do this one I’ve been using http://msdn.microsoft.com/en-us/library/windowsazure/ff683671.aspx where you can collect some of this information and additional one.

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  • Simple Little Registry Editor - New Release

    - by Bruce Eitman
    I have posted a new release of the Simple Little Registry Editor found in Windows CE: Simple Little Registry Editor.  This release fixes a problem with writing DWORD values when the most significant bit is set.  The application uses RegistryKey.SetValue.  There seems to be a problem with how the .NET CompactFramework (and the full framework) handle the second argument during the call which causes an exception. So the following does not work: RegistryKey.SetValue( "TestValue", 0xFFFFFFFF, RegistryValueKind.DWord ); But, this does: RegistryKey.SetValue( "TestValue",unchecked((int) 0xFFFFFFFF), RegistryValueKind.DWord ); Copyright © 2012 – Bruce Eitman All Rights Reserved

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  • Fixing LINQ Error: Sequence contains no elements

    - by ChrisD
    I’ve read some posts regarding this error when using the First() or Single() command.   They suggest using FirstOrDefault() or SingleorDefault() instead. But I recently encountered it when using a Sum() command in conjunction with a Where():   Code Snippet var effectiveFloor = policies.Where(p => p.PricingStrategy == PricingStrategy.EstablishFloor).Max(p => p.Amount);   When the Where() function eliminated all the items in the policies collection, the Sum() command threw the “Sequence contains no elements” exception.   Inserting the DefaultIfEmpty() command between the Where() and Sum(), prevents this error: Code Snippet var effectiveFloor = policies.Where(p => p.PricingStrategy == PricingStrategy.EstablishFloor).DefaultIfEmpty().Max(p => p.Amount);   but now throws a Null Reference exception!   The Fix: Using a combination of DefaultIfEmpty() and a null check in the Sum() command solves this problem entirely: Code Snippet var effectiveFloor = policies.Where(p => p.PricingStrategy == PricingStrategy.EstablishFloor).DefaultIfEmpty().Max(p =>  p==null?0 :p.Amount);

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  • BizTalk: History of one project architecture

    - by Leonid Ganeline
    "In the beginning God made heaven and earth. Then he started to integrate." At the very start was the requirement: integrate two working systems. Small digging up: It was one system. It was good but IT guys want to change it to the new one, much better, chipper, more flexible, and more progressive in technologies, more suitable for the future, for the faster world and hungry competitors. One thing. One small, little thing. We cannot turn off the old system (call it A, because it was the first), turn on the new one (call it B, because it is second but not the last one). The A has a hundreds users all across a country, they must study B. A still has a lot nice custom features, home-made features that cannot disappear. These features have to be moved to the B and it is a long process, months and months of redevelopment. So, the decision was simple. Let’s move not jump, let’s both systems working side-by-side several months. In this time we could teach the users and move all custom A’s special functionality to B. That automatically means both systems should work side-by-side all these months and use the same data. Data in A and B must be in sync. That’s how the integration projects get birth. Moreover, the specific of the user tasks requires the both systems must be in sync in real-time. Nightly synchronization is not working, absolutely.   First draft The first draft seems simple. Both systems keep data in SQL databases. When data changes, the Create, Update, Delete operations performed on the data, and the sync process could be started. The obvious decision is to use triggers on tables. When we are talking about data, we are talking about several entities. For example, Orders and Items [in Orders]. We decided to use the BizTalk Server to synchronize systems. Why it was chosen is another story. Second draft   Let’s take an example how it works in more details. 1.       User creates a new entity in the A system. This fires an insert trigger on the entity table. Trigger has to pass the message “Entity created”. This message includes all attributes of the new entity, but I focused on the Id of this entity in the A system. Notation for this message is id.A. System A sends id.A to the BizTalk Server. 2.       BizTalk transforms id.A to the format of the system B. This is easiest part and I will not focus on this kind of transformations in the following text. The message on the picture is still id.A but it is in slightly different format, that’s why it is changing in color. BizTalk sends id.A to the system B. 3.       The system B creates the entity on its side. But it uses different id-s for entities, these id-s are id.B. System B saves id.A+id.B. System B sends the message id.A+id.B back to the BizTalk. 4.       BizTalk sends the message id.A+id.B to the system A. 5.       System A saves id.A+id.B. Why both id-s should be saved on both systems? It was one of the next requirements. Users of both systems have to know the systems are in sync or not in sync. Users working with the entity on the system A can see the id.B and use it to switch to the system B and work there with the copy of the same entity. The decision was to store the pairs of entity id-s on both sides. If there is only one id, the entities are not in sync yet (for the Create operation). Third draft Next problem was the reliability of the synchronization. The synchronizing process can be interrupted on each step, when message goes through the wires. It can be communication problem, timeout, temporary shutdown one of the systems, the second system cannot be synchronized by some internal reason. There were several potential problems that prevented from enclosing the whole synchronization process in one transaction. Decision was to restart the whole sync process if it was not finished (in case of the error). For this purpose was created an additional service. Let’s call it the Resync service. We still keep the id pairs in both systems, but only for the fast access not for the synchronization process. For the synchronizing these id-s now are kept in one main place, in the Resync service database. The Resync service keeps record as: ·       Id.A ·       Id.B ·       Entity.Type ·       Operation (Create, Update, Delete) ·       IsSyncStarted (true/false) ·       IsSyncFinished (true/false0 The example now looks like: 1.       System A creates id.A. id.A is saved on the A. Id.A is sent to the BizTalk. 2.       BizTalk sends id.A to the Resync and to the B. id.A is saved on the Resync. 3.       System B creates id.B. id.A+id.B are saved on the B. id.A+id.B are sent to the BizTalk. 4.       BizTalk sends id.A+id.B to the Resync and to the A. id.A+id.B are saved on the Resync. 5.       id.A+id.B are saved on the B. Resync changes the IsSyncStarted and IsSyncFinished flags accordingly. The Resync service implements three main methods: ·       Save (id.A, Entity.Type, Operation) ·       Save (id.A, id.B, Entity.Type, Operation) ·       Resync () Two Save() are used to save id-s to the service storage. See in the above example, in 2 and 4 steps. What about the Resync()? It is the method that finishes the interrupted synchronization processes. If Save() is started by the trigger event, the Resync() is working as an independent process. It periodically scans the Resync storage to find out “unfinished” records. Then it restarts the synchronization processes. It tries to synchronize them several times then gives up.     One more thing, both systems A and B must tolerate duplicates of one synchronizing process. Say on the step 3 the system B was not able to send id.A+id.B back. The Resync service must restart the synchronization process that will send the id.A to B second time. In this case system B must just send back again also created id.A+id.B pair without errors. That means “tolerate duplicates”. Fourth draft Next draft was created only because of the aesthetics. As it always happens, aesthetics gave significant performance gain to the whole system. First was the stupid question. Why do we need this additional service with special database? Can we just master the BizTalk to do something like this Resync() does? So the Resync orchestration is doing the same thing as the Resync service. It is started by the Id.A and finished by the id.A+id.B message. The first works as a Start message, the second works as a Finish message.     Here is a diagram the whole process without errors. It is pretty straightforward. The Resync orchestration is waiting for the Finish message specific period of time then resubmits the Id.A message. It resubmits the Id.A message specific number of times then gives up and gets suspended. It can be resubmitted then it starts the whole process again: waiting [, resubmitting [, get suspended]], finishing. Tuning up The Resync orchestration resubmits the id.A message with special “Resubmitted” flag. The subscription filter on the Resync orchestration includes predicate as (Resubmit_Flag != “Resubmitted”). That means only the first Sync orchestration starts the Resync orchestration. Other Sync orchestration instantiated by the resubmitting can finish this Resync orchestration but cannot start another instance of the Resync   Here is a diagram where system B was inaccessible for some period of time. The Resync orchestration resubmitted the id.A two times. Then system B got the response the id.A+id.B and this finished the Resync service execution. What is interesting about this, there were submitted several identical id.A messages and only one id.A+id.B message. Because of this, the system B and the Resync must tolerate the duplicate messages. We also told about this requirement for the system B. Now the same requirement is for the Resunc. Let’s assume the system B was very slow in the first response and the Resync service had time to resubmit two id.A messages. System B responded not, as it was in previous case, with one id.A+id.B but with two id.A+id.B messages. First of them finished the Resync execution for the id.A. What about the second id.A+id.B? Where it goes? So, we have to add one more internal requirement. The whole solution must tolerate many identical id.A+id.B messages. It is easy task with the BizTalk. I added the “SinkExtraMessages” subscriber (orchestration with one receive shape), that just get these messages and do nothing. Real design Real architecture is much more complex and interesting. In reality each system can submit several id.A almost simultaneously and completely unordered. There are not only the “Create entity” operation but the Update and Delete operations. And these operations relate each other. Say the Update operation after Delete means not the same as Update after Create. In reality there are entities related each other. Say the Order and Order Items. Change on one of it could start the series of the operations on another. Moreover, the system internals are the “black boxes” and we cannot predict the exact content and order of the operation series. It worth to say, I had to spend a time to manage the zombie message problems. The zombies are still here, but this is not a problem now. And this is another story. What is interesting in the last design? One orchestration works to help another to be more reliable. Why two orchestration design is more reliable, isn’t it something strange? The Synch orchestration takes all the message exchange between systems, here is the area where most of the errors could happen. The Resync orchestration sends and receives messages only within the BizTalk server. Is there another design? Sure. All Resync functionality could be implemented inside the Sync orchestration. Hey guys, some other ideas?

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  • Favorite Visual Studio 2010 Extensions

    - by Scott Dorman
    Now that Visual Studio 2010 has been released, there are a lot of extensions being written. In fact, as of today (May 1, 2010 at 15:40 UTC) there are 809 results for Visual Studio 2010 in the Visual Studio Gallery. If you filter this list to show just the free items, there are still 251 extensions available. Given that number (and it is currently increasing weekly) it can be difficult to find extensions that are useful. Here is the list of extensions that I currently have installed and find useful: Word Wrap with Auto-Indent Indentation Matcher Extension Structure Adornment This also installs the following extensions: BlockTagger BlockTaggerImpl SettingsStore SettingsStoreImpl Source Outliner Triple Click ItalicComments Go To Definition Spell Checker Remove and Sort Using Format Document Open Folder in Windows Explorer Find Results Highlighter Regular Expressions Margin Indention Matcher Extension Word Wrap with Auto-Indent VSCommands HelpViewerKeywordIndex StyleCop Visual Studio Color Theme Editor PowerCommands for Visual Studio 2010 Extension Analyzer CodeCompare Team Founder Server Power Tools VS10x Selection Popup Color Picker Completion Numbered Bookmarks   Technorati Tags: Visual Studio,Extensions

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  • Displaying the Saved Pictures in the Windows Phone 8 emulator

    - by Laurent Bugnion
    One cool feature of the Windows Phone emulator is that it allows you to select pictures from your app (using the PhotoChooserTask) without having to try your app on a physical device. For example, this code (which I used in some of my recent presentations) will trigger the Photo Chooser UI to be displayed on the emulator too: private Action<IEnumerable<IImageFileInfo>> _callback; public void SelectFiles(Action<IEnumerable<IImageFileInfo>> callback) { var task = new PhotoChooserTask { ShowCamera = true }; task.Completed += TaskCompleted; _callback = callback; task.Show(); } void TaskCompleted(object sender, PhotoResult e) { if (e.Error == null && e.ChosenPhoto != null && _callback != null) { var fileName = e.OriginalFileName .Substring(e.OriginalFileName.LastIndexOf("\\") + 1); var info = new FileViewModel(e.ChosenPhoto, fileName); var infos = new List<IImageFileInfo> { info }; _callback(infos); } } In Windows Phone 8 however, when you execute this code, you will be shown an almost empty Photo Chooser UI: Notice that the “Saved Pictures” album is missing. At first I thought it was just not there at all, but you can actually restore it with the following steps: Press on the Windows button On the main screen, press on Photos Press on Albums Open the so called “8” photo album Press Back until you are back into your app and try again. This time you will see the saved pictures, and can perform your tests in more realistic conditions! Happy coding! Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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  • Secretara si seful

    - by interesante
    Un bancher discuta cu prietenul sau:- Iti inchipui, m-am indragostit de secretara mea!Ea are 20 de ani, eu 65! Ce crezi, sansele mele vor creste daca ii voi spune ca am 50?- Sansele tale vor creste daca ii vei spune ca ai 80!Vezi si alte chestii haioase pe profilul meu de pe acest siteProprietarul unu hotel era nelamurit la calcularea unei facturi. Se decide sa-si intrebe secretara.- Asa-i ca ai terminat Politehnica?- Da, ii raspunde secretara.- Bun, atunci spune-mi, daca ai avea 20.000 de dolari din care ai scadea 14%, cu ce ai mai ramane?- Cu nimic in afara de cercei!

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  • Powershell: Install-dotNET4 function

    - by marc dekeyser
    This function will download and install ,NET 4.0. It uses the Get-Framework-Versions function to determine if the installation is necessary or not. Internet Connectivity will be required as the script auto downloads the setup file (and sleeps for 360 seconds... I had a function in there to monitor for install completion at first, turns out the setup file spawns so many childprocesses the function just got confused and locked up -_-)Alternatively you could drop the installation file in the folder specified on the $folderPath variable too. That will skip the download and use the file. This function easily adapts in to other versions f.e. I use it for Powershell 3 installs as well!Function install-dotNet4 () {    if(($InstalledDotNET -eq "4.0") -or ($InstalledDotNET -eq "4.0c")){        write-host ".NET 4.0 Framework is already installed" -foregroundcolor Green    } else{            #set a var for the folder you are looking for        $folderPath = 'C:\Temp'        #Check if folder exists, if not, create it        if (Test-Path $folderpath){            Write-Host "The folder $folderPath exists." -ForeGroundColor Green        } else{            Write-Host "The folder $folderPath does not exist, creating..." -NoNewline -ForegroundColor Red            New-Item $folderpath -type directory | Out-Null            Write-Host " - done!" -ForegroundColor Green        }        # Check if file exists, if not, download it        $file = $folderPath+"\dotNetFx40_Full_x86_x64.exe"        if (Test-Path $file){            write-host "The file $file exists." -ForeGroundColor Green        } else {            #Download Microsoft .Net 4.0 Framework            Write-Host "Downloading Microsoft .Net 4.0 Framework..." -nonewline -ForeGroundColor DarkYellow            $clnt = New-Object System.Net.WebClient            $url = "http://download.microsoft.com/download/9/5/A/95A9616B-7A37-4AF6-BC36-D6EA96C8DAAE/dotNetFx40_Full_x86_x64.exe"            $clnt.DownloadFile($url,$file)            Write-Host " - done!" -ForegroundColor Green        }        #Install Microsoft .Net Framework        Write-Host "Installing Microsoft .Net Framework..." -nonewline -ForegroundColor DarkYellow        $dotNET4 = $folderPath+"\dotNetFx40_Full_x86_x64.exe /quiet /norestart"        Invoke-Expression $dotNET4        write-host " - done!" -ForegroundColor Green        start-sleep -seconds 360    }}

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  • DRY and SRP

    - by Timothy Klenke
    Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

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  • Heading out to Dallas GiveCamp 2011

    - by dotgeek
    The day has finally arrived for twelve local charities here in the Dallas area, when they’ll get some help from various local Developers with their website initiative needs at this years Dallas GiveCamp. I’m really looking forward to helping out at this year event and what I hope will be the start of many more GiveCamps to follow. Similar to Habitat for Humanity, where people gather to help build and improve homes for people in need, GiveCamp brings together programmers and equips them with the virtual tools they need to build and improve their existing websites. Tonight is when things will kickoff for this weekends events and teams will start working on their various projects. The building continues on through the night then and all the way through until Sunday afternoon. The end goal for the teams and charities is to have a completed and working website for each charity to begin using and turn over all the production code and digital assets to them. None of this would be possible with out the great sponsors we have returning once again and their donations of various products to help these charities out with their projects, like Telerik's CMS product Sitefinity 4.0, paired with a year of hosting from Verio to mention just a few of them. Just like the skilled builders who might help train volunteers in the use of a nail gun in building a house. Training is also available here on site for the Developers and these local Charities. Giving them all the skills in how to manage and use these products, from site development and then into actual production is a key to the success of this weekends event.     Tonight's training sessions will kick off with a real treat from Giovanni Gallucci, as he speaks about Social Media for NPOs and then later Gabe Sumner from Telerik will begin a training session on Sitefinity for Developers. These training sessions will continue through out the weekend with .Net Nuke and Mojo Portal sessions also planned as well. If you’re a developer and would like to help out in the future, then check in your area and with your local User Groups to find out if you already have a GiveCamp near you to help out. If you don’t have one available, then consider starting up a local GiveCamp and then you too can help Code it Forward. About GiveCamp GiveCamp is a weekend-long event where software developers, designers, and database administrators donate their time to create custom software for non-profit organizations. This custom software could be a new website for the nonprofit organization, a small data-collection application to keep track of members, or a application for the Red Cross that automatically emails a blood donor three months after they’ve donated blood to remind them that they are now eligible to donate again. The only limitation is that the project should be scoped to be able to be completed in a weekend. During GiveCamp, developers are welcome to go home in the evenings or camp out all weekend long. There are usually food and drink provided at the event. There are sometimes even game systems set up for when you and your need a little break! Overall, it’s a great opportunity for people to work together, developing new friendships, and doing something important for their community. At GiveCamp, there is an expectation of “What Happens at GiveCamp, Stays at GiveCamp”. Therefore, all source code must be turned over to the charities at the end of the weekend (developers cannot ask for payment) and the charities are responsible for maintaining the code moving forward (charities cannot expect the developers to maintain the codebase).

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  • Agile Development Requires Agile Support

    - by Matt Watson
    Agile developmentAgile development has become the standard methodology for application development. The days of long term planning with giant Gantt waterfall charts and detailed requirements is fading away. For years the product planning process frustrated product owners and businesses because no matter the plan, nothing ever went to plan. Agile development throws the detailed planning out the window and instead focuses on giving developers some basic requirements and pointing them in the right direction. Constant collaboration via quick iterations with the end users, product owners, and the development team helps ensure the project is done correctly.  The various agile development methodologies have helped greatly with creating products faster, but not without causing new problems. Complicated application deployments now occur weekly or monthly. Most of the products are web-based and deployed as a software service model. System performance and availability of these apps becomes mission critical. This is all much different from the old process of mailing new releases of client-server apps on CD once per quarter or year.The steady stream of new products and product enhancements puts a lot of pressure on IT operations to keep up with the software deployments and adding infrastructure capacity. The problem is most operations teams still move slowly thanks to change orders, documentation, procedures, testing and other processes. Operations can slow the process down and push back on the development team in some organizations. The DevOps movement is trying to solve some of these problems by integrating the development and operations teams more together. Rapid change introduces new problemsThe rapid product change ultimately creates some application problems along the way. Higher rates of change increase the likelihood of new application defects. Delivering applications as a software service also means that scalability of applications is critical. Development teams struggle to keep up with application defects and scalability concerns in their applications. Fixing application problems is a never ending job for agile development teams. Fixing problems before your customers do and fixing them quickly is critical. Most companies really struggle with this due to the divide between the development and operations groups. Fixing application problems typically requires querying databases, looking at log files, reviewing config files, reviewing error logs and other similar tasks. It becomes difficult to work on new features when your lead developers are working on defects from the last product version. Developers need more visibilityThe problem is most developers are not given access to see server and application information in the production environments. The operations team doesn’t trust giving all the developers the keys to the kingdom to log in to production and poke around the servers. The challenge is either give them no access, or potentially too much access. Those with access can still waste time figuring out the location of the application and how to connect to it over VPN. In addition, reproducing problems in test environments takes too much time and isn't always possible. System administrators spend a lot of time helping developers track down server information. Most companies give key developers access to all of the production resources so they can help resolve application defects. The problem is only those key people have access and they become a bottleneck. They end up spending 25-50% of their time on a daily basis trying to solve application issues because they are the only ones with access. These key employees’ time is best spent on strategic new projects, not addressing application defects. This job should fall to entry level developers, provided they have access to all the information they need to troubleshoot the problems.The solution to agile application support is giving all the developers limited access to the production environment and all the server information they need to see. Some companies create their own solutions internally to collect log files, centralize errors or other things to address the problem. Some developers even have access to server monitoring or other tools. But they key is giving them access to everything they need so they can see the full picture and giving access to the whole team. Giving access to everyone scales up the application support team and creates collaboration around providing improved application support.Stackify enables agile application supportStackify has created a solution that can give all developers a secure and read only view of the entire production server environment without console or remote desktop access.They provide a web application that provides real time visibility to the important information that developers need to see. An application centric view enables them to see all of their apps across multiple datacenters and environments. They don’t need to know where the application is deployed, just the name of the application to find it and dig in to see more. All your developers can see server health, application health, log files, config files, windows event viewer, deployment history, application notes, and much more. They can receive email and text alerts when problems arise and even safely query your production databases.Stackify enables companies that do agile development to scale up their application support team by getting more team members involved. The lead developers can spend more time on new projects. Application issues can be fixed quicker than ever. Operations can spend less time helping developers collect server information. Agile application support starts with Stackify. Visit Stackify.com to learn more.

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  • Organization &amp; Architecture UNISA Studies &ndash; Chap 5

    - by MarkPearl
    Learning Outcomes Describe the operation of a memory cell Explain the difference between DRAM and SRAM Discuss the different types of ROM Explain the concepts of a hard failure and a soft error respectively Describe SDRAM organization Semiconductor Main Memory The two traditional forms of RAM used in computers are DRAM and SRAM DRAM (Dynamic RAM) Divided into two technologies… Dynamic Static Dynamic RAM is made with cells that store data as charge on capacitors. The presence or absence of charge in a capacitor is interpreted as a binary 1 or 0. Because capacitors have natural tendency to discharge, dynamic RAM requires periodic charge refreshing to maintain data storage. The term dynamic refers to the tendency of the stored charge to leak away, even with power continuously applied. Although the DRAM cell is used to store a single bit (0 or 1), it is essentially an analogue device. The capacitor can store any charge value within a range, a threshold value determines whether the charge is interpreted as a 1 or 0. SRAM (Static RAM) SRAM is a digital device that uses the same logic elements used in the processor. In SRAM, binary values are stored using traditional flip flop logic configurations. SRAM will hold its data as along as power is supplied to it. Unlike DRAM, no refresh is required to retain data. SRAM vs. DRAM DRAM is simpler and smaller than SRAM. Thus it is more dense and less expensive than SRAM. The cost of the refreshing circuitry for DRAM needs to be considered, but if the machine requires a large amount of memory, DRAM turns out to be cheaper than SRAM. SRAMS are somewhat faster than DRAM, thus SRAM is generally used for cache memory and DRAM is used for main memory. Types of ROM Read Only Memory (ROM) contains a permanent pattern of data that cannot be changed. ROM is non volatile meaning no power source is required to maintain the bit values in memory. While it is possible to read a ROM, it is not possible to write new data into it. An important application of ROM is microprogramming, other applications include library subroutines for frequently wanted functions, System programs, Function tables. A ROM is created like any other integrated circuit chip, with the data actually wired into the chip as part of the fabrication process. To reduce costs of fabrication, we have PROMS. PROMS are… Written only once Non-volatile Written after fabrication Another variation of ROM is the read-mostly memory, which is useful for applications in which read operations are far more frequent than write operations, but for which non volatile storage is required. There are three common forms of read-mostly memory, namely… EPROM EEPROM Flash memory Error Correction Semiconductor memory is subject to errors, which can be classed into two categories… Hard failure – Permanent physical defect so that the memory cell or cells cannot reliably store data Soft failure – Random error that alters the contents of one or more memory cells without damaging the memory (common cause includes power supply issues, etc.) Most modern main memory systems include logic for both detecting and correcting errors. Error detection works as follows… When data is to be read into memory, a calculation is performed on the data to produce a code Both the code and the data are stored When the previously stored word is read out, the code is used to detect and possibly correct errors The error checking provides one of 3 possible results… No errors are detected – the fetched data bits are sent out An error is detected, and it is possible to correct the error. The data bits plus error correction bits are fed into a corrector, which produces a corrected set of bits to be sent out An error is detected, but it is not possible to correct it. This condition is reported Hamming Code See wiki for detailed explanation. We will probably need to know how to do a hemming code – refer to the textbook (pg. 188 – 189) Advanced DRAM organization One of the most critical system bottlenecks when using high-performance processors is the interface to main memory. This interface is the most important pathway in the entire computer system. The basic building block of main memory remains the DRAM chip. In recent years a number of enhancements to the basic DRAM architecture have been explored, and some of these are now on the market including… SDRAM (Synchronous DRAM) DDR-DRAM RDRAM SDRAM (Synchronous DRAM) SDRAM exchanges data with the processor synchronized to an external clock signal and running at the full speed of the processor/memory bus without imposing wait states. SDRAM employs a burst mode to eliminate the address setup time and row and column line precharge time after the first access In burst mode a series of data bits can be clocked out rapidly after the first bit has been accessed SDRAM has a multiple bank internal architecture that improves opportunities for on chip parallelism SDRAM performs best when it is transferring large blocks of data serially There is now an enhanced version of SDRAM known as double data rate SDRAM or DDR-SDRAM that overcomes the once-per-cycle limitation of SDRAM

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  • Talking JavaOne with Rock Star Kirk Pepperdine

    - by Janice J. Heiss
    Kirk Pepperdine is not only a JavaOne Rock Star but a Java Champion and a highly regarded expert in Java performance tuning who works as a consultant, educator, and author. He is the principal consultant at Kodewerk Ltd. He speaks frequently at conferences and co-authored the Ant Developer's Handbook. In the rapidly shifting world of information technology, Pepperdine, as much as anyone, keeps up with what's happening with Java performance tuning. Pepperdine will participate in the following sessions: CON5405 - Are Your Garbage Collection Logs Speaking to You? BOF6540 - Java Champions and JUG Leaders Meet Oracle Executives (with Jeff Genender, Mattias Karlsson, Henrik Stahl, Georges Saab) HOL6500 - Finding and Solving Java Deadlocks (with Heinz Kabutz, Ellen Kraffmiller Martijn Verburg, Jeff Genender, and Henri Tremblay) I asked him what technological changes need to be taken into account in performance tuning. “The volume of data we're dealing with just seems to be getting bigger and bigger all the time,” observed Pepperdine. “A couple of years ago you'd never think of needing a heap that was 64g, but today there are deployments where the heap has grown to 256g and tomorrow there are plans for heaps that are even larger. Dealing with all that data simply requires more horse power and some very specialized techniques. In some cases, teams are trying to push hardware to the breaking point. Under those conditions, you need to be very clever just to get things to work -- let alone to get them to be fast. We are very quickly moving from a world where everything happens in a transaction to one where if you were to even consider using a transaction, you've lost." When asked about the greatest misconceptions about performance tuning that he currently encounters, he said, “If you have a performance problem, you should start looking at code at the very least and for that extra step, whip out an execution profiler. I'm not going to say that I never use execution profilers or look at code. What I will say is that execution profilers are effective for a small subset of performance problems and code is literally the last thing you should look at.And what is the most exciting thing happening in the world of Java today? “Interesting question because so many people would say that nothing exciting is happening in Java. Some might be disappointed that a few features have slipped in terms of scheduling. But I'd disagree with the first group and I'm not so concerned about the slippage because I still see a lot of exciting things happening. First, lambda will finally be with us and with lambda will come better ways.” For JavaOne, he is proctoring for Heinz Kabutz's lab. “I'm actually looking forward to that more than I am to my own talk,” he remarked. “Heinz will be the third non-Sun/Oracle employee to present a lab and the first since Oracle began hosting JavaOne. He's got a great message. He's spent a ton of time making sure things are going to work, and we've got a great team of proctors to help out. After that, getting my talk done, the Java Champion's panel session and then kicking back and just meeting up and talking to some Java heads."Finally, what should Java developers know that they currently do not know? “’Write Once, Run Everywhere’ is a great slogan and Java has come closer to that dream than any other technology stack that I've used. That said, different hardware bits work differently and as hard as we try, the JVM can't hide all the differences. Plus, if we are to get good performance we need to work with our hardware and not against it. All this implies that Java developers need to know more about the hardware they are deploying to.” Originally published on blogs.oracle.com/javaone.

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  • C#/.NET Little Wonders: Skip() and Take()

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. I’ve covered many valuable methods from System.Linq class library before, so you already know it’s packed with extension-method goodness.  Today I’d like to cover two small families I’ve neglected to mention before: Skip() and Take().  While these methods seem so simple, they are an easy way to create sub-sequences for IEnumerable<T>, much the way GetRange() creates sub-lists for List<T>. Skip() and SkipWhile() The Skip() family of methods is used to ignore items in a sequence until either a certain number are passed, or until a certain condition becomes false.  This makes the methods great for starting a sequence at a point possibly other than the first item of the original sequence.   The Skip() family of methods contains the following methods (shown below in extension method syntax): Skip(int count) Ignores the specified number of items and returns a sequence starting at the item after the last skipped item (if any).  SkipWhile(Func<T, bool> predicate) Ignores items as long as the predicate returns true and returns a sequence starting with the first item to invalidate the predicate (if any).  SkipWhile(Func<T, int, bool> predicate) Same as above, but passes not only the item itself to the predicate, but also the index of the item.  For example: 1: var list = new[] { 3.14, 2.72, 42.0, 9.9, 13.0, 101.0 }; 2:  3: // sequence contains { 2.72, 42.0, 9.9, 13.0, 101.0 } 4: var afterSecond = list.Skip(1); 5: Console.WriteLine(string.Join(", ", afterSecond)); 6:  7: // sequence contains { 42.0, 9.9, 13.0, 101.0 } 8: var afterFirstDoubleDigit = list.SkipWhile(v => v < 10.0); 9: Console.WriteLine(string.Join(", ", afterFirstDoubleDigit)); Note that the SkipWhile() stops skipping at the first item that returns false and returns from there to the rest of the sequence, even if further items in that sequence also would satisfy the predicate (otherwise, you’d probably be using Where() instead, of course). If you do use the form of SkipWhile() which also passes an index into the predicate, then you should keep in mind that this is the index of the item in the sequence you are calling SkipWhile() from, not the index in the original collection.  That is, consider the following: 1: var list = new[] { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // Get all items < 10, then 4: var whatAmI = list 5: .Skip(2) 6: .SkipWhile((i, x) => i > x); For this example the result above is 2.4, and not 1.2, 2.2, 2.3, 2.4 as some might expect.  The key is knowing what the index is that’s passed to the predicate in SkipWhile().  In the code above, because Skip(2) skips 1.0 and 1.1, the sequence passed to SkipWhile() begins at 1.2 and thus it considers the “index” of 1.2 to be 0 and not 2.  This same logic applies when using any of the extension methods that have an overload that allows you to pass an index into the delegate, such as SkipWhile(), TakeWhile(), Select(), Where(), etc.  It should also be noted, that it’s fine to Skip() more items than exist in the sequence (an empty sequence is the result), or even to Skip(0) which results in the full sequence.  So why would it ever be useful to return Skip(0) deliberately?  One reason might be to return a List<T> as an immutable sequence.  Consider this class: 1: public class MyClass 2: { 3: private List<int> _myList = new List<int>(); 4:  5: // works on surface, but one can cast back to List<int> and mutate the original... 6: public IEnumerable<int> OneWay 7: { 8: get { return _myList; } 9: } 10:  11: // works, but still has Add() etc which throw at runtime if accidentally called 12: public ReadOnlyCollection<int> AnotherWay 13: { 14: get { return new ReadOnlyCollection<int>(_myList); } 15: } 16:  17: // immutable, can't be cast back to List<int>, doesn't have methods that throw at runtime 18: public IEnumerable<int> YetAnotherWay 19: { 20: get { return _myList.Skip(0); } 21: } 22: } This code snippet shows three (among many) ways to return an internal sequence in varying levels of immutability.  Obviously if you just try to return as IEnumerable<T> without doing anything more, there’s always the danger the caller could cast back to List<T> and mutate your internal structure.  You could also return a ReadOnlyCollection<T>, but this still has the mutating methods, they just throw at runtime when called instead of giving compiler errors.  Finally, you can return the internal list as a sequence using Skip(0) which skips no items and just runs an iterator through the list.  The result is an iterator, which cannot be cast back to List<T>.  Of course, there’s many ways to do this (including just cloning the list, etc.) but the point is it illustrates a potential use of using an explicit Skip(0). Take() and TakeWhile() The Take() and TakeWhile() methods can be though of as somewhat of the inverse of Skip() and SkipWhile().  That is, while Skip() ignores the first X items and returns the rest, Take() returns a sequence of the first X items and ignores the rest.  Since they are somewhat of an inverse of each other, it makes sense that their calling signatures are identical (beyond the method name obviously): Take(int count) Returns a sequence containing up to the specified number of items. Anything after the count is ignored. TakeWhile(Func<T, bool> predicate) Returns a sequence containing items as long as the predicate returns true.  Anything from the point the predicate returns false and beyond is ignored. TakeWhile(Func<T, int, bool> predicate) Same as above, but passes not only the item itself to the predicate, but also the index of the item. So, for example, we could do the following: 1: var list = new[] { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // sequence contains 1.0 and 1.1 4: var firstTwo = list.Take(2); 5:  6: // sequence contains 1.0, 1.1, 1.2 7: var underTwo = list.TakeWhile(i => i < 2.0); The same considerations for SkipWhile() with index apply to TakeWhile() with index, of course.  Using Skip() and Take() for sub-sequences A few weeks back, I talked about The List<T> Range Methods and showed how they could be used to get a sub-list of a List<T>.  This works well if you’re dealing with List<T>, or don’t mind converting to List<T>.  But if you have a simple IEnumerable<T> sequence and want to get a sub-sequence, you can also use Skip() and Take() to much the same effect: 1: var list = new List<double> { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // results in List<T> containing { 1.2, 2.2, 2.3 } 4: var subList = list.GetRange(2, 3); 5:  6: // results in sequence containing { 1.2, 2.2, 2.3 } 7: var subSequence = list.Skip(2).Take(3); I say “much the same effect” because there are some differences.  First of all GetRange() will throw if the starting index or the count are greater than the number of items in the list, but Skip() and Take() do not.  Also GetRange() is a method off of List<T>, thus it can use direct indexing to get to the items much more efficiently, whereas Skip() and Take() operate on sequences and may actually have to walk through the items they skip to create the resulting sequence.  So each has their pros and cons.  My general rule of thumb is if I’m already working with a List<T> I’ll use GetRange(), but for any plain IEnumerable<T> sequence I’ll tend to prefer Skip() and Take() instead. Summary The Skip() and Take() families of LINQ extension methods are handy for producing sub-sequences from any IEnumerable<T> sequence.  Skip() will ignore the specified number of items and return the rest of the sequence, whereas Take() will return the specified number of items and ignore the rest of the sequence.  Similarly, the SkipWhile() and TakeWhile() methods can be used to skip or take items, respectively, until a given predicate returns false.    Technorati Tags: C#, CSharp, .NET, LINQ, IEnumerable<T>, Skip, Take, SkipWhile, TakeWhile

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  • SSIS Technique to Remove/Skip Trailer and/or Bad Data Row in a Flat File

    - by Compudicted
    I noticed that the question on how to skip or bypass a trailer record or a badly formatted/empty row in a SSIS package keeps coming back on the MSDN SSIS Forum. I tried to figure out the reason why and after an extensive search inside the forum and outside it on the entire Web (using several search engines) I indeed found that it seems even thought there is a number of posts and articles on the topic none of them are employing the simplest and the most efficient technique. When I say efficient I mean the shortest time to solution for the fellow developers. OK, enough talk. Let’s face the problem: Typically a flat file (e.g. a comma delimited/CSV) needs to be processed (loaded into a database in most cases really). Oftentimes, such an input file is produced by some sort of an out of control, 3-rd party solution and would come in with some garbage characters and/or even malformed/miss-formatted rows. One such example could be this imaginary file: As you can see several rows have no data and there is an occasional garbage character (1, in this example on row #7). Our task is to produce a clean file that will only capture the meaningful data rows. As an aside, our output/target may be a database table, but for the purpose of this exercise we will simply re-format the source. Let’s outline our course of action to start off: Will use SSIS 2005 to create a DFT; The DFT will use a Flat File Source to our input [bad] flat file; We will use a Conditional Split to process the bad input file; and finally Dump the resulting data to a new [clean] file. Well, only four steps, let’s see if it is too much of work. 1: Start the BIDS and add a DFT to the Control Flow designer (I named it Process Dirty File DFT): 2, and 3: I had added the data viewer to just see what I am getting, alas, surprisingly the data issues were not seen it:   What really is the key in the approach it is to properly set the Conditional Split Transformation. Visually it is: and specifically its SSIS Expression LEN([After CS Column 0]) > 1 The point is to employ the right Boolean expression (yes, the Conditional Split accepts only Boolean conditions). For the sake of this post I re-named the Output Name “No Empty Rows”, but by default it will be named Case 1 (remember to drag your first column into the expression area)! You can close your Conditional Split now. The next part will be crucial – consuming the output of our Conditional Split. Last step - #4: Add a Flat File Destination or any other one you need. Click on the Conditional Split and choose the green arrow to drop onto the target. When you do so make sure you choose the No Empty Rows output and NOT the Conditional Split Default Output. Make the necessary mappings. At this point your package must look like: As the last step will run our package to examine the produced output file. F5: and… it looks great!

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