Silverlight Hack

Silverlight & related .NET technologies

About Me

Welcome to  This is a site where you can find many articles on Silverlight, Windows Phone 7 and .NET related technologies.  

My name is Bart Czernicki.  I have been working with computers since 1988 and have over 12 professional years in the IT field focusing on architecture, technology strategy and product management.  I currently work as a Sr. Software Architect at a large software development company.

Below is the cover of my new book that shows how Silverlight's unique RIA features can be applied to create next-generation business intelligence (BI 2.0) applications.

Silverlight 4 Business Intelligence Soft 


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NONE of the comments or opinions expressed here should be considered ofmy past or current employer(s).  The code provided is as-is without anyguarantees or warranties.

Windows Phone 7 RTM charting using the Silverlight Control Toolkit

Abstract: This article will show you the steps to surface charting data visualizations using the Silverlight Control Toolkit on the Windows Phone 7.  I will also cover the reasoning behind these steps and the gotchas/errors you may encounter.  Source code is included with a sample Windows Phone 7 project.

Windows Phone 7 RTM tools have been released a few weeks ago.  Many developers are starting to develop their new apps and getting them ready for the Windows Marketplace.   If you are a seasoned Silverlight develper, you probably want to leverage existing Silverlight frameworks or toolkits (i.e., MVVM, networking, charting, custom controls etc.) in your Windows Phone 7 application.  If you have looked for a charting solution, you probably came across several articles that "claim" to show you how to easily surface charting on the Windows Phone 7.  Most examples are out of date (because the Windows Phone 7 bits changed so much) and some of them simply have misinformation (i.e., I read one article and the author doesn't even know what assembly he is using :))

Background Info

As you may know the Windows Phone 7 RTM includes a Silverlight runtime.  Scott Guthrie announced during the MIX 2010 conference that "this isn't Silverlight Lite.....this is Silverlight" and I wrote an article that shows this is not the case.  The Windows Phone 7 RTM runtime is based off of Silverlight 3 RTM and includes some additional things from Silverlight 4 and some custom inner workings for the Windows Phone 7 (i.e. UI thread and Composite thread).  Basically, what this means is that most Silverlight 2 and Silverlight 3 code "should just compile and work" on the Windows Phone 7.  If you have written Silverlight 4 code that takes advantage of new features it will simply not work in the Windows Phone 7 Silverlight runtimes (although this will probably change and both Silverlight runtimes will converge in functionality).

There is a lot of misinformation out there (even from Microsoft) that the Silverlight 4 Control Toolkit is compatible with the Windows Phone 7 and it's not.

Steps to Get Silverlight Control Toolkit Data Visualizations to Work in Windows Phone 7

  1. Download the November 2009 Silverlight 3 Control Toolkit (
    • The April 2010 Silverlight Control Toolkit dropped support for Silverlight 3.  The November 2009 release is the latest stable release for Silverlight 3.
  2. Create a new Windows Phone 7 project
  3. Add a reference to the System.Windows.Controls.DataVisualization.Toolkit.dll
    • Ensure the DLL comes from the Silverlight 3 toolkit (November 2009) NOT the Silverlight 4 toolkit
    • The default location is: C:\Program Files (x86)\Microsoft SDKs\Silverlight\v3.0\Toolkit\Nov09\Bin\System.Windows.Controls.DataVisualization.Toolkit.dll
  4. Add a reference to the System.Windows.Controls.dll
    • Ensure the DLL comes from the Silverlight 3 client SDK
    • The default location is: C:\Program Files (x86)\Microsoft SDKs\Silverlight\v3.0\Libraries\Client\System.Windows.Control.dll
  5. Drag over chart and series from Asset library; start using the chart data visualizations normally
    • I have tested pie, line and bar charts and all seem to work nicely


In the figure below, you can see the Windows Phone 7 emulator running a Pie Chart data visualization with a slider.  I decided to style the Pie Chart, bind it to sample data, double bind one of the elements to a slider to test the rendering engine of the Windows Phone 7.  I am happy to say that everything looks like it is working on the Windows Phone 7 as expected.  Source code is located here.

What Will Happen If you use the Silverlight 4 Toolkit Assemblies?

In short, you will see everything work great in Blend 4 or Visual Studio designer.  However, as soon as you deploy the project to the emulator the project will launch and promptly close throwing an exception of:"Invalid attribute value charting:DisplayAxis for property TargetType".  I am guessing there is a Silverlight 4 feature being used (i.e. element binding) that may be causing the error in the Windows Phone 7.  If you receive this error, then you need to reference the Silverlight 3 version of the System.Windows.Controls.DataVisualization.Toolkit.dll


What Will Happen If you forget to add the System.Windows.Controls.dll assembly?

The Blend designer and Visual Studio designer will both work.  However, if you deploy the project to the Windows Phone 7 it will promptly error out by throwing an exception.  The exception is going to be the generic XAML error "AGE_E_PARSER_BAD_TYPE line...".  The reason this error happens is that the charting controls need artifacts that are located in that assembly that are missing from the Windows Phone 7 Silverlight controls.  Luckily, since the Windows Phone 7 runs Silverlight 3 (plus some enhancements) we can use the Silverlight 3 assemblies.  Please note that this will likely change when the Windows Phone 7 and full Silverlight runtimes converge in functionality. 



Until Microsoft converges the Silverlight runtime functionality with the appropriate Silverlight Control Toolkits, you will have to be aware of the supported functionality in each version.  In order to surface charting data visualizations in the Windows Phone 7, use the November 2009 Silverlight 3 Toolkit and reference the System.Windows.Control.dll from the Silverlight 3 SDK. 

Source Code: (1.32 mb)

Posted: Oct 08 2010, 10:12 by Bart Czernicki | Comments (5) RSS comment feed |
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Technical Book Sales Insight Through Real-Time Amazon Rankings Analytics

As a published author, I have a product available to the masses.  The obvious question that comes to mind after the product is released is "How well is my product selling?".  If you are a technical author, you receive a statement every quarter for the previous three quarters.  For example, my publisher which is Apress sent me a summary at the end of March 2010 for Q4 2009.  Essentially, you are getting data that is 3-6 months behind.

Average technical books usually sell somewhere in the range of 2,000-3,000 copies during their lifetime.  Really popular books can sell up to 6,000-8,000 copies.  Furthermore, these books tend to have a short shelf life of about 1-2 years where 90%+ of the sales come from.  This is especially true for a technology like Silverlight which is on a 9 month cadence.  Technical books also have limited marketing budgets.  Even authors like Pretzold don't have commercials on TV for their books :)  This makes it very important to make sure you can get as many sales as possible quickly before your book becomes "old news".  Waiting three months for a quaterly statement can dramatically limit your recourse to improve sales.  What can a technical author do?

Using Amazon's Domination to Your Advantage

Amazon is one of the world's largest online retailers specializing in many items especially books.  Since a very large percentage of sales go through Amazon, we take advantage of this.  This is especially true for technical resources.  If you are a technical author, chances are, your book is not being carried by a brick and mortar bookstore (unless it is ultra popular or covers a broad topic).  Obviously, this is not the same for authors of fiction books like Dan Brown (DaVinci Code fame).  After talking to my publisher, the estimate is that about 50%-75% of the book sales will come from Amazon.  Using this information, I can start to get a good idea of how my sales are doing now.  This topic is a lot more interesting to me because I wrote a book about Business Intelligence and Silverlight.  In Business Intelligence software, you want to have a tool that can provide you insight that you can make wise decisions from quickly.

Amazon Sales Rankings

Amazon receives tremendous sales volume.  Amazon publicly provides some sales information on sales on its site.  While you will never get detailed information as how many books have been sold over time, Amazon does provide a sales rank system.  Amazon's formula is secret.  However, you will find a lot of guesstimates on the web from people who have tried to reverse engineer it.

The Amazon Sales rankings are a ranking (lower is better) over a rolling time frame (a year?).  The sales rankings are updated hourly on Amazon's site and displayed on the book's Product Details section.  Notice the screen shot below and the description explicitly say not Amazon.  The reason is that Amazon has multiple domains that tailor the site specific to the locale.  For example, other popular Amazon sites include: (Canada), (Japan), (Germany), (France).  Each of these domains tracks sales seperately. Sales Rank of my book for April 8th 2010

Every time you sell a book, your ranking drops lower (which is good).  If you don't sell a book, your ranking starts to creep up every hour.  If you don't sell a book in several months, you will quickly be looking at a sales rank of millions.
Knowing this information, we can manually track our sales and see how well we are doing.  Luckily, Amazon includes public APIs that can be used to track this as well.

Amazon Sales Rankings - What they Mean

What does a ranking of 1,000 or 100,000 mean?  How many books does that translate to per month?  Based on the data I have seen, this is how I grouped the sales numbers into sales ranking buckets.  (Note: The focus of this article is technical books.  Therefore, I am skipping buckets like Top 50).  The rankings are based on a logarithmic scale.  So as you go into further lower ranking, you are selling exponentially more than rankings that are higher.

Logarithmic scale of book sales (source:  Data is from 2007.  

  • Consistent ranking 200 - 1,000: You are selling extremely well. Well over 1,000 per month on Amazon domains!  Example:  The Design of Design: Essays from a Computer Scientist.
  • Consistent ranking 1,001 - 10,000:  Your book is doing very very well.  You are selling between 400-900 per month on Amazon domains.  Example: Pro Silverlight 3 in C# or C# 4.0 In a NutShell
  • Consistent ranking 10,001 - 50,000:  Your book is selling well.  You are selling between 80-350 per month on Amazon domains.  Example: (my book) Next-Generation Business Intelligence Software with Silverlight 3 or Programming WCF Services
  • Consistent ranking 50,0001 - 125,000:  Your book is doing OK.  You are selling between 40-70 per month on Amazon domains.  Example: ASP.NET MVC In Action
  • Consistent ranking 125,001 - 300,000:  Your book is doing below average.  You are selling between 10-35 books on Amazon domains.
  • Consistent ranking 500,000 - 1,250,000:  You are selling a very small amount of books.  You are selling between 1 - 9 books on Amazon domains.
  • Consistent ranking > 1,250,000:  You are not selling anything at all. Maybe 1-2 books per month.
When I was researching this for the last several months, I found most sites to be wrong or have outdated information.  For example, some sites only report sales from  While the core has the bulk of the sales, a very large percentage of sales come from international domains; in some cases, almost half the sales!  A lot of sites that claim to have deciphered the Amazon Sales Rank formula paint only half the picture. automates tracking Amazon sales data is a great site that is provided for FREE from Mario Lurig.  Mario essentially took advantage of the fact that Amazon updates their site hourly and they provide APIs.  He was able to figure out a formula that accurately can extrapolate sales information from the sales rankings.  Its a fantastic feature provided for FREE.
The API provided can track sales on the 6 most popular Amazon domains and provide data visualizations for analysis.  You can also create your own page to compare other book's data.
NovelRank analysis page of my book's sales for the first week of April 2010.  Click here to see the tool in action live.

You can even export the data into Excel to use, place a sales widget on your portal, filter the graphs etc.  The site also includes many valuable insights about Amazon sales information.  Using this tool, I was able to come up with my own Amazon sales figures you see above.  I think these paint a much more accurate picture that you are going to find. After the month's data is complete, if you multiply the number by 1.5-2.0, that is a good estimate of the amount of sales a technical book will do in a given month.
Note: The Amazon sales rank and APIs are public information.  While I guess it is considered "snooping" on someone's data, I don't think it violates any privacy issues.  You can add any book that is on Amazon's domains for tracking and analysis.

Insight Gained from NovelRank Analytics

Improving Book Sales 

The only way you are going to improve sales is through marketing yourself and your product (which is your book).  Using a real-time analytics tool like NovelRank allows you to adjust your book's marketing efforts appropriately.  Here is some insight that I gained:

  • At the time the MIX 2010 conference was held, my book was consitently in the 1,001-10,000 range.  Technical book sales go up during related conferences.
  • Make sure you have a blog.  Write about content related to your book.  Advertise your book prominantely on the site.
  • Create a companion site for the book.  For example, for my book, I created  This allows me to target readers that don't have Visual Studio installed or don't feel like compiling the demos.
  • When posting on forums, add your book info to your signature.  For example, I am active on the Silverlight forums and have a link to my book's Amazon listing.
  • Do speaking engagements if you can.  If you are a good speaker and have something interesting to say, it is a good idea to advertise yourself.
As you do these items, you should see spikes in books sales.

Thinking about writing a book in....

If you are thinking about writing a technical book to make additional income, you can improve the financial results by using NovelRank.

  • General book topics usually do better.  For example, a book on C#, Intro to Silverlight or WCF will do better than a highly specific book or a niche technology area.  For example, my book focuses on Business Intelligence and Silverlight.  This obviously has a much smaller audience than just a vanilla C# syntax book.  In my case, this is mitigated by a price point that is almost 50% higher than most other books.
  • Going with a technical publisher is better than going at it alone.  Some sites like Lulu allow you to publish your own work.  Readers usually like to stick with the big technical resource names like Manning, O'Reilly or Apress.
  • You can use NovelRank to see how your competition is doing or if there is strength in particular topics.  Using the tool, I can clearly see there is a ton of interest in iPhone development.  There are more than several books in the top 1,000 on that topic alone.
How are Silverlight book sales?
I was curious about how Silverlight book sales are doing.  This is what I saw:
  • The current best selling Silverlight book is Matthew MacDonald's Pro Silverlight 3 in C#.
  • The best selling books are targeted towards Silverlight version 3.  I think this will change when Silverlight 4 comes out in April 2010.
  • Silverlight 2 books are still selling a little.  Some books like Data-Driven Services with Silverlight 2 are still selling better because a lot of the concepts will still apply to Silverlight 3 and 4.
  • Silverlight 3 sales will continue to be strong for another several months.  The reason I say this is because of the coupling of Silverlight 4 with Visual Studio 2010.  Not all development shops are ready to move to .NET 4.0 and Visual Studio 2010.  Therefore, this will keep Silverlight 3 interest for quite some time.
  • Looking at the sales of the iPhone development books, authors for Windows Phone 7 development should make a killing in the next several months.



I hope you can see how an automated tool like NovelRank can help technical authors gain valuable insight into their sales, competition, make better decisions about writing a second edition, etc.  Hopefully current and future authors will find this information useful.  Lastly, use the self-service tool!

In a secondary point, I would like to say that this is a great example of Business Intelligence 2.0.  By using the self-service NovelRank tool, we are able to make wise decisions from real-time data.  This is a good example of a great business intelligence analytics tool that is simple and effective.


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Posted: Apr 08 2010, 10:41 by Bart Czernicki | Comments (2) RSS comment feed |
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Top 10 Reasons why HTML 5 is not ready to replace Silverlight

Note: I know this topic is controversial, so I want to preface that this article is meant to be a conversation.  If you don't agree with something or I have information incorrect, please add a comment or e-mail me.  As the HTML 5 spec evolves, I will update this article.

"HTML 5 is born old"

Update 06/02/2011: Facebook is a great example of "all in HTML5"..they provide NO native iPhone/iPad application.  Their answer is HTML5.  Yet the MOST POPULAR iPhone/iPad applications are FaceBook apps.  If HTML5 was almost equal to RIA applications, why do people prefer native over HTML5?  Something to think about when drinking the HTML5 kool aid...covered in this article here.

Update 12/08/2010: Firefox 4 and Opera browsers are disabling WebSocket support, because of serious vulnerabilities in the way sockets are designed in HTML 5.  This is ANOTHER example of why HTML 5 is still a while out, before it is implemented by all browsers widely.

Update 10/17/2010:  The Silverlight team posted an excellent article on "The Future of Silverlight".  Obviously it is a biased article, but it highlights a lot of the same topics I cover in the HTML 5 versus Silverlight discussion.  The article can be accessed here.  They highlight the same things you will see below; that Silverlight provides a first-class framework for: premium HD media and streaming, fast release cadance, advanced features that you can use now (multithreading up to 8 cores, GPU acceleration etc.), out of the browser applications etc.

Update 10/18/2010: Last week the W3C announced that HTML 5 is not ready for websites, because of compatibility issues.  Article can be found here.  HTML 5 might be the future, but even the W3C is telling us not to code HTML 5 web sites :)  There are web patterns (polyfills) that allow you to use native HTML 5 APIs and do the cross-browser stuff "for you"...doesn't seem like HTML 5 is the savior everyone thinks it will be.


HTML 5 is the next update to the HTML standard that powers the web.  There are many new exciting features being added like the the canvas element, local offline storage, drag and drop and video playback support.  HTML needed to evolve and added these features in order to stay relevant as the de facto markup language that can provide a rich web experience. 

This upcoming featureset is encroaching on areas dominated by RIA (Rich Internet Application or Rich Interactive Application) frameworks like Flash, Silverlight and JavaFX.  Unlike most RIA frameworks, HTML is not a proprietary language/framework and its standards are maintained by the World Wide Web Consortium (W3C).  This has led speculation that HTML plus the new RIA-like features can spell doom to proprietary RIA frameworks.  This article aims to cover what is in HTML 5 (as of February 2010) and how some features in the spec are lacking compared to RIA like Silverlight.  This is not a complete overview of HTML 5, nor is it a "HTML 5 vs. Silverlight" article.  Below is a quick list of items that I will be covering to try to prove my assertion that HTML 5 is not ready to replace RIAs like Silverlight:

  1. HTML 5 is not here...Yet
  2. Audio and Video Tag limitations
  3. Web Browser Compatibility
  4. Javascript Limitations
  5. Productivity
  6. Only targets the general Web
  7. No hardware acceleration
  8. No webcam or microphone device support
  9. HTML 5 standard or Google/Apple spec?
  10. HTML 5 is already behind Silverlight
  11. No Pub-Sub Model (updated 2/28/2010)

1) HTML 5 is not here...Yet

There are some really nice demos appearing of certain HTML 5 features (HTML 5 capable browser required like Safari, Chrome or Firefox 3.x).  As you can see, HTML 5 is very capable in creating RIA-like experiences:

A very large majority of current "HTML 5 demos" center around three key features: the new canvas, audio, and video tags.  The HTML 5 spec is MUCH larger than this.  For example, look at how many differences there are between HTML 4 and HTML 5.  However, many people (including technologists and developers) see one or two demos called "cool HTML 5 demo" and clamor on Twitter that RIA frameworks are gone.  If you dig down deeper, only a small fraction of the HTML 5 spec is implemented in some of the browsers.  Furthermore, the HTML 5 spec is still evolving (You will see some examples below of changes that have occured in the last few weeks).  Some have speculated it might take three to five years to implement the "full" HTML 5 spec once it is finalized.  Will it take that long?  I think companies like Google and Apple who have a very strong vested interest in moving HTML 5/WebKit along are going to push this faster.  However, the HTML 5 spec has to be finalized FIRST (to see the full scope of the implementation) before we can speculate on how long the undertaking will be.

Some of the new demos and features are great to play with.  However, I would be very hesitant to start rolling out HTML 5 features until the spec is finalized.  Most likely we will see the HTML 5 spec implemented in piecemeal over multiple releases.  In two plus years we should see browsers with taglines of "full HTML 5 compliant".  Until then, don't get caught up in the hype...HTML 5 is not here yet!

Note: Browsers like Chrome and Safari (based on WebKit) will probably implement features together in the WebKit framework and they will flow through into the browser.  I would bet on Chrome, Safari and Firefox to lead the charge in HTML 5 spec implementation.
Update 2/17/2010: This is a great article on the problems with the HTML 5 spec.  A great point by the author on how some engineers are accusing others of "sabatoge".  I particularly like the comment by Dorian Taylor about the heavy dependency on Javascript (which I go into detail below) that is a problem with HTML 5.

2) Audio and Video Tag Limitations

One of the biggest additions to the HTML 5 spec is the audio and video element tags which allows you to embed media files directly into the HTML markup.  This allows you to use these media files very similar to the way you would use the the img tag for example.  Providing the location of the resource is all that is required (Additional attributes allow you to create the behavior of the media elements such as streaming).  This is a simple and standard way to enhance your HTML with media files.

HTML 5 video tag markup from W3 Schools

I think HTML takes the right step with the audio and video tag additions.  However, providing a great multimedia experience is more than just playing a video file or a music mp3.  Here are some limitations of the audio/video elements and how it compares to Silverlight:

  • Realtime manipulation/inspection of audio files is not possible.  You can set some additional options like autoplay or buffering; however, you cannot manipulate the audio stream and provide your own equalizer changes.  Flash and Silverlight both can do this.  The HTML 5 audio tag will simply not suffice for more advance scenarios.
  • Limitations of the video tag (similar to audio tag).  You can set options like autoplay or buffering but more common and advanced features are missing.  In Silverlight, you have a wide array of options like applying shaders directly to the video and smooth streaming in HD 1080p.  These options allow you to provide a much richer and advanced video viewing experience.

HD Silverlight video with a 3D transformation and pixel shaders applied in real-time (from Mix 2009 conference)


  • No DVR-like/smooth streaming capabilties.  Creating a video viewing website like YouTube is possible in HTML 5.  In fact, Youtube is experimenting with delivering its own video content via HTML 5.  However, if you want to create a rich DVR-like experience with live video, you need a technology like Silverlight.  Silverlight's HD smooth streaming allows for picture in picture, pausing live video, rewinding, slow motion and downstreaming when bandwith slows down.  With smooth streaming, the buffering is minimized and you can jump to different spots of the video almost in real-time.  You can try the Silverlight smooth streaming experience here (Notice how the experience is better than just a simple YouTube video). This technology is so poweful that Silverlight smooth streaming is being used by the NBC Olympics and Netflix to provide HD video in 1080p to tens of millions of consumers.   This is the difference between a one-way stream from server to host (i.e., HTML 5 progressive download with simple stop, pause and play) and a two-way stream the viewer can interact with (i.e., the DVR-like experience).
    • Note: Providing an engaging experience to users is a huge deal.  Users who use DVR-like functionality watch three times more video than users who do not.  What does that mean?  Web sites that use a more engaging technology keep the viewers at their site. This is not limited to just Silverlight.  For example, provides a very similar experience using Flash with HD add-ons.
  • Content protection/DRM does not exist in the video tag in HTML 5.  This is a huge problem for hosting copyright or sensitive content that you don't want viewers to copy or save to their hard drive.  Can you imagine Netflix using an HTML 5 video tag for a new Hollywood movie and everyone were able to save a copy to their hard drive?  Until this changes, the HTML video tag will only be used for non-sensitive media.  Silverlight supports a variety of digitial rights management architectures/encryption options.
    • One simple test is to go on YouTube and play a movie.  Next, go to your temporary internet files folder and find a file that was generated around the time you watched the video (It should be one of the largest files).  Rename that file to an .flv extension and the file is yours.  This is possible because progressive download temporarily stores the video file on your hard drive.  This makes simple tools like possible.  As you can see from our simple little test, this simply will not fly for any commercial media.

Note: Silverlight is not the only technology that offers smooth streaming.  Apple's Quicktime Streaming and Adobe's Flash Media Server are two examples of technologies that offer streaming and DVR-like capabilities.  It is worth noting that Silverlight Smooth Streaming is a FREE value-add to Windows Server 2008 IIS 7.x.


3) Web Browser Compatibility

The HTML 5 spec is partially supported by the latest versions of Safari, Chrome and Firefox.  Internet Explorer from Microsoft is the key browser missing HTML 5 support.  The fact remains that Internet Explorer is still one of the most widely used browsers in the world.  Designing a site without Internet Explorer in mind would probably not be a great idea.  Isn't evil Micro$oft simply blocking innovation?  I don't think so.  Internet Explorer 9 is rumored to have HTML 5 support.  Furthermore, Microsoft would further degrade the use of Internet Explorer if they simply decided to skip the HTML 5 standard.  No matter what your open-source/Linux fanboy tells you, that won't happen.

Let's say the next version of Internet Explorer comes out and it supports HTML 5 tomorrow!  As an architect/CTO, are you going to design a new web site in HTML 5 with over 66% of the web running Internet Explorer 6-8?  There are so many web connected devices out there that simply will not support HTML 5 for a long time.  Remember web connected devices include mobile phones as well.  Furthermore, many casual users (like your parents) may not upgrade their browser for the entire lifetime of the "family computer".  Furthermore, the HTML 5 specification is pretty big and different browsers support various features.  You can see from this Wikipedia article that no current browser supports the current HTML 5 spec (because it is still evolving).


Internet Explorer is losing its dominance. However, even a 10% drop would be equivalant to hundrends of millions of users stopping use of Internet Explorer (I wrote this article in February 2010 and as of October 2010 IE moved from 67.1% to 62.7%...about 5% drop in 8 1/2 months.).  I don't see a 20% drop until two to three years from now.  You can check out the web browser trends for yourself:

Note: Providing fallback markup is a valid option; however, this leaves yet another architecture/code path to put through QA.  That works great for sites that are template-based (like YouTube).  However, creating a large scale business app with fallback markup has a large cost associated with it.


4) Javascript Limitations

If you have done any sort of web development, you have probably used Javascript to provide dynamic content on the client browser.  The same applies for manipulating HTML 5 content.  So what is the problem?

  • Javascript does not provide a true parallelism.  Today's desktops and laptops come with two to four available cores.  Even future iPhone specs plan for multiple cores.  How can you rely on a language/framework that can't take advantage of all available cores?  Silverlight's .NET framework can scale up to eight processor cores.  You can see my two previous articles on how this makes a pretty substantial difference in performance.
    • Note: Web Workers for JavaScript will eventually provide the ability to utilize multiple threads.  The problem is that Javascript is a hybird between a imperative/declerative language.  For example, parallelizing for loops is not going to be possible without a re-write.  In .NET, I can use LINQ/F# or other declarative techniques to easily parallel multiple tasks.
  • Javascript is a cross between a functional and object-oriented language.  It implements only some of the functional and object-oriented language features.  The great thing about being based on the .NET framework is that Silverlight dynamic content can be created using C#, VB.NET, F#, and Iron Python (dynamic langauges).  This gives you tremendous flexibility and functionality that Javascript simply does not provide.  You can chose the right language for the task.  Some languages provide features that others do not (even in .NET).  For example, take a look at my asynchronous workflows in Silverlight with F# article.  
  • Javascript limits code sharing.  Do you have any server component code written in Javascript?  Stupid question, right?  However, if you are a .NET shop, you probably have business rules engines or components written in a .NET language.  The great part about this is that this code can be distributed to the Silverlight client.  Another example of sharing Silverlight code is with WPF.  Because both technologies have a lot of synergies, a large majority of code can be shared between Silverlight and WPF.  In the near future, this will be expanded to Silverlight Mobile as well.
  • Javascript is not the fastest framework.  There is not much to be said here.  There might be some minor exceptions but a well-written JavaScript application will almost always perform slower than a similarly written .NET Silverlight application (If anyone has examples that differ, please share). New web browsers are trying to "complile" JavaScript code natively to make it run faster.
  • Code Security.  Javascript suffers from the fact that the code can easily be inspected using just the browser (page -> view source).  Silverlight suffers a similar fate.  However,  Silverlight code is harder to inspect.  You essentially need to find the cached assemblies and use a tool like reflector to dissasemble them (Silverlight Spy is another tool that can inspect Silverlight code on the fly). However, as mentioned before, a person that wants to reverse engineer a Silverlight app has to go through more steps.  If you must deploy Javascript or Silverlight code on the client, always use an obfuscator and make the hacker work harder. :)
    • Note: As a rule of thumb, any code that you consider IP should not be placed on the client. 


5) Productivity

In this article, I define productivity as a set of architecture and design tools, add-on frameworks, and developer tools that makes me more efficient in crafting and maitaining an application.  HTML, CSS and Javascript suffer from a wide variety of productivity problems.  Have you used a web tool that does everything for you on a complex project?

  • HTML and CSS problem. CSS is language that allows you to enhance HTML with styles.  The combination works great in theory.  However, as the web has evolved to more "fluid HTML/CSS" designs (i.e., div tables with CSS), the web tools have struggled to catch up.  Furthermore, browsers like IE not supporting all of the CSS 2.x standard has led to cross-browser compatibility issues.  This has led to developers having to jump around manually getting their hands dirty in CSS (While that is not bad, it's not productive).  CSS is not a pretty language and large stylesheets are a MESS to work with.  For example, try looking at the CSS for SharePoint 2007.  This has been solved by creating CSS Metaframeworks that allow for cool features like CSS style inheritance which translates to smaller, more maintainable CSS.   Which web design tool that you use integrates with a new open-source meta framework?  Sure, the preview might work; however, you are still manually editing CSS in the end.
  • I can do anything that Silverlight can do with [insert JavaScript web framework here]. I recently got into a debate with a web developer about Silverlight.  All the things I was listing Silverlight can do, his reponse was, I can download "this open-source framework".  Want to improve HTML DOM development? jQuery.  Need a declerative query language like .NET LINQ? jLinq.  How about a Javascript charting package? JS Charts. By the time we were done, his application included five to six additional frameworks.  I find this a productivity problem for a several reasons:
    • Open source/commercial javascript frameworks rarely integrate easily with web design tools (Some frameworks like jQuery that are hugely popular have enterprise tool integration like in Visual Studio 2008/2010).  An add-on framework will help productivity; however, the developer is not working in a design tool 100%.  Therefore, they are not being as productive as they can be.
    • Designers cannot design.  This makes the entire process of web design much harder for non-developers.  A designer should work in a design canvas and have the end result automatically translate to the markup language and pass this off to a developer for interactivity.  How is this possible with HTML/CSS/Javascript not being standardized in simple design tools?
    • Add-on framework maintenance.  On large-scale projects having to juggle multiple add-on frameworks can waste a lot of time.  For example, picking the correct framework, ensuring licensing is compliant, is the framework going to be maintained in the future, etc., are all tasks that need to be handled by someone.
  • Cross-browser issues.  Cross-browser issues are still a huge problem even for large companies like Google who announced this year they are phasing out Internet Explorer 6 support.  There isn't much to add here.  However, if you are a web developer and have not faced these issues, I would like to meet you. :)
  • Control/UI component development. Support for creating reusable UI components in Javascript is virtually non-existant.  It requires developers to be involved and write Javascript that crafts dynamic HTML.  For example, how would you create a Javascript control that renders a gauge?  
  • Integration with server technologies. Working with technologies like ASP.NET or PHP adds another level of complexity to HTML.  This further degrades productivity, by having to manage local client state between server calls (i.e., cookies, temp cache).  Tools like Visual Studio do a very poor job in making a designer feel like home when having to integrate server/client technologies together.

The Silverlight framework handles the productivity issues in a cohesive set of tools that include design tools, developer tools, and a rich .NET foundation.

  • Many architectural/code patterns can be leveraged using .NET:  MVVM/commanding design pattern is built into Silverlight 4, MEF allows for loose coupling of components, Silverlight Unit Test framework, LINQ (declerative query framework for data structures), asynchronous programming model, functinal language support like F#, etc.
  • Silverlight and the accompanying control toolkit include a ton of controls that can be easily extended or styled.  (Toolkit is open-source).
  • Advanced media capabilities like encoding an HD smooth streaming video and providing a DVR-like experience to the viewer can all be done with Expression Encoder and the Silverlight Media Framework.
  • Developer productivity is powered by Visual Studio 2008/2010 and the Silverlight framework.  Debugging parallel tasks in Visual Studio 2010 is easier than ever.  If you want to know if your application is taking advantage of GPU acceleration, Silverlight can highlight the areas affected!  Furthermore, helpful tools like FPS counters are all built into the framework.
  • Design in Silverlight is done using Expression Blend.  This tool can be used by both designers and developers to create UI controls, interactivity, and transitions easily in a single form.  The combination of design features like Sketchflow, behaviors, design-time data and visual state manager allow designers to design without writing code.  These tools allow designers to perform tasks like applying a pixel shader to a video, adding physics (gravity) to an object, and being able to create design-time data representations without writing any code.

Expression Blend Sketchflow allows designers to prototype applications with data, interactivity, and transitions without writing code.


With Silverlight you can target not only the web, desktop, cloud but the Windows Phone 7 platform using a .NET language and development IDE


I could add a lot more to this topic.  However, my experience on working on Silverlight has been "night and day" in terms of productivity.  Projects I have worked on allowed developers/designers to seemlessly create complex controls and extend existing ones and create very unique product designs.  The combination of Silverlight frameworks/tools and what you gain from .NET makes it a pleasure to work with compared to HTML/Javascript/CSS.  The tools that accompany the HTML 5 spec have to truly go through a revolutionary transformation in order to keep up with the design experience provided by Silverlight and Flash.


Note: I have a friend who recently got laid off from a "large" video game studio...pretty talented C++/graphics developer.  With the game industry hurting he moved onto web development/databases/services...regular business stuff.  He told me the same "mess" that occurs with video game development is the same thing he hates about web development.  Having to juggle between different graphics programs, exporting assets editing shaders, code etc.  was analogous to him with having to jump between ASP.NET, Javascript, CSS, HTML etc.  I thought this was a great analogy.


6) Only target the general Web

HTML 5 is a markup language for the web.  You essentially need a web browser to interpret HTML content.  Silverlight allows you to write once and deploy to desktop, web and now Windows Phone 7/Symbian/Android.  Additional features like multi-touch features allow you to take advantage of next-generation hardware natively, without having to rely on the browser.

Note:  I realize that technology like Mozilla's Prism allows for "installing" HTML/Javascript sites locally on the desktop.  But that technology is not very popular and I haven't met anyone that uses it widely commercially,


7) No Hardware Acceleration for Graphics (GPU support) or 3D support

The current HTML 5 spec does not have support to offload rendering to the GPU.  There are plans to support it in the future with WebGL technology using the HTML 5 canvas.  WebGL should provide 3D, hardware-acceleration, and pixel shaders to HTML/Javascript.  Silverlight (as of Version 3) already supports 3D projections, hardware-acceleration, and Pixel Shader 2.0.  Furthermore, the GPU acceleration is not limited to just one layout control (canvas in HTML5).  There are also many physics and 3D engines out there for Silverlight.

The screen shot below is from a chapter in my book that shows a piece of XAML layout that was GPU accelerated.  As you can see, GPU acceleration does free up noticable CPU resources.

One of the ugly parts of the WebGL implementation is that you are still using Javascript to provide dynamic content to the 3D Canvas.  I can imagine this being passable for simple 3D demos, but it won't work for complex interactive 3D scenes.  Doing complex 2D/3D vector math or matrix computations in Javascript isn't going to perform well.  For example, some military simulations for the HUD of a cockpit use a Flash UI for training.  Rendering these complex visuals and providing real-time event-driven calculations is important.

Broad WebGL support is probably a ways off as the spec is still changing.  The future Firefox 3.7 release will suport WebGL/3D Canvas. Other browers like Chrome and Safari will get support as well via the WebKit compatibility.  I would estimate we should see decent WebGL support for Chrome, Firefox and Safari in one to two years.  The reason why I think it is still a year (or two) away is because there are major revisions yet to be implemented and tested.  Furthermore, WebGL is an extension of the HTML 5 canvas.  Therefore, it would make sense that once the canvas tag has matured, WebGL will probably have some upcoming changes.


8) No Webcam or Microphone Device Support

Providing device support integrated into the browser is a huge deal for social, collaboration, and media applications.  Web cam and microphone device support is becoming a big deal for mobile applications as well.  The HTML 5 spec does not support these devices.  There is a plan to add device support in post HTML 5 (5.01 or 5.1, etc.)  Conversely, Silverlight 4 supports both of these devices.

Augmented Reality Applications (shown below), web conference/chat (, or real-time photo manipulation (and more) applications can all be done with Silverlight 4 device support.  (As the HTML 5 spec stands now, these types of applications cannot be done natively with HTML/Javascript).

Rene Schulte's great example of Silverlight 4 augmented reality

9) HTML 5 standard or Google/Apple spec?

A large majority of the HTML 5 spec is being pioneered by the Google and Apple engineers; not that this is a bad thing.  However, note that both Google and Apple do not have RIA or popular graphics frameworks.  They have to do something and have a very vested interest in HTML 5 coming out ASAP.  Rather than creating their own RIA-type frameworks, they are trying to evolve the HTML 5 spec to compete with the rich RIA web experiences.  Here are a couple of interesting points to think about:

  • Do you trust Google to evolve the spec "the right way"?  Google has this aura of being the "not evil corporation" which you would be naive to truly believe.  Will they push for a HTML 5 spec that is serving their own services/technology roadmap or pioneer changes for the greater good of the web community?
  • Adobe is a wildcard here.  What if Apple purchases Adobe? (This acquisition makes sense on many levels).  Will Apple still be as vested to evolve the WebKit/HTML 5 spec?
  • Apple has a proprietary/highly locked down framework with the iPhone/iPad SDK.  What if they decide to use that as the next RIA alternative? You have the same framework on smart phones/tablets; why not move it to desktops?
  • Will Apple/Google alienate other companies like Microsoft, SAP, Oracle, IBM with the way the spec evolves?

As you can see here from this article/chart, Google and Apple are #1 and #2 in evolving the WebKit spec.  In this article, I referenced the HTML 5 spec numerous times.  Notice how a large majority of the spec "owners" are Google engineers.

Update 2/21/2010: Looks like Google has officially scrapped evolving Google Gears (the HTML RIA-like framework) in favor of the investment in HTML 5.  BTW Ian Hixon (the "owner" of the HTML 5 spec from Google's end and some would say the entire HTML 5 spec) was the one that said "Adobe was blocking the spec".  So no one can object the HTML 5 spec if it doesn't support Google's plans?  See where this can get really bad?

10) HTML 5 is already behind Silverlight

This is the last point, however the most important.  After reading all of the "new" HTML features like: video tag, audio tag, canvas, Web Workers, WebGL, future device tag support etc. you should have realized that HTML 5 is JUST CATCHING up to Silverlight.  Furthermore, the HTML 5 spec is not close to being implemented. Lets assume that the full HTML 5 spec is implemented in 2 years (assuming a very aggressive schedule)...where will Silverlight be by then?  Silverlight is on about a 9 month release cycle.  Therefore, by the time HTML 5 is "implemented"...Silverlight will be on version 6 or 7of the platform.  HTML will have to play catch up....again.

Some features HTML 5 will NEVER get.  For example, there will never be a DRM layer for HTML 5 videos.  Why? As mentioned in this article here, if the HTML 5 spec provided an open DRM platform it would be "hacked in 2 days".

11) No good pub-sub model

The current web is built upon the request response architecture.  You navigate your browser to a domain or a service URL -> click go -> receive a response payload.  Once you are done the content is static.  What if the server has new/updated content?? Additional Javascript can be run in order to update the content (make an Ajax call) or the user can manually click a link or refresh the content.  This works, however it is slow and prone to a lot of additional code.  For example, if you have watched a gamecast/box score of a live sporting event you have probably seen a client-side timer refresh (shown below).

ESPN refreshes their gamecast content with timers initiated from the browser client:



The client calls (even if they are automated) have to be initiated by the client, hence the name: request response. 

Wouldn't it be better if the client could "subscribe" to the content offered by the server? This way anytime the server's content has changed it would automatically send the update to the clients that have subscribed.  Silverlight has great support for the pub-sub model that runs on the net.tcp protocol as well as WCF duplex polling.  The performance increases are tremendous (thousands of percentage points).  Pub/sub is another great option for the Silverlight architect/developer. (A great article on using the WCF net.tcp binding with Silverlight 4 can be found here).

Note: HTML 5 is supposed to include something called web sockets, which are going to add pub-sub capabilities to web applications.  More info can be found here. (As mentioned several times before, there are other competing architectures in the spec waiting to be ratified which makes this more of a mess).



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Posted: Feb 08 2010, 10:31 by Bart Czernicki | Comments (32) RSS comment feed |
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Silverlight 3 and F# Support in Visual Studio 2010

The goal of this blog post is to make you aware of F# support in Silverlight in Visual Studio 2010.  In addition, this blog post shows an example why F# is going to be very important for Silverlight architects and developers.  Note:  This is NOT an intro to F#.

Demo and Visual Studio 2010 source code are provided with this article.

In Visual Studio 2010, F# is a first-class language.  Over the last several months, the language has been "productized."  It is officially part of the Visual Studio 2010 ecosystem (tools and .NET 4.0 framework).  However, F# is not limited to the full .NET framework; it is also available in the Silverlight runtime.  This is really exciting as this allows you to take advantage of functional programming features in Silverlight.


In Visual Studio 2010, the "F# Silverlight Library" project is natively supported.


Silverlight 3 application that includes an F# assembly.


Why should I care about F# in Silverlight?

Most C# developers/architects who do not have experience with functional programming language features could assume that F# is another language like Visual Basic, J# or C++.  It would be wrong to compare F# to any of these languages (including C#).  As a functional language, F# allows developers to design software using the functional paradigm.  What does that mean?  This means functional patterns such as interactive programming, pattern matching, immutable data types, type inference, lambda expressions, workflows, higher-order functions, discriminated unions, etc., are all included in F#.  While taking advantage of these features, a developer using F# can use the type system, implement object-oriented design and make use of the .NET classes.  This makes F# a very unique language that combines all the features of a first-class .NET language (i.e., C#) and a professional functional language.

Note: F# compiles to IL just like any other .NET language.  However, F# has been designed from the ground up over the last couple of years.  Therefore, the IL it generates has been optimized and many new language optimization features have been implemented.  For example, you may have seen blog posts that compare C# and F# syntax that shows F# compiling into cleaner IL and faster code.  Conversely, C#'s core functionality has not been redesigned in about a decade (C#/.NET has been extended with functional features such as type inference, extension methods, lambdas, AST, LINQ, etc.)


Show me some code that proves how F# can add value to Silverlight

This short blog post is not meant to be an F# introduction (Please see links below for intro material).  However, I did want to pick at least one compelling feature that really shows off the power and functional brevity of F# married with Silverlight functionality.  The feature that I decided to show off in a Silverlight F# module is a concurrent programming pattern.

If you do not already know, Silverlight supports distributing logic up to eight processor cores (This frustrates me that Microsoft doesn't adverstise this enough). In my opinion, concurrent programming is THE biggest feature of Silverlight over other RIA technologies (i.e., Flash, JavaFX).  However, implementing asynchronous patterns in Silverlight is not trivial.  The callback pattern is messy and leads to a lot of code.  Silverlight runs in an STA mode and requires UI elements to only be modified by the main thread (dispatching or synchronization).  Even asynchronous constructs like the BackgroundWorker that are supposed to make concurrent programming simple lead to many messy lines of code with events.  Wouldn't it be great to get the benefit of asynchronous programming without having to write many lines of additional code?

One of the fantastic features of F# is that the default type immutability and functional design allows the language to express the desired result declaratively.  This means you write F# syntax by telling the program what you want it to do rather than how to do it.  For example, if you are using constructs that use secondary threads and allocate code to these threads, then you are writing imperative code.  A lot of lines of code are wasted telling the code how we want it to behave.  Wouldn't it be better to define pieces of logic and simply say that we want them to execute in parallel?  Functional declarative code in F# can do exactly that.  F# includes a feature called asynchronous workflows that allow you to write logic by composition with the aim to be executed in parallel.

Initial Steps

  • I created a simple Silverlight application.
  • I added an "F# Silverlight Library" project
  • In the F# assembly, I added an F# code file called ConcurrencyTest.fs.
  • I created an F# function called addNumbers that takes two parameter:
    • The first parameter is an accumulator that is the existing sum in the running sequence (This will be passed by the reduce sequence function).
    • The second parameter is the number in the sequence we want to add.
  • I created an F# function called squareNumber that takes two parameters:
    • The first parameter is an accumulator that is the existing square sum in the running sequence (This will be passed by the reduce sequence function).
    • The second parameter is the number in the sequence we want to square.
  • I created an F# function (equivelant to a C# method) that takes no input parameters named PerformTwoLongRunningTasks:
    • Inside that function, I defined two tasks that use the addNumbers and squareNumber functions to add the numbers across a sequence of numbers from 0 to 10,000,000
    • The PerformTwoLongRunningTasks function returns an array of 64-bit integers.  The array of 64-bit integers are the results of the two aggregates functions.
    • The first function returns the sum of the numbers.  The second function returns the square of the numbers.

The F# static method/function is shown below (Some familiarity with F# is required to understand what is going on, but I commented on the code for those unfamiliar with F#):

Now that we have this function (static method) defined in our F# library, it is ready to be used.  In the Silverlight application, we can add a reference to the F# library and then we can call the function (static method) as shown below in our C# Silverlight MainPage class.  Note that below we are calling the function just like we would call a static method with the [Name of Class].[Name of public function].  Notice also that because F# uses the base .NET type system, the returned array of integers does not need special casting/marshalling to C#.

Parallizing the Tasks

Now it is time to parallize the two tasks and scale it across multiple logical/physical processor cores.  As mentioned earlier, we are going to accomplish this with asynchronous workflows. In the figure below, I highlighted the changes to the function and it now scales across multiple cores.  This was done in two steps:

  • Wrap the body of the member functions with the async {... } syntax.
    • Add a return keyword (This signifies the return parameter/completion of the body).
    • The body of the function Seq.reduce addNumbers {0L..10000000L} now becomes async { return Seq.reduce addNumbers {0L..10000000L} }.
  • The main function (PerformTwoLongRunningTasks) now returns an array of async tasks.  These can be thought of delegates that need an Invoke-type command to execute them.  We simply change let results = [| task1; task2 |] to let results = Async.RunSynchronously (Async.Parallel [ task1; task2 ]).
    • All this does is tells the F# compiler to parallize these tasks.  However, run the result synchronously.  Therefore, the code returns to the main thread and we do not need dispatching/synchornization, etc.  This is analogous to creating a wait event in C# and having the two pieces of logic scheduled on secondary threads and waiting for this process to come back.

Asynchronous workflows allowed us to simply wrap the tasks as an "async function" declaratively.  This is a very important distinction as we just declared the logic and told it we want this to run in parallel.  Notice we didn't tell it "how to run in parallel" (imperative code).  Therefore, we did not have to:

  • explicitly start, stop threads (i.e., Thread.Start)
  • use BackgroundWorker
  • use callbacks (AsyncCallBack)
  • use BeginExecute asynchronous pattern

We simply told the code we want the tasks distributed among multiple cores and let the F# compiler figure out the hard part and generate the IL.  This is really powerful and in the very near future of "declarative parallel processing".  This is an example of what I mentioned earlier that the F# compiler has been designed recently and can include this type of "magic" right in the language.  C# does not have this feature and needs to be extended to provide this kind of automation.

Can't I do this with PLINQ?

Those familiar with the Parallel Extensions Libraries that will be added to .NET 4.0 might be aware that LINQ has been extended with parallelism features.  This allows you to extend your existing LINQ queries with parallism features.  This is known as PLINQ (parallel LINQ).  For example, a screen shot below shows a LINQ query that can be easily parallized by simply adding the AsParallel() extension method.

Unfortunately, the Parallel Extensions Library will NOT be available for Silverlight for the Visual Studio 2010 release.  However, I think that there is a good chance future versions of Silverlight will eventually get this feature.  There are some big features in the Silverlight assemblies that are simply missing and need to be added before features like PLINQ can be added.  This is exactly where asynchronous workflows can be substituted for PLINQ in a Silverlight application.  If you are working with large data sets, complex math computations, AI for a game, etc., parallelizing your code in F# libraries makes pefect sense for a Silverlight application.  This is MUCH easier than writing your own imperative multithreaded code.

How about the Performance?

I extended the functions and created functions for two, four and eight tasks and put this in a Silverlight application.  On my workstation (four cores), there was about a 50% improvement by parallelizing the two tasks.  With four tasks, the improvement in performance was about 3.5x.  As you can see, asynchronous workflows can easily dramatically improve the performance of your code on the Silverlight client.

Click the picture below to launch the demo application


Getting started with F#

Information on F# has been around for several years.  There are many articles, white papers, and books on F#.  However, you do have to be careful and get content that is recent and relative to the current F# release.  The F# specification has changed dramatically over the last several months as the language was being "productized" and many methods/functions simply don't exist in F# anymore.   Below are some links I put together where to get started.


  • Getting Started with F# - This video (from the 2008 PDC) is the place to start if you have zero F# experience and/or if you want a really good introduction into functional programming and some F# examples.

Books (I have read four different F# books and the two below are by far the best ones and most current.  Don Syme's F# book is good but a little outdated.)


  • This the main Microsoft F# page.  Includes numerours links, downloads for Visual Studio, F# extensions, etc.
  • Don Syme's blog - Don Syme is one of the main "creators" of F#.  His blog is a must read to get insight into advanced topics and upcoming F# news.


I hope this post gets Silverlight architects/developers exited about upcoming F# support.  F# is another tool that software architects can use that helps them create better software.  Furthermore, F# suport is another example of Microsoft's ability to integrate the Silverlight runtime across the .NET development stack.

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Posted: Nov 04 2009, 16:16 by Bart Czernicki | Comments (0) RSS comment feed |
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