There's been a lot of discussion since Microsoft's BUILD conference on the fate of Silverlight. (Something that is an issue for us because Sybase was originally looking at supporting it for web app development in PowerBuilder 15.) Contrary to what a number of the pundits and would-be pundits have said, I don't think it's quite accurate to say that Silverlight is dead in Windows 8. I think it's more accurate to say it's evolved.

As background for those who haven't been following this closely, Microsoft announced that the Windows 8 operating system would support two kinds of applications: traditional "desktop apps" and the newer "metro style apps." What would not be available in the Internet Explorer provided with Windows 8 would be support for any plugins, either Silverlight or Flash (see Figure 1).

It's that last part (no plugins) that have raised the concern about the death of Silverlight. True enough, Silverlight apps running in a plugin within Internet Explorer will be dead. But if you look at the technologies used to develop "Metro style apps," they fall into two classes: those created with HTML and JavaScript, and those created with XAML and a .NET language. That latter category is where Silverlight lives on in a new form. As others have noted, it's fairly straightforward to migrate a Silverlight app to Metro apps [1], or to write a "cross-platform" application that supports both Silverlight and Metro app models.[2]

Primarily this means three things for PowerBuilder:

• Silverlight (or at least Silverlight technology) is still available as a means of deploying "native" Metro applications for the Windows 8 operating system. Note that SL is also shown in the diagram as supported for Desktop App deployment under Windows 8.
• Silverlight is no longer an adequate option for developing web applications. When Microsoft itself gives up on providing a plugin for its own browser to support Silverlight, it's over as a web deployment methodology. As I've mentioned earlier, I'm a late and reluctant convert to the use of HTML5 to generate web applications. I still believe it's an immature technology. I imagine the real test will come when Facebook releases their new HTML5-based interface (not released at the time of this writing). If there are holes in HTML5 capabilities, the folks at Facebook are going to run into them trying to support a wide variety of devices from a single code base and implementing a less than trivial interface. What will be interesting to see is if:

a. The HTML5 interface provides the same capabilities as the current native and web implementations and

b. Whether it will require a lot of browser-specific customization that is typical of current web applications. One of the points of HTML5 is to largely eliminate such customizations, but the uneven support for it now may still require it.

• Under Windows 8, HTML5 becomes another solution for developing "native" applications. Under Windows 8, HTML/JavaScript gains an equal footing with XAML/C# for developing Metro apps. This may eventually lead to the long dreamed of goal of being able to support both web and desktop applications from the same code base. However, it won't be until Windows 8 becomes the predominant operating system before most people can make that move. It wasn't until this month that Windows 7 (released two years ago) finally slightly edged out Windows XP for the most-used operating system.[3]

I wouldn't recommend that Sybase give up on Silverlight targets in PowerBuilder 15. They probably need to abandon hope of using such a target as a primary means for web deployment though. They may need to look at using it to leverage the development of an XAML-based Metro app target as well. But it's beginning to look like HTML5 may become not only the best long-term bet for web deployment, but for desk-
top deployment as well.

References

1. http://msdn.microsoft.com/en-us/library/windows/apps/hh465136%28v=VS.85%29.aspx
2. http://www.scottlogic.co.uk/blog/colin/tag/silverlight/
3. http://www.zdnet.com/blog/btl/windows-7-overtakes-windows-xp-global-share/59469