As we discussed in the new interface section, Windows 8 now supports two different kind of applications: the new Metro Style apps and conventional desktop software. What’s more, Microsoft is launching its own Store to sell them both from.

Metro Style apps

The full-screen Metro Style apps are likely to be web apps; the kind you would typically expect to find on a tablet. Things such as Twitter clients, video players and news readers, rather than full-blown desktop software such as Office or Photoshop.

Although they can be coded in conventional programming languages such as C and C++, they can also be created using standard web technologies such as HTML, CSS and JavaScript (but not, rather controversially, Microsoft’s own Silverlight). And because they are based on web technologies, they are the only applications that can be used across both the x86 and ARM-based versions of Windows 8 without any recompiling.

Microsoft has created a completely new app model and set of APIs for these Metro apps, and they open up some interesting possibilities.

Metro Style apps can, for example, talk to one another. Pictures stored in a photo app can be easily shared with a social networking app. Likewise, you can click the “share” button whilst in Internet Explorer 10, and post a link to straight to a Twitter or email client. “Two apps can share data between them, without the two apps knowing anything about one another,” said Jensen Harris, Microsoft’s director of program management.

The good news for developers is these apps are relatively simple to create. Microsoft showed just how easy it was to create a Metro app using HTML/JavaScript, with an on-stage demonstration that saw a relatively sophisticated drawing app coded in less than 30 minutes using Visual Studio.

There are advantages for users, too. Metro Style apps can be synchronised in the cloud from device to device. Not only does this mean you get the same set of apps across all your Windows devices, but it allows you to pick up where you left off. So if you were half-way through a game on your home desktop, you can continue playing on your tablet on the way to work.

Microsoft app Store

As you would expect, Microsoft will sell both the new Metro apps and conventional desktop software via its own App Store. Indeed, that will be the only way you can get hold of Metro Style apps.

Windows 8 in depth:
Find out about the new interface, apps and the store, performance and Windows 8 on ARM

Like Apple, Microsoft will vet and digitally sign Metro apps before they appear on the Store. All applications will have to pass security, technical and content compliance checks, but in a thinly-veiled swipe at Apple, Microsoft claimed the vetting procedure would take a matter of hours – not days and weeks – and that developers will be kept fully abreast on the progress of their apps.

Microsoft will also give app developers the opportunity to offer free trials of their applications, saving them from having to code separate “free” or “lite” versions of their apps. The software will be automatically removed from users’ machines when the trial period expires.

Developers of conventional desktop software won’t have to alter their code or licensing model to appear in Microsoft’s app Store. However, Microsoft didn’t reveal what cut it would take on apps sold via its Store.

The Microsoft Store is very much a work in progress – the Store link on the developer build of the operating system we’ve been supplied merely links to a holding page.

Now click here for further details on:

The new interface
Performance
Windows 8 on ARM