Windows 8 Application Delivery – AppX and App Stores

As information about Windows 8 starts to become more common, a few sites are starting to discover details about the new application delivery model Microsoft are adopting called AppX.

In a world where applications have become ‘apps’, and app stores look set to become the dominant distribution method for software, MS seem to have targeted AppX as a delivery model that will support as many types of application and distribution models as possible.

In it’s structure AppX looks very similar to Silverlight’s XAP format, the distributable file is essentially a zip archive that contains the source media and an XML manifest file that describe:

• – The applications identity – it’s publisher, the applications name, version etc.
• – The target architecture for the application – the required processor architecture (presumably important for an OS that will soon once again span more than just x86), OS pre-requisites, any application frameworks required (.net, Silverlight etc.)
• – Application pre-requisites – other applications which are required on the system, for example if the AppX package contains a plug-in for an application, this section might list the name, publisher and minimum version of the pre-requisite app.
• – Required Capabilities – any capabilities which the application will request such as file system or networking. It will be interesting to see whether it will be possible for an app to check for specific system performance through the Windows Experience Index. This would help developers ensure applications always ran on systems capable of running them as designed.
• – OS Extensions – such as file type associations
• – Tile customization – This an interesting one, as AppX is similar to the formats used in Windows Phone 7 this could be a carry over from there so that the format is reusable, or it could be a hint towards new interfaces within Win8. It covers properties such as logo, name, and colours.
• (Info from the excellent I Started Something)

One of the interesting questions that AppX raises is what this new format will mean for business and enterprise customers. Many will currently be investing small fortunes in readying their applications for Windows 7, either in traditional Windows Installer (msi) format or through application virtualisation technologies such as Microsoft’s own AppV. Adding a third format into that mix will, and does complicate matters.

It could be that AppX can act as a wrapper for more traditional deployment tools, or it could be an addition – perhaps for surfacing apps though the App Store interface for example. Or it could be that newly developed apps will need to be in that format to make use of Win8’s new features. We also don’t really know whether the format will be limited only to MS’s forthcoming application store or whether it will be more commonly used for traditional download or CD installs.

With many large organisations having made big investments in internal application delivery tools such as System Center Configuration Manager (SCCM), let alone then checking and fixing apps for Vista/Win7 compatibility, it will be interesting to watch how the interaction between the new App Store and these internal systems will develop. If the Apple app store is anything to go by people will want to make use of the tools and utilities on offer even in a business context. Company IT organisations will come under pressure to make these apps available alongside the apps they typically provide.

It could be that the Windows app store will have a mechanism to publish existing applications though the App Store interface, or alternatively App Store applications could be made available though internal mechanisms such as SCCM (much like Windows Update apps are now).

Personally I would rather be able to surface internal application portfolios through the MS store, perhaps though a ‘My Company Store’ section or something of that nature. I think that’s a neater solution and will make it easier for end users – if you want an app on any Windows systems you happen to use, there’s just one place to go. Even if the App Store interface is then going off an using SCCM (or equivalent) for the actual installation tasks.

There are a number of pitfalls to that approach however. Businesses use different purchasing process to consumers – at least for now. People aren’t going to be keen to buy AutoCAD on their own credit card for example! The App Store would therefore need to have some form of approval workflow so people can request an app, their manager can approve the request and some sort of internal billing/purchase mechanism kicked off. It’s all achievable though, even through technology MS already sell and have at their disposal.

The AppX format could work well for surfacing these internal apps. If internal SCCM host apps could be wrapped with an AppX manifest to inform the app store how to publish them, there’s no reason why internally packaged apps couldn’t be included.