Tell me about Windows 8 package

Posted: September 3, 2012 in Architecture, Windows 8

Ok so you are a windows 8 App developer you create packages that you install in your or in some machines, and maybe you had already submit to the store your app. But, what’s a Windows 8 package after all, in this post we will try to answer that question and show how everything is processed.

The windows 8 package is presented in the form of a file with the appx extension.

This file behaves as a zip file that contains some files and is descriptions and dependencies.

This file contain’s not only the app code but also a manifest the app resources an AppBlockMap and the libraries used by the application.

The manifest is the part of the app where we describe the capabilities of the app and her platform needs (webcam, Localization etc). The manifest describes also the app dependencies, and enumerate some of the identity of the app like the name and logos.

The AppBlockMap describes how the memory blocks of the application are assigned, the blockmap allow us also to determine what parts of an app have been updated between different versions of the application. This is particular useful to the store to optimize the download of the new version of an application sending only the blocks that are related to the new version.


The appx contains also a certification signature that is given by the Windows Store to certified the application (in an initial stage this signature is given by the visual studio)

After publishing an app to the Windows store, any user who has access to the Windows Store can download and install your application.

When selecting install an app from the Windows Store, the appx package is downloaded to the device and installed automatically along with is dependencies. The installation process intends the creation of a folder where the app will be extracted.

The installation process will also make the necessary installations in the registry and enables the different needs present in the appx Manifest.

One of the questions the author can think right now is about acceptance of the Licence terms or the payment of the application, all this are integrated with the install action of the application in the store.

  1. andy knight says:

    sounds like an upgraded desktop gadget to me 🙂

  2. H Joseph D'silva says:

    Useful stuff, Thanks 🙂

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