Leaked document details Windows Phone 7 architecture


The Dutch boys at Tweakers.net got the hands on an internal Windows Phone 7 document detailing the architecture of the new OS. This Architecture Guide for Windows Phone 7 OS is the source of the info that was leaked here right before the official announcement at MWC10.

The first slide posted shows the Kernel architecture of the OS. As you can see WP7 is composed of two distinct layers: the user Space & the Kernel Space. Inside the User Space you have the OS services, the shell etc. The Kernel Space on the other hand contains the Kernel itself, the file system, graphics rendering, radio, drivers etc.


In this one you can see the Kernel Memory Space which is composed of a System Trap area of 256Mb , Kernel Virtual Memory and DPA Mapping. The whole Kernel Memory Spce is 2Gb.

According to Tweakers (who unfortunately didn’t post all the slides) Windows Phone 7 is composed of two different file systems: IMGFS and TexFAT. IMGFS is intended for system files and is compatible with Windows desktop file system. TexFATan ‘extended’ version of FAT that can handle files larger than 4GB.


Here you can see how Microsoft is going to handle Direct2D/3D on the OS. Microsoft is supplying the SDK/Framework (which is DirectX11 compatible) and OEMs will supply the 2D and 3D Drivers. Contrary to what Tweakers is saying the Phone can only handle DirectX9 level of graphics (I guess they got a little bit confused here) as seen clearly in the slide (Feature Level9_OM). For more infon on the WP7 rendering pipeline click here.


Here we have the minimum specifications requirement for WP7 hardware.

A Windows Live ID will be required to use the handset (the user will be asked to login on the first boot up) and will be the only way to gain access to the Marketplace,MyPhone synchronization and all the other cloud based services.

This final slide doesn’t need to be explained I guess. Microsoft is finally implementing a robust unified update system for Windows Phone 7. As you can see OEMs and Microsoft will submit their updates to Windows Phone Sustained Engineering and it’s only after that the finally packaged will by pushed OTA or via download (and installation through the Zune desktop application.

One final interesting bit is that OEMs and carriers can only install 60Mb worth of applications (and 6 apps max) on the handset. Those applications will also have to be approved by Microsoft (and not trialware will be allowed).

Source: Tweakers.net