News >> Browse Articles >> Company Hiring & Layoffs


Windows Phone 7 Architecture Leaks

Windows Phone 7 Architecture Leaks

Windows Phone 7's memory model, which allocates 2 GB to the kernel and 2 GB to apps. Source:

Jason Mick

April 20, 2010

This week, details about both the Windows Phone 7 architecture and low-end phone hardware for developing nations was aired.

Microsoft faces much the same position as Palm does in the smartphone market - it’s losing marketshare to a charging Google and is falling farther away from entrenched market leaders Apple and Research in Motion.

Microsoft’s answer is a complete reboot of its smartphone franchise, however, some are skeptical.  The initial implementation of Microsoft’s new operating system -
Windows Phone 7 reportedly will lack many features that competitors have, such as support for multi-tasking and copy/paste.  Still, many are intrigued to see what the new design will bring. received leaked slides showing the architecture of the new smartphone OS.  The OS is a 32-bit operating system.  Under the memory model, application processes get up to 2 GB of memory, 1 GB of which is virtual memory.  The kernel, likewise, gets its own 2 GB of memory space.

The mandated processor will be an ARMv7 design.  Multi-touch, FM Tuner, Wi-Fi, GPS, and camera are also mandated.  The default screen resolution is 800×480 pixels, but developers can go as low as 480×320 (the resolution of the current iPhone).

Microsoft is providing OEMs with 2D graphics and DirectX 10-based Direct3D 11 runtimes, while they will be responsible for providing drivers for their graphics hardware.  

Bluetooth 3.0 and 4.0 support is noticeably absent, though the phone will support the widespread Bluetooth 2.1 standard.  Microsoft hopefully plans an update at some point to add support for later versions of the wireless communication standard, but there’s no specific details at this point.

Interestingly the OS utilizes two different file systems -
TexFAT for user files or IMGFS for system files.  There’s talk about putting the phone in a mostly disabled state if key system files are deleted.

More interestingly the slides indicate that Microsoft is planning memory card support.  Previously, at developers events, several sources were told by Microsoft executives that memory cards were confusing to users and that it was omitting them to “simplify” the design.  At this point its unclear whether memory card support is in, out, or coming soon.

Microsoft has strict rules with OEMs when it comes to software.  Bing is the default search engine for the phone - that cannot be changed.  OEMs can change the default search engine within Internet Explorer, though.  Likewise, the home screen tiles are non-negotiable.  However, OEMs can add their own extra tiles to the home screen.  Finally, trial apps are disallowed and OEMs are only allowed to add 6 apps and not use more than 60 MB of storage space.

In separate Windows Phone 7 news, Sudeep Bharati, who works on Microsoft India’s Visual Studio team, says that a special fourth chassis will be added for phone sold in developing nations.  He describes, “The low-cost version of the phone will have a different chassis than version 1 to be launched by 2010 end.”

While he mentioned that it would be “low-cost” -
perfect for developing countries like India or China — he did not mentioning anything about cutting the minimum hardware requirements, raising questions about how Microsoft will be cutting costs on the developing nations-targeting handset.

Three chassis designs were previously announced for the U.S. models, including the wide design (similar to the Zune), a slide out keyboard version, and a third, unannounced, chassis.  The third chassis has been speculated by some to be a candy bar or slider design.

_© 2009, DailyTech.’