Windows Phone 7 相关细节越来越清楚，根据国外XDA论坛的最新消息，.XAP格式将取代.CAB成为Windows Phone 7的安装文件格式，虽然.XAP也仅是基于ZIP压缩的，但这个沿用多年的安装文件格式的改变，届时还是会让很多人不习惯吧。
【感受】：其实Windows Phone 7 本身和iPhone一样，安装程序都不通过电脑，而是直接通过程序商店完成下载和安装的，但考虑破解（俗称越狱）的问题，安装文件的提取和重新制作肯定是必然的，因此这个消息可以先让大家淡定一下下（XDA原帖甚至提供CAB转XAP格式的转换工具），至于Windows Phone 7究竟怎样，还是等正式发布出来溜溜再说。
Windows Phone 7 – Introduction to the .xap (replaces .cab)
So, with WP7, we lose all support for the .cab and associated API as it exists now. Replacing it is the .xab format.
What’s a .xap?
A .xap is a simple, every day .zip file, renamed to .xap. Inside, it contains the app and all relevant dependencies. There are a number of possible .xml files that could be included inside the .xap to determine things like required security access level, to tell the system which .dll contains the main() for the application, etc.
I believe the .zip also provides a container for the virtual filesystem available to the app (not sure on that, it may be stored in a separate container, have to analyze more)
At least initially, .xaps will only be available for deployment through the Marketplace.
Regarding preloaded applications by OEM/MO: Requirements are much more strict in this regard now due to frequent end-user complaints about “slow, laggy, etc” Stock ROMs. I know every one of you reading this knows what I mean Preloaded App Requirements (which will be distributed as .xap) as follows:
•Maximum of 6 preloaded applications on the device, not to exceed 60MB
•All preloaded apps must pass Marketplace submission process (some extended APIs are available to OEM/MO so the process is slightly relaxed in that regard)
•The application(s) and all future updates must be free of charge.
•The apps must launch without dependency on network availability.
•The apps must persist through a “hard reset”.
•The apps must be updatable and revocable (!!!!) through the Marketplace.
•The apps must notify the user at first launch of any capabilities to be utilized and get user consent (to access compass, accelerometer, network, etc.)
I’ve attached a .xap to this post for your examination. It’s renamed to .zip for the attachment system to allow it.