That's because the application itself, according to some observers, remains a managed application relying on Microsoft's Silverlight environment.

Windows Phone 7, like other leading mobile operating systems, requires all applications, including games, to run as "managed code" in a virtual machine (supplied in this case either by the run-time environment from Microsoft's Silverlight or XNA Studio tools). The virtual machine interprets the application's requests and passes them off to the underlying operating system. Microsoft's previous mobile OS, Windows Mobile, allowed native applications, which could directly address the operating system resources.

Technically, Windows Phone 7 is the user interface layer, with some additional innovations and features, built atop the latest, and so far unreleased, version of Microsoft Windows Embedded CE (which is not based on Windows binaries). That version, which will be named , is currently in what Microsoft calls "public Community Technical Preview."

Another blogger says that Walsh's accomplishment is important because he was able to gain "root access" to the underlying OS. Walsh was "able to deploy a WP7 app using the developer sideloading process keeping in mind hounsell's entire idea," says Waisy Babu, a regular blogger at . "This gave him root access to the system, which is a must for "jailbroken" apps to be able to run in the future."

But in fact that doesn't appear to be the case, according to two other programmers, both with experience in Windows Phone 7. They say that Walsh has simply gained access to some coding privileges not available to most programmers.