- Windows CE is designed to operate on small-footprint systems. Windows CE is the technical basis behind many smartphones, which have substantially less memory than a desktop system. As such, the Windows CE kernel can operate in as little as a few megabytes of what little memory a compact device might have. Rather than being a paired-down version of their desktop Windows operating systems, Windows CE is built from the ground up to be lightweight.
- When Windows CE is licensed to an OEM, large parts are offered in source code, rather than strictly in binary format. This means that licensees have access to the actual code used to program parts of the Windows CE system. OEMs can modify the source code so that it can operate more closely with their devices. Microsoft does not give out the full source code to the entire operating system, however. Some core components that need not be adapted from source code for specific hardware are still only distributed in binary to protect Microsoft's technology.
- Microsoft's Visual Studio development software suite supports programming projects for Windows CE and CE-based operating systems, including their own Windows Phone operating system. Programs and platform images can be compiled and run either on the desktop computer under an emulator or on an attached mobile device. The Microsoft Platform Developer tool is used for building the OS kernel, drivers, and also the user experience from the source code. Generally, Windows CE development is done using Microsoft-provided tools.
- Windows Mobile is a Microsoft mobile operating system designed for use in smartphones. The last version of Windows Mobile is 6.5, based on the Windows CE 5.2 operating system kernel. It is the basis for a number of smartphones, both with and without a touchscreen, and features a some of basic applications meant to mimic their desktop Windows counterparts. Windows Mobile was designed to provide a user experience similar to desktop versions of Windows, both in aesthetics and features.
- Windows Mobile was renamed "Windows Phone" after version 6.5 to indicate its focus on the smartphone experience. The old Windows Mobile operating system was seen as being too dated to be competitive in a market increasingly dominated by Apple's iPhone and Google's Android smartphone operating systems. Microsoft entirely scrapped Windows Mobile and rewrote their smartphone OS, using a new Windows CE core and a new user interface experience. Windows Phone 7 is based on their latest embedded systems technology, Windows CE 7, and it features a user interface that closely resembles their Zune portable media players.