Project PDA

Microsoft operating system for handheld devices. The model takes as its Windows CE operating system Microsoft Windows 95, so its use may be very familiar to most users. Its evolution into the world of PDA is called Microsoft Windows Pocket PC, that is, the operating system for PDA-type Pocket PC.

The major competitors to Pocket PC are Palm OS and Symbian OS, featured on similar ARM-based hardware platforms.

WinCE's major competition is VxWorks, iTRON, eCos, OSE, QNX, Symbian OS, Linux derivatives such as uClinux and, most notably, Palm OS. Some device manufacturers handcraft their own system.

Windows CE is optimized for devices that have minimal storage—a Windows CE kernel may run in under a megabyte of memory. Devices are often configured without disk storage, and may be configured as a "closed" system that does not allow for end user extension (for instance, it can be burned into ROM). Windows CE conforms to the definition of a real-time operating system, with a deterministic interrupt latency. It supports 256 priority levels and uses priority inheritance for dealing with priority inversion. The fundamental unit of execution is the thread. This helps to simplify the interface and improve execution time.

Microsoft has stated that the "CE" is not an intentional initialism, but many people believe CE stands for "Consumer Electronics" or "Compact Edition"; users often disparagingly called it "Wince." Microsoft says it implies a number of Windows CE design precepts, including "Compact, Connectable, Compatible, Companion, and Efficient."cite web

• title = The Meaning of "CE" in Windows CE
• work = Q166915
• publisher = Microsoft
• date = 2002-09-03
• url = http://support.microsoft.com/default.aspx ?scid=kb;EN-US;Q166915
• accessdate = 2006-09-15 The first version, known during development under the codename "Pegasus", featured a Windows-like GUI and a number of Microsoft's popular applications, all trimmed down for smaller storage, memory, and speed of the palmtops of the day.

Often Windows CE, Windows Mobile, and Pocket PC are used interchangeably. This practice is not entirely accurate. Windows CE is a modular/componentized operating system that serves as the foundation of several classes of devices. Some of these modules provide subsets of other components' features (e.g. varying levels of windowing support; DCOM vs COM), others which are mutually exclusive (Bitmap or TrueType font support), and others which add additional features to another component. One can buy a kit (the Platform Builder) which contains all these components and the tools with which to develop a custom platform. Applications such as Word Mobile/Pocket Word are not part of this kit.

Windows Mobile is best described as a subset of platforms based on Windows CE underpinning. Currently, Pocket PC (now called Windows Mobile), SmartPhone, and Portable Media Center are the three main platforms under the Windows Mobile Umbrella. Each platform utilizes different components of Windows CE, as well as supplemental features and applications suited for their respective devices.

Pocket PC and Windows Mobile is a Microsoft-defined custom platform for general PDA use, and consists of a Microsoft-defined set of minimum profiles (Professional Edition, Premium Edition) of software and hardware that is supported. The rules for manufacturing a Pocket PC device are stricter than those for producing a custom Windows CE-based platform. The defining characteristics of the pocket pc are the digitizer as the primary Human Interface Device and its extremely portable size.