Windows CE is built from a number of discrete modules, each providing specific functionality. Several of these modules are divided into components. Components enable Windows CE to become very compact (less than 200 KB of ROM), using only the minimum ROM, RAM, and other hardware resources that are required to run a device.
Windows CE contains four modules that provide the most critical features of the operating system: the kernel; the object store; the Graphics, Windowing, and Events Subsystem (GWES); and communications. Windows CE also contains additional, optional modules that support such tasks as managing installable device drivers and supporting COM.
The kernel is the core of the OS, and is represented by the Coredll module. It provides the base operating system functionality that must be present on all devices. The kernel is responsible for memory management, process management, and certain required file management functions. It manages virtual memory, scheduling, multitasking, multithreading, and exception handling.
Most components of the Coredll module are required for any configuration of Windows CE. There are some optional kernel components, however, that are needed only when you include such operating system features as telephony, multimedia, and graphics device interface (GDI) graphics. For more information on the kernel, see the Microsoft® Windows® CE Programmer's Guide.
The Filesys module supports the Windows CE object store API functions. The following table shows the types of persistent storage that the object store supports.
Type of storage |
Description |
| File system | Contains application and data files |
| System registry | Stores the system configuration and any other information that an application must access quickly |
| Windows CE database | Provides structured storage |
The object store offers an alternative to storing user data and application data in files or in the registry. These various object store components can be selected or omitted during the operating system build process to include only those features that are required. For more information on the object store, see the Microsoft® Windows® CE Programmer's Guide.
GWES is the graphical user interface between a user, your application, and the OS. GWES handles user input by translating keystrokes, stylus movements, and control selections into messages that convey information to applications and the OS. GWES handles output to the user by creating and managing the windows, graphics, and text that are displayed on display devices and printers.
Central to GWES is the window. All applications need windows in order to receive messages from the OS, even those applications created for devices that lack graphical displays. GWES provides controls, menus, dialog boxes, and resources for devices that require a graphical display. It also provides the GDI, which controls the display of text and graphics. For more information on controls, GDI, windows, and messaging, see the Microsoft® Windows® CE User Interface Services Guide.
The communications component provides support for the following communications hardware and data protocols:
For more information on the communications component, see the Microsoft® Windows® CE Communication Services Guide.
In addition to the primary modules just described, other operating system modules are available. These include modules and components in the following categories:
Each module or component provided in Windows CE supports a group of related API functions that are available to you.