Microsoft Windows

Abstract

DOS has long been the Achilles heel of the PC and has limited its development. It has also been its strength in that it provides a common platform for all packages. DOS and Windows 3.x operated in a 16-bit mode and had limited memory accessing. Windows 3.0 provided a great leap in PC systems as it provided an excellent graphical user interface to DOS. It suffered from the fact that it still used DOS as the core operating system. Windows 95/98 and Windows NT have finally moved away from DOS and operate as full 32-bit protected-mode operating systems. Their main features are:

• Run both 16-bit and 32-bit application programs.

• Allow access to a large virtual memory (up to 4 GB).

• Support for pre-emptive multitasking and multithreading of Windows-based and MS-DOS-based applications.

• Support for multiple file systems, including 32-bit installable file systems such as VFAT, CDFS (CD-ROM) and network redirectors. These allow better performance, use of long file names, and are an open architecture to support future growth.

• Support for 32-bit device drivers which give improved performance and intelligent memory usage.

• A 32-bit kernel which includes memory management, process scheduling and process management.

• Enhanced robustness and clean-up when an application ends or crashes.

• Enhanced dynamic environment configuration.