| The Windows Architecture
Since the IBM PC was introduced in 1981, personal computers have become much more diverse in capability and in configuration. This diversity will increase in the next few years as personal computers based on RISC processors and multiprocessor systems are introduced.
These diverse systems have different operating system needs. For example, a low-end battery-operated portable requires minimal memory and hard disk footprint to minimize weight and cost. It also requires power management to extend battery life. In contrast, network servers and mission-critical desktops require sophisticated security to ensure the integrity of data. RISC-based systems require portability for both the operating system and the applications.
Some vendors feel that the diverse range of hardware requires totally different operating systems with incompatible applications. They sell different operating systems for personal computers, workstations, servers, and in the future, pen-based systems. Each of their operating systems require unique, incompatible applications. Connectivity between these divergent platforms is complicated.
Microsoft is focused on a much simpler solution. We’re extending Windows into multiple, fully compatible implementations. Different implementations of Windows will be optimized for different classes of hardware. Customer investment in Windows development and Windows applications will be protected. Windows applications will run across the spectrum of hardware, from notepad-sized pen systems, to mission-critical desktops, to multiprocessor and RISC based systems.
Microsoft Windows is evolving into a complete operating system architecture. The Windows architecture addresses diverse requirements by supporting different modes of operation. Today Windows has three modes: Real-mode, Standard-mode, and Enhanced-mode. Real-mode provides compatibility with previous versions of Microsoft Windows. Standard-mode is optimized for an 80286 processor and provides access to the full 16 MB of memory supported by that chip. Enhanced-mode takes advantage of the 80386 and 80486 processors by providing support for multiple DOS applications and thru a technique called demand paging, provides applications with access to more memory then is physically present in the machine. All three modes support both DOS and Windows applications.
Building upon the success of Microsoft Windows Version 3.0, Microsoft will introduce Version 3.1 in late 1991. Version 3.1 incorporates significant customer feedback; it improves performance, introduces a newly designed file manager, improves network connectivity, and improves system reliability. Version 3.1 will support Windows Standard-mode and Enhanced-mode.
Also during 1991, Microsoft will enhance Windows Standard-mode and Enhanced-mode by providing extensions for sound, animation, and CD-ROM access, called Windows with Multimedia. We will also release extensions for clipboard and pen-style computing, called Microsoft Windows for Pen Computing.
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