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Microsoft’s latest product is likely to become the industry standard for advanced user interface.

Reprinted from PC World, issue 1/1984, pp. 58-61.

Microsoft Windows made quite a stir when it was announced at COMDEX in Las Vegas last November. The program runs popular software using windows and mice and was demonstrated simultaneously by more than a dozen vendors.

Windows and mice have recently become very popular topics in the personal computer industry. Windows because they allow computers to present information in a way that closely resembles the way people work, and mice because they are the best device yet devised for converting human instructions to computer actions. Windows and mice are both the result of research done at Xerox Corporation’s Palo Alto Research Center during the early ‘70s.

Mice are technically known as “pointing devices,” because they are used to move the cursor and point to locations on the screen. A mouse is generally about the size of a deck of cards, fits comfortably in one hand, and is designed to rest on the table next to the computer keyboard. When you move the mouse, it sends information to the computer to indicate direction and distance, which the computer translates into cursor movements on the screen. You can point to any location on the screen by moving the mouse around on the table. Most mice have one to three buttons that you can push to execute frequently used commands.

Mice have been available for several years, but their use is not widespread, probably because most popular programs are not designed to take advantage of them. Consumers won’t buy mice unless programs use them, and software companies don’t want to write the programs unless consumers have mice. Further compounding the problem is the fact that there is no standard way to connect a mouse to a computer. Some mice plug into a serial port, some plug into a game paddle port, and others require a special interface card. Also, different brands of mice send different signals to indicate direction and distance.

Windows have been used for many years. If you have used WordStar or have programmed in BASIC on the IBM PC, you have already seen windows in action. WordStar uses separate windows to display command menus and text, and BASIC uses a one-line window at the bottom of the screen to display the values assigned to the function keys. A window is an area of the screen that operates independently from the rest of the screen.

Many spreadsheet programs let users define windows to separate information displayed on the screen. One limitation with these windows is that they can display only information generated by the spreadsheet program. There is no way, for example, to divide the screen into two windows and then use one window to run a separate word processing program.

VisiCorp offers the Visi/ON system as a standard software interface that can be used to operate a variety of programs in a mouse and window environment. Visi/ON provides true window capabilities that enable users to define different areas of the screen for each program, but it also has several drawbacks. Programs must be specially written to use Visi/ON, and the software interface is very complex, requiring a major investment for software companies. Visi/ON is also expensive. In addition to its $495 price, the system requires a hard disk drive and at least 256K memory.

Microsoft Windows

The ideal mouse and window system would be inexpensive, would work with off-the-shelf programs, and it would require a minimal amount of disk storage and memory. That is a good description of Microsoft Windows. It works with most off-the-shelf software, requires only two floppy disk drives and 192K of memory, and is intended to be sold at low-cost or included with DOS when buy a computer. The product is scheduled for release in April.

Microsoft Windows is an extension of MS-DOS, providing a standard interface to the mouse and the screen in the same way that MS-DOS itself provides a standard interface to disk drives and other devices.

Microsoft divides programs that will work with Microsoft Windows into three categories. In the first category are programs that use standard MS-DOS functions to perform all input and output. These programs work well with Microsoft Windows and can share the display with similar programs. The second type are those that perform their own screen operations. Most spreadsheet programs fall into this category because the MS-DOS screen functions are too slow to provide the fast changes in the screen display necessary for good performance. Microsoft Windows can recognize these programs and allows them to use the entire screen until they terminate.

In the third category are programs that have been designed to operate in conjunction with Microsoft Windows. Such programs are portable; the same program can be run on two different machines and can make the best use of each machine’s capabilities. Microsoft Windows automatically compensates for the differences. These programs also benefit from Microsoft Windows’ extensive library of special functions such as the ability to pass data between windows.

Functional Description

Figure 1: Overlapping windows of a typical window management system
This image can be zoomedFigure 1: Overlapping windows of a typical window management system
Unlike other window management systems, Microsoft Windows does not have overlapping windows. Instead, it uses a technique called tiling, which arranges windows to fill the screen completely and make the best use of the screen display area. Figure 1 shows three overlapping windows, and Figure 2 shows how tiling arranges three windows to prevent overlap. According to Microsoft Windows Product Manager Scott McGregor, research has shown that most users prefer to have windows arranged neatly. Microsoft Windows’ tiling feature does this automatically, arranging two windows so that each takes up one-half of the screen, or three windows so that each occupies one-third. Of course, the user can change the size and position of any window. Microsoft Windows simply makes a guess at correct placement.

Figure 2: Windows tiled to prevent overlap
This image can be zoomedFigure 2: Windows tiled to prevent overlap
Windows in Microsoft Windows are normally composed of four parts, as shown in Figure 3. At the top is the caption, which shows the name of the program or file using the window. Below the caption is an optional menu area and below that the window display area. Finally, there are horizontal and vertical scroll bars. Scroll bars allow the user to visualize which portion of the data can be seen through the window. Moving the scroll bars with the mouse changes the contents of the window.

Figure 3: Typical window as displayed by Microsoft Windows
This image can be zoomedFigure 3: Typical window as displayed by Microsoft Windows
At the left and right edges of the caption are icons, symbolic representations of functions that Microsoft Windows can perform. To execute a function you simply move the mouse to position the cursor over the icon and then press a button. Icons are much easier to use than typed commands, and they convey information more rapidly. Microsoft Windows can change icons to reflect status graphically. A printer icon, for example, can be flashed on and off to indicate that the printer is out of paper.

Icons that affect the entire display rather than just one window appear at the bottom of the screen. A window-specific icon might enlarge a window to fill the entire screen or move the window to another location. An icon with a screen-wide effect might open a new window or prepare the system to be shut down at the end of the day. One Microsoft Windows feature reduces an entire window to an icon that is then displayed at the bottom of the screen. Selecting the icon restores the window to its original form.

In short, Microsoft Windows provides a simple, powerful, and inexpensive user interface that works with most popular programs. That alone is enough to guarantee consumer support to make it the de facto standard of the personal computer market.

Hardware manufacturers will also benefit because Microsoft Windows uses installable device drivers for the mouse and the video display. Manufacturers will be able to provide a device driver without concern for the programs that the buyer will be using. A manufacturer of a high-resolution color graphics interface, for example, will need to provide a driver that reflects only the display capabilities. All the programs written to use Microsoft Windows will automatically adjust to the higher resolution.

Widespread use of Microsoft Windows will have many long-term benefits for the entire personal computer industry. Microsoft Windows insulates programs from the actual mouse and screen hardware, which means that advances in technology are realized as consumer products much more rapidly. Software companies will need to sell only one version of a program; the Microsoft Windows interface for any particular machine will be written by the hardware manufacturer.

Technical Notes

Microsoft intends to modify all their programming languages to support Microsoft Windows, and as it gains popularity, you can expect to see more programs designed to take advantage of its special features.

One special feature allows an application program to “register interest” in another program’s data. Microsoft Windows will inform the first program whenever the data changes. A graphics program, for example, can use this feature to draw a new graph whenever data from a spreadsheet program changes.

Microsoft Windows has a datapassing protocol that allows programs to exchange data in the most efficient manner. Some programs can exchange data in the form of text only; others can support binary data or other protocols that have been defined by the computer industry. Microsoft Windows determines the highest protocol the programs have in common and then uses that protocol to pass data between them.

It provides those features passively; that is, it gives programs access to a variety of data concerning the display but does not require them to use or acknowledge that information. Thus, Microsoft Windows maintains compatibility with currently available software.

Although Microsoft representatives refused to discuss DOS 3.00, they did indicate that Microsoft Windows has been designed to take advantage of the multitasking abilities of that prospective operating system. Under DOS 2.00, you may display several windows, but only one window is active at a time. Multitasking will allow users to run several programs simultaneously; for example, a communications program can run in one window while a word processing program is used in another.

Microsoft Windows should have a lasting effect on the entire personal computer industry. It frees hardware manufacturers to concentrate their efforts on producing the best possible product without regard for maintaining compatibility with any other machine. For software authors it means that programs can be sold to a much wider market, because differences among computers will no longer require time-consuming modifications. For the consumer, Microsoft Windows provides tremendous flexibility in the selection and use of personal computers.

Steven Cook

Steven Cook is Manager of the Technical Department at PC World.

Page added on 21st August 2004.

Copyright © 2002-2006 Marcin Wichary, unless stated otherwise.