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COMPUTER FILE / Richard O'Reilly

A New Window to Multiple Tasks

January 07, 1988|RICHARD O'REILLY | Richard O'Reilly designs microcomputer applications for The Times. and

This will be a revolutionary year for IBM PC-style computing because of the advent of two features. One is called "multitasking," which is running more than one program at a time.

The other doesn't have a simple name. Some people call it "graphical user interface," a daunting way to describe the way an Apple Macintosh operates. It divides the computer screen into sections with various colors or tones and lets you pick programs to run or functions to perform by moving a pointer directed by a hand-held "mouse" and clicking a button.

Microsoft, the Redmond, Wash., software firm, two years ago brought the point-and-click approach to the screens of IBM PC compatible computers with a program it calls "Windows." Now, both features are available in a new program called Windows/386, which promises to be much more useful and popular than plain Windows.

Compaq, which developed Windows/386 with Microsoft, was the first to offer it, introducing the software in October along with its line of speedy Deskpro and portable computers equipped with Intel's most powerful microprocessor, the 80386. The program is now available from software dealers for other brands of computers with 80386 microprocessors, which are the "brains" of a personal computer.

There also is a simpler, new version of the software for computers without 80386 chips called Windows 2.0, which sells for $99. It looks the same on the screen but allows only one program at a time to run.

In many ways, Windows/386 is a preview of the new OS/2 operating system jointly developed by Microsoft and IBM. When the final versions of OS/2 become available late this year, they will have the Windows look but will call it a "presentation manager."

Priced at $195, Windows/386 isn't really a substitute for OS/2 because it won't work with the generation of software that will be introduced this year to take advantage of the much larger memory access allowed by OS/2. Standard DOS programs--the only kind that work with Windows/386--typically are limited to a maximum of 640 kilobytes of random access memory, or RAM, although some use special mechanisms to exceed that limitation.

Windows/386 takes advantage of a special programming feature of the 80386 chip that enables the computer to behave as if it were multiple computers all housed within the same box. Theoretically, Windows/386 can run up to 64,000 programs simultaneously, according to Adrian King, Microsoft's director of marketing for operating systems. But the practical limit is probably about a dozen, and most users undoubtedly will limit themselves to just a few programs.

Three Ways to Run Program

There are three ways to run an application program under Windows/386. One is to give the application exclusive control of the computer, in which case you don't have multitasking because the operation of all other programs is suspended. Some programs may require this.

Most of the popular software packages will run just fine in the second mode, which is full-screen but not exclusive. In other words, that mode gives you multitasking, but you'll see only one program at a time. The others will be hidden behind it, while still performing the tasks you have given them.

The third way is to run a program within a window that covers just a portion of your screen. If you have several such programs running, you can see each of them. Programs that have been especially written for the Windows operating environment work best in that mode.

For instance, you could have WordPerfect word processing software fully displayed on your screen, and at the same time dBASE III database software could be running in the background. Tapping a couple of keys lets you flip-flop the programs.

Whenever Windows/386 runs more than one program, it gives one program--the one in the foreground or the last one started if several are displayed--two-thirds of the computer's processing time. The other one-third is shared more or less equally by all the other programs running, King explained.

Thus, whenever you run a program under Windows/386 while others are operating, it will run at least one-third slower than if you ran it alone. And programs running in background will really crawl, compared to their normal performance, especially if there are several. So the price you pay for the convenience of running multiple programs is that suddenly your fast 80386 computer will seem as slow as an AT-class computer with its slower 80286 chip.

There are practical multitasking applications, nonetheless. For instance, if you had a large spreadsheet to recalculate or a database to sort, you could start the work and switch it to the background while you use a word processor to write a report.

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