Multitasking showdown. (Windows vs DESQview) (evaluation)
by Jack Nimersheim
We've all seen representations of Shiva, the many-armed Hindu god, his multiple hands in several different attitudes, holding symbols of life and death, while he simultaneously dances and meditates. Humans are at least touched by the divine: We often work at more than one thing at a time, despite the fact that we have only two hands. We can switch between tasks fairly rapidly.
The PC is burdened with a one-track mind. A typical PC operating under MS-DOS is designed to take on a single task, complete it, and move to its next assignment.
People, however, are rarely afforded the luxury of dedicating themselves to one task and one task only. More commonly, we find our attention jumping around among multiple projects. We may, for instance, be working on last year's annual sales report and next year's budget at the same time, but yesterday's PC running yesterday's software can't even keep up with this relatively simple mental juggling act.
If you could transform your single-tasking DOS-based PC into a multitasking tool, would you be interested?
The good news is that this can be accomplished with relative ease and at a surprisingly low cost.
Two popular programs, DESQview (Quarterdeck Office Systems, 606-B Venice Boulevard, Venice, California 90291; 213-314-3240;$129) and Windows (Microsoft, One Microsoft Way, Redmond, Washington 98052;206-882-8080;$149), specialize in endowing DOS with the ability to multitask: to run multiple applications concurrently on your DOS-based PC.
Equally important, since both DESQview and Windows themselves run under DOS, they permit you to multitask virtually any DOS application already on the market. By contrast, OS/2, Microsoft's much-touted second-generation operating system, requires that you replace your current DOS applications with all new software (much of which has yet to be written) before you'll be able to take full advantage of its multitasking capabilities.
Despite their shared goal of adding the ability to multitask to your PC arsenal, DESQview and Windows differ radically in many critical areas. But before looking at these differences, let's examine one of the most obvious similarities between DESQview and Windows--specifically, the basic technique used by both programs to accomplish the feat of multitasking under DOS.
Sleight of Hand
To get an idea of how DESQview and Windows work, you need look no farther than your kitchen. Suppose you had to prepare a three-course meal on a single-burner hot plate. One way to accomplish this would be to complete each course before starting the next. Unfortunately, by the time the final course was ready, the food prepared first would be too cold to serve (assuming that vichyssoise was not on the menu).
But what if, instead, you heated up the first course for a short time, then removed it and began cooking the second? Several minutes later, you'd replace the second course with the third. After a bit, you could remove the third course and go back to heating up the first, then replace the first with the second, the second with the third, and so on--continuing to dedicate a short period of burner time to each course until all three items were adequately cooked.
Using this technique, your entire dinner would be ready to serve at approximately the same time, with none of your guests ever suspecting that you had been forced to prepare their three-course meal on a single burner.
Both DESQview and Windows use a variation on this technique (called time slicing) to multitask programs running under DOS. By providing CPU time in round-robin fashion to however many programs you have loaded into RAM, DESQview and Windows fool each application into thinking that it, and it alone, has exclusive access to your system resources. Furthermore, this prestidigitation occurs at such a rapid pace that you'll barely be aware that it's happening.
There are similarities in the ways Windows and DESQview manipulate your CPU, but what sets them apart from one another? Let's begin with their appearance.
Words of Pictures
DESQview eschews the colorful displays and stylized icons that define a graphical user interface (GUI) like Windows, opting instead for a spartan interface not very different from the one employed by MS-DOS.
All DESQview display elements (command options, pull-down menu boxes, window borders, and the like are generated using the standard PC character set on the text screen. DESQview is perfectly capable of running graphics programs in a multitasking session; only DESQview's toplevel user interface is limited to character-based operation.
Windows, on the other hand, relies on a bitmapped display, where each picture element (pixel) must be individually controlled. A typical VGA display is composed of over 300,000 pixels. As you might suspect, the added resources required to manage the graphical Windows display can slow a system down considerably. Therefore, DESQview gets the nod over Windows at least as far as speed is concerned.
However, a GUI such as Windows has several advantages over a character-based operating environment. GUIs are generally easier to learn and use. These factors take on added significance on a system used by newcomers to PCs. And the fact that one Windows program bears at least a passing resemblance to another makes retraining less troublesome when it comes time to upgrade or change applications.
With the recent release of Windows 3.0, Microsoft finally delivered on its longstanding promise to provide a true graphical interface for DOS-based personal computers. The result is an operating environment that even PC neophytes should have little trouble navigating, once they've mastered a few basic techniques.
Windows' reliance on icons, mouse support, and pull-down menus greatly simplifies most PC operations. Starting an application in Windows, for example, is a simple matter of positioning a mouse pointer over that application's icon and then double-clicking the mouse button. This point-and-click paradigm carries over into virtually all areas of Windows operations.
If you've ever worked in standard DOS, the command COPY/V C: \ TEMP \ BUDGET90 D: \LOTUS \ DATA \ will look depressingly familiar. This kind of command structure--in this case, a relatively simple command whose sole purpose is to copy a file from one DOS directory to another--can induce nightmares in people just learning how to use a PC. By contrast, performing this same COPY operation under Windows is as easy as dragging an icon associated with the BUDGET90 file from its initial location on the Windows display to a second window representing the destination directory. In short, Windows simplifies DOS operations to such a degree that computer journalists can now legitimately include the words intuitive and PC in the same sentence.
Moving into Multitasking
The goal of any multitasking environment is to permit you to run multiple applications under DOS. Therefore, multitasking is the most critical area for comparison between DESQview and Windows. How well does each program set up and manage a multitasking session?
The flippant answer to this question is, quite well. Admittedly, DESQview and Windows had their share of growing pains through the years. Both take some potentially risky liberties with DOS's native, single-tasking architecture. Early releases of each package were not always 100-percent dependable, especially when it came to managing so-called misbehaved programs--applications that bypassed the standard BIOS routines to improve their performance.
Subsequent upgrades of both DESQview and Windows have eliminated most of these incompatibility problems. With rare exceptions, both DESQview and Windows are now capable of handling virtually and DOS program.
I've been working with the latest versions of both DESQview and Windows 3.0 for several months and have yet to encounter a conflict that could not be resolved with a relatively minor adjustment to either the multitasking environment itself or the problematic application program.
Since they're roughly equal in technical proficiency, the choice between DESQview and Windows boils down to a personal one based on how you'll use a multitasking environment rather than all the possible uses to which such an environment can be applied.
The Machine Matters
Given the strain time slicing places on your system's CPU, it only makes sense that the kind of computer system you own will influence the overall performance of your multitasking environment.
DESQview will run on any IBM-compatible PC, including 8088- or 8086-based XT-compatible systems having only 512K of RAM. Of course, multitasking on such a system would be severely limited; all your multitasking programs would have to fit within 512K. You'd have trouble finding programs of consequence that would take up so little room.
Windows will run--in real mode--on an 8088 or 8086 machine with 640K, but real mode has the same limitation as we found in DESQview: All the multitasking programs must fit entirely within the 640K of conventional memory. You can multitask programs designed to run under Windows (these programs are sometimes described as Windows-aware) using extended memory under Windows in standard mode, which, at minimum, requires an 80286-based AT with at least one megabyte of memory, including at least 256K of extended memory. But once again, all the multitasking programs must fit within 640K of conventional memory. If you want to multitask DOS programs under Windows, your minimum system must be an 80386 with two megabytes of RAM. These three aspects of Windows are covered in full in the accompanying article "Three Faces of Windows."
Of course, the more advanced your PC, the more efficiently it will multitask, regardless of whether you ultimately settle on DESQview or Windows--or even a combination of the two (see "The Best of Both World").
The performance of DESQview improves dramatically when it's run on a 80286 AT compatible. And both programs are designed to take full advantage of the advanced memory-management features built into Intel's 80386 and 80486 microprocessors.
DESQview users will need to buy a second program--Quarterdeck's $59 QEMM-386 memory manager--to accomplish this (these products can be bought as a set), while the basic Windows package includes everything required to run Windows efficiently on any IBM-compatible computer (see "Three Faces of Windows").
Making the Choice
In some situations, choosing between DESQview and Windows is a relatively straightforward proposition. If you work exclusively with standard, character-based DOS applications--that is, programs not specifically designed to run under Windows--then DESQview is the logical choice.
The great speed of the DESQview text-based interface makes this decision on easy one. Additionally, DESQview is slightly more utilitarian if your PC is an 8088- or 8086-based XT compatible and the only choice if your computer lacks a graphics adaptor capable of running the Windows GUI or has only 512K.
On the other hand, Windows offers the user-friendly attributes commonly associated with GUIs: icons, point-and-click procedures, interactive dialog boxes, and the like. If you're new to personal computing and want to avail yourself of the advantages of multitasking, it's hard to imagine a DOS environment easier to install, learn, or use than Windows 3.0.
Given Windows' graphical interface, it's also the logical choice if you work primarily in graphics-based applications such as desktop publishing, CAD, draw programs, and the like--especially if the specific programs you use for these activities are Windows-aware.
The third alternative is a mix-and-match environment, where you use both standard DOS and Windows applications. In this case, the choice of whether to organize you multitasking under DESQview or Windows requires a little more thought.
DESQview handles both character-based and graphics programs with equal ease. Its speed and flexibility should influence your decision.
However, accessing some of DESQview's more advanced features requires a level of technical knowledge surpassing that demanded by Windows 3.0. Unlike DESQview and, to a certain degree, earlier versions of Windows itself, Windows 3.0 puts its own house in order. It places few demands on the user.
In the final analysis, Windows and DESQview perform exactly as promised, bringing almost divine power to the world of silicon. Each endows DOS with the ability to multitask. Regardless of which one you choose, adding multitasking capability to your system will improve your efficiency and increase your overall PC productivity. It will allow your computer to work efficiently on multiple projects at your own pace. And that, after all, is what using a personal computer is all about. [Tabular Data Omitted]
Context Switching and Multitasking
Context switching is an alternative to multitasking. If you often want to access more than one application during the course of your normal PC operations but you don't need to have these applications running when they aren't in view, context switching (also known as task switching) may be what you need.
Context switching differs from multitasking in that only a single program is actually executing code at any given time, even if multiple applications have been loaded into memory. If you're using context-switching software and access one program, any other application running in that session is temporarily suspended, and a snapshot of its current operation is maintained in memory or stored to a disk file. Calling up one of the suspended applications causes it to be shuffled back into active RAM and once again made operational.
For example, one popular context-switching program, Switch-It (Better Software Technology, 55 New York Avenue, Framingham, Massachusetts 01701; 800-848-0286; $99.95), lets you load up to 100 programs in a 640K system--providing, of course, that you have enough free disk space or expanded memory (EMS) to support program swapping on such a large scale.
In truth, context switching resembles using the hold button on a multiline telephone. While it's not possible to carry on more than one conversation at a time under such conditions, you can quickly switch your attention between two or more callers. Context switching provides a convenience to people who don't require full multitasking but would profit from quick and easy access to several DOS applications.
Three Faces of Windows
Starting with Windows 3.0, Microsoft eliminated the need to buy different versions of Windows for different PC systems. Rather than existing as discrete products (like Windows/286 and Windows/386), Windows 3.0 can configure itself to run in one of three operational modes: real, standard, and 386 enhanced.
When running in real mode, Windows 3.0 is limited to performing all of its multitasking operations in that 640K block of memory commonly referred to as conventional RAM.
If the total memory required by the programs you're using exceeds 640K, Windows automatically reverts to context switching rather than multitasking (see "Context Switching and Multitasking"). Windows 3.0 automatically configures itself to operate in real mode on any system that has less than one megabyte of RAM.
When running in standard mode, Windows can transfer some of its operations to extended memory. This increases the amount of conventional RAM available to actually run standard DOS applications. A second major benefit to running Windows in standard mode is that it actually allows text-based programs that employ standard DOS extenders to run in so-called protected mode, thus effectively breaking that infamous 640K DOS barrier. (Perhaps the best know program that currently employs DOS extenders is Lotus 1-2-3 release 3.)
The ultimate Windows configuration is 386-enhanced mode. In addition to supporting all of the features associated with running Windows in standard mode, 386-enhanced mode takes advantage of the advanced memory-management capabilities built into Intel's 80386 and 80486 microprocessors. Primary among these is their ability to use extended memory to set up so-called virtual 8086 machines--discrete segments of RAM that function as if they were isolated 8086-based XT-compatible systems.
Generally, Windows itself determines its best operating mode for your system hardware. However, by including the appropriate command switch with the WIN command normally used to start Windows, you can override this default configuration. Starting a multitasking session with a WIN /R command, for example, forces Windows to run in real mode.
The Best of Both Worlds
I'm going to let you in on a little secret: It's possible to set up Windows 3.0 so that it will run under DESQview. Why would you ever want to do this? That's easy. Running Windows within a DESQview multitasking session allows you to access most of the advanced features associated with each of these DOS multitasking environments--the best of both worlds.
You'll be able to run the impressive Windows-aware programs currently flooding the PC market (Arts & Letters: Excel; Ventura Publisher, Windows Edition; Ami Professional; Word for Windows; Microphone II, and so forth) and still take advantage of the fact that DESQview will execute and switch between standard DOS applications more quickly than its graphics-based competition.
The most critical caveat attached to setting up this hybrid configuration is that, at the time of this writing, the only way to avoid conflicts with Windows is to run it in real mode. Rumor has it, however, that a planned DESQview upgrade will be compatible with all three Windows modes.