Categories: Windows 95/NT

Continued from What It Means

Strictly speaking, saying that an application is 32-bit means that it uses 32-bit instructions and has access to a larger address space. In Windows, however, the term 32-bit has a greater significance. A 32-bit Windows application uses 32-bit code, but it is also accorded special treatment by the operating system. Here are just a few of the differences between 16- and 32-bit Windows applications:

• 32-bit Windows apps are preemptively multitasked, while 16-bit Windows apps are cooperatively multitasked. The former is a superior form of multitasking that divides processor time between applications more efficiently. As a result, 32-bit Windows apps are generally more responsive than their 16-bit counterparts when two or more applications are running concurrently. In addition, a 32-bit application that goes too long without checking for messages will not affect other applications, but an ill-behaved 16-bit application can gum up the works--even freeze the system--for everyone.
• 32-bit Windows apps can spawn additional threads of execution to do work in the background while the primary thread runs in the foreground. Used correctly, multiple threads can dramatically increase an application's speed and responsiveness.
• 32-bit Windows apps use long filenames; 16-bit Windows apps do not unless they are rewritten with special code to add long filename support.
• 32-bit Windows apps have access to the richer Win32 application programming interface (API); 16-bit apps are still stuck with the old Windows 3.1 API.

In general, you will find Windows 95 to be a better operating system if you use 32-bit applications: 32-bit apps run more smoothly and are generally more capable than 16-bit apps. A perfect example is the Windows 95 equivalent of Print Manager; documents are transmitted to the print queue much faster in Windows 95 than they were in Windows 3.1, thanks to a 32-bit rewrite of the code and the wonders of multithreading. But don't expect to see this dramatic a difference in every piece of software. Upgrading to 32-bit versions of your favorite apps should, on the average, deliver a modest increase in performance, but only a few apps will markedly outperform their 16-bit predecessors.

If you're wondering whether to make the move to 32 bits, keep in mind that, over time, 16 bits will go away and 32 bits will become the norm. It's really just a matter of which end of the curve you want to be on. And about the time you finish replacing all those 16-bit apps with 32-bit versions, the industry will begin the move to 64 bits.

I'll bet you can hardly wait.

Published as Tutor in the 11/07/95 issue of PC Magazine.