DESQview

The last two I want to mention aren’t really operating systems per se, but rather operating environments. But, if Windows 9x can qualify as an operating system, so can these. The first is DESQview.

DESQview was a program that ran on top of DOS that allowed you to multitask DOS programs. As a matter of fact, until Microsoft introduced Windows 95, with the exception of OS/2 the best way to run multiple character based DOS programs was through the use of DESQview.

DESQview didn’t multithread programs, because such technology didn’t exist at the time. Rather, through the use of QEMM, DESQview used expanded memory on your computer if it had an 80386 CPU to run DOS programs simultaneously. If you only had a 286, you couldn’t use expanded memory, but DESQview would still task-switch programs through extended memory. It wasn’t as efficient as running on a 386, but it still got the job done.

Of course, Windows 3.x could multitask DOS programs. Compared to DESQview however, Windows 3.0 it had so much overhead, that it was slower and often wouldn’t leave enough lower 640Kb memory behind for DOS programs to run. If you had enough extended memory in your computer, QEMM, DESQview’s memory manager, could actually free almost the entire lower 640Kb memory area for program use.

DESQview was one of the first victims in the PC tradition of Good Marketing Beats Better Technology. Even though DESQview multitasked DOS programs better than Windows, Microsoft ultimately won the day. Quarterdeck, the maker of DESQview, tried creating a GUI-version of it called DESQview/X, but this never went anywhere. Ultimately, Quarterdeck sold out to Symantec. Symantec still owns the rights to DESQview, but doesn’t market it.

I used DESQview extensively in college. Even on a 80286 without QEMM, you could still multitask programs very well using DESQview. Unfortunately, I couldn’t find my copy of DESQview to grab a screenshot for this blog post. I’ll see if I can find it and get one. For now, I found this very grainy image from Charles Petzold’s Web site.