Page 403 - Windows 10 May 2019 Update The Missing Manual: The Book That Should Have Been in the Box

FREQUENTLY ASKED QUESTION REALLY ANCIENT
APPS

Will Windows 10 run my really old, really important app?

You’ll never really know until you try. And this chapter outlines all the
tools available to help you make the old app run. But here are some
specifics on what you can expect.

First of all, 16-bit programs are so old, they were written when
Windows 3.1 roamed the earth and the first George Bush was president.
(Programs written for Windows 95 and later are known as 32-bit

programs; Windows 10 can even run 64-bit programs.) But, amazingly
enough, the 32-bit versions of Windows 10 (though not the 64-bit
versions; see the box on “UP TO SPEED A Little Bit About 64 Bits”)

can run most of these programs. They do so in a kind of software
simulator—a DOS-and-Windows 3.1 PC impersonation called a virtual
machine.

As a result, these programs don’t run very fast, don’t understand the
long filenames of modern-day Windows, and may crash whenever they
try to “speak” directly to certain components of your hardware. (The

simulator stands in their way, in the name of keeping Windows stable.)
Furthermore, if just one of your 16-bit programs crashes, then all of
them crash, because they all live in the same memory bubble.

Even so, it’s impressive that they run at all, 15 years later.

DOS programs are 16-bit programs, too, and therefore they run just fine
in 32-bit versions of Windows, even though DOS no longer lurks

beneath the operating system.

To open the black, empty DOS window that’s familiar to PC veterans,
press +R, type command.com, and then press Enter.

For the best possible compatibility with DOS programs—and to run
DOS programs in a 64-bit copy of Windows—try out DOSBox
(dosbox.com), which emulates a classic 16-bit computer, complete with