CertiGuide to A+ (Operating Systems)  9  Chapter 0100:  New Technology       9  II  NT Fundamentals

II  NT Fundamentals 1 2 Navigation

Windows NT/2000 Memory Model

NT/Windows 2000 differ in many ways from DOS/Windows 3.x/9.x/Me. One huge difference is the fact that NT 3.x/4/W2K are true 32-bit Operating Systems that use a flat model for memory. That is to say there is no HIMEM.SYS or EMM386.EXE, as there was in DOS and earlier versions of Windows, because there is no real and extended memory. All memory starts at zero and just goes up. Applications that are written to operate in a 32-bit memory mode always run in their own separate memory space.

Even with this strong distinction between different processes, NT sometimes tries to take a few little short-cuts in the name of efficiency. One of these is that all the Windows Explorer windows you have open, potentially viewing many folders at once, are managed by the same copy of the Windows Explorer program. This is done because it’s faster to open a window if you’re not ALSO starting up a new copy of a program at the same time. Alas, if Windows Explorer locks up due to a problem in one window, your other Windows Explorer windows also lock up. This is not good for reliability. So, Microsoft provides the option to run each folder window with a separate copy of the Windows Explorer, if you’re willing to trade a bit of speed for increased reliability.

To enable this go the Control Panel , open the Folder Options applet, click the View tab and check the “Launch folder windows in a separate process” box, as shown in Figure 147.

II  NT Fundamentals 1 2 Navigation