Professional Windows 7 Development Guide

Chapter 16. Writing 64-Bit Applications for Windows 7

WHAT'S IN THIS CHAPTER?

• Using 64-bit applications to your advantage

• Defining the requirements for building and using 64-bit applications

• Considering 64-bit application development issues

• Creating a 64-bit application

Windows 7 is the first version of Windows in which a 64-bit setup is not only practical but actually a good idea. As Windows has become more complex, and users do more with their systems, the old 3 GB memory limit of 32-bit Windows presents too many limitations. (You may have thought that 32-bit Windows had a 2 GB limit because that's the limit Microsoft usually presents, but the site at http://msdn.microsoft.com/library/aa366778.aspx tells the whole story.) When you use 64-bit Windows, the system has a 7 TB or 8 TB limit, depending on which processor you use. Unfortunately, to gain access to all this memory you must combine 64-bit Windows with 64-bit applications. There are other advantages to working with 64-bit Windows, and this chapter begins by telling you about them.

Note

You must exercise caution when discussing Windows 7 memory support. For example, while an application can access 3 GB memory maximum using 32-bit Windows 7, the physical memory limit is 4 GB. Likewise, the physical memory limit for 64-bit Windows 7 is 192 GB when using Windows 7 Ultimate, but only 8 GB when using Windows 7 Home Basic. The site at http://msdn.microsoft.com/library/aa366778.aspx discusses physical memory limits in more detail.

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