Windows® via C/C++, Fifth Edition

Address Windowing Extensions

As days go by, applications require more and more memory. This is especially true of server applications: As an increasing number of clients make requests of the server, the server’s performance diminishes. To improve performance, the server application needs to keep more of its data in RAM and reduce disk paging. Other classes of applications—such as database, engineering, and scientific—also require the ability to manipulate large blocks of storage. For all these applications, a 32-bit address space is just not enough room.

To help these applications, Windows offers a feature called Address Windowing Extensions (AWE). Microsoft had two goals when creating AWE:

• Allow applications to allocate RAM that is never swapped ...