Address Windowing Extensions
From Wikipedia, the free encyclopedia
Address Windowing Extensions (AWE) is a set of extensions that allows an application to quickly manipulate physical memory greater than 4GB. Certain data-intensive applications, such as database management systems (for example Microsoft SQL Server) and scientific and engineering software, need access to very large caches of data. In the case of very large data sets, restricting the cache to fit within an application's 2GB of user address space is a severe restriction. In these situations, the cache is too small to properly support the application.
AWE solves this problem by allowing applications to directly address huge amounts of memory while continuing to use 32-bit pointer. AWE allows applications to have data caches larger than 4GB (where sufficient physical memory is present). AWE uses physical non-paged memory and window views of various portions of this physical memory within a 32-bit virtual address space.
AWE places a few restrictions on how this memory may be used, primarily because these restrictions allow extremely fast mapping, remapping, and freeing. Fast memory management is important for these potentially enormous address space.
AWE usage is encoded into the application itself. In Microsoft Windows, an application must have the Lock Pages in Memory privilege to use AWE. To obtain this privilege, an administrator must add Lock Pages in Memory to the user's User Rights Assignments.
