Address windowing extension

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Address Windowing Extensions ( AWE ., English for extension (by) addressing window ) is a Windows - programming interface to support more than 4  GiB memory on i386 -compatible 32-bit platforms.

AWE allows a program to reserve physical address areas and to show them in the virtual address area of ​​the process. If the reserved memory area is larger than can be displayed all at once, the mapping must be switched to access the remaining memory areas. Only part of the reserved address range can then be accessed. This technique, known as “overlay” or “windowing”, is basically comparable to the EMS memory offered under DOS .

With the AWE, up to 2 36 bytes (= 64 GiB) main memory can be addressed.

Usable memory with Windows 2000 Server 32-bit versions:

  • Windows 2000 Standard Server: 4 GiB
  • Windows 2000 Advanced Server: 8 GiB
  • Windows 2000 Data Center Server: 64 GiB.

Usable memory in Windows Server 2003 32-bit versions:

  • Windows Server 2003 R2 Standard Edition: 4 GiB
  • Windows Server 2003 R2 Enterprise Edition: 32 GiB
  • Windows Server 2003 R2 Datacenter Edition: 64 GiB

Windows XP and Windows Vista (32-bit versions) are limited to 4 GiB for reasons of compatibility (driver and PCI subsystem). The AWE is dependent on the Physical Address Extension (PAE) insofar as the AWE functions cannot reserve a working memory (RAM) over 4 GiB without PAE technology.

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