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Enabling application memory tuning support in your applications

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Enabling application memory tuning support in your applications

The changes to support application memory tuning, also known as 4-gigabyte tuning (4GT), are done at both the system and application levels. For background information, see Application memory tuning.

System changes

After you have installed Windows Server 2003, Datacenter Edition, you must modify the Boot.ini file to enable application memory tuning. To do this, add the /3GB parameter to the ARC path, as shown in the following example for Windows Server 2003, Datacenter Edition:

multi(0)disk(0)rdisk(0)partition(2)\%systemroot%="Windows Server 2003, Datacenter Edition" /3GB

For more information, see Enable application memory tuning.

Application changes

No new application programming interfaces (APIs) are required for application memory tuning support. However, it would be ineffective to automatically provide every application with a 3-gigabyte (GB) address space, therefore this feature is not enabled upon initial installation of the operating system.

Executable files that can use the 3-GB address space are required to have the bit IMAGE_FILE_LARGE_ADDRESS_AWARE set in their image header. Some manufacturers preconfigure their applications to use application memory tuning, making it unnecessary for you to make any changes. For more information, see your application documentation and contact your application vendor to determine if they support Large Address Awareness (which allows them to address 3 GB of virtual memory instead of the 2 GB normally allocated to each application process), or whether you can enable Large Address Awareness in their application.

Notes

  • When modifying executable files to make use of application memory tuning, be aware that it is not necessary to modify the associated DLLs.

  • This topic does not apply to Windows Server 2003, Web Edition.