Microsoft KB Archive/302594

= The System hive memory limitation is improved in Windows Server 2003 =

Article ID: 302594

Article Last Modified on 12/3/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise x64 Edition
 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, 64-Bit Datacenter Edition
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Advanced Server, Limited Edition
 * Microsoft Windows Small Business Server 2003 Premium Edition
 * Microsoft Windows Small Business Server 2003 Standard Edition

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This article was previously published under Q302594



SUMMARY
This article describes the System hive and the startup process.



MORE INFORMATION
Windows Server 2003 increases the amount of memory that is available when the computer starts. In Microsoft Windows 2000, 16 megabytes (MB) of memory are available during the startup process. In this 16 MB of memory, the following items must load: The System hive, the Page Frame Number (PFN) database, the Windows NT Loader (NTLDR), the kernel, the hardware abstraction layer (HAL), and the boot drivers. Typically, only the resources that are required to start up the computer can transfer information into the System hive.

Windows Server 2003 can increase the size of the memory that is available for the startup process as follows:
 * Windows Server 2003 (32-bit): The System hive size can be up to one-quarter of the physical memory (up to a maximum of 200 MB).
 * Windows Server 2003 (32-bit) with the /3gb switch: The whole startup process is limited to 16 MB, including the System hive. In Windows Server 2003 Service Pack 1 (SP1), the limit increases to 110 MB.
 * Windows Server 2003 (IA-64): The System hive is limited to 32 MB. The System hive plus HAL, kernel, and drivers can use up to 64 MB.

If the computer does not restart, you must consider the type of installation, how many drivers are loaded, and whether the drivers store excessive amounts of information in the System hive. However, when you consider the new increased memory limits in Windows Server 2003, and the fact that Domain Name System (DNS), Distributed File System (DFS), Dynamic Host Configuration Protocol (DHCP), and so on, have moved their databases from the System hive to the Software hive, the size of the System hive is not an issue. For more information about the System hive and Windows 2000, click the following article number to view the article in the Microsoft Knowledge Base:

269075 Error message: Windows 2000 could not start because the following file is missing or corrupt: \Winnt\System32\Config\Systemced

For more information about components that can remove entries from the System hive, click the following article numbers to view the articles in the Microsoft Knowledge Base:

216369 Unable to create a large number of Dynamic Host Configuration Protocol (DHCP) scopes

259930 Cannot start Windows 2000 with a large number of DNS zones

For more information about components that can remove entries from the System hive, click the following article number to view the article in the Microsoft Knowledge Base:

270028 Windows NT may not start with many DFS shares

Additional query words: systemced systemecd pae registry limit

Keywords: kbenv kbinfo kbnetwork KB302594

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