Open Software Solutions

On a computer that is running Windows Server 2008 for Itanium-Based Systems, you use the Dynamic Hardware Partitioning (DHP) features to hot-replace CPUs. When you do this, you may receive a Stop error message that resembles the following message:

Notes

•	You can add or remove a device to a computer while the computer is running, and the operating system automatically recognizes the change. This is known as hot replacement.
•	Not all 0x0000003B Stop errors are caused by this problem.
•	The first parameter of the Stop error message is 0xc00002c9.
•	The last three parameters in this Stop error message vary, depending on the actual configuration.
•	This problem is not specific to the DHP feature. This problem may also occur when the operating system returns from deferred procedure calls (DPCs).

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When you use the Dynamic Hardware Partitioning (DHP) features to hot-replace CPUs, a deferred procedure call (DPC) may be triggered. When a DPC occurs, the part of memory that holds the stacked registers is switched. This part of memory includes RNAT values that are passed. In certain circumstances, the RNAT values can be corrupted when the operating system calls back from a DPC. Therefore, the value of the NaT bit that is returned is incorrect, and the operating system raises the following exception:

Note See the More information section for a definition of RNAT and NaT.

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Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a Hotfix download available section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

Note The Hotfix download available form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

This hotfix requires that Windows Server 2008 for Itanium-Based Systems is installed on the computer.

Restart requirement

You have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2008 for Itanium-Based Systems

File name	File version	File size	Date	Time	Platform
Ia64_4b12814014dc9789bca52778011ebc02_31bf3856ad364e35_6.0.6001.22202_none_098da6a878d5ea68.manifest	Not Applicable	699	13-Jun-2008	18:07	Not Applicable
Ia64_microsoft-windows-os-kernel_31bf3856ad364e35_6.0.6001.22202_none_6cbda4dbcd3ceb03.manifest	Not Applicable	16,819	13-Jun-2008	04:42	Not Applicable
Package_1_for_kb951684~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,782	13-Jun-2008	18:07	Not Applicable
Package_2_for_kb951684~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,787	13-Jun-2008	18:07	Not Applicable
Package_3_for_kb951684~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,787	13-Jun-2008	18:07	Not Applicable
Package_for_kb951684_sc_0~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,425	13-Jun-2008	18:07	Not Applicable
Package_for_kb951684_sc~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,426	13-Jun-2008	18:07	Not Applicable
Package_for_kb951684_server_0~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,429	13-Jun-2008	18:07	Not Applicable
Package_for_kb951684_server~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,434	13-Jun-2008	18:07	Not Applicable
Package_for_kb951684_winpesrv_0~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,426	13-Jun-2008	18:07	Not Applicable
Package_for_kb951684_winpesrv~31bf3856ad364e35~ia64~~6.0.1.0.mum	Not Applicable	1,433	13-Jun-2008	18:07	Not Applicable
Ntoskrnl.exe	6.0.6001.22202	9,499,192	13-Jun-2008	03:48	IA-64

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Dynamic Hardware Partitioning (DHP)

On a dynamically partitioned server that is running Windows Server 2008, partition units can be added or replaced without restarting the operating system. Windows Server 2008 supports the hot-replacing of CPUs, memory, and I/O host bridges. Windows Server 2008 also supports the hot replacement of CPUs and of memory on x64-based or Itanium-based systems.

NaT

On an Itanium-based server, some 64-bit registers are actually 65 bits. The additional bit is the Not a Thing (NaT) bit. This bit is set when the register does not contain a valid value.

RNAT

RSE NaT collection registers (RNATs) are collections of NaT bits. RNAT holds the NaT bits for values that the register stack engine (RSE) stored. These bits are saved automatically in the register stack backing store.

Deferred procedure call (DPC)

A queued call to a kernel-mode function is usually executed later. Drivers use DPCs to schedule I/O operations. Additionally, DPCs can be safely postponed until the interrupt request level (IRQL) of a processor is lowered. Because an interrupt service routine (ISR) must execute as quickly as possible, drivers usually postpone the DPC operation until the ISR returns. Therefore, the system provides support for DPCs because DPCs have a lower interrupt request level (IRQL) than the ISRs.

For more information about DPC objects and DPCs, visit the following Microsoft Web site:

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Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the Applies to section.

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