Microsoft KB Archive/274560

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INFO: ParentObjectTitleIndex in LogicalDisk Instance Definition

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Q274560

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The information in this article applies to:


 * Microsoft Win32 Application Programming Interface (API), included with:
 * the operating system: Microsoft Windows 2000
 * the operating system: Microsoft Windows NT 4.0

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SUMMARY
This article explains how the Performance Library (Perflib) represents the relationship between LogicalDisk and PhysicalDisk performance objects on Windows NT 4.0 and Windows 2000.

MORE INFORMATION
On Windows NT 4.0, a physically disk is typically divided into partitions. Those partitions are also called logical disks. Because a partition always resides on a certain physical disk in Windows NT 4.0, the physical disk is called the parent of the logical disk. The Performance Library represents this relationship by setting the ParentObjectTitleIndex attribute of the PERF_INSTANCE_DEFINITION structure in the LogicalDisk object to point to the PhysicalDisk object.

On Windows 2000, the system can have dynamic logical disks. Logical volumes that span multiple physical disks are more common. Partitions that reside on different physical disks can make up one logical volume. More often, there is no pure parent-child relationship between physical disk and logical partitions. So the Performance Library on Windows 2000 always sets the ParentObjectTitleIndex attribute of PERF_INSTANCE_DEFINITION in LogicalDisk object to 0 (zero).

On Windows 2000, the physical disk is represented as a multiple instance object. The name of each instance reflects what logical volumes reside on the physical disk. For example, if disk 0 has several partitions on it, those partitions are part of logical volume C:, D:, and E:. The instance name is &quot;0 C: D: E:&quot;.

Additional query words: PERF INSTANCE DEFINITION

Keywords : kbAPI kbKernBase kbOSWinNT400 kbOSWin2000 kbPerfMon kbSDKWin32 kbDSupport kbGrpDSKernBase

Issue type : kbinfo

Technology : kbAudDeveloper kbWin32sSearch kbWin32API