Microsft Knowledge Base article Q268343, begins:

"The user-mode dump heap (UMDH) utility works with the operating system to analyze Windows heap allocations for a specific process. This utility and the other tools associated with it are targeted for Windows 2000, although you may be able to use it with Microsoft Windows NT 4.0 Service Pack 5.0 (SP5) or later. This article discusses how you can use UMDH to help locate memory leak problems. A self-extracting executable is include that contains the following tools:

Umdh.exe	This utility is used to dump the heap allocation information for a process.
Gflags.exe	This utility sets the appropriate registry entries for the application that will be analyzed. The operating system looks at the registry entries to determine if an application's heap allocations will be tracked.
Tlist.exe	This application lists all of the processes running on a machine and all of their related process IDs.
Dhcmp.exe	This tool is used to compare two UMDH dumps to determine where a possible memory leak is occurring.
Dhcmpgui.zip	This tool also compares two UMDH logs but has a user interface to make it easier to retrieve information. The .zip file contains the Dhcmpgui.exe file and its source code.