To ascertain that a dump file is created when a Stop error occurs, you need to simulate a Stop error. You can manually initiate a Stop error by creating a registry value and pressing a special character sequence. Then, after Windows 7 restarts you can verify that the dump file was actually created.
Memory dump files allow you to analyze the root cause of a problem by performing an offline examination of the information stored in the dump file using analysis tools. When a Stop error occurs, Windows 7 writes the information to the paging file (pagefile.sys) on the %SystemDrive% root by default. Then, following a restart Windows 7 uses the paging file information to create a memory dump file in the %SystemRoot% folder.
The kernel memory dump file includes contents of memory allocated to the Executive, Kernel, Hardware Abstraction Layer (HAL), and file system cache, in addition to nonpaged pool memory allocated to kernel-mode drivers and other kernel-mode routines. The kernel memory dump file records only kernel memory contents and its size varies (several megabytes) but it is always less than the size of the system memory. Also, it takes longer to create than a small dump file and this increases the downtime associated with a system failure.
A memory dump during a crash of Windows 7 will fail if your system drive (%SystemRoot%) has less than 25GB of free space! Memory dumps help you diagnose crash issues and it is always recommended to allow enough free space on your system drive for debugging information to be logged and for better overall performance. You can set the dump file to be stored on a different local drive with ample storage space or disable this feature, but in cases where this is not possible and regardless of free space, you can force Windows 7 to create a dump file using the following new registry entry: