What is a Kernel Memory Dump File?
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.
The kernel memory dump file does not include unallocated memory or any memory allocated to user-mode programs but it contains information that might help you troubleshoot Stop errors! It contains more information than a small memory dump file and is smaller than a complete memory dump. It omits those portions of memory that are unlikely to have been involved in the problem.
When a Stop error occurs, Windows 7 saves a kernel memory dump file to a file named %SystemRoot%\Memory.dmp and creates a small memory dump file in the %SystemRoot%\Minidump folder.
When Windows 7 creates the dump file, it first writes the information to the paging file, which may make the paging file to grow to the size of the physical memory, and later the dump file information is extracted from the paging file to the actual memory dump file. That’s why it is important to make sure that your system drive has enough free space (a little bit more than the size of the physical memory). It is recommended to have about 50MB to 800MB or one-third the size of physical memory available on the boot volume for the paging file.
Remember that by default a new kernel memory dump file overwrites an existing one. To change this default setting go to Control Panel\All Control Panel Items\System click System Properties and from the System Properties window click the Advanced tab and Settings under Startup and Recovery. Clear the Overwrite any existing file check box.