Conventionally, when some processing ends abnormally, the OS (operating system) mounted on a computer outputs the memory image at that time onto a magnetic disk, and creates a dump file. Then, the system administrator or the like analyzes the created dump file by using a predetermined analysis tool, thereby diagnosing the cause of the failure.
The OS reserves a predetermined space for creating the dump file on the magnetic disk in order that it can create the dump file whenever a processing ends abnormally. The predetermined space depends on the capacity of the memory mounted on the computer, and increases as the memory capacity increases.
In recent years, the memory capacity has increased, and the dump file size has increased accordingly. Since this decreases the space of the magnetic disk that the user can use, it is desired that the dump file size be reduced. However, if the dump file size is simply reduced, the information necessary at the time of failure analysis cannot be outputted to the dump file. Therefore, it is desired that the dump file size be reduced to the extent that the information necessary at the time of failure analysis can be outputted to the dump file.