enum DEVICE_USAGE_NOTIFICATION_TYPE

typedef enum _DEVICE_USAGE_NOTIFICATION_TYPE
{
         DeviceUsageTypeUndefined = 0,
         DeviceUsageTypePaging = 1,
         DeviceUsageTypeHibernation = 2,
         DeviceUsageTypeDumpFile = 3
} DEVICE_USAGE_NOTIFICATION_TYPE;

Windows Vista Kernel Structures