about the preventive contract。 because this CSAM has been used for a long time, if there is a problem, it can only be repaired according to the specific situation. For example, the operating system used by the computer of this equipment should be Windows 2000, and Microsoft no longer maintains this system. If the system has problems, it is difficult to get Microsoft's support.Therefore, if the equipment fails and cannot be used, it will be more appropriate for us to put forward a treatment scheme according to the specific situation.