Device system, information processing device, and operation proposal method

A device system comprising:

• a terminal device which is usable by a worker who checks a device installed in a plant;
• and
• an information processing device which is connectable to the terminal device through a network,
• wherein the terminal device comprises:
• a detector configured to detect at least one of data representing an operation performed by the worker with respect to the terminal device, data representing an environmental value of the plant, and data representing biological information of the worker;
• and
• a first notifier configured to notify, to the information processing device, first historical data representing a history of data currently detected by the detector,
• wherein the information processing device comprises:
• a storage which stores second historical data representing a history of data detected by the detector in the past;
• and
• a proposer configured to propose an operation which should be performed with respect to the terminal device by using the first historical data notified by the first notifier and the second historical data stored in the storage.