1. Field of the Invention
The present invention relates to a data updating system for updating sets of data internally managed by an information processing apparatus, and more particularly, to a data updating system which can recover a data element for a current data when an error is generated during the updating of the data element.
2. Description of Related Art
Conventionally, an information processing system includes a data updating system having a function for updating a data internally and a function for recovering an original data using a back-up data when a data error is generated during the updating process. Such a data updating system is shown in FIG. 1.
Referring to FIG. 1, the conventional data updating system includes a data processing section 102 having a current data storage unit 140, and an external back-up data storage unit 150. The data processing section 102 includes a main controller 114. The main controller 114 is connected to an interface circuit 112, a back-up controller 116, an update controller 122 and a read section 130. The back-up controller 116 is connected to a current data back-up section 118 and a current data recover section 120. The update controller 122 is connected to a data element update section 126.
The main controller 114 includes a timer and issues a back-up instruction to the back-up controller 116 for every predetermined period of time. Also, the main controller 114 issues a recover instruction to the back-up controller 116 when a data error is found. The back-up controller 116 issues a current data back-up instruction to the current data back-up section 118. The back-up section 118 reads all the current data stored in the storage unit 140 in response to the instruction to write in the back-up data storage unit 150. The back-up controller 116 issues a current data recover instruction to the current data recover section 120. The recover section 120 reads all the back-up data stored in the storage unit 150 in response to the instruction to write in the current data storage unit 140 to recover the current data. When receiving a connection information setting request from the user by the interface circuit 112, the main controller 114 issues an update instruction to the update controller 122. The update controller 122 issues a data element back-up instruction to the data element update section 126. The data element update section 126 updates the current data stored in the storage unit 140 with new data elements designated by the data element update instruction in response to the instruction. If any data error is generated during the update processing, the data element update section 126 informs it to the main controller 114 through the update controller 122. The main controller 114 issues the recover instruction to the back-up controller 116, as described above.
In this manner, in the conventional data updating system, the whole current data needs to be recovered even if the data error is generated only in a part of the current data. Therefore, it takes a long time to recover the current data.
Further, when the data error is generated immediately before the back-up instruction is issued from the main controller 114, the recovered current data is occasionally different from the current data before the data error is generated.