| 摘要 |
PURPOSE:To update from a CPU even during the data is transferring from a main magnetic disk to a magnetic disk for storage, by using three magnetic disk devices for update and control of information with regard to each data section. CONSTITUTION:Data from a storage device 1 is written on not an M disk 4, but a T disk 6 firstly in response to a write request in backup mode and an update flag is set in an update field in an update control table 32 corresponding to the sector number of the written part. After the data is transferred completely from the M disk 4 to a B disk 5, a magnetic disk controller 3 checks the contents of the update control table 32 to transfer data on the T disk 6 corresponding to the sector number of the set update number to the same location of the M disk 4, and resets the update flag corresponding to the sector number. |
