Patent ID: 7039659

Claim:
A method for copying data organized in designated data blocks from addressed locations in a source storage device to addressed locations in a destination storage device with a series of copying operations by using a copy program that has a data block selection control for defining the designated data blocks to be copied, said method including the steps of: A) recording, during a given interval between successive copying operations, the occurrence of a change to any data block in the source and destination storage devices respectively, whereby at the end of the given interval the source and destination data block change recordings identify each data block in the source and destination storage devices, respectively, that changed during the given interval, and B) at the beginning of a successive interval: i) combining the information in the source and destination change recordings and in the data block selection control thereby to identify those of the designated data blocks that need to be copied by virtue of each change during the given interval, and ii) changing the source and destination data block recordings whereby the recordings thereafter reflect only the occurrence of changes made to the source and destination device data blocks during the successive interval.