1. A computer program product comprising a computer-readable storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a data copy method, the method comprising: performing a first copy operation to generate first copy data in a first backup format, without generating a corresponding index for browsing the first copy data in the first copy format; performing a second copy operation on the first copy data in the first copy format to generate second copy data in a second copy format; and generating an index table comprising entries for one or more data items from the first copy data stored in the second copy data in the second copy format, wherein each entry includes— first access information for a data item to allow access to the data item in the second copy data, and second access information to allow access to the data item in the first copy data, thereby allowing direct access to the data item based on information from the index table.