Always build your tables and indexes in different table space (TABLESPACES). Never use an object does not belong to ORACLE stored in the internal system of the SYSTEM table space. At the same time, ensure that the data table space and index table space into different hard disk.
" At the same time , ensure that the data table space and index table space with a different set of hard disk . " Might be more accurate to read as follows " At the same time , ensure that the data table space and index table space with a different set of hard disk controller card controls the hard disk . "