hi,all we find a very interesting thing: we copy the WINDOWS2000 datafile to linux (they have the same byte order) and , dd a linux datafile header to cover the windows datafile header(the header block is not include in dba_data_files),the block is not seem in database ,it is for OS. ls -l can see ,the datafile size is bigger than dba_data_files for one oracle block. when we change the OS file header,we can create controlfile and open the database ,and we can query /create table ... etc. the db version is oracle9204,not 10g. and someone told me that he can copy the datafile from windows and solaris for x86 pc to linux , and not change the header with oracle8i. is there someone can discuss it? Best regards msn: biti_rainy@xxxxxxxxxxx a dba from alibaba(china) -- //www.freelists.org/webpage/oracle-l