hi,Marquez, Chris the first os block of the datafile include platform and db version (magical number)/ file blocks / block size/ chkval when the file size changed,the chkval changed,and , the same file size datafiles has the same chkval. there are magic numbers for paltform and db version, oracle 920: windows: 6C6D 6A6B linux :5c5d 5a5b ------ little endian oracle 8.0.4 for solaris 5.6 : 5a5b 5c5d ------- big endian i did a test,it looks that with same db version and os and same file size,the first block are the same *block* : D:\oracle\ora92\rainy>dd if=users01.dbf bs=8192 count=1|od -x 0000000000 0000 0000 2000 0000 FA00 0000 6C6D 6A6B 0000000020 DC06 0000 0000 0000 0000 0000 0000 0000 0000000040 0000 0000 0000 0000 0000 0000 0000 0000 1+0 records in 1+0 records out * 0000020000 D:\oracle\ora92\rainy>ls -l total 2559363 -rwxrwxrwa 1 Administrators SYSTEM 1613824 Jan 21 21:01 CONTROL01.CT L -rwxrwxrwa 1 Administrators SYSTEM 1613824 Jan 21 21:01 CONTROL02.CT L -rwxrwxrwa 1 Administrators SYSTEM 1613824 Jan 21 21:01 CONTROL03.CT L -rwxrwxrwa 1 Administrators SYSTEM 26222592 Jan 21 21:01 INDX01.DBF -rwxrwxrwa 1 Administrators SYSTEM 10486272 Jan 21 20:58 REDO01.LOG -rwxrwxrwa 1 Administrators SYSTEM 10486272 Jan 21 21:01 REDO02.LOG -rwxrwxrwa 1 Administrators SYSTEM 10486272 Jan 21 20:58 REDO03.LOG -rwxrwxrwa 1 Administrators SYSTEM 262152192 Jan 21 21:01 SYSTEM01.D BF -rwxrwxrwa 1 Administrators SYSTEM 41951232 Jun 8 2004 TEMP01.DBF -rwxrwxrwa 1 Administrators SYSTEM 209723392 Jan 21 21:01 TOOLS01.DB F -rwxrwxrwa 1 Administrators SYSTEM 209723392 Jan 21 21:01 UNDOTBS01. DBF -rwxrwxrwa 1 Administrators SYSTEM 524296192 Jan 21 21:01 USERS01.DB F -rwxrwxrwa 1 hz None 8192 Jan 20 14:16 tmp -rwxrwxrwa 1 hz None 8192 Jan 20 14:17 tmp1 -rwxrwxrwa 1 hz None 8192 Jan 20 14:19 tmp2 D:\oracle\ora92\rainy>sqlplus "/ as sysdba" SQL*Plus: Release 9.2.0.1.0 - Production on Fri Jan 21 20:14:22 2005 Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved. Connected to an idle instance. SQL> startup ORACLE instance started. Total System Global Area 101784276 bytes Fixed Size 453332 bytes Variable Size 75497472 bytes Database Buffers 25165824 bytes Redo Buffers 667648 bytes Database mounted. Database opened. SQL> select 524296192/1024/1024 from dual; 524296192/1024/1024 ------------------- 500.007813 SQL> select (524296192 - 8192)/1024/1024 from dual; (524296192-8192)/1024/1024 -------------------------- 500 SQL> !pwd SP2-0042: unknown command "!pwd" - rest of line ignored. SQL> host pwd D:/oracle/ora92/rainy SQL> alter database datafile 'D:/oracle/ora92/rainy/tools01.dbf' resize 500m; Database altered. SQL> exit Disconnected from Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production With the Partitioning, OLAP and Oracle Data Mining options JServer Release 9.2.0.1.0 - Production D:\oracle\ora92\rainy>ls -l total 3173763 -rwxrwxrwa 1 Administrators SYSTEM 1613824 Jan 21 21:16 CONTROL01.CT L -rwxrwxrwa 1 Administrators SYSTEM 1613824 Jan 21 21:16 CONTROL02.CT L -rwxrwxrwa 1 Administrators SYSTEM 1613824 Jan 21 21:16 CONTROL03.CT L -rwxrwxrwa 1 Administrators SYSTEM 26222592 Jan 21 21:01 INDX01.DBF -rwxrwxrwa 1 Administrators SYSTEM 10486272 Jan 21 21:14 REDO01.LOG -rwxrwxrwa 1 Administrators SYSTEM 10486272 Jan 21 21:14 REDO02.LOG -rwxrwxrwa 1 Administrators SYSTEM 10486272 Jan 21 21:14 REDO03.LOG -rwxrwxrwa 1 Administrators SYSTEM 262152192 Jan 21 21:01 SYSTEM01.D BF -rwxrwxrwa 1 Administrators SYSTEM 41951232 Jun 8 2004 TEMP01.DBF -rwxrwxrwa 1 Administrators SYSTEM 524296192 Jan 21 21:16 TOOLS01.DB F -rwxrwxrwa 1 Administrators SYSTEM 209723392 Jan 21 21:01 UNDOTBS01. DBF -rwxrwxrwa 1 Administrators SYSTEM 524296192 Jan 21 21:01 USERS01.DB F -rwxrwxrwa 1 hz None 8192 Jan 20 14:16 tmp -rwxrwxrwa 1 hz None 8192 Jan 20 14:17 tmp1 -rwxrwxrwa 1 hz None 8192 Jan 20 14:19 tmp2 D:\oracle\ora92\rainy>dd if=users01.dbf bs=8192 count=1|od -x 0000000000 0000 0000 2000 0000 FA00 0000 6C6D 6A6B 0000000020 DC06 0000 0000 0000 0000 0000 0000 0000 0000000040 0000 0000 0000 0000 0000 0000 0000 0000 1+0 records in 1+0 records out * 0000020000 D:\oracle\ora92\rainy>dd if=tools01.dbf bs=8192 count=1|od -x 0000000000 0000 0000 2000 0000 FA00 0000 6C6D 6A6B 0000000020 DC06 0000 0000 0000 0000 0000 0000 0000 0000000040 0000 0000 0000 0000 0000 0000 0000 0000 1+0 records in 1+0 records out * 0000020000 D:\oracle\ora92\rainy> Best regards msn: biti_rainy@xxxxxxxxxxx a dba from alibaba(china) ---- from the mail----- > >I personal don't have first hand experience wih this but... >a while back on another list there was a long thread on the very >subject. > >Seems it all has mostly to do with "Little Endian" vs. "Big Endian". >http://www.webopedia.com/TERM/b/big_endian.html > >Once of the dba's on the list promised that he regularly moved (copied)=20 >his Oracle database on windows x86 (NTFS?) to Red Hat Linux x86 (EXT3?). > >I never got the time to try it. > >I do remember that several people on the list (smarter than I) explained >clearly that=20 >it was NOT the file system type that makes the difference but "Little >Endian" vs. "Big Endian" issue. > >hth > >Chris Marquez >Oracle DBA >HEYMONitor(tm) - heymonitor.com >"Oracle Monitoring & Alerting Solution" > > > >-----Original Message----- >From: oracle-l-bounce@xxxxxxxxxxxxx >[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of biti_rainy >Sent: Thursday, January 20, 2005 1:24 AM >To: oracle-l >Subject: (NEW) very interesting thing about migrate db from different >OS(oracle 9.2.0.4,not 10G) > > >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? > =20 > >Best regards >msn: biti_rainy@xxxxxxxxxxx >a dba from alibaba(china) > > >-- >//www.freelists.org/webpage/oracle-l >-- >//www.freelists.org/webpage/oracle-l > >. -- //www.freelists.org/webpage/oracle-l