SQL>  select blocks,block_id,file_id from dba_extents where segment_name='OBJ$'
  2  order by block_id;

    BLOCKS   BLOCK_ID    FILE_ID
---------- ---------- ----------
         8      94505          1
         8      94585          1
         8      95001          1
         8      95025          1
         8      95057          1
         8      95073          1
         8      95097          1
         8      95121          1
         8      95137          1
         8      95185          1
         8      95193          1

    BLOCKS   BLOCK_ID    FILE_ID
---------- ---------- ----------
         8      95225          1
         8      95233          1
         8      95257          1
         8      95297          1
         8      95321          1
       128      95369          1
       128      95881          1
       128      96521          1
       128      96905          1
       128      97417          1
       128      97673          1

    BLOCKS   BLOCK_ID    FILE_ID
---------- ---------- ----------
       128      98057          1

23 rows selected.


SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> exit


[oracle@node1 chf]$ bbed
Password: 

BBED: Release 2.0.0.0.0 - Limited Production on Sun Jan 15 23:16:46 2012

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

************* !!! For Oracle Internal Use only !!! ***************

BBED> set filename 'system01.dbf'
        FILENAME        ./system01.dbf


BBED> set block 95370
        BLOCK#          95370


BBED> set mode edit
        MODE            Edit

BBED> set blocksize 8192
        BLOCKSIZE       8192


BBED> p tailchk
ub4 tailchk                                 @8188     0x02990601


BBED> show offset;
        OFFSET          8188


BBED> d
 File: ././././system01.dbf (0)
 Block: 95370            Offsets: 8188 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 01069902 

 <32 bytes per line>

BBED> m /c 11112222
 File: ././././system01.dbf (0)
 Block: 95370            Offsets: 8188 to 8191           Dba:0x00000000
------------------------------------------------------------------------
 31313131 

 <32 bytes per line>

BBED> sum
Check value for File 0, Block 95370:
current = 0x05f8, required = 0x0160

BBED> verify
DBVERIFY - Verification starting
FILE = ././././system01.dbf
BLOCK = 95369

Block 95369 is corrupt
Corrupt block relative dba: 0x00417489 (file 0, block 95369)
Fractured block found during verification
Data in bad block:
 type: 6 format: 2 rdba: 0x00417489
 last change scn: 0x0000.00db0299 seq: 0x1 flg: 0x06
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x31313131
 check value in block header: 0x5f8
 computed block checksum: 0x498


DBVERIFY - Verification complete

Total Blocks Examined         : 1
Total Blocks Processed (Data) : 0
Total Blocks Failing   (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing   (Index): 0
Total Blocks Empty            : 0
Total Blocks Marked Corrupt   : 1
Total Blocks Influx           : 2
Message 531 not found;  product=RDBMS; facility=BBED

BBED> exit

[oracle@node1 chf]$ dbv file=system01.dbf

DBVERIFY: Release 11.2.0.3.0 - Production on Sun Jan 15 23:28:54 2012

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

DBVERIFY - Verification starting : FILE = /opt/oracle/oradata/chf/system01.dbf
Page 95369 is influx - most likely media corrupt
Corrupt block relative dba: 0x00417489 (file 1, block 95369)
Fractured block found during dbv: 
Data in bad block:
 type: 6 format: 2 rdba: 0x00417489
 last change scn: 0x0000.00db0299 seq: 0x1 flg: 0x06
 spare1: 0x0 spare2: 0x0 spare3: 0x0
 consistency value in tail: 0x31313131
 check value in block header: 0x5f8
 computed block checksum: 0x498



DBVERIFY - Verification complete

Total Pages Examined         : 172800
Total Pages Processed (Data) : 132214
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 15768
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 3542
Total Pages Processed (Seg)  : 1
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 21275
Total Pages Marked Corrupt   : 1
Total Pages Influx           : 1
Total Pages Encrypted        : 0
Highest block SCN            : 16959419 (0.16959419)

[oracle@node1 chf]$ exp "'/ as sysdba'" tables=chf.t_undo file=/tmp/chf.dmp log=/tmp/chf.log INDEXES =n \
> COMPRESS =n CONSISTENT =n GRANTS =n STATISTICS =none TRIGGERS =n CONSTRAINTS =n

Export: Release 11.2.0.3.0 - Production on Sat Jan 14 19:04:19 2012

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.


Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing option
EXP-00008: ORACLE error 1578 encountered
ORA-01578: ORACLE data block corrupted (file # 1, block # 95369)
ORA-01110: data file 1: '/opt/oracle/oradata/chf/system01.dbf'
EXP-00000: Export terminated unsuccessfully