SQL> create user hm identified by hm;

User created.

SQL> grant dba to hm;

Grant succeeded.

SQL> SELECT username,default_tablespace FROM DBA_USERS where username='HM';

USERNAME                       DEFAULT_TABLESPACE
------------------------------ ------------------------------
HM                             USERS

SQL> conn hm/hm;
Connected.
SQL> create table fruit(name varchar2(32));

Table created.

SQL> insert into fruit values('orange');

1 row created.

SQL> commit;

Commit complete.

SQL> alter system switch logfile;

System altered.

SQL> select * from fruit;

NAME
--------------------------------
orange

SQL> select dbms_rowid.rowid_block_number(rowid) blk,name from fruit;

       BLK NAME
---------- --------------------------------
       772 orange

SQL> show parameter block;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_block_buffers                     integer     0
db_block_checking                    string      FALSE
db_block_checksum                    string      TRUE
db_block_size                        integer     8192
db_file_multiblock_read_count        integer     16

[oracle@localhost XUHM]$ dd if=users01.dbf ibs=8192 skip=771 count=1 |strings
1+0 records in
16+0 records out
8192 bytes (8.2 kB) copied, 6.5e-05 seconds, 126 MB/s
[oracle@localhost XUHM]$ dd if=users01.dbf ibs=8192 skip=771 count=2 |strings
2+0 records in
32+0 records out
16384 bytes (16 kB) copied, 0.00013 seconds, 126 MB/s
orange