Please Help!!

I have a site running on Oracle 8.1.5 under Lynux. Due to some resons unknown suddenly it is giving error :

ORA-01115: IO error reading block from file 1 (block # 62887)
ORA-01110: data file 1: '/u02/oradata/orcl/system01.dbf'
ORA-27072: skgfdisp: I/O error
Linux Error: 5: Input/output error
Additional information: 62886

Plese tell me how can I save the system datafile from geeting currupted.
I am not able to access records in my user schema due to this Error.