OCP 1Z0 052 153

153. The database instance has the following parameter setting: 
OS_AUTHENT_PREFIX = OPS$ 
OS_ROLES = FALSE 
REMOTE_OS_AUTHENT = FALSE 
REMOTE_OS_ROLES = FALSE 
TIMED_OS_STATISTICS = 0 
You have a  local operating system user SKD. You create a database user OPS$SKD, and  then assign 
external  authentication.  The  user  OPS$SKD  has  the  CREATE  SESSION  privilege. What  would  you 
achieve by the above process? 
A.The database user OPS$SKD will be able to administer the database.  
B.The authentication detail for the database user OPS$SKD is recorded in the password file.  
C.The local operating system user SKD will be able to access the database instance without specifying 
the username and password. 
D.The database user OPS$SKD has to login with the password of the local operating system user SKD to 
access the database instance. 
Answer: C

OS_AUTHENT_PREFIX

PropertyDescriptionParameter typeStringSyntaxOS_AUTHENT_PREFIX = authentication_prefixDefault valueOPS$ModifiableNo

OS_AUTHENT_PREFIX specifies a prefix that Oracle uses to authenticate users attempting to connect to the server. Oracle concatenates the value of this parameter to the beginning of the user's operating system account name. When a connection request is attempted, Oracle compares the prefixed username with Oracle usernames in the database.

The default value of this parameter is OPS$ for backward compatibility with previous versions. However, you might prefer to set the prefix value to "" (a null string), thereby eliminating the addition of any prefix to operating system account names.