PL/SQL connection Oracle Database old report ora-12541: TNS: No listener

Today with PL/SQL to connect to a database old report ora-12541: TNS: No listener error.

Solution:

Refer to the SQL * Plus User's Guide and reference for more information.
[Oracle @ vserever75 ~] $ Sqlplus/nolog

SQL * Plus: Release 10.2.0.4.0-production on Thu Apr 25 10:28:11 2013

Copyright (c) 1982,200 7, Oracle. All rights reserved.

SQL> Conn/As sysdba
Connected to an idle instance.
SQL> startup
Oracle instance started.

Total system global area 2147483648 bytes
Fixed size 2085320 bytes
Variable Size 1308626488 bytes
Database buffers 822083584 bytes
Redo buffers 14688256 bytes
Database mounted.
Database opened.
SQL> quit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.4.0-64bit Production
With the partitioning, OLAP, data mining and real application testing options
[Oracle @ vserever75 ~] $ LSNRCTL start

LSNRCTL for Linux: Version 10.2.0.4.0-production on 25-apr-2013 10:29:35

Copyright (c) 1991,200 7, Oracle. All rights reserved.

Starting/Oracle/APP/DB/bin/tnslsnr: Please wait...

Tnslsnr for Linux: Version 10.2.0.4.0-Production
System parameter file is/Oracle/APP/DB/Network/admin/listener. ora
Log messages written to/Oracle/APP/DB/Network/log/listener. Log
Listening On: (description = (address = (Protocol = TCP) (host = xxx. xxx.3.75) (Port = 1521 )))
Listening On: (description = (address = (Protocol = IPC) (Key = extproc0 )))

Connecting to (description = (address = (Protocol = TCP) (host = xxx. xxx.3.75) (Port = 1521 )))
Status of the listener
------------------------
Alias listener
Version tnslsnr for Linux: Version 10.2.0.4.0-Production
Start date 25-apr-2013 10:29:35
Uptime 0 days 0 HR. 0 min. 0 sec
Trace Level off
Security on: Local OS Authentication
SNMP off
Listener parameter file/Oracle/APP/DB/Network/admin/listener. ora
Listener log file/Oracle/APP/DB/Network/log/listener. Log
Listening endpoints summary...
(Description = (address = (Protocol = TCP) (host = xxx. xxx.3.75) (Port = 1521 )))
(Description = (address = (Protocol = IPC) (Key = extproc0 )))
Services summary...
Service "plsextproc" has 1 instance (s ).
Instance "plsextproc", status unknown, has 1 handler (s) for this service...
Service "boss1" has 1 instance (s ).
Instance "boss1", status unknown, has 1 handler (s) for this service...
The command completed successfully
[Oracle @ vserever75 ~] $

PL/SQL login successful!