C:\Users\abc>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Sat Jul 15 12:34:14 2017

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> connect hd/hd
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Process ID: 0
Session ID: 0 Serial number: 0

Warning: You are no longer connected to ORACLE.

Database Instance
Host: abc-PC
Port: 1521
SID: mydb
Oracle Home: D:\app\abc\product\11.2.0\dbhome_1

Listener
Status: Down
Host: abc-PC
Port: 1521
Name: LISTENER
Oracle Home: D:\app\abc\product\11.2.0\dbhome_1
Location: D:\app\kaos\product\11.2.0\dbhome_1\NETWORK\ADMIN
Details: Although a Listener with name "LISTENER", is running on this host at port: "1521", it was not started using this target's "LISTENER.ORA" file. CORRECTIVE ACTION: To monitor this "EM Listener Target" with its present configuration, you must stop the currently running listener process, and start it again using the Listener Parameter file: D:\app\kaos\product\11.2.0\dbhome_1\NETWORK\ADMIN/listener.ora . Alternatively, you can update this target's "LISTENER.ORA Location" parameter with the location of the currently running Listener, which was started using: D:\app\abc\product\11.2.0\dbhome_1\NETWORK\ADMIN\listener.ora

C:\Users\john>sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Sat Jul 15 08:24:20 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Connected to an idle instance.

orclz> startup
ORACLE instance started.

Total System Global Area  788529152 bytes
Fixed Size                  3050600 bytes
Variable Size             373293976 bytes
Database Buffers          406847488 bytes
Redo Buffers                5337088 bytes
Database mounted.
Database opened.
orclz>

SYS> alter database close;

Database altered.

SYS> show parameter diag
NAME                                 TYPE        VALUE
------------------------------------ ----------- -------------------------------------------------------------
diagnostic_dest                      string      E:\ORACLE\ADMIN\MIKB2\TRACE
SYS> show parameter dump_dest
NAME                                 TYPE        VALUE
------------------------------------ ----------- -------------------------------------------------------------
background_dump_dest                 string      E:\ORACLE\ADMIN\MIKB2\TRACE\diag\rdbms\mikb2\mikb2\trace
core_dump_dest                       string      E:\ORACLE\ADMIN\MIKB2\TRACE\diag\rdbms\mikb2\mikb2\cdump
user_dump_dest                       string      E:\ORACLE\ADMIN\MIKB2\TRACE\diag\rdbms\mikb2\mikb2\trace

SQL> startup
ORACLE instance started.

Total System Global Area  631914496 bytes
Fixed Size                  1376436 bytes
Variable Size             515903308 bytes
Database Buffers          109051904 bytes
Redo Buffers                5582848 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 10424
Session ID: 5 Serial number: 1


SQL> show parameter
ERROR:
ORA-03114: not connected to ORACLE


SQL> show parameter background
ERROR:
ORA-03114: not connected to ORACLE

SYS> startup nomount
ORACLE instance started.
Total System Global Area  644468736 bytes
Fixed Size                  1407172 bytes
Variable Size             515901244 bytes
Database Buffers          121634816 bytes
Redo Buffers                5525504 bytes
SYS> show parameter diag
NAME                                 TYPE        VALUE
------------------------------------ ----------- ----------------------------------------------------------------------
diagnostic_dest                      string      E:\ORACLE\ADMIN\MIKB2\TRACE
SYS> show parameter dump_dest
NAME                                 TYPE        VALUE
------------------------------------ ----------- ----------------------------------------------------------------------
background_dump_dest                 string      E:\ORACLE\ADMIN\MIKB2\TRACE\diag\rdbms\mikb2\mikb2\trace
core_dump_dest                       string      E:\ORACLE\ADMIN\MIKB2\TRACE\diag\rdbms\mikb2\mikb2\cdump
user_dump_dest                       string      E:\ORACLE\ADMIN\MIKB2\TRACE\diag\rdbms\mikb2\mikb2\trace

C:\Users\abc>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Sat Jul 15 15:21:58 2017

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup nomount
ORACLE instance started.

Total System Global Area  631914496 bytes
Fixed Size                  1376436 bytes
Variable Size             515903308 bytes
Database Buffers          109051904 bytes
Redo Buffers                5582848 bytes
SQL> show parameter diag

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
diagnostic_dest                      string      D:\APP\ABC
SQL> show parameter dump_dest

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
background_dump_dest                 string      d:\app\abc\diag\rdbms\mydb\myd
                                                 b\trace
core_dump_dest                       string      d:\app\abc\diag\rdbms\mydb\myd
                                                 b\cdump
user_dump_dest                       string      d:\app\abc\diag\rdbms\mydb\myd
                                                 b\trace