Login problem of oracle DB

Hi,all

When I login to oracle database, a strange problem occurs, here comes the details:

Platform: Solaris8
Steps:

1. Create database, sid = TEST.
2. Create a user, user = test/test
3. Create service in tnsnames.ora, service name is test.

Problems:
1. login operation system with user:test
(SVR) /export/home/test (392)$ sqlplus test/test
SQL*Plus: Release 8.1.7.0.0 - Production on Fri Aug 12 12:40:48 2005
(c) Copyright 2000 Oracle Corporation. All rights reserved.
ERROR:
ORA-03113: end-of-file on communication channel Enter user-name:

Result: Failed, prompt to enter user name and password.

2. login operation system with user:test
(SVR) /export/home/test (393)$ sqlplus test/test_at_test
SQL*Plus: Release 8.1.7.0.0 - Production on Fri Aug 12 12:41:54 2005
(c) Copyright 2000 Oracle Corporation. All rights reserved.
Connected to:
Oracle8i Enterprise Edition Release 8.1.7.0.0 - Production With the Partitioning option
JServer Release 8.1.7.0.0 - Production
SQL> Result: Log in succesfull.

3. (SVR) /export/home/oracle (525)$ sqlplus test/test SQL*Plus: Release 8.1.7.0.0 - Production on Fri Aug 12 12:42:25 2005
(c) Copyright 2000 Oracle Corporation. All rights reserved.
Connected to:
Oracle8i Enterprise Edition Release 8.1.7.0.0 - Production With the Partitioning option
JServer Release 8.1.7.0.0 - Production
SQL> Result: Log in succesfull.

I wonder why the first senario can not login database? Thanks. Received on Fri Aug 12 2005 - 01:38:26 CDT