PRVF-5507 NTP Prerequisite check failed

During GI Installation prerequisite checks, it failed for NTP. The screenshot is as below:

To resolve if you are not using NTP:
mv /etc/ntp.conf /etc/ntp.conf.orig
Do it on all the nodes of cluster. Rerun the check again.

Hope this helps.

Xlib: No protocol specified

I was trying to run Oracle GI installation by using ./runInstaller and got below error:
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified

Below are the steps performed to resolve the error:

Note: xhost + has to be done by root user.

Hope this helps.

dbms_output.enable doesn't work ???

Well, it works as it supposed to be.
I was thinking that once I have dbms_output.enable, it would write or spool using dbms_output.put_line. But it did not.

Then came across http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1968769482859

Which explains that we need to do:
set serveroutput on

to see output at sqlplus screen or spooled file.

Also explains purpose of dbms_output.enable.