How to write file into Fat32 USB?

Problem background:

I have a USB drive with Fat32 format, but I could not write any files into that drive.

The solution:

1. ls /media/disk -l

This to verified that whether my USB have write access on it. When I use this command, it show me something like below:

drwx------ 2 root root

2. chown -R root:root

This command is to give the ownership to the root user too.

[Reference]
1. CHMOD Help.
2 chmod by the Numbers.