[CentOS] how to install centos on the attached external usb hard disk?

Mon Jul 26 12:31:05 UTC 2010
John Doe <jdmls at yahoo.com>

From: hadi motamedi <motamedi24 at gmail.com>
>Sorry. You mean I do not need to install grub boot loader when installing on the 
>usb disk? Please comment.

Did you enable usb booting in the bios...?