Here You Will Know, How To Format A Pen Drive On Mac Os X.
I Hope This Will Be Of Help To All The Newbies With Mac.


1: Plug the USB drive into the Mac.

Avoid plugging it into a USB hub or the USB port on a Mac keyboard.



2: Open the Drive Utility software. This is located in the Utilities folder,

Inside the Applications folder, on the top level of your hard drive.

This software was installed as part of the Macintosh OS.



3: Select the drive in the list on the left-hand side of the window

and highlight it. In the name field, enter your chosen name for the pen drive.



4: Select the "Erase" tab in Disk Utility,

making sure the flash drive is selected in the list on the left-hand side of the window.



5: Choose the desired format that you want the pen drive to have.

If you're planning to use it between computers with different platforms,

then select MS-DOS (Fat), which will allow it to be read by both Windows

and Macintosh computers. If you're planning only using for Macs,

then select Mac OS Extended (Journaled).



6: Click on the "Erase..." button.

Remember, this will destroy all the data on the pen drive,

so back up any data you want to save before getting to this point.



7: Eject the pen drive, either by dragging it into the trash,

or using the eject button (the triangle icon) in the finder window.