Answer: The procedure varies slightly depending on which version of iTunes you have.
To enable disk use, connect your iPod to your computer. Now run iTunes (iTunes may open automatically when you connect your iPod). There is no disk use option for iPhone or iPod Touch. The iPhone and iPod Touch are not compatible with ChemDuet.
If you have iTunes 7 or iTunes 8, click on the iPod under "Devices" on the left
side of the iTunes window. Now click the "Summary" tab, and towards the bottom
of the window under "Options" make certain that "Enable disk use" is checked. Then click "Apply".
If you have iTunes 6, open iTunes preferences. Click the "iPod" tab.
You'll see something like the display below. Click Music, then click Enable disk use
. That's all. Now you can install ChemDuet.
If you have iTunes 4, open iTunes preferences. Click the "iPod" tab. You'll see something like the display below. Click General, then click Enable disk use. That's all. Now you can install ChemDuet. And, you can now use your iPod as a hard drive!
Note that you do not need to leave disk use enabled after you've installed ChemDuet,
unless you want to update or remove ChemDuet on your iPod. Leaving disk use enabled
means that you must manually eject your iPod after each music sync or update.