Digital Heaven has announced Disksomnia 4.0, an upgrade of their Mac OS X utility that stops hard disks from going to sleep. The new version sports a completely rewritten menu bar that works in the background to keep disks awake, even those that ignore Energy Saver preferences.
Disksomnia 4.0 requires Mac OS X 10.7.3 or higher. It costs US$9.99 and is available at the Mac App Store. Go to http://tinyurl.com/nx7ekh for more info.