These downloads are standalone programs that run without other software. The programs access their data [maps and images (in jpeg format), and movies] from a file server at UMass using the web, thus requiring fast internet connections. All DDMs can access data from CDs or Hard Drives, if the data is available in those locations. To see any included movies, both Windows and Mac based computers must have the latest QuickTime Player installed (free from Apple for both platforms, at www.apple.com). Computers with less than 512 MB of free RAM will run these programs very slowly at best.