The 120GB hddss.bin file for the Xbox 360. Might be useful if you're planning on creating your own Xbox 360 hard drive.
You need this file to flash your custom hard drive Xbox360-compatible with HDDHackr program in case you can't, or don't want to dump it from your own Xbox 360 hard drive.If you don't know what this is, you likely don't need it.
Remember that there's a chance, a very remote one though, that you might get Xbox Live -banned for using this hddss.bin instead the one from your Xbox hard drive.