In this tutorial, Shawn Powers shows us hot to update ISOs with Zsync. First, download and install this, then type in "i" and enter in the c file. Then, enter the http address where the zsync file lives, and press enter. After this, it will download the file and compare it to your 'c' file. You can also use a desktop CD as a seed and use the change for an alternate CD if you prefer. When finished, exit out of the program and you will be done. This will save you bandwidth and only take a few short minutes, and you can use this on any operating system you have.