Andy’s OS is my distrabution of Linux namely openSuse 12.1. Info about the build is 5.04 GB 64-bit Operation System.
Use the Live CD/DVD, if you want to try out the OS without installing it. This is useful for testing and debugging or if you do not have a spare hard disk available at the moment.
Use the preload ISO, if you want to boot from CD/DVD and dump it to your hard disk without knowing too much about the details of the dump procedure. A preload ISO is an image wrapped as a bootable CD/DVD. After you have booted, it offers to overwrite your hard disk. If you select Yes, the image will be dumped to your hard disk.