If we installed from the DVD then the DVD will remain as “an installation source” or “software repository”. This is ok but is does mean that you will be prompted to add the DVD when searching for or adding new software. Network installation sources from http web servers, NFS files share or samba file shares can be popular and we shall look at these when we cover file services. However, for a single PC adding the contents of the DVD to a directory and then using that will be fine. Rather though than just add the directory we will create a compressed or “squashed” file system with squashfs. This then give us a single file that represts the DVD much like an ISO but in a compressed format. The file needs to be mounted to an empty directory and we can then use that directory as an installation source. Using the squashfs adds some practical Unix / Linux experience as we start to learn more.