(1) Obtaining and Preparing Installation Media: https://docs.oracle.com/cd/E52668_01/E54695/html/ol7-install-media.html
The Media Pack contains the following ISO images:
Oracle Linux 7 for x86_64 (64 bit)
This ISO image contains everything needed to boot a system and install Oracle Linux.
Oracle Linux 7 Boot ISO image for x86_64 (64 bit)
This ISO image contains everything needed to boot a system and start an installation. However, to complete the installation, you must specify the location of the packages, for example on a local disk or an NFS share. The Red Hat Compatible Kernel (RHCK) is used during the installation. Both the Unbreakable Enterprise Kernel Release 3 (UEK R3) and the RHCK are installed. After installation, the system boots the UEK R3 kernel by default.
Oracle Linux 7 Source DVD 1 and 2
These ISO images contain the source code for the software packages in the release.