# Build Prerequisites Before you build the ISO, verify that you have the performed the following tasks: * Installed a build operating system running the 64-bit version of Ubuntu 14.04 or later version. * Downloaded and installed the following packages: `bison`, `gawk`, `g++`, `createrepo`, `python-aptdaemon`, `genisoimage`, `texinfo`, `python-requests` * Installed Docker * Downloaded the source code from the Photon OS repository on GitHub into `$HOME/workspaces/photon`.