Vault City designer notes

Obtaining the Holodisc
The disc is required to use the computer terminal described in the disc. Perception 7 is required to detect the plug in on the computer; it is not necessary, having spotted the plugin, to download the Vault City Travel Notes. There are some pretty good RP reasons not to; after all, it does ask you to reformat the Pipboy. The holodisc can only be acquired after defeating the inhabitants of the oil rig. The computer with the plugin and disc is the 'talking' one to the 'east' of level 3 of the Vault city vault, that gives the location of Vault 15. The computer described in the disc is actually the 'southernmost' one in the 'northwest', or "upper left" area.