(NOTE: This is fan fiction and as such, I reserve the right to alter lore any way I see fit.)
On Aperture
Aperture was a large company. And an old one, at that. It's many corridors and matanince shafts could go years without a soul setting foot in them. Now, there are two ages of it that people mainly see. The Age Of Cave, when they went up the test shafts with large orb like chambers and the Age Of GLaDOS; with the ASHPD and the testings of Chell. But what of the years between? There was a good ten to twenty years before GLaDOS was activated when Caroline was in charge. The Age Of Caroline was so ignored that the ones reading this likly doubt its existence. It was an age with both the technology of the Age Of GLaDOS but the human operators of the Age Of Cave; not to mention the personality cores which ran many things.
On Innhabitants
Now in this age there were four main types if beings in Aperture Science. The first are, of course, the Human Opperators; scientist and any other general Aperture employee. The second would be the AIs; the numorous cores, turrets, party escort bots, and all the other computer devises in the facility. Next is the Test Subjects, whom were anyone from employees "recently orphaned" doughters to hobos from street sides. The last of them all are the Lost; escaped Test Subjects, rouge AIs, maddened employees, and anyone else living the hermit like life in the facility's bowls. Though Lost are rare, even the most stable minded scientist can be scarred senseless by the static of radio in dark corridors, and the absurd and disturbing scrallings on the walls, and the echo of distant footsteps in a darkened matinince shaft.