GLaDOS: It's been a long time. . . How have you been? I think we can put our differences behind us. . . for science. . . you Monster.

In 1953, Cave Johnson founded Aperture Science as a shower curtain manufacturer. The name "Aperture Science", seemingly random, is chosen "to make the curtains appear more hygienic". In 1956, the Eisenhower administration signs a contract with Aperture Science to manufacture shower curtains to all branches of the US Military, except the Navy. From 1957 to 1973, the company produced mostly shower curtains, and eventually making Cave Johnson a billionaire(somehow).

In 1974, Cave Johnson was exposed to mercury while secretly developing a dangerous mercury-injected rubber sheeting from which he plans to manufacture seven deadly shower curtains to be given as gifts to each member of the House Naval Appropriations committee, likely because the decision of the Navy not getting its shower curtains from Aperture Science depended on that committee, and Johnson probably held a grudge against them for that.

In 1976, both of Cave Johnson's kidneys fail. Brain damaged, dying, and incapable of realizing time is not now flowing backwards (thus realizing his time will come soon), he lays out a three tiered research and development program. The results, he says, will "guarantee the continued success of Aperture Science far into the fast-approaching distant past." What happens to Cave Johnson afterward is unknown.

The three tiers of this research and development program are:

Tier 1: The Heimlich Counter-Maneuver - "A reliable technique for interrupting the life-saving Heimlich Maneuver." In other words, ensure choking.
Tier 2: The Take-A-Wish Foundation - "A charitable organization that will purchase wishes from the parents of terminally ill children and redistribute them to wish-deprived but otherwise healthy adults." It counters the real-life Make-A-Wish Foundation, designed to grant wishes to terminally ill children.
Tier 3: The 'Portal' project - As said by Johnson when it was first laid lout: "Some kind of rip in the fabric of space... That would... Well, it'd be like, I don't know, something that would help with the shower curtains I guess. I haven't worked this idea out as much as the wish-taking one." This is what will become the 'Portal' project, involving the Aperture Science Handheld Portal Device and its creation of portals.

From 1981 to 1985, work progresses on the “Portal” project. Several high ranking Fatah personnel choke to death on lamb chunks despite the intervention of their bodyguards.

By 1986, word reaches Aperture Science management that another defense contractor called Black Mesa is working on a similar portal technology. In response to this news, Aperture begins developing the Genetic Lifeform and Disk Operating System (GLaDOS), an artificially intelligent research assistant and disk operating system.

In 1996, after a decade spent bringing the disk operating parts of GLaDOS to a state of more or less basic functionality, work begins on the Genetic Lifeform component.

We At Aperture Science Wish You A Happy Holiday!