GLaDOS

"All I know is I'm the only thing standing between us and them. Well, I was."

- GLaDOS

GLaDOS (Genetic Lifeform and Disk Operating System) is the guide and, later on, the main antagonist of Portal.

Background
When Black Mesa reportedly started on similar portal technology in 1986, Aperture Science began construction of GLaDOS. A presentation on a projector seen briefly in game suggests that GLaDOS was at one point designed to compete with Black Mesa for a Defense logistics contract looking to develop a Fuel System Icing Inhibitor (FSII). Aperture Science's proposal argued that their solution was not only cheaper than Black Mesa's but it was a 'fully functioning disk operating system' and 'arguably alive' as a bonus.

The Disk Operating part of the A.I.'s namesake was completed in 1996, after which work began on the genetic lifeform area. GLaDOS was switched on for the first time several years later, during Aperture Science's first annual bring-your-daughter-to-work day. Initial tests are said to have gone well.

How and when GLaDOS became self aware and took control of Aperture Laboratories are open to speculation. The installation of the red phone and the morality chip are evidence that GLaDOS was not able to seize control of the Enrichment Center immediately after she developed the desire to do so, and that her creators had some inkling of the extent of her psychopathy. This suggests that there was a protracted struggle for power between GLaDOS and the human occupants of Aperture. It is also possible that GLaDOS overtook the Enrichment Center prior to the Black Mesa Incident as the presentation seen in the observation areas makes mention of Black Mesa. It would be unlikely that after the incident Black Mesa would have been a viable company, and therefore competing with Aperture for government contracts.

External factors may have intervened. Towards the end of the game GLaDOS makes several references to the world outside Aperture Laboratories. She says "much has changed" since Chell last saw it, that she is the only thing "between us... and them", and Chell would find death preferable to what is currently going on outside. This seems to reference the Combine invasion of Earth, which would place the events of Portal somewhere after the Seven Hour War and the lead up to Half-Life 2; however, so characteristically vague are GLaDOS's words that she could be referencing something completely different, or indeed making things up.

Valve have stated that they deliberately kept this and GLaDOS's fate ambiguous, because they are as yet undecided as to whether and how to tie future Portal releases into the Half-Life series. However, references to the Aperture Science research vessel the Borealis in Half-Life 2: Episode Two suggest at least some degree of continuity between the two stories.

Portal
GLaDOS talks to and aids Chell as she progresses through the Aperture Science test course, issuing instruction in the use of the Portal Gun and offering oblique and occasionally sinister advice and warnings. Her smooth female voice, issued through a PA system which pervades the whole of Aperture Science Enrichment Center, is the only outward face of the organization the player is ever aware of, or allowed to be aware of. It is not completely obvious who or what GLaDOS is, and what her actual role is at Aperture, until the very end of the game, though it is strongly hinted at the beginning when GLaDOS says "... Computer Aided Enrichment Activity ...".

At the end of the test course, it becomes apparent that GLaDOS never intended to let the player leave the labs alive, a fact which she had actually been making clear all along. The platform Chell is riding on carries her into a fire pit, echoing GLaDOS's strange statement in Chamber 18- 'You will be baked, and then there will be cake'. When Chell escapes through the use of the Portal Gun, GLaDOS's behavior starts to become alarmingly erratic. As Chell advances through abandoned labs and the industrial areas of Aperture, GLaDOS demands then pleads with the player to turn back, maintaining that cake will be served if Chell just stops behaving badly.

Eventually GLaDOS is discovered to be the "Genetic Lifeform and Disk Operating System", a huge supercomputer which is now apparently the only occupant of the Aperture Science Enrichment Center. A red phone was installed in the central chamber which GLaDOS occupies to be used as a warning system should she turn rogue; this has, for reasons not revealed, not worked. There is some suggestion that GLaDOS murdered the former human incumbents through the use of a neuro-toxin, which after the player destroys her morality program she gleefully turns on Chell. However, thanks to the appearance of a malfunctioning Rocket Sentry after the first "eye" is destroyed, Chell is able to redirect the fired rockets and eventually destroy GLaDOS by knocking off and incinerating the rest of her cores.

The cores appear to be programs that control different aspects of GLaDOS, and are in order of incineration: Morality, Curiosity, Cake (Intelligence), and Anger.

At the game's end, a cutscene reveals many more of GLaDOS's cores lighting up in a storage area (with the infamous cake in the center, and the Companion Cube to the right), and during the credits sequence, GLaDOS can be heard singing that she is "Still Alive".

Note: In the advanced version of Test Chamber 17 ,these same light up balls are used instead of the Companion Cube.

Appearance
GLaDOS represents Aperture Science, and guides the player from their chamber into and through the test course. It swiftly becomes obvious that despite her polite and equable tones GLaDOS is neither particularly bothered by what happens to the player, nor entirely rational. She frequently lies about such concerns as the deadliness of acid pits, and also has a fixation with Cake, which she insists will be served after the test is completed. She presents this and the bewildering and dangerous tasks the player is forced to perform as common procedure at Aperture. GLaDOS is also prone to seemingly intentional vocal malfunction, often blotting out important pieces of information in bursts of static. Whether this is a malfunction, however, is still to be speculated.

Behind the scenes



 * "GLaDOS" is a pun with the words "glad", "DOS" ("disk operating system"), and Gladys, a female personal name (the game files show a folder called "gladdysDestruction").
 * GLaDOS's "Anger Sphere" is voiced by Mike Patton, lead singer of the bands Mr. Bungle and Faith No More, among numerous others. It should also be notted that he provided all the sounds made by the Common Infected in Left 4 Dead.
 * As stated in the commentary by Jeremey Bennett, GLaDOS went through several design iterations. Earlier versions included a floating brain, a sprawling, spidery mechanism, and an upside-down version of Botticelli's painting "The Birth of Venus" built out of robot parts and wire. Eventually, the team settled on a huge mechanical device with a robotic figure dangling out of it, conveying both GLaDOS's raw power and femininity.
 * A fan website says found that when looked at from a certain point of view, GLaDOS looks like a girl, but hanging upside down by her feet, her hands tied in the back, making her look like an insane or captured person.

Trivia

 * GLaDOS is more than slightly reminiscent of HAL 9000, the murderous AI computer of 2001: A Space Odyssey. However, those who read the book, 2001: A Space Odyssey, will find that the HAL 9000 was not self-aware, and driven to his actions in an attempt to rationalize two conflicting orders, to conceal the true mission objective and to never hide anything from the crew. Because GLaDOS became self-aware, and developed a sinister personality, it is safe to assume she is more alive, and more antagonistic, than the HAL 9000. In the film version of 2001: A Space Odyssey, it is strongly hinted that HAL 9000 is self-aware in the disconnection scene, where HAL 9000 is reduced to begging for his life.
 * GLaDOS is featured in the game "Rock Band" through Jonathan Coulton's song entitled "Still Alive," which is the credits theme for Portal. As of April 16, 2008 this song is free on the XBox Live Marketplace and was released free on the Playstation Network on April 24, 2008.
 * Google made an extremely elaborate fake AI for April Fools Day 2009: The AI is likely inspired very much by GLaDOS, especially because in the end it "Went rampant" and had to be shut off. Also, where GLaDOS had odd fixation with cake, Google's fake AI had fixation with pandas.

List of appearances

 * Portal