Inside a Computer System

""What is real? How do you define real? If you're talking about what you can feel, what you can smell, what you can taste and see, then real is simply electrical signals interpreted by your brain.""

- Morpheus, The Matrix

This is a relatively new branch of Science Fiction, it deals with the aspects of people being either partially or completely attached to, and part of a computer system. Virtual Reality taken to the next step, or perhaps, Virtual Reality as reality.

Being partially attached means that you "jack in" or otherwise connect, and you then experience whatever the computer system shows you, typically providing audio and visual quality at the maximum of human perception. It might go further and give you taste, touch, smell and more, or as Dennis Miller once put it, "If some unemployed punk in Trenton, New Jersey can buy a plug-in for $29.95 to let him make love to Cindy Crawford, virtual reality is going to make crack cocaine look like Sanka." (More than one sci-fi story has this happen: Humanity dies out because everyone is so busy having hot virtual sex that there's no-one left to make any actual babies.)

If you're completely attached, either your consciousness has been transferred into the system and you don't have a "real body" outside of the system, or you are "stuck in a pod" and are connected to it. You may or may not know you're within a computer system.

While there is some overlap between the two concepts, this differs from Cyberspace in that when you're Inside a Computer System, it may be completely self-contained and have no connection to the outside world. You might also be alone in there. Cyberspace implies a connection between the computer system to the real world, and has multiple people connected to it. Although The Matrix fits both definitions.

To make things easier on the audience (not to mention, where relevant, special effects budgets) the computer environment is generally depicted as being very similar to the physical world; i.e. people still look like people, they still have a "body" and a "location" and they obey most of the laws of "physics", etc. These rules are almost always tampered with (e.g. defying gravity in The Matrix), but the fundamentals are mostly the same (e.g. Matrix-people have only 4 limbs).

The real Deep-Immersion Gaming. If the user thinks it's real, it becomes a Lotus Eater Machine. See also Win to Exit, when the characters enter a video game, and must compete to get out of it.

Anime & Manga

 * Serial Experiments Lain has this as the central theme of the story. Notably, it treats Inside a Computer System as a mystical experience, without any technological peripherals connecting people to the virtual reality; the only "scientific" explanation given to the out of body experiences is the Earth's electromagnetic Schumann Resonance, which in the story can link human brains and computer equipment together without anyone noticing.
 * In Silent Mobius, this is Lebia Maverick's main shtick.
 * Ghost in the Shell
 * Everyone in .hack// is inside a MMORPG.
 * Except in .hack//Liminality, which is all about what's going on on the outside.
 * Dennou Coil has the real and virtual world coexisting.
 * The second season of Superbook had the pet dog one of the first season's regulars getting trapped in a computer after a freak accident caused it to merge with the Superbook (the Bible, only with a magic ability to transport people into the stories). The new hero of the season then had to travel into the computer to get her back.
 * Chisame of Mahou Sensei Negima, being a Playful Hacker, gains an Artifact that lets her do this.
 * Corrector Yui.
 * Like .hack//, everyone in Mythic Quest is in the MMORPG Mythic Quest.
 * Digimon. That is all.
 * Also an example of Cyberspace.
 * can be considered to be an example of this trope, albeit one where the computer is simulating entities instead of abstract information mentioned under the "Real Life" folder of this trope. Still... this only borders on the very fringes of this (as designing a computer system that crashes in the way the series describes would be very odd and, likely, not an optimal way of doing things). (Maybe the series' simulation has some way of tracking sentient entities and crashes when too many of them are active?)

Comics

 * Kimmie 66 takes place almost entirely in "lairs", basically VR environments.
 * In Nth Man: The Ultimate Ninja, Reality Warper Alfie O'Meagan traps John Doe and Colonel Novikova inside a video game, complete with horrible 8-bit music, Goomba Stomping, and secret Warp Zones.
 * Minor Firestorm villains Bug and Byte are a brother and sister with the power to physically enter computer systems (à la Tron.)

Films

 * We did mention The Matrix once or twice, didn't we?
 * Johnny Mnemonic, starring the indomitable Keanu Reeves, had scenes in cyberspace, but the movie mostly took place in meatspace.
 * Arnold Schwarzenegger in Total Recall is trying to determine if what is happening to him is real, or if it is memories that have been implanted in his brain because he's on a console.
 * Tom Cruise in Vanilla Sky may be simply be having a series of really bad experiences, or he's stored in a computer system and is living a fantasy existence.
 * Natalie Wood's last film, Brainstorm, worked with equipment that could do the whole virtual reality thing over a telephone line. Not DSL, either; a simple modem that hooked up to someone's phone, or could be acoustically coupled and transferred over a pay phone.
 * The movie eXistenZ had a virtual reality gaming system that people entered, and in some cases you couldn't tell whether they were in a game or in reality. This movie came out about the same time as The Matrix and The Thirteenth Floor.
 * In Freejack, the "soul" of the character played by Anthony Hopkins is stored in a computer because his body has died, and needs a replacement body to be transferred into within 24 hours or his soul will also die.
 * Tron (and its sequel Tron: Legacy) are variations on this. The protagonists physically enter a computer network when their bodies are reduced to component information by a teleportation device (actually a laser, but the same principle is involved).
 * The Thirteenth Floor revolved around a city in a computer system owned by the protagonist's company -.
 * Strange Days features video recordings that provide direct sensory stimulus when played back, like virtual reality home videos.
 * In Virtuosity, Denzel Washington is a cop, convicted of manslaughter, who gets time off from his sentence to fight Sid, an entity inside a computer who is an amalgam of the personality of dozens of serial killers and mass murderers. When Sid ends up getting himself released into the real world, Washington has to be let out of prison to stop him before Sid kills lots more people than his initial bloodbath takes out.
 * The main premise of the Detective Conan Non-Serial Movie Phantom of Baker Street involves Cocoon, a virtual reality gaming system that puts injects the senses of the players by neural stimulation when sat inside the pods. And then, the boss of the software company murders the chief engineer of the project on the day of testing; the said engineering spread an AI that hacked into the gaming system, which in turn caused Holodeck Malfunction...
 * The main premise of the Detective Conan Non-Serial Movie Phantom of Baker Street involves Cocoon, a virtual reality gaming system that puts injects the senses of the players by neural stimulation when sat inside the pods. And then, the boss of the software company murders the chief engineer of the project on the day of testing; the said engineering spread an AI that hacked into the gaming system, which in turn caused Holodeck Malfunction...

Literature

 * Cyberspace in the Sprawl Trilogy of William Gibson pioneered this trope.
 * One of the Hitchhiker's Guide to the Galaxy books featured a description of an alien computer terminal which worked in this way. However, one could exit at any time, and reality and virtual reality were quite distinct.
 * This trope is central to the original book's premise:  is a very elaborate computer created to discover   The behavior of the beings on the planet are a goodly part of the computations.
 * The Otherland series by Tad Williams is about a Ragtag Bunch of Misfits who break into a virtual reality network (in a time where VR is commonplace) and become trapped there, unable to go offline. Furthermore, they can apparently be killed there too. One of the mysteries they must solve is why this is the case.
 * G.A. Effinger's book When Gravity Fails has a system where people meet in a Virtual Reality system, and can even have sex while in the system, and it's indistinguishable from the real thing. In one case, eight people lie down on the Virtual Reality couches, and only seven get up; one of the visitors figured a way to kill one of the others by causing their "soul" not to go back into the body, but to stay and effectively be purged when the machine was shut down.
 * In the Matter of: Instrument of God is about the Afterlife, set up inside a massive computer system, where the occupants are aware both that they are dead and that they are within a computer system.
 * Vivian Van Velde's novel Heir Apparent rests completely on this idea. Gianine gets trapped in a virtual reality fantasy game when it's damaged, and has to win the game to escape.
 * Piers Anthony's Killobyte involves a paralyzed cop and a diabetic player who are both trapped in a virtual reality game by a hacker and in danger of dying in reality.
 * The majority of the storyline of Realtime Interrupt by James Hogan is Inside a Computer System. The apparent strangeness of reality the character experiences is explained to him as mental illness.
 * Permutation City is a remarkably hard scifi look at this trope, with some strange philosophical added in.
 * Greg Egan is quite good at this. Diaspora features a relatively in-depth look at the Polises, underground supercomputers simulating posthuman intelligences several times faster than real time.
 * The subject of any number of philosophical papers from the classic "Brain In a Jar" introduction to epistemology, to Robert Nozick's Experience Machine, which raises the question of whether or not it would be ethical to plug into one.
 * Three of Jack Chalker 's better novels (the Wonderland Gambit trilogy) feature people who have been inside the machine so long they've created thousands of alternate universes—all of which keep running after they're gone.
 * Altered Carbon and the Takeshi Kovacs series features this trope put toward particularly gruesome ends. Torture victims could be implanted into a computer world, where they would be tortured for hours of subjective time every minute, for as long as the computer stays running. In theory, a person's consciousness could experience millennia of agony without the mercy of death.
 * Timothy Zahn's Conqueror's Trilogy: The Copperhead fighter pilots have implants that allow them to jack into their fightercrafts: the pilots become the craft. They have expanded fields of vision, data from the ship's status comes in as taste, smell and touch. It is an extremely addictive feeling, leading to some pilots remaining jacked in between missions. Recently the Commonwealth military had set up better screening processes to avoid this. Reception to these new tests is varied.
 * Most of the events in Sergey Lukyanenko's Labyrinth trilogy take place in a virtual city called Deeptown, made possible due to a psychosis-inducing video that is played every time someone logs on. A full body suit is necessary for an immersive experience, although the first case of perceiving a virtual world as reality occurred with a guy playing Doom afted watching the video. A special group of people are able to exit the "deep" at will. These so-called "Divers" can also see security holes and backwoods as... holes and doors. The trilogy also features a "super-Diver" with the ability to see how things really are and affect them (e.g. walking through a solid object after realizing it's only a computer-generated model).
 * Overdrawn at the Memory Bank by John Varley (and its infamous film adaptation) has a man whose consciousness is loaded into a computer to keep him alive after his body is misplaced.

Live Action TV

 * Caprica has the holo-bands, your own personal Matrix. Portrayed somewhat realistically as a new user, who just got his own avatar, doesn't know how to move without moving his physical legs. Also, he spawns in a drab concrete room with a single door, along with his guide, who apologizes for the lack of décor.
 * A notably early example was in the 1976 Doctor Who story The Deadly Assassin, where the Doctor travels into a surreal virtual world inside a computer matrix.
 * The Stargate SG-1 episode "The Gamekeeper" featured a planet whose inhabitants deliberately plugged themselves into virtual reality pods after the planet was devastated. By the time SG-1 found it, it got better.
 * The planet had definitely recovered into a near-paradise. Too bad that the "Gamekeeper" didn't bother to tell the inhabitants of the planet. Fortunately, SG-1 was there to save the day... again.
 * Stargate Atlantis also did this a few times. In one episode, McKay has to get Sheppard out of a VR where he's imprisoned. Later they use a VR system to dive into each others' minds., and there's also a VR pod that a friendly replicator girl gets plugged into to keep her on ice, while giving her the impression of living a normal life.
 * In VR 5, Syd can draw the subconscious mind of anyone she calls on a telephone into virtual reality. As in Brainstorm, this involves an acoustic modem. Which was already about ten years out of date when the show aired.
 * The half-dozen people who actually watched the whole series eventually discovered that the much-maligned "acoustic modem" was not off-the-shelf technology, but Applied Phlebotinum from a buried Secret Project.
 * J-drama Sh15uya centres on a group of fifteen-year-olds trapped in a virtual replica of Shibuya.
 * Red Dwarf had a slew of games and realities of this type, generally known as Total Immersion Gaming. The sims ranged from Better Than Life, a free-form fantasy enabler; to Streets of Laredo, a wild-west game that allowed players to play as one of three cowboys with their own unique skills; to Jane Austen World, which is exactly what it sounds like.
 * Superhuman Samurai Syber-Squad.
 * The Star Trek: Voyager episode "The Thaw".
 * The premise of the Bonus Round on Nick Arcade.

Music

 * The song "Mastermind" on the Heavens Gate album Menergy has the title character monitoring our life which is actually inside a computer.

Tabletop Games

 * In Shadowrun, any character equipped with a data-jack and a cyberdeck can enter the Matrix, a network that connects just about every computer system in the Seattle area. Deckers specialize in this sort of thing. Some do it to mine data and sell it to the highest bidder, while others use it to shut down corporate security systems. The Otaku were able to access it without any sort of gear, but their powers faded when they reached adulthood; following the Second Crash, the Fading stopped, and those with the power rechristened themselves technomancers.

Theatre

 * Possible Worlds by John Mighton has two detectives investigating the theft of a human brain. At one point they go to a scientist who studies brains, and one takes a machine hooked up to a rat brain with him. He muses what it would be like to be like the rat brain and believe things are real although they are really just electrical pulses. His partner tells him not to be ridiculous. Also,  Fascinating play, but bloody confusing.

Video Games

 * The video game A Mind Forever Voyaging has you as a computer AI, with the real world around you simulated, and now you've been let in on the gag. Believe it or not, it was released in 1985.
 * The people of Tranquility Lane in Fallout 3 are all in pods hooked up into the main computer a la The Matrix.
 * In the add on Operation: Anchorage The player character can enter a military training simulation, it is obviously not real from the players perceptive but the computer generated characters see it as totally real.
 * McGraw also mentions that the sim had it's safety protocols turned off, meaning that getting killed in the sim results in your character going into cardiac arrest in the "real" world.
 * Star Ocean: Till the End of Time
 * The Mega Man Battle Network series for the GBA integrates this into gameplay. The player controls Mega Man's human counterpart who can "Jack In" Megaman into various computer systems to solve various puzzles and progress through the plot.
 * Kingdom Hearts II gives us Space Paranoids, the Tron level. That's without mentioning
 * Kingdom Hearts coded is also based entirely around the trope.
 * On Pokémon, you store the titular monsters inside one. And items inside another. The anime is more sensible; Ash just teleports his mons to Professor Oak.
 * Actually it's sensible either way, as in the games you're just teleporting the pokeball into storage; Not really digitalizing it.
 * Actually Pokemon are indeed stored in cyberspace in the games. Similar storage systems exist in the Anime "however, unlike in the games, Pokémon are not stored electronically." - Bulbapedia.
 * This trope is heavily at work in Galerians: ASH, with.

Web Comics

 * The webcomic The Noob is set in the VR of the "Clichequest" MMORPG. (Mostly, at least.)
 * Used for a shameless Matrix parody during the Sluggy Freelance mini-arc "The Quatrix".
 * Near the end of Narbonic,.

Web Original

 * Merry, in the Whateley Universe, is a cyberpath who can interface with computer networks simply by being within a few feet of a powerful CPU hooked to the network. When she does this, she's "in" the computer network. She meets a Whateley Academy kid who can do almost as much as she can, but who prefers the Tron visuals for his version of cyberspace.
 * Darwin's Soldiers story Schrodinger's Prisoners takes place primarily in one of these.
 * AIs are important in the Chaos Timeline, so expect this.

Western Animation

 * Re Boot
 * This was also the plot of a second-season episode of Hanna-Barbera's Pac-Man: Pac-Baby gets lost inside his daddy's new home computer, and so Pac-Man and his nephew P.J. have to rescue him.
 * The entire premise of Code Lyoko. Going further than just "connected", though, the heroes are physically transported into the virtual world.
 * Scooby-Doo and his buds did the Tron version of this trope, being disassembled in the real world and dropped into a video game in Scooby-Doo and the Cyber Chase.
 * Same with Courage the Cowardly Dog: In the episode "Hard Drive Courage", Courage's computer catches a virus and kidnaps Muriel into its digital world in the hopes of curing its "illness" as Courage goes to rescue her. Things like computer mice, a "RAM" and a hard drive named Bill are out to kill Courage as well.
 * Featured in the One Hundred and One Dalmatians TV series.
 * This was a common plot in Animated Series from The Eighties:
 * Centurions: "The Incredible Shrinking Centurions"
 * DuckTales: "Scrooge's Last Adventure"
 * Filmations Ghostbusters: "Cyman's Revenge", which was very similar to...
 * He-Man and the Masters of the Universe: "Day of the Machines"
 * Johnny Test When

Real Life

 * René Descartes actually grappled with a very similar idea in his Meditations On First Philosophy, first published in 1641. Descartes proposes the idea that there could be an evil genius or other outside influence keeping him trapped and exposing him to false experiences (a real, full simulated world). This shortly follows his own proof of his own existence (the famous Cogito Ergo Sum he is more well known for) and is ultimately resolved, then he goes on to prove that God exists and otherwise codifies his own philosophy and weltanschauung.
 * A common idea is that Real Life is in fact a computer simulation and that everyone is either a body that's hardwired in, or just sophisticated pieces of software, being run by who-knows-what. Some have even argued that the quantum uncertainty principle (that is, that all particles of matter fundamentally do not have a definite position or velocity, making everything a tiny bit "fuzzy"), might be due to rounding errors in the simulation software.
 * In fact, if the multi-verse theory is true then there are probably many more simulated universes than real ones simply because there would be huge numbers of universes where at least some one has created at least one simulated universe, and if one persons done it once then there would probably be many universes with huge numbers of simulated universes in them (and then some of those might make their own simulated universes). But it all depends on there being a multi-verse really.
 * A similar theory goes as follows: Assume the Universe is finite. If the Universe is finite, it can be perfectly recreated in a simulation, given sufficient resources. If we can perfectly simulate the Universe, our simulation will contain individuals who will attempt to perfectly simulate their universe. As their (simulated) Universe is finite, they will be able to do so. This recurses infinitely. Therefore, there are potentially an infinite number of simulated universes, each containing one or more simulated universes, with one (real) Universe at the top of the stack. It is therefore INFINITELY more likely that we exist within a simulated Universe than the real one.
 * I, for one, hope the Universe is infinite.
 * An infinite universe can simulate other infinite universes within itself, so long as it confines the simulation to an expanding finite region. Our universe, for example, could be infinite and as long as the portion of it that is simulated expands outward at the speed of light, we would never be able to tell. This can also be used to construct infinite simulations-within-simulations.
 * This idea is the subject of philosopher Nick Bostrom's "simulation hypothesis", described in detail at Are You Living in a Computer Simulation?. To an SF fan, the argument can be quite convincing, considering that the technical premises of the argument are very mild speculations in comparison to the kinds of tech described in SF, even the hard variety.
 * An important note about this concept that is often forgotten: there is no logically meaningful difference from our inside perspective whether the universe is a simulation or the stack-top. For some reason a lot of people seem to find the idea that the universe could suddenly be revealed as "not real" disturbing, when it really makes no difference at all (as long as the programmers don't interfere, anyway). And no, there is absolutely no way we could somehow cost more computation power in our reality by running our own simulated universes.
 * One bizarre philosophical twist on this idea is the notion that the Universe is at once a computer, and computer program, that simulates itself.
 * Another one. The Universe is computer and all the mass/energy inside it is the program. Once you boil it all down in the abstract, all matter and energy is just information. Still inside a computer, but it's not a simulation of anything else. So it's still 'real'. Yea...
 * To a certain extent, life right now in the 2000's. Consider how prevalent an Internet-capable device is (iPod, cellphone, etc) used in the modern world and how easy it is to use them. Some programs like Mumble (a VOIP program) even work via Bluetooth and such without requiring a computer persay. Thus it's entirely possible to never be disconnected from the Internet.
 * Marshall Brain, founder of the website HowStuffWorks.com, has argued that one day we will likely all live in a simulated environment, probably within the lifetimes of many people reading this page.