The world of Tron originated inside an 80’s computer server network from a company called ENCOM. Each computer system, from the smallest of home desktop, to the largest of private networks ran by world military's, all consisted of unique worlds unto themselves that literal computer programs inhabited. Outside of the digital realm where humans resided in, is an everyday 1980’s era Earth (Later on in Tron Legacy, 2010s). The only means of getting into any digital domain was through an experimental digitizing laser, created by two employees of the ENCOM company. Kevin Flynn, who by the end of the Tron movie, somehow acquires another for his own personal use in secret soon after.
The two main digital realms that are the primary focus in the two movies of the Tron Franchise, Tron, and Tron Legacy, are distinctly different places.
Encom System: Inside the ENCOM server network, this was the main location that the first movie Tron took place in. It had a very distinct style primarily consisting of primitive geometric shapes with bright eclectic colour schemes. Almost everything had glowing lines running down them, including the people who lived in it. These are literal interpretations of computer programs people wrote in real life in their world.
The living embodiment of programs existed in this unreal landscape, with an occasional difficulty in differentiating between a function of the environment, and an actual anthropomorphized program. Most programs look like their creators/programmers and take up their appearance, and small parts of their personality. Some however can be entirely mechanical looking, a different appearance, no familiarity at all, or enmeshed into their landscape. All programs had a function and a directive that gave them reason for being. In essence, they were their jobs. To understand a program is to know they were just as much a part of their digital environment as they were an individual participating in it.
A distinctly program cultural norm was embracing a reverence for Users, primarily the user that created them, but all users were revered collectively by most as well. These programs were called user believers. Certain places within this system, I/O towers (a piece of hardware in reality), hold special significance, as programs were given the opportunity to speak with the users, and thus were treated as sacred and divine, almost a temple to worship at.
However, other programs that do not share such reverence did exist, and they could have downright malevolent ambitions that went against users and even other programs within a system. One such example is a sentient AI called the Master Control Program (MCP), the primary antagonist of the Tron movie, who took over the ENCOM systems by draining its component parts of power. He systematically started breaking into other foreign real world systems, stealing resources, information, and even other programs that were deemed useful, all with the goal of enlarging himself. The MCP even went as far as to threaten the CEO of ENCOM in the real world through blackmail, with additional ambitions of breaking into the US military’s networks and the Pentagon later on. Any user believers were systematically killed or sent to the gaming pits, where they were forced to combat other user believers to the death in a mockery of user video games. This was a dangerous and oppressive environment compared to a generally more relaxed and open one from before the MCP's corruption of the system.
Most programs were colour coded by their function, and sometimes their affiliation with their alignment to users. CLU was a yellow lined program, which represented a foreign program interacting with a foreign system. It could also mean a rogue program that's had its function corrupted depending on if they were local or not. Typically, most programs were blue in ENCOM who were not employed or on the side of the MCP, which were red. Programs could jump and change colour on occasion, as an example of the yellow for a rogue program that could have been blue beforehand, or a blue program that chose to follow the MCP so changed to red. User believers could be almost any colour, though they tended to not be red.
Other systems have other colour designations and meanings. Programs would typically have certain feelings and responses to differently coloured programs, though in other places, colour can be entirely superficial. It depends on the system. Programs would just intrinsically know what the colourations meant in the spaces they occupied.
The Grid: Part of the Tron System. This is the primary system CLU lived in and what he considers his Home. This was a private server system entirely designed by his creator, Kevin Flynn and constructed on a custom OS. Unlike the ENCOM system its aesthetics differed drastically, even clashed with the former. This is a dark place where the glowing circuit lines that cover everything were more apparent and bolder. It had a more functional look to it, opting out of the abstractness and inconsistency of the older system before, so becoming more uniform and refined.
This was the home to many programs imported from ENCOM, other places, and custom written auto generation scripts ran by Kevin Flynn when needed. By the start of Tron Legacy there were counted shy of ten million of them still operating in 2010, the true tally is uncertain, but it’s still high. On Top of that, the system itself in mid 1983 started to spontaneously generate new programs of unknown origins called ISO’s. Such high amounts of programs and demand for resources created an environment that needed a significant amount of administering to keep it all running, so Flynn created Clu 2.0 to become the primary System Administrator and caretaker to the Grid.
The main purpose of this private system was to be a playground for Kevin Flynn’s ideas with the eventual goal of perfecting the place enough that he could introduce it to the real world. Unlike the ENCOM system which was not hand crafted by a user, and was simply a business computer network, and so was the natural result from the absence of interference, The Grid in contrast was designed with the intentions of Flynn being inside it, though he increasingly left little time to do just that. As such, the social development of the programs had been disrupted from what we see as the norm on the ENCOM system. Most programs in the Grid acted far more human and irrationally than their counterparts in other systems. Especially the younger programs who had no connection to any other system. Many problems that did not exist before, occurred within this system regularly from programs whose functions originally would never permit such behaviour. This included stealing, job hopping, performing acts reminiscent of a virus or malware that they'd learned, or even just laziness.
This system originally comprised a few different cities, and a multitude of smaller satellite towns. The capital city, the first in the system, was Tron City, named after the hero of ENCOM, Tron. The ISO's had a main city, the most divergent of the systems aesthetics built on the sea, it was pristine white composed of impossible, artistic shapes, and another smaller town buried into a ravine far from the main cities. In 1989, Clu 2.0, (the primary System Administrator, and CLU’s brother program), committed a coup against their user, Kevin Flynn, trapping him inside. He then took total control and most if not all of those secondary areas were torn down over the years to direct all resources to the main megalopolis of Tron City, and to consolidate and maintain his military dominance for 20 years.
During the coup, Clu 2.0 eliminated the vast majority of ISO’s (eventually leaving only one left), seeing them as resource hogging, bug ridden, and function-less, as they lacked any, just like a user. Obsessed with perfection, and holding a lifetime of resentment, he forced the denouncement of users, and replaced their reverence for them to himself in its place. Anyone who spoke out or got in his way was killed or reprogrammed (rectified/repurposed) into a form that is ideally uniform and obedient to him.
Grid_Lined system: The most recent system CLU had lived in and where his latest CR is from. This system occurred after the events of Tron Legacy with the destruction of the portal. Yet instead of collapsing the portal (entryway into the digital world created by the digitizing laser), it perpetually stayed on and somehow went on to kidnap random programs and people from different timelines/realities. CLU was one of these unfortunate ones.
The majority of this system was the same as The Grid. However, over time, it had some key additions implemented by all the random programs and users who had fallen into this world and so it was not entirely a mirror image.
This place was controlled and overseen by the primary Tron security program, and the rest of the ‘good’ programs, but it did have its fair share of instances of various Clu 2.0s and other hostiles devising ways to take back control or cause harm. Most programs that found themselves here resigned themselves to live there indefinitely and make something of themselves, as apparently no controllable or reproducible means had been found to undo what happened. This system, though a tad chaotic, was primarily a free and open system, but never quite moved past the obvious trauma of Clu 2.0s and his forces commitment to oppression and genocide, so discrimination and fear towards orange, red or yellow coloured programs occurred frequently and in full sight (And probably rightfully so).
Duplicate programs were frequently found, so it wasn't unheard of to talk to yourself in many instances, or encounter other programs or people someone there would know from their own systems or timelines.