- "It's the ISOs, man! Isomorphic Algorithms."
- ―Kevin Flynn[src]
|Derezzed Date||1989 (mostly)|
|Circuitry Color||Various; namely, White and Green|
|Description||Normal program appearance|
|Out of universe information|
Isomorphic Algorithms (better known as ISOs) were a race of programs that spontaneously evolved on the Grid, as opposed to being created by users. Their existence was considered a miracle by Kevin Flynn; however, Clu considered them be an obstruction in his mission to create the perfect system.
ISOs differed from Basic programs in their appearance and capabilities, but their uniqueness lay in their code base. While regular programs conform to the rigid structure defined by their users, ISOs had evolved, complete with a genetic code of sorts that even Kevin Flynn could scarcely comprehend. This inner structure of their code would potentially have allowed ISOs to develop beyond the capabilities of regular programs.
Kevin Flynn and Clu discovered the first ISO in 1984 at the edge Tron City. As the ISO population grew, they attempted to integrate with the Grid's population, but met resistance from Basics, and thereafter formed their own colonies. Subsequent to his betrayal, Clu initiated a genocidal assault on the ISOs which was later referred to as the Purge. By the time of TRON: Legacy, Quorra is the last known ISO alive, after Kevin Flynn saved her from the Purge.
There are thought to be no ISOs remaining in the system after Quorra left the Grid.
ISOs have a glowing symbol on their arm and some depictions also show other markings on their skin. Their color circuitry is usually white, but the Bostrumites, such as Gibson, modified their circuitry to glow bright green.
The symbol in their arm represents their gender. The female ISO symbol is a hexagon, followed by a "T" shape, while the male ISO symbol replaces the cross with a sideways "V" shape. In TRON: Evolution - Battle Grids the male/female choice is distinguished by each of these symbols.
- Jalen (Later reconfigured into the Virus Abraxas)
- Quorra (The last ISO)
- Unnamed ISO (Named by the player in TRON: Evolution - Battle Grids)
- The male and female ISO symbols each include a hexagon, a symbol widely used on Kevin Flynn's Grid and possibly symbolic of organic life, since the hexagonal benzene ring is present inside the four building blocks of DNA. The sideways T is the logical symbol for implication; thus the female symbol could be read as implying organic life. The symbols also resemble the traditional symbols for male and female, ♂ and ♀, stylized with a hexagon for the circle, and the protruding arrow and sideways T each detached to stand separately.
- A key to intelligence, according to Godel, Escher, Bach, is analogy. ISOs' ability to quickly grasp patterns such as analogies, swiftly building knowledge despite lacking preprogrammed directives, may have lent to Kevin Flynn's perception of them as "unimaginably wise."
- Flynn speculated that ISOs differed from Basics through possessing free will, which could not be programmed. However, many Basic programs have been seen to possess initiative, choice, and both will and ability to change, leaving Flynn's criteria questionable.