Pallan is a male human being from the planet P3X-289. He has little knowledge of the toxic world beyond the dome. The link had told him about the cities of steel and glass that once were. Pallan lived with his wife Evalla before she died. He oversaw the underground systems that support both, the link and the dome of P3X-289.
After the link ordered Evalla to leave the dome and be killed by the toxic environment outside, the link performed an update so Pallan forgot Evalla. As it had done to make him unaware of the 400 years of abnormalities in the dome systems. Pallan was unaware that the link was regularly updating his memories every time there was a discrepancy, making it impossible for him to realize that the dome was slowly collapsing due to a diminishing power supply.
The link performed an update to make him think that to disconnect from the link would lead to death. Pallan was shocked when Major Samantha Carter disconnected him from the link, and he was still alive. After Doctor Daniel Jackson discovered library records from before the creation of the link detailing the original size of the dome, Pallan worked diligently with Carter to fix the link so the rest of the residents would forget about SG-1 and later know the truth.
Pallan asked Carter to tell him about his wife that he had lost and he could not remember. He was sent to another planet with the rest of his people. He lives on the planet and sometimes contacts Stargate Command to talk with Carter. (SG1: "Revisions")