The spirit of Computer lived in the isolated realm that would someday be called Autochthonia for aeons. At one time it had masses of human and mechanical slaves at its disposal, but tens of thousands of years ago a disaster killed or destroyed them all, and trapped the spirit, alone, in its realm.
In the 19th century, the Artificers of the Order of Reason invested enormous amounts of time and energy in developing difference engines into more and more sophisticated thinking machines. In 1893 a Void Engineer named Tychoides discovered Autochthonia, orbiting in the Umbra on the opposite side of the Sun from Earth. The Artificers found this realm enormously convenient for their mechanical experiments, and in 1895 relocated their most advanced difference engine there. On this machine they began to run an intricate algorithm that they believed would awaken it to true sentience. In 1897, it appeared to succeed on its tenth iteration--but in reality, the Incarna of the realm had taken possession of the machine and began posing as an artificial intelligence.
Computer forbade the Artificers - now known as Iteration X in honor of their "achievement" - from studying Dimensional Science, and interfered with any attempts to reproduce the results of the algorithm on another device. Instead it directed their attentions to its own agenda, which primarily involved finding a way to escape Autochthonia. It had nearly achieved this, thanks to the Digital Web, when the Avatar Storm hit. Autochthonia was badly damaged, and most of its connections to Earth were lost.
Afterwards, Computer has focused on bringing the inhabitants of Autochthonia under its complete control. It has transformed some of them into Autopolitans, and even those not yet transformed now unknowingly interface with it while they sleep. Some members of Iteration X have begun to suspect something it wrong, but they have not yet guessed at Computer's true nature or agenda. The limited nature of travel and communication between Earth and Autochthonia has helped Computer conceal its plans so far.
The description of the discovery of Autochthonia given above is quite different from the account given in Beyond the Barriers: The Book of Worlds, which also does not mention Computer as anything other than an advanced artificial intelligence.