Ziggy

Made of biological elements & technology, circuitry parallels the human brain
Tracked all the changing histories as they occurred without losing the original data;
Could predict what the leaper had to accomplish to complete each leap
Big ego, self-aware, able to think on its own rather than just running programs
An entire year's worth of data could be accessed & assimilated in 12 hours
Turned off & dismantled when the government shut down Quantum Leap
Rebuilt by Ian Wright, 30 years later, when Quantum Leap was resumed