Jupiter Station Diagnostic Program Alpha-11 was a diagnostic computer program with a holographic interface, a recreation of Doctor Lewis Zimmerman, in a recreation of the Jupiter Station Holoprogramming Center on Jupiter Station. It was a self-aware, learning hologram. In many ways it was similar to the Emergency Medical Hologram Mark I, and was actually an adjunct program whose purpose was to act as a diagnostic tool in case the EMH developed faults.
When The Doctor began suffering memory problems due to a cascade failure, B'Elanna Torres and Kes required the diagnostic program's assistance in finding a solution without completely wiping The Doctor's memory of the previous two years. Kes eventually discovered a solution, by "grafting" the EMH diagnostic program onto the damaged EMH, thereby increasing The Doctor's available memory after which the diagnostic program itself would no longer exist. As the program noted: "It's been a brief existence, but, I'm assured, a noble one." (VOY: "The Swarm")