2.4.09: Was the Sharom the Dark One's Prison?
No. Demandred's analysis [LOC: Prologue, The First Message, 15] implies that the DO is imprisoned OUTSIDE the world/Pattern, in some sort of "Dungeon Dimension." The Bore is a kind of thinning of the universe, a weakness in the space-time continuum, by which the DO can reach out of the Dungeon Dimension to affect/enter the Real World.
From the RJ Online Q-and-A session on Compuserve (19 October, 1994), RJ says, "The Sharom and the Collam Daan are a university/research center." The Guide expands on this, saying, "The Sharom was one of the classic examples of functional beauty. It might seem impractical to suspend a building high in the air, especially a scientific research facility that required its visitors to use an airborne transport or the OP...." [Guide: 3, The Age of Legends, 34]. So, the Sharom was some sort of HEP (High-Energy Power) research facility, and its only connection with the DO's prison is that Mierin and Beidomon created the Bore inside it.