The Mainframe is an auxiliary support structure specializing in the construction and maintenance of Hero units.
During their research of all the Koprulu Sector races, the Vaul found that some units seemed stronger than others. Certain Zerg breeds, such as Hunter-Killers, were especially deadly despite appearing as regular Hydralisks. These units showed remarkable endurance, strength, and special abilities compared to their more standard counterparts. In order to counter such powerful units, the Vaul devoted these buildings to the research, construction, and maintenance of their own "Heroes".
Due to the high cost of creating these units, the Vaul have installed special back-up crystals to digitally store any and all memories and experiences for all Heroes. Should any unit die, they are automatically uploaded into a new body before returning onto the field to resume battle (Battlestar Galactica: Resurrection Ship; Stargate - Atlantis: Central data core). This ensures that Hero units receive a degree of immortality as long as the building remains and there is enough resources to rebuild them.