  KEKB completed all of the technical milestones, and had offered important
insights into the flavor structure of elementary particles, especially the CP
violation. The accelerator control system at KEKB and injector linac was
initiated by a combination of scripting languages at the operation layer and
EPICS at the equipment layer. During the project many features were implemented
to achieve extreme performance out of the machine. Especially the online
linkage to the accelerator simulation played an essential role. In order to
further improve the reliability and flexibility two major concepts were
additionally introduced later in the project, namely the channel access
everywhere and the dual-tier controls. Based on the improved control system a
concept of virtual accelerators were realized that enables the single injector
linac serve as three separate injectors to KEKB HER, LER and Photon Factory,
respectively. Those control technologies are indispensable for the future
particle accelerators.
