Commissioning status of the KEKB linac

After entering into the full-commissioning phase of the KEKB linac in May, 1998, we have established two linac injection modes for the KEKB ring: an 8-GeV electron beam and a 3.5-GeV positron beam, as well as beam modes for the rings of the synchrotron light sources. All modes are easily switched for almost one minute without any trouble. The linac, beam characteristics have been substantially improved by introducing several fine-tuning procedures, while key features concerning stable operation have been pursued by employing, for instance, energy-feedback loops. We report on the present status of the linac commissioning while especially emphasising the operational characteristics.