JOSEPH BAR ABBA, gaon of *Pumbedita 814–816. Joseph was a student of Shinai gaon of Pumbedita and successor of Avumai (or Akhumai). In his noted epistle, *Sherira Gaon relates that, as a scholar, his contemporary Mar Rav Kemoi was a more suitable choice for the gaonate, but he did not possess the miraculous powers of Joseph b. Abba, who was very pious and advanced in years. It was believed that Elijah revealed himself to Joseph b. Abba. Sherira relates that on the day of Joseph's death the earth trembled. R. Judah gaon, the grandfather of Sherira, was Joseph's secretary. Only a few of his responsa have been transmitted, and it is even uncertain
J. Mueller, Mafte'aḥ li-Teshuvot ha-Ge'onim (1891), 79–82; B.M. Lewin (ed.), Iggeret Rav Sherira Ga'on (1921), 109; Abramson, Merkazim, 10.