(Telecompaper) Apple has appointed senior vice president Jeff Williams as COO, taking up a role that was left vacant when Tim Cook became CEO in 2011. Williams joined Apple in 1998. Williams becomes Apple's fourth C-level executive, alongside Cook, CFO Luca Maestri and chief design officer Jonathan Ive. Williams was already responsible for overseeing supply chain and operations, so the new title is a formality. Apple has also named Johny Srouji as senior vice president for hardware technologies and Tor Myhren as vice president of marketing communications.