Simi Valley-based Qualstar, a provider of tape storage systems, has lost its CFO. Qualstar said Monday that Frederic T. Boyer, its VP and CFO, has resigned to join another company. Boyer will leave the firm August 18th. According to Qualstar, Boyer has accepted a position with another company that does not compete with Qualstar. William Gervais, the firm's President and CEO, will serve as Interim CFO while finding a successor.