Qualstar Corp. has entered into an agreement with Sony Imaging Products & Solutions Inc. to develop an optical disc archive system for computer data, the company has announced. Under the agreement, the Simi Valley manufacturer will receive installment payments for its design and development services, which are expected to be complete by the end of March. After the agreement ends, the companies may enter into additional agreements relating to production of the enterprise class optical disc archive library. Qualstar makes tape data storage and computer power supply equipment. Shares of Qualstar (QBAK) closed Wednesday down 12 cents, or 1.7 percent, to $6.94 on the Nasdaq.