Computer retailer CompUSA has upped its stake to 50% in software developer InfoSource Inc on undisclosed financial terms. Back in June, CompUSA had announced that it was taking a 10% stake in the Winter Park, Florida company as it entered an alliance with it to develop proprietary computer training courses. Under the new deal, Blackwell Publishers Ltd, an academic journal and textbook publishing house based in Oxford, England will also retain a 50% interest in InfoSource. CompUSA said it currently purchases a wide variety of computer-based training software and skills assessment tools and applications from InfoSource. The retailing giant began offering computer and software training in 1991 and now claims to operate over 500 fully-equipped classrooms in its locations across the US that cater to both individual and business customers.