Times are so hard in the mainframe leasing business hat Comdisco Inc is having to drop everything not vital to its core businesses – including one or two operations few even knew it had. It is selling Comdisco Systems Inc, which provides electronic design systems for dignal processing and communications applications to Cadence Design Systems Inc on undisclosed terms, although the settlement will be in new Cadence shares. Cadence said the deal reflects its belief that to grow the electronic design automation market, it has to provide untapped customers with new technology and abilities.