Part of the once mighty Control Data Systems Inc has been acquired for $284m, by CDSI Holdings Inc, a company controlled by investment firm Welsh, Carson, Anderson & Stowe. CDSI is to offer $20.25 for each of the 14 million or so Control Data shares outstanding. Control Data Systems, along with Ceridian Corp, now a separate company, are the remnants of Control Data Corp, once a venerable name in the world of high-end mainframe systems. Control Data Systems moved into systems integration and services , and had contracts with Sun Microsystems, Silicon Graphics Inc and Hewlett-Packard Co. It also had an electronic commerce division. The acquiring company – which has also been named recently in connection with acquisition talks centered around CompuServe Corp, has made a specialty of acquiring companies for later resale or public offerings.