In 1984 Durbetaki began designing an expansion chassis for the IBM PC. Durbetaki, who had left Intel Corp. after five years as an engineer and project manager, decided, along with brothers Keith and Ken Seymour, to start his own company to develop add-on instrumentation for the PC."[1] Durbetaki began creating his own schematic capture tool for his use in the PC expansion chassis project; but eventually shelved the hardware project entirely in favor of developing low-cost, PC-based CAD software. The company's first product was SDT (Schematic Design Tools), which shipped first in late 1985.