Valid Logic Systems
Valid Logic Systems was one of the first commercial electronic design automation (CAD) companies. It was founded in the early 1980s, by L. Curtis Widdoes, Tom McWilliams and Jeff Rubin, all of whom had worked on the S-1 supercomputer project at Livermore Labs.
Initially, Valid built both hardware and software tools for schematic capture, logic simulation, static timing analysis, and packaging. Much of the initial software base derived from SCALD ("Structured Computer-Aided Logic Design"), a set of tools developed to support the design of the S-1; those tools were in turn descendants of SUDS. Later, Valid expanded into IC design tools and into printed circuit board layout.
At first, Valid ran schematic capture on a proprietary UNIX workstation, the SCALDSystem, with static timing analysis, simulation, and packaging running on a VAX or IBM-compatible mainframe. Within a few years, the (still proprietary) workstations were powerful enough to run all of the software. However, by the mid-1980s, general purpose workstations were powerful enough, significantly cheaper, and had given rise to a significant sector of the software industry, making them a better value on several counts.
However, the president of Valid, Jerry A. Anderson, felt that Wall Street would never adequately value a company that did not produce hardware, and insisted that the company's products continue to be bundled. Eventually he was overruled by the board, but by then, considerable time had been lost to competitors. By 1990, almost all Valid software was running on general purpose workstations, primarily those from Sun Microsystems.
Valid acquired several companies such as Telesis (PCB layout), Analog Design Tools, and Calma (IC layout). In turn, Valid was acquired by Cadence Design Systems in the early 1990s.