A description is given of a VLSI CAD workstation with a massively parallel computer, the connection machine, as hardware accelerator. The connection machine offers workstation users general-purpose acceleration capabilities and high interactivity. Workstation software includes a novel CAD-system kernel and tools operating on the connection machine. The system kernel, designed to permit efficient interfaces to existing tools and tool environments, also includes more advanced design tools (e. g. , procedural tools) providing a suitable basis for knowledge-based tool development.