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Circuit Design Aids (CDA) on Plan 9
By A. G. Hume, M. Kahrs, T. J. Killian.
"CDA is a system for the design and prototyping of digital systems. At the front end it provides hierarchical schematic entry, programmable logic device design and board layout; at the back end it produces data for various manufacturing technologies, in partic- ular wire-wrap and multiwire."