for PCB manufacture. The fabrication data consists of a set of Gerber files, a drill file, and a pick-and-place file containing the location and alignment of the devices generated for automated placement of the devices in the assembly process. Field-programmable gate array The process of placing and routing for an FPGA is generally not performed by a person, but uses a tool provided by the FPGA Vendor or another software manufacturer. The need for software tools is because of the complexity of the circuitry within the FPGA and the function the designer wishes to perform. FPGA designs are described using logic diagrams containing digital logic and hardware description languages such as VHDL and Verilog. These will then be put through an automated place-and-route procedure to generate a pinout, which will be used to interface with the parts outside of the FPGA. Integrated circuits The IC place-and-route stage typically starts with one or more schematics, HDL files, or pre-routed IP cores, or some combination of all three. It produces an IC layout that is automatically converted to a mask work in the standard GDS II or the OASIS format. History The final layout of early ICs and PCBs was stored as a tape-out of Rubylith on transparent film. Gradually, electronic design automation automated more and more of the place-and-route work. At first, it merely sped up the process of making many small edits without spending a lot of time peeling up and sticking down the tape. Later design rule checking sped up the process of checking for the most common sorts of errors. Later auto routers speed up the process of routing. Some people hope that further improvements in autoplacers and autorouters will eventually produce good layouts without any human manual intervention. Further automation leads to the idea of a silicon compiler. References Electronic design automation