pcb is a handy tool for laying out printed circuit boards.
Pcb was first written by Thomas Nau for an Atari ST in 1990 and ported to UNIX and X11 in 1994. It was not intended as a professional layout system, but as a tool which supports people who do some home-developing of hardware.
The second release 1.2 included menus for the first time. This made Pcb easier to use and thus a more important tool.
Release 1.3 introduced undo for highly-destructive commands, more straightforward action handling and scalable fonts. Layer-groups were introduced to group signal-layers together.
Release 1.4 provided support for add-on device drivers. Two layers (the solder and the component side) were added to support SMD elements. The handling of libraries was also improved in 1.4.1. Support for additional devices like GERBER plotters started in 1.4.4. The undo feature was expanded and the redo-feature added in 1.4.5.
harry eaton took over pcb development beginning with Release 1.5, although he contributed some code beginning with Release 1.4.3
Release 1.5 provides support for rats-nest generation from simple net lists. It also allows for automatic clearances around pins that pierce a polygon. A variety of other enhancements including a Gerber RS-274X driver and NC drill file generation have also been added.
Release 1.6 provides automatic screen updates of changed regions. This should eliminate most of the need for the redraw ((R key). Also some changes to what order items under the cursor are selected were made for better consistency - it is no longer possible to accidentally move a line or line point that is completely obscured by a polygon laying over top of it. Larger objects on the upper most layers can be selected ahead of smaller objects on lower layers. These changes make operations more intuitive. A new mode of line creation was added that creates two line on 45 degree angles with a single click. The actual outline of the prospective line(s) are now shown during line creation. An arc creation mode was added. Drawn arcs are quarter circles and can be useful for high frequency controlled impedance lines. (You can have eighth circle arc if the source is compiled with -DARC45, but be aware that the ends of such arcs can never intersect a grid point). Two new flags for pins and vias were created - one indicates that the pin or via is purely a drill hole and has no copper annulus. You can only toggle this flag for vias - for elements, it must be an integral part of the element definition. The other flag controls whether the pad will be round or octagonal. There is also now a feature for converting the contents of a buffer into an element.
Release 1.6.1 added the ability to make groups of action commands bound to a single X11 event to be undone by a single undo. Also a simple design rule checker was added - it checks for minimum spacing and overlap rules. Plus many fixes for bugs introduced with the many changes of 1.6
Release 1.7 added support for routing tracks through polygons without touching them. It also added support for unplated drill files, and drawing directly on the silk layer. A Netlist window for easily working with netlist was also added.
Release 2.0 adds an auto-router, a new simpler library mechanism, much improved support for graphically creating (and editing) elements, viewable solder-mask layers (and editing), snap to pins and pads, netlist entry by drawing rats, element files (and libraries) that can contain whole sub-layouts, metric grids, improved user interface, a GNU autoconf/automake based build system, and a host of other improvements.
Special thanks goes to:
Thomas Nau (who started the project and wrote the early versions).
C. Scott Ananian (who wrote the auto-router code).
Bernhard Daeubler (Bernhard.Daeubler@physik.uni-ulm.de)
Harald Daeubler (Harald.Daeubler@physik.uni-ulm.de)
DJ Delorie (djdelorie@users.sourceforge.net)
Larry Doolittle (ldoolitt@recycle.lbl.gov)
Dan McMahill (danmc@users.sourceforge.net)
Roland Merk (merk@faw.uni-ulm.de)
Erland Unruh (Erland.Unruh@malmo.trab.se)
Albert John FitzPatrick III (ajf_nylorac@acm.org)
Boerge Strand (borges@ifi.uio.no)
Andre M. Hedrick (hedrick@Astro.Dyer.Vanderbilt.Edu)
who provided all sorts of help including porting Pcb to several operating systems and platforms, bug fixes, library enhancement, user interface suggestions and more. In addition to these people, many others donated time for bug-fixing and other important work. Some of them can be identified in the source code files. Thanks to all of them. If you feel left out of this list, I apologize; please send me an e-mail and I'll try to correct the omission.
