The infamous pigpen file

摘要

The PGP file has been called the Pigpen file for as long as I can remember. I'm not sure who originally knighted this file with the unsavory title, but it has certainly stuck over the years. In the early days of AutoCAD we used the PGP file to access DOS commands from inside of AutoCAD (long before the days of Windows and the ability to multitask). This process was called "Shelling." The ability to format a floppy disk without leaving AutoCAD seemed like magic.