A de facto standard is a standard that comes about because of widespread acceptance or adoption. It has not been worked on or approved by any standards body and may be controlled by a single company. GDS II is a de facto standard originally created by Calma and now owned by Cadence. Another example of a de facto standard within EDA is the adoption of the TCL/TK scripting language to control tools. While the language itself is a standard, its adoption by so many tools vendors counts as a de facto standard because there is no industry standard that says tools should have this scripting language built into them.