VCV Rack modules are similar to the “plugins” or “externals” or “opcodes” used in other popular open-source or commercial standards in that they are compiled into a dynamic library that is loaded at runtime by the application. VCV Rack is a commercial project with an open-source codebase, which makes it quite different from the others. In Rack, a plugin is rather a collection of objects, and these objects are often called modules, although the proper name for us programmers is Models. Sample-wise processing is a necessary ingredient to make Rack get very close to the behavior of modular systems. In essence, all cables in Rack are polyphonic, however, when they revert to monophonic mode if the output port they are connected to is not poly-capable. A Rack plugin, practically speaking, requires several components to be found by the application at startup.