The basic idea of OpenDoc was to create small, reusable components, responsible for a specific task, such as text editing, bitmap editing or browsing an FTP server. OpenDoc provided a framework in which these components could run together, and a document format for storing the data created by each component. These documents could then be opened on other machines, where the OpenDoc frameworks would substitute suitable components for each part, even if they were from different vendors. In this way users could "build up" their documents from parts. Since there was no main application and the only visible interface was the document itself, the system was known as document centered.