Any process could make requests to the file server for the creation of files (returning a file capability), ask to read or write files (by presenting a file capability), etc. For example, the act of reading a file generally required three buffer tables, one to send the request to the file server, one to receive the reply from the file server, and one to receive the data from the file. These three requests were generally submitted at one time to the message system, sometimes bundled with other requests.
Processes could initiate actions on the file server for creating files (returning a file capability), requesting reads or writes (by providing a file capability). For example, reading a file usually required three buffer tables: one for sending requests to the file server, another for receiving replies from the file server, and a third for capturing data. These requests were typically submitted together to the message system, sometimes bundled with other actions.