For example, a workstation requesting the contents of a file from a file server is a client of the file server. A client sends requests to a server, according to some protocol, asking for information or action, and the server responds. There may be either one centralized server or several distributed ones. Command Line Interfaces A means of communication between a program and its user, based solely on textual input and output. Commands are input with the help of a keyboard or similar device and are interpreted and executed by the program.
Results are output as text or graphics to the terminal.
Command line interfaces usually provide greater flexibility than graphical user interfaces, at the cost of being harder for the novice to use. A simple database might be a single file containing many records, each of which contains the same set of fields where each field is a certain fixed width. Dialup A temporary, as opposed to dedicated, connection between machines established over a telephone line using modems. Digital documents can be accessed through a CD-ROM or other localized database, or through a contractual database. The patron or librarian can then access digital documents from any PC, using a retrieval database.