LCARS
The Library Computer Access and Retrieval System (LCARS or simply library computer for short) was the name of the computer operating system employed by the United Federation of Planets, used aboard Starfleet vessels, starbases and space stations. It was accessible by both voice and keypad commands.
LCARS used sophisticated artificial intelligence routines to understand and execute vocal natural language commands. Starfleet personnel also frequently interfaced with LCARS with PADDs, tricorders and control panels.
In the 24th century, graphical controls housed underneath touch-sensitive clear panels allowed LCARS panels to be quickly reconfigured by users to suit the task at hand, including a tactile interface for visually-impaired officers. (VOY: "Year of Hell") This enabled even complicated tasks to be executed with just a few button presses. LCARS also controlled the retrieval and storage of files in the data banks housed within the ship's computer cores.
Depending on the starship, the LCARS design, especially the color scheme, differed. These colors could range from a yellow/white (found on the USS Enterprise-D) to blue/white scheme (found on the USS Enterprise-E).
In an alternate timeline in the 25th century, LCARS was further upgraded with three-dimensional control interfaces. (DS9: "The Visitor")
By the 29th century the LCARS system was, at least partially, replaced by the TCARS system. (VOY: "Relativity")
