USS Defiant (NCC-1764) library computer

The USS Defiant (NCC-1764) library computer was the primary computer system aboard the Federation starship USS Defiant (NCC-1764) in the 23rd century.

Specifications and history
As an example of Starfleet technology, this computer system was comprised of a series of computer banks and library storage systems that were made possible by duotronic circuitry. The Defiant computer was initially built into the prototype vessel in the mid-23rd century from duotronic designs by Richard Daystrom, and was continuously upgraded over the years.

The advent of duotronics made faster-than-light computation possible in order to tie the ship's sensors in with the warp drive and allow the ship to make near instantaneous decisions about course and speed, without lag time that had forced earlier vessels to require stopping periods where ships would be forced to halt, scan navigational input, and then resume warp speed. 

The earliest duotronic computers were very basic and had no real voice interaction at all. This changed in 2254, when the USS Enterprise (NCC-1701) was given advanced Calligar technology that allowed them to enhance their computers and allow voice interaction. The Enterprise first officer, Number One, decided to install the device aboard the Enterprise and programmed it with her voice as female voices were more authoritarian and cut through the air better than did male voices. When the Enterprise returned to Earth, this technology was copied and installed aboard other starships.