Megaquad

A quad was a measurement of information storage in Federation computers. While Federation computers used binary code in some capacity, they also are known to have used trinary code.

Measurement listing

The values of various amounts of quads could be expressed as kiloquads, megaquads, gigaquads, teraquads, petaquads, or exaquads, depending on the order of magnitude of the data being expressed.

Kiloquad

William T. Riker used some increasingly nonsensical computer jargon to confuse a Ferengi attempting to hijack the USS Enterprise-D's control functions. Among the other made-up references, he mentioned 14 kiloquad processors. (TNG: "Rascals")

In 2374, when USS Voyager made contact with Starfleet Command after years alone in the Delta Quadrant, they transmitted hundreds of kiloquads of data home about the region they had traversed. (VOY: "Message in a Bottle") In return, utilizing the same alien sensor relay network, Starfleet Command transmitted a large amount of encrypted data intended to reach USS Voyager but due to issues using such ancient alien technology, was badly degraded in transit. Arturis was able to reconstruct over 68 kiloquads of information, however, much of it was still garbled. (VOY: "Hope and Fear")

It is unclear if Arturis meant that much of the reconstructed 68 kiloquads was still "garbled," or that much of the original transmission, apart from the reconstructed segment, was still garbled.

Reginald Barclay described being transported as being converted into billions of kiloquads of data. (TNG: "Realm Of Fear")

Before being transported through a compressed data stream to the MIDAS array in the Alpha Quadrant from the USS Voyager in the Delta Quadrant, the Emergency Medical Hologram had to leave 12 megaquads behind to fit the bandwidth of the transmission. (VOY: "Life Line")

Gigaquad

After Chakotay's bioneural energy was restored to his corporeal body, The Doctor mentioned that the procedure responsible involved "three neural transceivers, two cortical stimulators, and fifty gigaquads of computer memory." (VOY: "Cathexis")
The Emergency Medical Holographic program Mark I took up 50 million gigaquads of computer memory, which was "considerably more than most highly developed humanoid brains." (VOY: "Lifesigns")
The Doctor had accumulated 15 thousand gigaquads of unnecessary information in his holomatrix, including opera and romantic relationships. (VOY: "The Swarm")
After the warp ten test flight by Tom Paris on the Cochrane, the sensor logs of the shuttle collected data on every cubic centimeter of a sector, totalling nearly five billion gigaquads of information. (VOY: "Threshold")
Seven of Nine collected over 30 thousand gigaquads of research about romantic relationships. (VOY: "Someone to Watch Over Me")
After a long ordeal while in contact with a being known only as "the distortion ring" B'Elanna noted that they had over twenty million gigaquads of new information input into the ship's computer. (VOY: "Twisted")
The fictional EMH in The Doctor's holonovel Photons Be Free had 50 gigaquads of memory devoted to music, 42 gigaquads for daydreams and another 10 gigaquads for expanding his sexuality. (VOY: "Author, Author")

Teraquad

The crew collected 60 teraquads of data about the graviton ellipse. (VOY: "One Small Step")

The Doctor's matrix became destabilized after he assimilated more than 1000 teraquads of data. Seven of Nine and B'Elanna Torres averted his decompilation by purging his excess subroutines. (VOY: "Renaissance Man")

Seven of Nine analyzed 30 million teraquads of data to support a conspiracy theory after being driven to paranoia by an influx of information. (VOY: "The Voyager Conspiracy")

The futuristic Borg drone named One assimilated 47 billion teraquads of information upon maturation. (VOY: "Drone")

The fan mail sent by the Qomar to The Doctor consisted of millions of teraquads of data, leading Seven of Nine to suspect an attempt to sabotage Voyager's communications system. (VOY: "Virtuoso")

Kathryn Janeway claimed to have sifted through teraquads of data, separating fact from rumor, before discovering the truth about Tuvok's birthday. (VOY: "Fury")

Background information

This terminology was originally developed by technical advisers to Star Trek: The Next Generation. The unit of measurement originated in the Star Trek: The Next Generation Technical Manual, and was also used in the Star Trek: Deep Space Nine Technical Manual.

The terms quads and kiloquads in TNG were used in a manner consistent with the system defined in the Technical Manual. However, by the time Star Trek: Voyager was airing, they started using extremely large numbers that lacked internal consistency, such as "billions of gigaquads" and "billions of teraquads." If these are accurate, USS Voyager's computers are more advanced and have a capacity that is orders of magnitude greater than the ones just seven years earlier in TNG.

Writers and advisers deliberately used prefixes used with bytes in modern day notation (mirroring kilobyte, megabyte, gigabyte, and terabyte). The terminology "quad" was used to detract from comparisons possible with modern-day computing power, since reality frequently outstrips fiction when it comes to computer science. Current capabilities are orders of magnitude greater than what scientists expected them to be only 20-30 years ago, with capacities and speeds roughly doubling every two years as per Moore's Law.