Microtape

Microtapes, also called tapes, were a type of computer memory storage medium used by Earth and Federation space exploration vessels from the 21st through the 23rd centuries.

In 2065, the recorder marker of the SS Valiant was so equipped. When the marker was recovered by the USS Enterprise (NCC-1701) in 2265, both Captain Kirk and Science Officer Spock hoped that "its tapes were still intact" despite the age of the marker and its distressed condition. Spock later commented that the tapes were burned out, but he was able to interpolate data stored in the memory banks. 

Whatever the mechanics of these tapes might be, they are susceptible to being scanned and understood by advanced races. The Talosians did so in 2254, as well as Balok in 2266. vessels routinely carried a large number of entertainment tapes; more than other class vessels, including the Antares. In addition, the sensors aboard Constitution-class vessels maintained "microtape" records. In 2267, the USS Constellation (NCC-1017)'s tapes were pulled and beamed to the Enterprise for analysis of the planet killer. 

A version of these tapes resembled 20th century floppy discs but with far greater capacity.