A holodisk, holotape or THT Tape, is a high-density, laser-readable, manufactured-crystal storage device produced by Wattz Electronics.
Based on the Tape Holography Technology, each holodisk is capable of storing their information safely for extreme periods, without causing read errors or data corruption. The THT reels are stored inside a resistant, stainless casing outfitted with a universal I/O port for connectivity.
The development of technology progressed rapidly and while early holotape models could store only as much as 256 kilobytes of data (though typically, they could only hold between 128 and 64 kilobytes), the latest models from 2077 could store up to 4 terabytes (4,000 gigabytes) of data, but are far less common than holotapes due to their short time frame of availability.
Holodisks and tapes had many uses before the war besides just personal data storage. Specific models were meant to hold entertainment such as music and movies with specific players for playing anything on a screen.