I-O Data (株式会社アイ・オー・データ機器, Kabushikigaisha Ai-Ō Dēta Kiki^?) is a Japanese computer peripheral manufacturer. They manufacture hard disk drives, Ethernet hubs, USB cables, etc. It gained fame for its durable external hard disk which survived the 122 cm (4 feet) drop test, which is used in some military equipment tests. Other than its headquarters in Tokyo, I-O Data owns many offices in Asia.

The name "i-o" means input - output. A similar name is used in Data I/O Corporation, another electronics manufacturer in the United States, but there is no connection between the two.

Data ( /ˈdeɪtə/ DAY-tə, /ˈdætə/ DA-tə, or /ˈdɑːtə/ DAH-tə) are values of qualitative or quantitative variables, belonging to a set of items. Data in computing (or data processing) are often represented by a combination of items organized in rows and multiple variables organized in columns. Data are typically the results of measurements and can be visualised using graphs or images. Data as an abstract concept can be viewed as the lowest level of abstraction from which information and then knowledge are derived. Raw data, i.e., unprocessed data, refers to a collection of numbers, characters and is a relative term; data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next. Field data refers to raw data collected in an uncontrolled in situ environment. Experimental data refers to data generated within the context of a scientific investigation by observation and recording.

The word data is the plural of datum, neuter past participle of the Latin dare, "to give", hence "something given". In discussions of problems in geometry, mathematics, engineering, and so on, the terms givens and data are used interchangeably. Such usage is the origin of data as a concept in computer science or data processing: data are numbers, words, images, etc., accepted as they stand.