(1) (DIRectory) A CP/M, DOS and OS/2 command that lists the file names on the disk. See DOS Dir.

(2) (DIR) (Digital Instrumentation Recorder) A high-performance magnetic tape technology from Sony that uses 19mm tape and a helical scan transport. It was earmarked end of life in 2004 with support through 2011. Based on the ANSI ID-1 recording format (D1), models provided up to 64 Mbytes/sec data transfer, which was extremely fast and suited to sonar, radar and other intelligence gathering applications. Tape cassettes came in 8.7GB, 43GB and 96GB capacities. DIR drives and libraries, once a de facto standard in the U.S. government, were gradually replaced by LTO and SAIT technologies. See DTF, LTO, AIT and magnetic tape.