Dir
(1) (DIR) (Digital Instrumentation Recorder) An earlier 19mm, helical-scan magnetic tape technology from Sony, earmarked end of life in 2004. Based on the D1 format, DIR was fast enough for sonar, radar and other high-speed data archiving. Cassettes came in 8.7GB, 43GB and 96GB capacities. Once a standard in the U.S. government, DIR was gradually replaced by LTO and SAIT technologies. See DTF, LTO, AIT and magnetic tape.
DIR Cassettes Were Huge
Next to the 4mm DAT cassette, the 96GB DIR cassette was enormous.
(2) (DIRectory) A DOS/Windows command that lists the file names in an internal or external storage drive. Originating with the CP/M operating system, Dir is widely used by Windows programmers and power users. Following are various examples:
GENERAL DIR COMMANDS dir names, date and size dir /w no date and size dir /p pause each screenful dir /ad only folders dir *. only folders or files without extensions dir *.jpg only JPEG files dir *.mp3 only MP3 files dir *.doc only DOC files dir *.exe only executables BY SORT ORDER dir /o folders, then files dir /oe by extension a to z dir /o-e by extension z to a dir /os small to large dir /o-s large to small dir /od earliest to latest dir /o-d latest to earliest BY FILE ATTRIBUTE dir /ar read only files dir /ah hidden files dir /aa files to be archived dir /as system files
Find Duplicate Files
The following example finds all files named X.BAT anywhere in the C: drive, because the command is initiated at the root of the drive (C:\>):
C:\>dir x.bat /s