Path Names, Directory Structures, and File Dialog Boxes

No concept is more fundamental to using computers than the ideas contained in file and path names. Once you fully understand the way information is stored and organized on a computer, using one becomes much easier. Ok. Some basic facts.

• A file is the basic unit of storage on microcomputers (and regular ones as well.)
• All information, programs, software, device drivers, sounds, pictures, word processing documents, etc. used on a computer are stored as files. (You might exempt the BIOS and OS bootup software, but even here the information is file-like, and is stored by address rather than naming conventions.)
• File names serve to identify what something is and where it is stored in the computer. The organizational structure is determined by the user - often with some initial organization provided by the operating System (OS) and software that has been installed.
• Path names have the following structure:
  • d:/dir/subdir/filename.ext
    where
    • d: refers to the drive
    • dir refers to the directory
    • subdir refers to a subdirectory
      (and there may be multiple levels of subdirectories.)
      d:/dir/subdir1/subdir2/subdir3/.../filename.ext
    • filename refers to the file's name, and
    • ext refers to the file extension, often used to identify the tye of file.
  • This information tells you the logical organization of the file storage system.
  • After booting up the computer, the OS sets some directory as the default or current directory. This is simply the directory where, in the absence of other information, the computer will look for or store information. It is often the root directory, which is the top level on the bootable hard disk drive. (C:/)
• Many extensions designate specific types of files
  • Executable files
    • .exe - compiled and executable programs
    • .com - executable programs under 64K in size
    • .bat - Batch files, usually comprised of MS-DOS commands
    • .cmd - Command files, usually scripts for software interpreters.

  • Other common file types by their conventional extension
    • .sys - System files
    • .drv - device drivers
    • .dll - dynamic link libraries
    • .res - system resource files
    • .GIF - Graphics Interchange Format
    • .JPG - Joint Photographic Experts Group
    • .wpd - WordPerfect 6.0+ document
    • .txt - an ASCII text document