Files, Folders, and Disks

Files are the basic unit of long-term storage on a computer. Files are organized into folders, which are stored on disks. (In DOS, Unix, and earlier versions of Windows, folders were more often referred to as directories , but both terms are still used.) This section reviews fundamental filesystem concepts, including file- and disk-naming conventions and file types.

Disk Names

Like every version of Windows that preceded it, Windows XP retains the basic DOS disk-naming conventions. Drives are differentiated by a single letter of the alphabet followed by a colon:


Represents the first “floppy” (usually 3.5-inch) disk drive on the system


Represents the second floppy disk drive, if present


Represents the first hard disk drive or the first partition of the first hard disk drive


Often represents a CD-ROM drive, but can represent an additional hard disk drive or other removable drive

E: - Z:

Represent additional hard disk drives, removable cartridges such as Zip or Jaz drives, or mapped network drives

By default, driver letters are assigned consecutively, but it’s possible to change the drive letters for most drives so that you can have a drive N: without having a drive M:.


Folders , which contain files, are stored hierarchically on a disk and can be nested to any arbitrary level.

The filesystem on any disk begins with the root (top-level) directory, represented as a backslash. Thus C:\ represents the root directory on the C: drive. Each additional ...

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