A file system is a method of organizing all of the files on an entire disk or hard disk volume. Directories (or folders) are used to divide the files on a disk into logical groups that are easy to work with. Their purpose is similar to that of file drawers containing groups of hanging folders, hanging folders containing smaller folders, and so on. (The terms directory and folder are not synonymous but often used as such in common Windows terminology. For accuracy, we use directory throughout these help files unless other folder types are also specifically applicable.)
Every drive has a root or base directory, and many have one or more subdirectories. Subdirectories can also have subdirectories, extending in a branching tree structure from the root directory. The collection of all directories on a drive is often called the directory tree, and a portion of the tree is sometimes called a subtree. The terms directory and subdirectory are typically used interchangeably to mean a single subdirectory within this tree structure.
Subdirectory names follow the same naming rules as files in each operating system (see File Names).
The drive and subdirectory portions of a file's name are called the file's path. For example, the file name C:\DIR1\DIR2\MYFILE.DAT says to look for the file MYFILE.DAT in the subdirectory DIR2 which is part of the subdirectory DIR1 which is on drive C. The path for MYFILE.DAT is C:\DIR1\DIR2. The backslashes between subdirectory names are required.
Under TCC-RT, the path and filename can be up to 32,767 characters, though many Windows applications (including CMD and Explorer) have trouble with path and filename lengths exceeding 260 characters. Shorter paths and names are advisable under Windows whenever feasible.
TCC-RT maintains both a current or default drive for your system as a whole, and a current or default directory for every drive in your system. Whenever a program tries to create or access a file without specifying the file's path, the operating system uses the current drive (if no other drive is specified) and the current directory (if no other directory path is specified).
The root directory is named using the drive letter and a single backslash. For example, D:\ refers to the root directory of drive D:. Using a drive letter with no directory name at all refers to the current directory on the specified drive. For example, E:JPSOFT.DOC refers to the file JPSOFT.DOC in the current directory on drive E:, whereas E:\JPSOFT.DOC refers to the file JPSOFT.DOC in the root directory on drive E:.
There are also two special subdirectory names that are useful in many situations: a single period [.] means "the current default directory." Two periods [..] means "the directory which contains the current default directory" (referred to as the parent directory). These special names can be used wherever a full directory name can be used. TCC-RT allows you to use additional periods to specify directories further "up" the tree (see Extended Parent Directory Names).