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Software Usage and Examples
In this hierarchical file structure, files and directories are organized as branches in a tree, and each must
have a unique name. Only directories can have other files or directories attached, called child files or
directories-the files or directories one level down in the hierarchy. Individual files (BASIC, text, LEX
etc.) cannot have children in the hierarchy. Any file or directory will always be attached to a directory
called its parent directory-the directory one level up in the hierarchy. (Note that a directory is not a
file-it is a file organizer.)
The only fixed directory is the root directory, called ..... , at the beginning of the tree. Its level is zero, and
its parent directory is also ..... .
On any level within a directory, all files and directories are in alphabetical order. Examples are files on
level 4 within the
hp:::OOO
directory, the directories on level 1 within the root directory, and the files
and directories on level 2 within the
pt-09t-ar'lS
directory.
Consequently, on any level across the
hierarchy, files and directories are not necessarily in alphabetical order (for example, the files and
directories on levels 2 and 3).
File searches start at the location specified in the path name, or at the root directory if no location is
given. A search goes along the left-most branch (alphabetically) of the tree until the end of the branch is
reached.
Then the search proceeds back up the branch to a directory and from there to the next
left-most branch until that branch has been searched. The search continues in this manner across the
hierarchy until the file has been found or the end of the file system is reached.
For example, to find the
TEF.:t'1
I
t'~AL
file, the electronic disc software searches the
1 e::d' i
1 es
directory, then the
pt-O';:tt-.:H'lS
directory. Within the
pt-o';:tt-ar'lS
directory, the
b.:wcode
directory
is searched, then the branch containing
cm·w
I G,
then the
d.:d. aCOP1Pl
directory.
Within the
d.:d. -3Cor'U'l
directory, the
hp:::[1[1[1
directory is searched, then the branch containg
TEF.:t'1 I t·mL.
Because of this search order,
TEF.:t'1
I
t·il=jL
will be found after
UPLOAD,
even though
TEF.:t'1 I t·iAL
is
LI
lower alphabetically.
. .
You can select the current directory (initially·····) with
DIP
I ::;. Then you have direct access to files
within the directory without including the directory name as part of the pathname. This is similar to
having the files in that directory as the only files on the electronic disc. Wild cards can be used to ease
file selection (discussed later).
Directory Levels
The maximum nesting of directory levels is 7 levels, including the root directory. . .... is level 0, so the
directories you create will be levels 1-6. The child files of a level 6 directory will be level 7, but no
directory can be on level 7. Directory levels are shown in the length field of the indented catalog listing
produced by
CAT
ALL
": ::·::t'1Et'1".
Directory levels are also shown in character position 17 in the
string returned by
::-m
I F.:$.
File and directory levels are shown in the tenth character position of the
string returned by
::<
C AT
$ (for directories, the level is at both positions 10 and 17).
Pathnames
You specify a file on the electronic disc with
II
pathname:
::·::t'1Et'1".
A pathname is the path that must be
followed through the hierarchy to reach the desired file. Syntactically, a pathname looks like this:
pathname
=
[location] [filename]
The location is the sequence of directories leading to the one containing the desired file, as follows:
52
l
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