Uses Of The Hierarchy: An Example - HP 9000 200 Series Manual

In the Figure 3-4, the directory named
KATHY
is subordinate to the directory named
Project_one
because
Project_one
contains the information describing
KATHY.
The direc-
tory named
PROJECTS
is at level 1, the "root" level. You cannot create a directory at a
higher level than the root level.
Each directory keeps information about each file or directory immediately subordinate
to it, in fixed-format records. Each time a subordinate file or directory is added to a
directory, one of these records is added to the directory.
Uses of the Hierarchy: An Example
Suppose you're managing several projects, each of which needs to access a shared disc. To
organize the files for each project separately, you can create a directory for each project
(as shown in the illustration). Within each project directory, you can have a subordinate
directory for each person working on the project as well as files to be shared among all
users. Each person may then construct a directory/file system for organizing files.
Because files at different locations in the directory structure can have the same file name,
you can use generic file names to identify similar project functions in the different projects.
At the same time, the division into separate directories isolates the projects, and thus
their individual functions, from one another. For example, the file named
budget
in the
Proj ect_one
directory is distinct from the file named
budget
in the
Proj ect_two
directory.
Directories also limit the number of files users must deal with at anyone time. For
example, people working on
Project_one
(see illustration) need never see the files in
Proj ect_ two
and may, in fact, confine most of their activity to within their own directories.
To maintain security, BASIC provides the capability of protecting access to directories
and files. For example, you may wish to allow only members of a project team to read
that project's files. Or, you may wish to prevent other users from altering the contents
of a personal file. See the "Protecting Files" section of the "Using Directories and Files"
chapter.
Mass Storage Concepts 3-11