EECS 1012 Lecture Notes - Lecture 7: Working Directory, Hard Disk Drive Performance Characteristics
13 Jun 2018
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EECS 1012 Lecture 7 Notes
Introduction
Graphical interface system
• In a graphical interface system, the current working directory is the folder that is
currently open.
• Folders can be created and deleted, which is equivalent to adding and removing
branches to the tree structure.
• Since there may be many folders open on the screen, it is easy to move from one
current working directory to another on a graphical interface system.
• The tree-structured directory system provides solutions to the problems described at
the beginning of this section.
• The tree structure provides flexibility that allows users to organize files in whatever way
they wish.
• The tree structure solves the problem of organization for a system with a large number
of files.
• It also solves the problem of growth, since there is essentially no limit on the number of
directories that the system can support.
• It also solves the problem of accessing files in an efficient manner.
• A directory is located by following the pathname from the current directory or from the
root, one directory file at a time.
• One negative consequence of this method is that it may require retrieval of several
directory files from different parts of the disk, with the corresponding disk seek times
• At least the path is known, so extensive searching is not necessary.
• Since duplicate names in a tree structure use different paths there is no confusion
between identical file names, because each has a different pathname.
• For example, the author has two different sets of files named and so on.
• One set is located in a directory with the (relative) pathname BOOK\4TH EDITION.
• The other set is in a directory called BOOK\3RD EDITION.
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