First Name:
Kenneth
Last Name:
Sarris
Major Department:
Computer Science
Thesis Director:
Frank Barry
Date of Thesis:
May 2012
The file is a concept as old as computers themselves. Even before computers had disks for storing files in memory, their programs and data were filed away in physical paper copies. After the transfer from paper to disk, file management became a key part of computer usage, growing in importance as the users' needs to access, edit, copy, delete, or view information about those files also grew. In the modern world, most file managers are very similar, each having nearly the same advantages, disadvantages, and features as the rest. A file manager is any sort of software tool that allows a computer user to view and manipulate the file hierarchy and any information about individual files in disk memory. This manipulation can include opening files, copying and moving files, and other functions to effect changes in the tree-like structure of the file system. File managers, with a few exceptions, have been relatively unchanged for almost twenty years, their evolution primarily limited to small aesthetic changes. One of the more interesting advancements in file management software, invented in the early 1990s, is known as the graphical disk map file manager. The graphical disk map file manager is an alternative to regular file managers that allow users to see and manipulate the data on their file system spatially. This is done with the treemap algorithm, invented by Dr. Ben Shneiderman, which allows for the compact visualization of a tree structure (the file system in this case) in a 2-dimensional grid-like map. This has certain benefits, mainly the speed with which the eye can view the thousands of nodes that have beencompressed into the 2-dimensional space and the ease with which the properties of two program- defined metrics- represented by node size and node color- can be observed. For example, if file size is used as the metric represented by node size, then the largest files on the file system will correspondingly appear as the largest rectangular nodes in the map, allowing the user to almost instantly identify the largest files on their disk. In a second example, the creation time of a file could be used as the metric, allowing the user to see the most recently created files on their system as the largest nodes. The immediate benefit of quickly locating files that are strong in a given property are quite clear to a user of the program, yet graphical disk maps are not commonly used today because ofsmall flaws in the programs. The disadvantages ofthe treemap, rather than its advantages, are the main obstacle to the acceptance of the graphical disk map as a general file management tool. While a regular file manager (like Windows Explorer) operates simply enough that it can be instantly opened to click on an individual file, graphical disks maps must deal with large loading and processing times. Also in the treemap files of small node size can be difficult to locate, if they even have values high enough to appear on the map at all. Graphical disk map applications to date simply cannot keep up with the modern file manager's speed, flexibility, and efficiency in performing simple operations.