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Installation Verification Utility
A tool that compares two different software installations using MD5 and displays any differences, including extra or missing files.
Date Posted: July 8, 2004
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Update: November 11, 2004
Version 2.0.2 supports zOS and adds many new features, such as live demos; new command line arguments easing inclusion of paths for verification; new path or file exclude feature (powerful when combined with -all or -include arguments); new scripts and executables.
What is Installation Verification Utility?
Installation Verification Utility is a tool that compares two different software installations using MD5 and displays any differences, including extra or missing files. It can help ensure that the same applications are installed on multiple systems. This utility works fully automatically and provides a history feature to keep track of the different snapshots taken of the file system.
Installation Verification Utility aids in determining the root cause of failures caused by faulty installations. It does this by pin-pointing mistaken files. For compressed files, such as zip and JAR files, it pin-points the contents that have changed within these compressed files.
This utility allows comparison of two different systems with the same file structure. It does this by obtaining the hash of the content using Message Digest-5 (MD5)* and displaying the differences, if any, from a reference set. If a file is missing from a reference set, it will display that in its report. It will also display any extra files, that is, files found on the file system that were not in the reference set of files.
*Note: Message Digest-5 (MD5) is a security message digestion algorithm. It is a one-way hash algorithm that would take about 2^128 operations to generate a message given a specific hash and 2^64 operations to find two messages that generate the same hash code. This means that the probability of error within this tool is greatly minimized by using the MD5 algorithm.
How does it work? By using the Message Digest-5 (MD5) algorithm provided by the JavaTM Virtual Machine (JVM), the Installation Verification Utility creates an inventory file that it uses as a baseline for comparison. Every time a user invokes the tool, the tool compares against this inventory file found on the disk (by default, the actual name of this file is sys.inv).
During comparison, if a file in the inventory set exists on the file system, the inventory's MD5 hash will be compared against the generated MD5 hash. And if the hashes are different, this difference is reported. If the file is a structured file such as a zip or JAR file, the actual contents of the file are inspected and any differences will be reported. Missing or extra files are also noted and are based on the contents of the inventory file; for example, when the inventory file does not contain a file that is found on the file system, this file is considered "extra."
This tool has a slew of other options and capabilities, including the ability to select the inventory file to compare against. The tool also has an off-line comparison feature that allows a user to take two inventory files and compare them on the desktop.
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| | About the technology author(s):
Michel Betancourt graduated from Florida International University in 2001 and has been working for IBM since then. He currently works on the World Wide WebSphere Solutions War Room for IBM WebSphere Application Server. |
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