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1.2.6. Package verification

RPM also maintains a variety of information about each installed file in this system database, such as what permissions each file should have and what size each file should be. Red Hat developers designed this database to be useful for software verification. Over time, installed software will fail to work for reasons as mundane as the system administrator setting incorrect permissions on files or as exotic as nuclear decay of one of the computer's atoms releasing an alpha particle that can affect the computer's memory, corrupting that bit of memory and causing errors. Although RPM cannot prevent all errors that cause installed software to fail (obviously, there's not a single thing any software can do to prevent nuclear decay), it can be used to eliminate common errors. When an application fails, you can use the RPM database to make sure that all files associated with that application still have correct Unix file permissions and that no files associated with that application have become altered or corrupted.