Types of Microsoft Windows Patches

• Critical update 
  Definition: A widely released fix for a specific problem that addresses a critical, non-security-related bug. 
• Definition update  Definition: A widely released and frequent software update that contains additions to a product’s definition database. Definition databases are often used to detect objects that have specific attributes, such as malicious code, phishing websites, or junk mail. 
• Driver  Definition: Software that controls the input and output of a device. 
• Feature pack  Definition: New product functionality that is first distributed outside the context of a product release and that is typically included in the next full product release. 
• Security update  Definition: A widely released fix for a product-specific, security-related vulnerability. Security vulnerabilities are rated by their severity. The severity rating is indicated in the Microsoft security bulletin as critical, important, moderate, or low.  Additional information: Microsoft security updates are available for customers to download and are accompanied by two documents: a security bulletin and a Microsoft Knowledge Base article. For more information about the format of Microsoft Knowledge Base articles for Microsoft security updates, click the following article number to view the article in the Microsoft Knowledge Base: 824689 Description of the format of Microsoft Knowledge Base articles for Microsoft Security Updates 
• Service pack  Definition: A tested, cumulative set of all hotfixes, security updates, critical updates, and updates. Additionally, service packs may contain additional fixes for problems that are found internally since the release of the product. Service packs my also contain a limited number of customer-requested design changes or features. 
• Tool  Definition: A utility or feature that helps complete a task or set of tasks. 
• Update  Definition: A widely released fix for a specific problem. An update addresses a noncritical, non-security-related bug. 
• Update rollup  Definition: A tested, cumulative set of hotfixes, security updates, critical updates, and updates that are packaged together for easy deployment. A rollup generally targets a specific area, such as security, or a component of a product, such as Internet Information Services (IIS).