Understanding software updates

Good piece of difference on Microsoft site...

Microsoft provides several different kinds of software updates for Windows SharePoint Services and Microsoft Office SharePoint Server. Before you study the details of these updates, it is recommended that you learn the key terminology. The following table provides information about the software update terminology used by Microsoft.

Software update concepts and terminology

Concepts and terms	Description and definition
Hotfix	A single cumulative package composed of one or more files used to address a problem in a product. Hotfixes address a specific customer situation and may not be distributed outside that customer organization.
Public update	A public update is usually a security-related hotfix that is released publically and is available for download. The Windows update configuration can identify these updates and install them automatically. You link to public updates from security bulletins. Typically, these hotfixes are released as required. Service packs are another example of a public update.
Service pack	A tested, cumulative set of all hotfixes, security updates, critical updates and updates, as well as additional fixes for problems found internally since the release of the product. Service packs can also contain a limited number of customer-requested design changes or features.
Scheduled delivery model	Microsoft Office is moving away from the current priority-driven hotfix release model to a scheduled delivery model. In the scheduled delivery model, hotfixes are released every two months. This schedule creates more predictability for customers. Customers who need an emergency fix can request a shorter turnaround time for a hotfix. The following delivery mechanisms support this new approach. · cumulative update (CU) · critical on-demand (COD) hotfix For more information, see Cumulative updates are available from the Microsoft Office team to deliver hotfixes for reported problems .
Cumulative update	A collection of hotfixes released every two months. A cumulative update (CU) rolls up previously released hotfixes and cumulative updates. A CU is sometimes called an update rollup. Available hotfixes include the following: · Fixes for issues that meet hotfix acceptance criteria. These criteria include workaround availability, effect on customers, reproducibility, and the complexity of the code that must be changed. · Any critical on-demand hotfixes that are currently released. · Any critical security or non-security updates that are currently released. For more information, see Office hotfixes to be delivered on a defined schedule in the form of Cumulative Updates (http://go.microsoft.com/fwlink/?LinkId=133358&clcid=0x409) blog post.
Critical on-demand (COD) hotfix	A critical on-demand (COD) hotfix is available to address critical problems that cannot be handled via the cumulative update delivery cycle. COD fixes are limited to emergency situations, for example, one in which the issue is blocking normal business operations for the customer, and/or for which there is no effective workaround. Critical on-demand (COD) hotfixes are included in the next cumulative update that is released. Note: COD releases have the versioning pattern 12.0.xxxx.500X. An example is a CU released with the version 12.0.6327.5000, with a COD hotfix subsequently required. In this example, the version of the COD hotfix is 12.0.6327.5001. If additional hotfixes are required before the next CU, the next version number is 12.0.6327.5002, and so on until the next CU is released.
Package	The downloaded item, an executable (.exe) file that is downloaded for a update rollup or hotfix. A package can contain one or more patches. Depending on the download mechanism that is provided, this executable file might be wrapped inside another password-protected executable file. After you extract the package, you have one or more .exe files that use a Knowledge Base (KB) number as part of its name; for example, Webfldrs-KB907306-ENU.exe. In this example, most customers run the Webfldrs-KB907306-ENU.exe executable file when they update their SharePoint servers.
Patch	Patches are stored inside packages. The patches run Windows Installer program (msiexec.exe) to update the original installation packages (which have the .msi file name extension) with new information or binaries. Patches that are installed by the Windows Installer program have the .msp file name extension. You can extract patches to a common folder to create a slipstream version of the patch. For more information, see Create an installation source that includes software updates (Windows SharePoint Services 3.0) or Create an installation source that includes software updates (Office SharePoint Server 2007).
Localized patch	A localized patch, or local patch, contains updates to language-specific strings or related code.
Global patch	A global patch is language-agnostic and can be applied to any server regardless of the base installation language or whether language packs are installed. Most software updates are delivered by means of global patches.
Upgrader	An upgrader is a specific piece of the product that evaluates the current state of related objects and possibly alters them to match newer schema, enable new functionality, or correct known issues.

---