Volume Licensing is just one of the modalities to acquire Microsoft software, but perhaps, as customers are concerned, it is also the most appealing because of the cost savings it implies. In contrast to the retail copies of Windows Vista, the main benefit of the Volume Licenses is that it takes the cost of the packaging and of the media out of the price equation of the product. And this, of course, is not valid just for Vista, now complete with Service Pack 1, but also for additional Microsoft solutions that make the object of Volume Licensing. In the Redmond giant's perspective, one of the most relevant benefits for volume license customers is the ability to acquire Software Assurance.

"Software acquired through Microsoft Volume Licensing is a software license only. A software license provides the right to run a Microsoft software product. Savings above retail boxed software prices can be realized by participating in a Microsoft Volume Licensing program. By acquiring software licenses through Volume Licensing, you can pay for only the software license. Or in the case of some Microsoft Volume Licensing programs, you can also purchase Software Assurance. Microsoft Software Assurance is a comprehensive maintenance offering that helps you get the most out of your software investment. It combines the latest software with phone support, partner services, training, and IT tools," the company explained in the Microsoft Volume Licensing Reference Guide made available for download.

As far as Windows Vista SP1 is concerned, customers running the Business SKU of the operating system can, through Software Assurance, upgrade to the Enterprise version. There are little architectural differences between the Business and Enterprise editions of Vista, such as the Windows BitLocker Drive Encryption features of the latter. However, advantages do exist beyond encryption, and the most important are related to virtualization.

"If you acquire Software Assurance, you have the right to use Windows Vista Enterprise Edition on the device instead of Windows Vista Business. This also permits you to run up to four additional copies or instances on the device. A device used for Windows Vista Enterprise may have Windows Vista Enterprise running in the physical operating system environment and a mix of Windows editions and versions running in four virtual operating system environments all on the same physical device," Microsoft added.