Last April, Microsoft announced that Windows 8 would have four different SKUs, which are the stockkeeping units used for tracking inventory. That's a major trim from the many licensing choices available for Windows 7. The four are Windows 8, Windows 8 Pro, Windows 8 Enterprise and Windows RT. Since RT is for ARM-powered devices only and isn't available on its own, only the first three matter here.
As its name implies, the Enterprise SKU of Windows 8 is intended for corporate use -- IT shops dealing with fleets of notebooks or departments full of desktop PCs. The "vanilla" Windows 8 SKU is for home users; Windows 8 Pro is for people sometimes called prosumers, a term that describes knowledgeable individuals who choose to buy professional-grade gear.
Windows 8 Enterprise, however, includes everything from Pro, along with some features not found anywhere else. It is available only through Microsoft's Software Assurance volume-licensing program.
One adage of commerce is "Don't pay for what you don't need," and some business users might conclude that the consumer version of the Windows 8 license is all they need. It doesn't have many enterprise features, such as full-disk encryption via BitLocker. This could encourage administrators to think that they could use the consumer SKU, save some money up front and make up the difference in features by way of a third-party product, such as TrueCrypt.
It's possible to do this, but one big argument against that approach is that some third-party feature replacements (including TrueCrypt) don't have native Group Policy management features. Such things would need to be supported manually, at greater effort and cost. Will such cost -- not to mention the cost of the product itself -- offset the savings brought on by using a cheaper SKU of Windows?
Also, Windows volume licensing is available for as few as five devices at once, which makes it more difficult to argue for non-volume licensing in organizations.
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In addition, some of the other new features available only through volume-licensed versions of Windows 8 make it possible to do things that would require buying additional Windows licenses. Chief among them is Windows To Go, which allows a full, separately bootable and centrally manageable copy of Windows 8 to be installed on a USB storage device.
Microsoft didn't wait for Windows 8 to come out before making revisions to Software Assurance. Most of those changes revolve around how clients -- phones, tablets, Windows RT devices -- can work with fully licensed instances of Windows 9, which will likely arrive in 2015 or 2016.
For instance, up to four "companion devices," like tablets or phones, can be used to access a given corporate desktop installation of Windows 8. Any scenario in which you remotely access a licensed copy of Windows running in one place, whether in the cloud or on a client PC, is going to be all the easier to properly deploy and license via volume licensing.
To sum up, the places where Windows 8 volume licensing won't work mostly exist in the low end: where fewer than five devices are in use, where no central management is used or where the enterprise features available only through volume licensing aren't going to be in use. Those may prove to be the minority of scenarios for a Windows 8 deployment.
Windows 8 has been designed to make the most of touch systems, but it has features clearly designed to expand its appeal beyond those devices alone. That said, touch devices may be the best first line of deployment for Windows 8 in your organization. The way legacy applications are handled -- especially 16-bit ones -- is still reminiscent of how Windows 7 worked, but don't assume that will last forever.
The tool set for migrating to Windows 8 is also a direct descendant of the tools used for previous editions of Windows, although only the most recent revisions of those tools will do the job. Enterprise-level licensing works best for enterprises, where the full gamut of professional-level Windows 8 features, as well as the added management functionality, become truly useful to end users and admins.