Microsoft won't let IT pros run legacy Internet Explorer on Windows 7 using application virtualization tools, but the company has devised a way to let developers virtualize IE without violating its own Windows licensing rules.
Microsoft officially said on its Sept. 7 blog that Windows 8 will include a Hyper-V client hypervisor to run pre-configured virtual machines that contain old versions of Internet Explorer (IE) with a stripped down version of Windows.
As reported by SearchVirtualDesktop.com last December, a Hyper-V client hypervisor in Windows 8 removes the licensing roadblocks that form the core of Microsoft objections against virtualizing Internet Explorer.
Microsoft prohibits abstracting Internet Explorer from Windows because the company claims its browser is inextricably tied to Windows -- even though it is technically possible to abstract IE from Windows using application virtualization tools, such as ThinApp.
"This allows them to save face around their existing policy and it gives customers a different way to use Hyper-V," said Mark Margevicius, an analyst with Gartner, Inc.
Today, compliant IT pros upgrading from Windows XP to Windows 7 use offerings such as Microsoft Virtual PC, Med-V, XP Mode or VMware Workstation to run legacy applications. The problem with those options is that a full instance of a Windows OS has to run with IE. That taxes IT resources and impacts performance.
With a Hyper-V client baked into Windows 8, developers will spin up a virtual machine with a slimmed down version of Windows (MinWin) with an old version of IE to run legacy applications on Windows 8.
For Microsoft, this reduces the application compatibility issues that hold back Windows upgrades. The operating system running on Hyper-V must also be licensed -- so a Hyper-V client running a MinWin also means additional OS license revenue for Microsoft.
Hyper-V client requirements, limitations
While the Hyper-V client in Windows 8 is a potential means to deliver legacy XP applications, it may not be useful to many Microsoft customers because of requirements and limitations.
Hyper-V requires a 64-bit system that has Second Level Address Translation (SLAT). SLAT is a feature present in current Intel and AMD's 64-bit processors, so customers using older chips won't be able to run the Hyper-V client. It also requires a 64-bit version of Windows 8 and at least 4 GB of RAM. Hyper-V does support creation of both 32-bit and 64-bit operating systems in the VMs.
Microsoft has to add support for x86 Windows applications, seamless apps and browser integration, said Ruben Spruijt, a technology officer with an IT infrastructure firm in the Netherlands.
In addition, features or applications that depend on specific hardware won't work well -- for example, Windows BitLocker and Measured Boot, which rely on Trusted Platform Module, as well as games or applications that require processing with GPUs.
Microsoft has not indicated whether the Hyper-V client will be a Type-1 (bare-metal) client hypervisor or a Type-2, which is tied to the operating system.
Either way, by delivering Hyper-V as part of the Windows 8 license Microsoft has lowered the bar for using client virtualization. This move is sure to pose competitive issues for client hypervisor vendors -- particularly Microsoft's close partner Citrix Systems.
Hyper-V client alternatives
Other ways to run legacy IE apps on new Windows platforms were introduced this year. Microsoft and Quest jointly launched a tool called IE6 AppCompat in June that uses Remote Desktop Session Host/Terminal Server and Quest vWorkspace to deliver IE6 as an application.
One IT pro who worked on IE6 AppCompat development and is familiar with the Hyper-V client said IE6 AppCompat overhead is lower than the Hyper-V client and it doesn't require SLAT. But, he said, "IE6 AppCompat was never meant to be a long-term solution. In fact, Microsoft has walked us into a few accounts already and there are some rules of engagement -- one year of use and customers need to start their roadmap to upgrading or re-writing their apps."
Another option for running legacy IE6 apps on Windows 7 is a Windows add-on called UniBrows that legally runs IE6 on Windows 7 by placing the IE6 rendering engine inside an IE8 or IE9 tab. Browsium, the company that provided this tool, is led by three former Microsoft executives.