I keep hearing about application virtualization, especially with regard to
Software Assurance (SA) and Enterprise Agreements. What's application virtualization
and how does it relate to these licensing agreements?
Application virtualization lets you run applications locally on a computer without
having to first install the actual application. Here's an outline of how application
virtualization works.
On a special PC called the Application Sequencer, which is a clean OS build
with no other applications installed, a special sequencing process monitors
the installation of an application and tracks all changes made to the file system,
registry, or services. It then writes this information to a single file data
stream. The sequencer also executes the installed application to see which pieces
of the data stream are needed to start the application.
A server is configured to place
icons on the desktops, Start menus,
or Quick Launch tool bars of application virtualization clients, which
notifies the clients that a virtualized
application is available.
If the user on the client machine clicks an icon that hasn't been clicked before,
the application is streamed to the user's machine. Only the part of the stream
that was marked as required to initiate the application (known as feature block
1) is sent and cached locally (so subsequent executions don't have to restream
the data). This stream is then run inside a special environment known as the
SystemGuard, which creates virtual file systems, registries, and other components,
allowing the application to run without being installed, while protecting the
underlying OS from any unwanted changes. However, you can save settings such
as application configuration options, if so desired.
Why would you want this functionality? Imagine what you can do if applications
execute in a contained, protected environment and don't interfere with each
other. Compatibility problems vanish because applications don't know the other
application is installed. Because compatibility problems are gone, developers
can test applications much easier and faster, giving quicker time to market
for new applications. And because applications aren't installed locally, the
client machine is much cleaner and less likely to have problems.
So, what does this have to do with SA? Microsoft purchased Softricity, the
maker of SoftGrid, which is the premier application virtualization tool. Instead
of selling SoftGrid, Microsoft bundled it with three other products from companies
Microsoft purchased and has made the bundle available as the Desktop Optimization
Pack, which sells for $7 to $10 per desktop. That's very inexpensive considering
that individually the products would cost hundreds of dollars. The catch is
that only SA customers can buy the Desktop Optimization Pack, so essentially,
Microsoft is using the pack as a way to get people to purchase SA.
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