"Operating system streaming" is a type of desktop virtualization that does not involve a hypervisor: The desktop devices do a network boot instead of a local hard disk boot. Then each machine mounts a disk image (virtual machine disk or virtual hard disk) across the network.
There are several OS streaming products on the market. The most popular is Citrix Provisioning Server -- which is bundled with XenDesktop -- although you can also do OS streaming via Double-Take Flex or Wyse Streaming Manager.
So where does OS streaming make sense?
The whole point of implementing OS streaming is to remove the hard drive (or the management of the hard drive) from the actual end-user device. The main reason companies do this is to simplify the management of end-user devices by consolidating them. All the OS streaming products on the market today allow multiple client devices to "share" a single disk image on the network. So instead of pushing out images each time you want to update client devices, you can simply update a centralized image that all your devices would simply use the next time they booted up.
In terms of practicality, OS streaming makes sense where you have a lot of devices that share the same image.
Note that all the OS streaming products on the market today require a consistent network connection between the client device and the server holding the image. This network connection has to be pretty fast, so it typically uses a wired connection instead of a wireless one. In the real world, we're talking about desktop devices instead of laptops (or disk images for VDI environments in a data center).
To figure out where OS streaming would be most practical, think about where there are large concentrations of many similar desktops that are hard-wired. The two most obvious use cases are call centers and classrooms.
But OS streaming's practicality doesn't stop there. It also makes a ton of sense in terminal server environments because they are usually built from many identical servers, and it's easy to put your OS streaming servers in the same data centers as them.
The last perfect place for OS streaming is in VDI environments where you're leveraging shared disk images with local storage. In those cases, OS streaming can be a great way to enable shared images without the expense of a storage area network.
ABOUT THE AUTHOR
Brian Madden is an independent industry analyst and blogger, known throughout the world as an opinionated, supertechnical desktop virtualization expert. He has written several books and more than 1,000 articles about desktop and application virtualization. Madden's blog, BrianMadden.com, receives millions of visitors per year and is a leading source for conversation, debate and discourse about the application and desktop virtualization industry. He is also the creator of BriForum, the premier independent application delivery technical conference.