A company called Fastscale Technologies has a product that is simple in concept and yet very powerful. Instead of using complete installs of heavy operating systems like Linux or Windows to run applications on virtual machines, they offer tools that provide minimal operating system configurations that are tailored to the needs of a particular application. Since only that application is going to be run on the virtual machine, this is sufficient. According to press reports, this means that you can run several times more virtual machines on a given host, compared to default OS installs. And boot an order of a magnitude faster.
The basic premise is definitely one that makes sense. We have seen this at Virtutech, working with stripped-down Linux images on various embedded boards. Turning on and off individual services often has a significant impact on both execution speed and memory consumption of a particular target. The gut reaction when setting up a new target is to think about what can be stripped out rather than on putting in everything that could be useful. Since that will result in a bloated image that will consume resources with little additional value.
The difference is even more obvious for Windows machines, where the speed of the same virtual machine running NT, 2000, XP, or Vista is incredibly different. With Vista and XP in particular, there is much going on in the background eating up memory and processor time. Some simple tuning tricks like turning off animations in the GUI or background indexing can have a very large impact on speed. Same thing goes for graphical desktop Linux distributions, where turning off eye candy results in significant speed increases.
So I believe that Fastscale can offer what they promise, it is a nice simple idea. But as always with a simple idea that makes for a powerful product, there is something more than just the idea. There is a somewhat tricky piece of execution.
The trick that Fastscale brings is to automate the process of creating a minimal but sufficient substrate for a particular application, given the app, target OS, and server hardware. Sounds like dependency checking once you have the data on what needs what, but finding out the particular dependence chains in any particular OS is hard work. Doing it manually is pretty painful, and the Linux kernel configurator is not always up to the task.
It is also a nice example of a case where open-source opens up for new innovation. Doing this kind of configuration to Windows is much harder in practice, if nothing else since you do not get to recompile the kernel yourself.
Also, Linux in particular has rather good support for removing non-essential components, I believe to some extent thanks to its extensive use in embedded software. Embedded people have a tradition of application-specific configurations, and here is a nice case of when that results in a better desktop/server product in the end. Who said embedded requirements were just for a niche market?