Project bridges Xen, KVM virtualization

Linux programmer Rusty Russell offers software that could unify some virtualization programming chores.

A programmer has offered software that could bridge a significant divide in the realm of open-source virtualization software.

Rusty Russell, a high-profile figure in the world of Linux kernel programming, has introduced software that would unify some chores for developers working on projects for the established open-source virtualization program Xen and its upstart rival KVM.

Specifically, Russell's work adds an abstract layer that handles communications with network devices and with "block storage" devices such as hard drives. This "virtual I/O" layer, as Russell called it in a mailing list posting announcing the work last week, would mean that hardware support could be written once for both projects instead of having to be created separately for both.

Russell, an IBM programmer, has the chops and street credibility for such a techno-diplomatic feat: he also was behind a software project called paravirt-ops that gave Linux a unified interface for Xen and today's widely used but proprietary VMware virtualization software so the same version of the open-source operating system will work on either virtualization foundation, or on neither at all.

And he got a warm reception from at least one significant party, KVM's lead programmer, Avi Kivity, who responded, "Good stuff."

Virtualization, which is sweeping the server industry and making some inroads into desktop computing, lets a single computer run multiple operating systems. That can mean advantages in efficiency, as a single system can replace multiple largely idle servers, and in flexibility, as software can be shifted relatively easily off an overtaxed or failing computer.

But to make virtualization a reality, programmers are having to rework large amounts of basic computing plumbing. For example, operating systems used to controlling computer hardware now cede some of that control to the underlying virtualization software.

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