Operating Systems

• Linux is a relatively well-behaved guest. It understands whether z/VM is present and can work cooperatively with it to improve performance and management. Work inside and outside IBM continues to improve this aspect. This is one area where the combined experience of the VM community has a lot to offer the VM and kernel developers (see Rob van der Heij: “Virtualization—Something New? History and Perspective of Virtualization on IBM Mainframes” at www.rvdheij.nl/Presentations/nluug-2007.pdf.)
• The portfolio of applications available to sites running z/VM has grown enormously.
• Linux has enabled major server consolidation that has helped reduce data center costs.

Many of the important hardware innovations from the Integrated Facility for Linux (IFL) to new instructions are a result of wanting to make Linux run better on System z.

The introduction of Virtual Image Facility (VIF) was a tacit admission that IBM’s desire to sunset VM was ill-considered. VIF was IBM’s answer to the question, “How do we reintroduce a technology we spent years talking down?” Still, today, there are customers who won’t run or be offered VM as they had been so thoroughly convinced to get rid of it. Considerable face would be lost were it to be reintroduced.

The speed of innovation—both technically and from a marketing perspective—was breathtaking. VM/ESA 3.1 begat z/VM and, with each subsequent version, there were major changes in the terms and conditions that made VM highly affordable and desirable. Similarly, from release to release, we’ve seen remarkable technical enhancements such as System Management Application Programming Interface (SMAPI) and Virtual Switch. The work of the Independent Software Vendors (ISVs), such as Velocity Software, CA Technologies, and Rocket Software, also must be acknowledged for providing capabilities that allow Linux on System z to thrive.

The Future

It’s been more than 10 years since Linux appeared on the scene and, coupled with z/VM, made and saved bucket loads of money. That is also about the timeframe when we see a new generation of executives rise to positions where they started eyeing z/VM with the same look its progenitors (CP-67, VM/370 and VM/SP) had received.

What form will this next battle take? What will be tomorrow’s equivalent of the OCO decision? Certainly, the global financial crisis has put all aspects of business under pressure. However, in contrast to the 1991 recession, z/VM and Linux can now be seen as helping businesses do more with less.

To assess potential threats to z/VM, it’s worthwhile to consider:

• What is IBM publically backing?
• What are we seeing being pushed upstream from the developers in Boeblingen?
• What is dominating the magazines in frequent flyer university?

Evidence suggests Kernel-based Virtual Machine (KVM) is being seen as the new savior that will displace z/VM and save IBM money. Consider the following in the context of the aforementioned questions:

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