Chapter Overview


The Compatible Time Share System (CTSS) was one of the first time-sharing operating systems invented. The largely forgotten but influential operating system was developed at MIT and first operated in a time-sharing environment in 1961. Its notable accomplishments include being one of the first operating systems to have interuser electronic mail and computerized text editing capabilities. But CTSS's most significant contribution to the computing industry was its demonstration that time-sharing was viable.[1] Time-sharing is an operating system feature that allows multiple users or tasks to be running concurrently on a single hardware platform. Without time-sharing, even the most powerful computers available were limited to a single user or task. The CTSS's time-sharing implementation paved the way for the time-sharing capabilities that are standard in virtually every operating system. Today's servers commonly have thousands of users connected simultaneously, and to a large degree the foundation for that capability was set many decades in the past with the CTSS.

[1] Fernando J. Corbató, Marjorie Merwin Daggett, Robert C. Daley, "An Experimental Time-Sharing System," available at http://larch-www.lcs.mit.edu:8001/~corbato/sjcc62.

Integrity Virtual Machines in HP's Virtual Server Environment take the time-sharing capabilities first demonstrated by the CTSS to a whole new level. Instead of simply allowing multiple users or tasks to run simultaneously on a single computer, Integrity Virtual Machines (Integrity VM) allows multiple operating systems to be running on a single computer. Integrity Virtual Machines allows a single server with four CPUs, for example, to host multiple operating system instances at the same time. In fact, the number of operating systems isn't even limited to the number of physical CPUs.

Employing Integrity Virtual Machines in an enterprise data center enables higher utilization of hardware resources and provides a flexible and dynamic foundation for workloads. Since multiple operating systems are able to run simultaneously on a single server platform, the operating systems with demanding workloads can be allocated the necessary resources to handle the peaks in resource requirements. Those operating systems with workloads demanding little resources receive a fraction of what they would be allocated in a nonvirtualized environment.

As an illustration, consider a software development environment. In typical development environments, each engineer has a dedicated hardware system. When the engineers are not using their system, the resources are left idle and unused. The same development environments can be deployed by using a single server that has a fraction of the hardware resources compared to the total of all the developers' individual systems. Then a virtual machine can be created for each of the developers, giving each of them a fully customizable and isolated operating environment. In such a system, which requires fewer hardware resources, the developers often experience higher performance because the underlying hardware hosting the Integrity Virtual Machines can be more powerful than the individual systems. When resource-intensive tasks such as source-code compilations occur, the resources that are not being used by other developers are allocated to the compilation processes, thereby increasing the overall performance and system utilization.

Another major benefit of Integrity Virtual Machines is the utilization of virtual hardware resources. While this statement may not seem profound, it has dramatic ramifications. When hardware resources are virtualized, an operating system running within Integrity Virtual Machines can be moved from one hardware platform to another without the traditional configuration and compatibility problems one encounters when the hardware resources are not virtualized.

This chapter begins with a discussion of the terminology of Integrity Virtual Machines, then it provides overview of the technology and a VM configuration overview. Next it describes the VM management paradigms. It concludes with an example scenario that illustrates the configuration and management capabilities of Integrity Virtual Machines.

It should be noted this chapter was written using a pre-release version of Integrity VMs and the Integrity VM management GUI. The screens and commands shown in this chapter will vary slightly from the final product.



The HP Virtual Server Environment. Making the Adaptive Enterprise Vision a Reality in Your Datacenter
The HP Virtual Server Environment: Making the Adaptive Enterprise Vision a Reality in Your Datacenter
ISBN: 0131855220
EAN: 2147483647
Year: 2003
Pages: 197

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