Virtually unlimited possibilities

AMD and Intel are putting virtualization extentions on some of their chips.

Virtualizing an operating system to consolidate resources or support multiple platforms is just one way the technology can work. Virtualization actually comes in a variety of flavors, including the type for large mainframes, long offered by companies such as IBM Corp. In that tried-and-true model, the hardware is segmented into partitions, each running a different OS.

In addition, virtualization is becoming increasingly accepted at the desktop and application levels. Desktop virtualization, often linked to thin-client computing, comprises a complete server-hosted environment that's accessed remotely. Companies such as Citrix Systems Inc., Sun Microsystems Inc. and VMWare offer variants of this architecture.

Application virtualization, offered in different models by companies such as Altiris Inc. [GCN.com/576] and Softricity Inc. [GCN.com/575] apply only to specific software programs. When an application is virtualized, it doesn't necessarily have to be installed on a computer. It can be streamed or sent over a network and executed locally or remotely.

Chip virtualization

One emerging area to keep an eye on revolves around the plans of chip manufacturers. Advanced Micro Devices Inc. of Sunnyvale, Calif., plans to add virtualization extensions to Opteron microprocessors starting this fall. Intel Corp. of Santa Clara, Calif., has already introduced virtualization extensions for its Xeon and Itanium chips. Both sets of extensions, called hypervisors, should accelerate other virtualization techniques by allowing the guest operating system to make calls directly to the hardware, rather than going through the host OS.

Low-level, chip-based virtualization could offer great benefits, including the ability to run guest operating systems only a fraction slower (less than 1 percent slower, companies say) than actual operating systems. It could also allow paravirtualization software, such as Xen, to finally run Microsoft Windows and other OSes without modifying the OS kernel.

The downside to this approach, however, is that because no one operating systems oversees all operations, you can't have multiple guest OSes accessing the same physical hardware at the same time, such as local disks or network cards, according to Donald Becker, chief scientist at Scyld Software. 'That would cause chaos.

About the Author

Joab Jackson is the senior technology editor for Government Computer News.

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