IBM throws weight behind multi-OS push

But Big Blue’s efforts aren’t likely to squash a potential rival just flexing its muscles.

IBM has released source code for its Research Hypervisor, or rHype, on its Web site, letting anyone examine the approach of a company renowned for its expertise in the field. One distinguishing feature: rHype works with multiple processor varieties, including IBM’s Power family, widely used x86 chips such as Intel’s Xeon, and the new Cell microprocessor codeveloped by IBM, Sony and Toshiba.

The project potentially competes with two commercial products–Microsoft’s Virtual Server and EMC’s VMware–and with the open-source Xen software that has attracted support from numerous computing heavyweights.

But given rHype’s open-source nature and IBM’s actions so far, rHype is more likely to be a help than a hindrance to Xen. Specifically, it could help Xen move from its current base of x86 chips to IBM’s Power.

“We’ve spent quite some time talking to its authors,” Xen founder Ian Pratt said. “Now that the rHype code is open source, it’s a great starting point for a port of Xen to Power.”

The rHype software may be incorporated directly into Xen because both packages are governed by the General Public License (GPL), Pratt said. And IBM isn’t shying away: Its programmers have been contributing to the Xen project.

It makes sense for IBM to help Xen, said Charles King, principal analyst of Pund-IT Research. “It sounds like a natural point of intersection, given IBM’s natural interest in open source and in virtualization,” King said.

IBM is the 800-pound gorilla when it comes to hypervisor software, which it has supported for decades on its mainframes and has brought to its Power-based Unix servers. But for x86 servers, IBM chose a partnership with VMware rather than bring its own technology to market.

IBM declined to comment on most details of rHype. However, Tom Bradicich, chief technology officer for IBM’s Intel-based xSeries server line, said Tuesday that it’s not likely IBM will turn rHype into a product.

“It’s in the realm of the possible, but we don’t foresee it at this time,” Bradicich said.

IBM has used rHype to aid three internal projects. One is sHype, the Secure Hypervisor project to build barriers between different virtual machines. Another is validating features of the Cell processor, which has nine separate processing cores. And a third is an IBM supercomputing project called PERCS (Productive, Easy-to-use, Reliable Computing System).

Hypervisor hype
A hypervisor–a term IBM is trying to trademark–is basic software that runs atop the processor, allocating resources such as processing power, memory and network links. By creating virtual connections to these resources–“virtualizing” them–the hypervisor provides a flexible foundation that can let a computer run multiple operating systems and thus multiple tasks more efficiently.

Juggling numerous tasks has long been a useful ability for corporate computing centers. Now such abilities are increasingly useful at home as computer networks get more complex and useful, King said.

“It’s fascinating to me that something that’s been seen as a benefit for enterprise data centers is percolating its way down into the set-top box,” King said.

The rHype software virtualizes only some resources, which makes it fall into the same “paravirtualization” category as the Xen hypervisor project. IBM developed security software called sHype on the rHype software, but in January it pledged to create a version that will work with Xen.

Among features IBM touts with rHype:

• A design that can handle sophisticated memory tasks and that works well with high-speed cache memory.

• Support for IBM’s open-source K42 operating system for multiprocessor servers.

• The ability to run on several processor simulators, including the “Mambo” simulator of IBM’s PowerPC 970 family of processors, the general-purpose QEMU simulator and the BOCHS x86 simulator. rHype also has run on VMware.

• Interfaces to use the software on servers with multiple processors and with multithreaded processors–those that can execute multiple simultaneous instruction sequences.

Divide and conquer
Xen and rHype contrast with virtual machine software such as VMware and Virtual Server, which employ full virtualization. That means an operating system doesn’t need to be modified, as generally is the case with paravirtualization today, but runs more slowly.

There are other ways of dividing a system so it can run multiple operating systems. Some higher-end IBM Intel servers have hardware-based partitions. And Linux-Vserver, SW-soft’s Virtuozzo and Solaris containers divides a single instance of an operating system so it appears that separate users have their own copies.

In addition to the rHype project, IBM has a commercial hypervisor running on machines that use its Power processors. Because rHype uses the same interfaces as the commercial hypervisor, Linux doesn’t have to be modified to run on an rHype-Power foundation. With rHype on x86 chips, Linux must be modified to work.

IBM isn’t the only company interested in helping Xen grow beyond x86 servers. Hewlett-Packard programmers have been working on Xen for computers using Intel’s Itanium 2 processor.