"What is the magic seat count number where it makes more sense to do this on a mainframe? And the z is not the kind of machine people have laying around. There is certainly a lot to think about here," he says.
Another issue is the System z was designed originally to do transaction processing, not the kind of workloads that are done on PCs today.
"But that said, the z is a very powerful and fast system," Ryder says. He says the design of the z9 and z10 and off-load engines in the mainframe, such as the IFL (Integrated Facility for Linux) make it likely the system could take on some workloads not anticipated in the system's traditional design.
Users who responded to Mantissa CEO Dennis when he floated the concept last summer approached the idea with intrigue and questions.
"We can hope that the version of Windows will be more stable than Windows Vista. Moving that kind of instability into z/VM is not particularly attractive. Otherwise, on a conceptual basis, it opens up many possibilities," said a discussion participant named John Baker.
Others speculated that the technology might work better for server applications that have fewer GUI requirements that could tax the mainframe.
"Most likely this would be to run things like MS SQL Server, MS Exchange, and other 'server' software. Not an end-user GUI session. Just like most z/Linux users are not running X applications. They are running 'servers' such as e-mail, web, WAS, etc," wrote poster John McKown.
The little information available on z/VOS from Mantissa doesn't give any hint whether the software will support both the Windows client and server operating systems.
In terms of licensing issues, Mantissa's Dennis doesn't see anything out of the ordinary with current virtualization licensing.
"We don't see anything in the Microsoft EULA that would permit or cause them to treat this environment any different than existing VM environments. This environment should work in their favor since the images (and therefore the licenses) can be deployed more efficiently than in a blade warehouse environment," Dennis wrote on the discussion list.
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