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A comment on IBM mainframe beats other platforms for cost and performance. Parent comment

Re:IBM mainframe beats other platforms for cost and performance by evol262 on Wednesday September 08, 2021 @10:28AM (#28457539)
VT-d is used for device passthrough. I suspect you're thinking of VT-x. But LPAR have been around forever, and aren't that different conceptually from jails, systemd-nspawn, LXC, and any other of a large number of OS-level virtualization solutions, except that you can stub in/out different kernels.

Yes, the kernels need to be "snowflakes", but that's not necessarily an issue if this is functionality you really need.

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Re:IBM mainframe beats other platforms for cost and performance by nix23 on Wednesday September 08, 2021 @03:11PM (#28461706)
LAPR is not a OS-level virtualization, you can install Linux on a LPAR (however you do it normally with z/vm), it's more like a Hard, Hardware divider.

https://en.wikipedia.org/wiki/Logical_partition

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Re:IBM mainframe beats other platforms for cost and performance by oneplane on Wednesday September 08, 2021 @04:53PM (#28462923)
Essentially it's a microcode hypervisor. You can indeed install Linux on an LPAR, but it will be a useless linux unless you intend to use it for classic 'bog box' installations. (with big box referring to the cardboard boxes that come with installation floppies/CD/DVD media type of software 'distribution')

While an LPAR could technically be HVM, the nature of the changes required to an OS make it PV-like.

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Re:IBM mainframe beats other platforms for cost and performance by nix23 on Wednesday September 08, 2021 @05:56PM (#28463536)
I just wanted to say that it's NOT like jails and it's not OS-Virtualization.
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Re:IBM mainframe beats other platforms for cost and performance by oneplane on Wednesday September 08, 2021 @08:07PM (#28464594)
If someone wanted to make a comparison, it's like additional 'rings' the x86 ring security model, but instead of nested rings it's parallel rings. You might as well have a single OS with containers.
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Re:IBM mainframe beats other platforms for cost and performance by oneplane on Wednesday September 08, 2021 @04:52PM (#28462899)
Yes, you are correct, I was thinking about the oldest of the VT's. The one that did accelerate but didn't even require an IOMMU.
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