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I first thought that Xen was a host hypervisor. But i later found that it was a bare metal hypervisor. How does Xen qualify as a Bare metal hypervisor ?

user44444444
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Because Xen can be booted to directly from BIOS, without any other operating system in between Xen and the hardware. VMware ESXi is similar (differentiating itself from VMware workstation which requires a host OS).

Xen's dom0 privleged guest can be installed on the system before Xen is enabled, thus confusing matters about whether it is a bare metal install or not, but it is technically a true bare metal install that starts the dom0 guest. Note that you can often boot an alternate kernel which will bypass Xen and boot the dom0 "guest" as a true non-virtualized host (without Xen enabled).

Seth Robertson
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  • can't xen be used under a host operating system ? – user44444444 May 23 '11 at 18:03
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    @user736468: I have added text which better explains the interaction. – Seth Robertson May 23 '11 at 18:11
  • @user736468: I'd like to remind you to upvote/accept useful answers. Not only this one, but all the other questions you asked as well. – Seth Robertson May 23 '11 at 19:41
  • @Seth Robertson Could you please tell me how xen discover the underlying hardware.if yes please answer the question https://stackoverflow.com/questions/59352074/xen-installation-in-odroid-xu4 – Gopika BG Dec 18 '19 at 10:30
  • @GopikaBG: As hinted above, Xen boots a kernel which discovers hardware the way it normally does without Xen. Which kernel? Well, linux, *BSD, Hurd, Open Solaris, and a few more obscure ones. Xen is apparently very non-discriminating in the lowest level operating system. Thus, I cannot answer your other question because I don't have enough information (and more to the point, I know nothing about the exynos5422). See https://wiki.xen.org/wiki/Dom0_Kernels_for_Xen for more hints. – Seth Robertson Dec 19 '19 at 03:26
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Another bare metal hypervisors are also RedHat Vitalization Hypervisor, and opensource oVirt.

user3134198
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