Oracle VM, User Manual

Page: 105 / 112

Glossary-1
Glossary
Domain
A configurable set of resources, including memory, virtual CPUs, network devices and
disk devices, in which virtual machines run. A domain is granted virtual resources
and can be started, stopped and restarted independently.
See also dom0 and domU .
dom0
An abbreviation for domain zero . The management domain with privileged access to
the hardware and device drivers. Dom0 is the first domain started by the Oracle VM
Server at boot time. Dom0 has more privileges than domU. It can access the hardware
directly and can manage the device drivers for other domains. It can also start new
domains.
domU
An unprivileged domain with no direct access to the hardware or device drivers. Each
domU is started by Oracle VM Server in dom0. The xm command-line tool is used to
interact with each domU.
Guest
A guest operating system that runs within a domain in Oracle VM Server. A guest
may be paravirtualized or hardware virtualized. Multiple guests can run on the same
Oracle VM Server.
Hardware virtualized machine
A virtual machine with an unmodified guest operating system. It is not recompiled for
the virtual environment. There may be substantial performance penalties running as a
hardware virtualized guest. Enables Microsoft Windows™ operating system to be run,
and legacy operating systems. Hardware virtualization is only available on Intel VT or
AMD SVM CPUs.
Host computer
The physical computer on which Oracle VM Server is installed.
Hypervisor
The hypervisor, monitor, or Virtual Machine Manager (VMM). It is the only fully
privileged entity in the system. It controls only the most basic resources of the system,
including CPU and memory usage, privilege checks, and hardware interrupts.
Management domain
See dom0 .