6.5.1

Table 1‑2. Virtual Machine Hardware and Descriptions (Continued)
Hardware Device Description
SCSI device By default, a SCSI device interface is available to the virtual machine. The SCSI
interface is a typical way to connect storage devices (floppy drives, hard drives, and
DVD/CD-ROMs) to a virtual machine. You can add, remove, or configure SCSI
devices.
SIO controller Provides serial and parallel ports, floppy devices, and performs system management
activities. One SIO controller is available to the virtual machine. You cannot configure
or remove this device.
USB controller The USB hardware chip that provides USB function to the USB ports that it manages.
The virtual USB Controller is the software virtualization of the USB host controller
function in the virtual machine.
USB device You can add multiple USB devices, such as security dongles and mass storage
devices, to a virtual machine. The USB devices can be connected to an ESXi host or a
client computer.
VMCI Virtual Machine Communication Interface device. Provides a high-speed
communication channel between a virtual machine and the hypervisor. You cannot add
or remove VMCI devices.
Virtual Machine Options and Resources
Each virtual device performs the same function for the virtual machine as hardware on a physical
computer does.
A virtual machine might be running in any of several locations, such as ESXi hosts, datacenters, clusters,
or resource pools. Many of the options and resources that you configure have dependencies on and
relationships with these objects.
Every virtual machine has CPU, memory, and disk resources. CPU virtualization emphasizes
performance and runs directly on the processor whenever possible. The underlying physical resources
are used whenever possible. The virtualization layer runs instructions only as needed to make virtual
machines operate as if they were running directly on a physical machine.
All recent operating systems provide support for virtual memory, allowing software to use more memory
than the machine physically has. Similarly, the ESXi hypervisor provides support for overcommitting
virtual machine memory, where the amount of guest memory configured for all virtual machines might be
larger than the amount of the host's physical memory.
You can add virtual disks and add more space to existing disks, even when the virtual machine is running.
You can also change the device node and allocate shares of disk bandwidth to the virtual machine.
vSphere Virtual Machine Administration
VMware, Inc. 13