Glossary

Append

Append mode stores changes in a redo log. It continually adds changes to the redo log until you remove the redo-log file or commit the changes using the commit command in vmkfstools.

Configuration

See Virtual machine configuration.

Configuration Editor

A point-and-click editor to view the configuration of a virtual machine. It may be launched from the Settings menu.

Disk mode

A property of a virtual disk that defines its external behavior but is completely invisible to the guest operating system. There are four modes: persistent (changes to the disk are always preserved when the virtual machine is powered off), nonpersistent (changes are never preserved), undoable (changes are preserved at the user's discretion) and append (changes are stored in a redo log until you remove the redo-log file or commit the changes using the commit command in vmkfstools).
See also Disk Modes.

Guest operating system

An operating system that runs inside a virtual machine. VMware ESX Server supports a variety of guest operating systems.

Memory

The amount of random access memory (RAM) that is used by virtual machines or by the host operating system to ensure continued operation.

Networking

Connecting virtual machines with other virtual machines or other host machines via local area networks or inter-computer communication.

Nonpersistent disk mode

All disk writes issued by software running inside a virtual machine with a disk in nonpersistent mode appear to be written to disk but are in fact discarded after the virtual machine is powered off. As a result, a virtual disk in nonpersistent mode is not modified by VMware ESX Server.
See also Disk Modes.

Persistent disk mode

All disk writes issued by software running inside a virtual machine are immediately and permanently written to a virtual disk in persistent mode. As a result, a virtual disk in persistent mode behaves like a conventional disk drive on a real computer.
See also Disk Modes.

Undoable disk mode

All writes to a disk in undoable mode issued by software running inside a virtual machine appear to be written to the disk but are in fact stored in a temporary file (.REDO file) on the host file system while the virutal machine is running. When the virtual machine is powered off, the user is given three choices: (1) permanently apply all changes to the disk; (2) discard the changes, thus restoring the disk to its previous state; or (3) keep the changes, so that further changes made the next time the virtual machine runs can be added to the log.
See also Disk Modes.

Virtual disk

A virtual disk is a file on the VMFS file system that appears as a physical disk drive to a guest operating system. This file can be on a remote file system. When you configure a virtual machine with a virtual disk, you can install a new operating system onto the disk file without the need to repartition a physical disk or reboot the server. VMware ESX Server virtual disk devices can also be mapped to partitions on the server.

Virtual machine

A virtualized x86 PC environment on which a guest operating system and associated application software can run. Multiple virtual machines can operate on the same management workstation concurrently.

Virtual machine configuration

The specification of what virtual devices (disks, memory size, etc.) are present in a virtual machine and how they are mapped to physical files and devices.

Virtual machine configuration file

A file containing a virtual machine configuration. It is used by VMware ESX Server to identify and run a specific virtual machine.