An alphabetized glossary of terms used on the SEMKEY website


  • Access Virtualization
    Hardware and software technology that allows nearly any device to access any application without either having to know too much about the other. The application sees a device it’s used to working with. The device sees an application it knows how to display. In some cases, special purpose hardware is used on each side of the network connection to increase performance, allow many users to share a single client system or allow a single individual to see multiple displays.
  • Application Virtualization
    Software technology allowing applications to run on many different operating systems and hardware platforms. This usually means that the application has been written to use an application framework. It also means that applications running on the same system that do not use this framework do not get the benefits of application virtualization. More advanced forms of this technology offer the ability to restart an application in case of a failure, start another instance of an application if the application is not meeting service level objectives, or provide workload balancing among multiple instances of an application to archive high levels of scalability. Some really sophisticated approaches to application virtualization can do this magical feat without requiring that the application be re-architected or rewritten using some special application framework.


  • Bare metal environment
    A virtual environment where the virtualization product is directly installed on physical hardware, acting like a host OS. The opposite of hosted environment.
  • Binding
    A process by which software components and layers are linked together. When a network component is installed, the binding relationships and dependencies for the components are established.
  • BT = Binary Translation
    Technique used by virtualization softwares to translate instruction set guest OSes send to virtual hardware in instruction set understandable by physical hardware. It's an alternative approach to paravirtualization.
  • Blade
    A hot-pluggable motherboard, equipped with processors, memory and disks for use in a Blade Server.
  • Blade Server
    An emerging modularized server configuration made by a standard rack featuring an embedded networking subsystem and several bays, where blades can be plugged while the system is turned on.


  • Capacity Planning
    The operation of calculating how many resources a physical server will need for hosting a certain amount of virtual machines. It's a critical task to be achieved at very beginning of any virtualization project.
  • Checkpoint
    A snapshot of a virtual machine that enables an administrator to roll the virtual machine back to its state at the moment the checkpoint was created.
  • Clustering
    A technology that lets you increase the availability of a server, service or application so it does not become a single point of failure. Clustering strategies are typically used for scaling out performance, load balancing, and recovery. Clustering is connecting at least two servers together with one acting as a standby for protection. Clustering solutions are rules based and require custom coding and scripting that define the failover and recovery policy and procedures unique to their environment.
  • CLI = Command Line Interface
  • Compact
    To reduce the size of a dynamically expanding virtual hard disk by removing unused space from the .vhd file.
  • Continuous Availability
    Continuous availability virtually guarantees a computing system is operational in the event of any disruption. The concerns for continuous availability focus on two things, the recovery of applications, data and data transactions prior to the moment of disruption, and 24×7 system availability regardless of the planned or unplanned downtime event.
  • CRM = Customer relationship management
    is a term applied to processes implemented by a company to handle their contact with their customers. CRM software is used to support these processes, storing information on customers and prospective customers.


  • Data Replication
    This is the term that has caused the most confusion within the market, yet provides the lowest level of availability and requires a fairly heavy implementation process. Data replication can be more accurately described as a data storage and backup strategy that involves moving data from one server to another server using an asynchronous model to allow for unlimited distances between servers.
  • Differencing virtual hard disk
    A virtual hard disk that stores the changes to an associated parent virtual hard disk for the purpose of keeping the parent intact. The differencing disk is a separate .vhd file that is associated with the .vhd file of the parent disk. Changes continue to accumulate in the differencing disk until it is merged to the parent disk.
  • Disaster Recovery
    Disaster recovery is a plan which enables the protection and restoration of critical information in the event of disruption. Disaster recovery management includes functions such as identifying the critical and vital information, determining recovery needs, developing backup solutions and implementing the backup/recovery solution.
  • DTU =Desktop Unit
    like Sun Ray
  • Dynamically expanding virtual hard disk
    A virtual hard disk that grows in size each time it is modified. This type of virtual hard disk starts as a 3 KB .vhd file and can grow as large as the maximum size specified when the file was created. The only way to reduce the file size is to zero out the deleted data and then compact the virtual hard disk.


  • Emulation
    A software technology allowing an operating system or an application to run on hardware other than the one for which it was developed.
  • ESX
    a hypervisor


  • Fault-Tolerant
    Fault-tolerant architecture allows a system to continue working even when part of the system fails. Fault-tolerant servers provide continuous availability through hardware failures by utilizing and operating redundant components.
  • Fixed-size virtual hard disk
    A virtual hard disk with a fixed size that is determined and for which all space is allocated when the disk is created. The size of the disk does not change when data is added or deleted.
  • FOG = Fail Over Group


  • Grid Computing
    An emerging computing model where a large amount of geographically separated, networked computers work like one single abstract infrastructure, able to compute multiple, complex tasks in parallel, required by multiple customers at a time.
  • Guest OS (Operating System)
    The operating system installed inside a virtual machine (or a partition). In a virtualization solution the guest OS can be completely different from the host OS. In a partitioning solution the guest OS must be identical to the host OS.
  • GUI = Graphical User Interface


  • Hypervisor
    The virtualization software layer managing hardware requests from a guest OS, simulating answers from a real hardware. Used as VMM (Virtual Machine Monitor) synonymous.
  • Host OS
    The operating system hosting one or more virtual machines (or partitions) and sharing physical resources with them. It's where the virtualization product or the partitioning product is installed.
  • Hosted Environment
    A virtual environment where the virtualization product is installed on top of a host OS, instead of being installed on physical hardware. The opposite of bare metal environment.


  • IEEE = Institute of Electrical and Electronics Engineers
    is an international non-profit, professional organization for the advancement of technology related to electricity.
  • ISV = Independent software vendor
    A business term for companies specializing in making or selling software, designed for mass marketing or for niche markets.
  • Integration services
    A collection of services and software drivers that maximize performance and provide a better user experience within a virtual machine. Integration services are only available for supported guest operating systems.



  • Key-value pair
    A set of data items that contains a unique identifier, called a key, and a value that is the actual data for the key.


  • Live Backup
    The operation of copying a whole virtual machine, while powered on, at the host OS level, for archiving purposes.
  • Live Migration
    The operation of moving a virtual machine, while powered on, from a host OS to another host OS, for maintenance or server consolidation purposes.



  • NanD Flash = NAND Flash is a special form of Flash memory.
    Flash memory is a memory technology that keeps data even when the power supply is cut off; this is known as a non-volatile memory type.


  • OEM = original equipment manufacturer
    typically a company which uses a component made by a second company in its own product, or sells the product of the second company under its own brand. The specific meaning of the term varies in different contexts.


  • P2V migration = Physical to Virtual migration
    The operation of migrating an operating system and every application installed on it from a physical computer to a virtual machine (or a partition), without reinstalling anything. The opposite of V2P (Virtual to Physical) migration.
  • Para-virtualization
    An enhancement of virtualization technology, where guest OSes need to be adapted (recompiled) before being ready for installation inside virtual machines. It reduces virtualization overhead and improves performances. It's an alternative approach to Binary Translation (BT).
  • Partitioning
    A software technology able to create multiple instances of the same host OS, called partitions, instead of reproducing multiple different physical machines like in virtualization.
  • Partition
    An isolated, new instance of the host OS, lying on it, and featuring autonomous characteristics like host name, network settings and installed applications. Partitions are management by a partitioning solution.
  • Parent partition
    The partition that manages the virtual machines.
  • Physical computer
    A hardware-based computer, as opposed to a software-based virtual machine.
  • Processing Virtualization
    Hardware and software technology that hides physical hardware configuration from system services, operating systems or applications. This type of Virtualization technology can make one system appear to be many or many systems appear to be a single computing resource to achieve goals ranging from raw performance, high levels of scalability, reliability/availability, agility or consolidation of multiple environments onto a single system.



  • RDP = Remote Desktop Protocol
  • RFID = Radio-frequency identification
    is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification using radio waves. Some tags can be read from several meters away and beyond the line of sight of the reader.
  • RIA = Rich Internet Application


  • SaaS = Software as a Service
    a model of software deployment where where an application is hosted as a service provided to customers across the Internet
  • SAN = Storage Area Network
    A high-speed, high-available storage system, able to serve multiple computers at a time, dedicated to backup and archival purposes. It can be reached by Fibre Channel (FC) or iSCSI protocols.
  • Saved state
    A manner of storing a virtual machine so that it can be quickly resumed, similar to a hibernated laptop. When you place a running virtual machine in a saved state, Virtual Server and Hyper-V stop the virtual machine, write the data that exists in memory to temporary files, and stop the consumption of system resources. Restoring a virtual machine from a saved state returns it to the same condition it was in when its state was saved.
  • Server Consolidation
    The operation of mitigating the so called server sprawl by optimizing resource usage and simplifying management of available computers. Consolidation can be logical (managing distributed computers with central management) physical (moving several computers in a central location) or rationalized (migrate several computers in virtual machines or partitions, hosted by a single physical computer).
  • Server Sprawl
    The irrational proliferation of multiple computers inside a company infrastructure.
  • SLA = Service Level Agreement
    An agreement between a service provider and a customer regulating offered service in several aspects, from amount of resources available to time availability, up to faults recovery timeframe.
  • SSD = Solid State Disk
    a data storage device that uses solid-state memory to store persistent data
  • SMB = Small and Medium-sized businesses
  • Storage Virtualization
    Hardware and software technology that hides where storage systems are and what type of device is actually storing applications and data. This technology also makes it possible for many systems to share the same storage devices without knowing that others are also accessing them. This technology also makes it possible to take a snapshot of a live system so that it can be backed up without hindering online or transactional applications.



  • UMTS = Universal Mobile Telecommunications System
    is one of the third-generation (3G) cell phone technologies, which is also being developed into a 4G technology.
  • Utility Computing
    An emerging business model where customers don't buy computer hardware but pay for its usage. Service providers own computer hardware leasing computation time on demand.


  • VC = Virtual Center by VMware
  • VDA = Virtual Desktop Access
  • VDI = Virtual Desktop Infrastructure
  • VDM = Virtual Desktop Manager by VMware
  • VIC = Virtual Infrastructure Client by VMware
  • VMTN = VMware Technology Network
  • VPN = Virtual private network (VPN)
    is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires.
  • VAR = Value-added Reseller
    a company that adds some feature(s) to an existing product(s), then resells it (usually to end-users) as an integrated product or complete "turn-key" solution. This practice is common in the electronics industry, where, for example, a software application might be added to existing hardware.
  • V2P migration = Virtual to Physical migration
    The operation of migrating an operating system and every application installed on it from a virtual machine or a partition to one or multiple physical computers, without reinstalling anything. The opposite of P2V (Physical to Virtual).
  • V2V migration = Virtual to Virtual migration
    The operation of migrating an operating system and every application installed on it from a virtual machine or partition hosted in a virtual infrastructure to another virtual machine or partition hosted in a different virtual infrastructure, without reinstalling anything. Mainly used when working with different virtualization technologies in the same environment.
  • Virtual floppy disk
    A file-based version of a physical floppy disk. A virtual floppy disk is stored as a file with a .vfd file name extension.
  • Virtual hard disk
    The storage medium for a virtual machine. It can reside on any storage topology that the host operating system can access, including external devices, storage area networks, and network-attached storage. The file name extension is .vhd.
  • Virtual machine
    A computer within a computer, implemented in software. A virtual machine emulates a complete hardware system, from processor to network card, in a self-contained, isolated software environment, enabling the simultaneous operation of otherwise incompatible operating systems. Each operating system runs in its own isolated software partition.
  • Virtual machine configuration
    The configuration of the resources assigned to a virtual machine. Examples include devices such as disks and network adapters, as well as memory and processors.
  • Virtual Machine Management Service
    The Hyper-V service that provides management access to virtual machines.
  • Virtual machine snapshot
    A file-based snapshot of the state, disk data, and configuration of a virtual machine at a specific point in time.
  • Virtual network
    A virtual version of a physical network switch. A virtual network can be configured to provide access to local or external network resources for one or more virtual machines.
  • Virtual Network Manager
    A Hyper-V component used to create and manage virtual networks.
  • Virtual switch
    See virtual network.
  • Virtualization
    A software technology allowing an operating system to run unmodified on an isolated virtual environment, called virtual machine, where a platform's physical characteristics and behaviours are reproduced.
  • VMM = Virtual Machine Monitor
    The virtualization software layer managing hardware requests from a guest OS, simulating answers from a real hardware. Used as Hypervisor synonymous.
  • VSMP (Virtual Symmetric Multiprocessing)
    The feature of mapping two or more virtual processors inside a single virtual machine or partition.


  • WMMTM QoS = Wi-Fi Multimedia Quality of Service
  • WEP = Wired Equivalent Privacy
    is a deprecated algorithm to secure IEEE 802.11 wireless networks.
  • Woodstock = a set of user interface components for rich internet applications.
  • Workload Management
    The operation of handling computation power demand and computation power unavailability.

  • WPA = Wi-Fi Protected Access (WPA and WPA2)
    is a certification program administered by the Wi-Fi Alliance to indicate compliance with the security protocol created by the Wi-Fi Alliance to secure wireless computer networks.
  • WTS = Windows Terminal Server




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