Windows Server 2003 Glossary - V

Applies To: Windows Server 2000, Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

For more Windows Server terms, see the Windows Server 2008 Glossary.

Glossary - V

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V.34

A data transmission standard that provides for up to 33,600 bits per second (bps) communications over telephone lines. It defines a full-duplex (two-way) modulation technique and includes error-correcting and negotiation.

See also: bits per second (bps)   full-duplex   modulation standards   V.90   

V.90

A data transmission standard that provides for up to 56,000 bits per second (bps) communications over telephone lines. The transmission speed from the client-side modem is 33,600 bps, the same as for V.34. The transmission speed from the host-side modem, such as an Internet service provider (ISP) or corporate network, is up to 56,000 bps, with an average speed of 40,000 to 50,000 bps. When the host-side modem does not support this standard, the alternative is V.34.

See also: bits per second (bps)   client   host   Internet service provider (ISP)   modem (modulator/demodulator)   modulation standards   V.34   

validation

The process of comparing files on local volumes with their associated data in secondary storage by Remote Storage. Volumes that are validated ensure that the correct data is recalled from remote storage when a user attempts to open the file from a local volume.

See also: Remote Storage   volume   

variable

In programming, a named storage location capable of containing a certain type of data that can be modified during program execution. System environment variables are defined by the operating systems in the Windows Server 2003 family, and they are the same no matter who is logged on to the computer. Administrator group members can add new variables or change the values, however. User environment variables can be different for each user of a particular computer. They include any environment variables you want to define or variables defined by your applications, such as the path where application files are located.

See also: environment variable   

variable bit rate (VBR)

An asynchronous transfer mode (ATM) service type that guarantees service based on average and peak traffic rates. VBR is used for traffic that requires little or no cell loss. It transmits data in spurts, or bursts, rather than in a continuous stream.

See also: asynchronous transfer mode (ATM)   service   

VBR

See other term: variable bit rate (VBR)  

VCI

See other term: virtual channel identifier (VCI)  

VDM

See other term: virtual DOS machine (VDM)  

VDS

See other term: Virtual Disk Service (VDS)  

vector

For Indexing Service, an ordered series of words or numbers used in a query. For example, a single document can have (Scott Cooper; Don Hall; Amy Egert) as a vector of coauthors.

See also: Indexing Service   query   

vector font

A font rendered from a mathematical model, in which each character is defined as a set of lines drawn between points. Vector fonts can be cleanly scaled to any size or aspect ratio.

See also: font   plotter font   

vendor class

An administrative feature that allows DHCP clients to be identified and leased according to their vendor and hardware configuration type. For example, assigning a vendor class of HP to a printer vendor such as Hewlett-Packard would allow all Hewlett-Packard printers to be managed as a single unit so they could all obtain a similar DHCP leased configuration.

See also: DHCP client   Dynamic Host Configuration Protocol (DHCP)   lease   

video adapter

An expansion board that plugs into a personal computer to give it display capabilities. A computer`s display capabilities depend on both the logical circuitry (provided in the video adapter) and the monitor. Each adapter offers several different video modes. The two basic categories of video modes are text and graphics. Within the text and graphics modes, some monitors also offer a choice of resolutions. At lower resolutions a monitor can display more colors. Modern adapters contain memory, so that the computer`s random access memory (RAM) is not used for storing displays. In addition, most adapters have their own graphics coprocessor for performing graphics calculations. These adapters are often called graphics accelerators.

See also: graphics mode   

virtual address

In a virtual memory system, the address the application uses to reference memory. The kernel and the memory management unit (MMU) translate this address into a physical address before the memory is actually read or written.

See also: virtual memory   

virtual channel identifier (VCI)

A section of the asynchronous transfer mode (ATM) cell header that contains the virtual channel address over which the cell is to be routed.

See also: asynchronous transfer mode (ATM)   

virtual cluster

A Network Load Balancing cluster that you create by assigning specific port rules to specific virtual IP addresses. With virtual clusters, you can use different port rules for different Web sites or applications hosted on the cluster, provided each Web site or application has a different virtual IP address.

See also: Network Load Balancing   Network Load Balancing cluster   port rule   virtual IP address   

virtual container

A container that allows any Lightweight Directory Access Protocol (LDAP)-compliant directory to be accessed through Active Directory.

See also: Active Directory   directory   Lightweight Directory Access Protocol (LDAP)   

Virtual Disk Service (VDS)

A set of application programming interfaces (APIs) that provides a single interface for managing disks. VDS uses two sets of providers to manage storage devices. The built-in VDS software providers enable the management of disks and volumes at the operating system level. The VDS hardware providers enable the management of disk storage subsystems and are supplied by the hardware vendor.

virtual DOS machine (VDM)

A protected environment subsystem that emulates MS-DOS and 16-bit Windows within 32-bit versions of the Windows Server 2003 family. A VDM is created whenever a user starts an MS-DOS program in 32-bit versions of the Windows Server 2003 family. Note that 64-bit versions of the Windows Server 2003 family cannot run MS-DOS and 16-bit Windows programs.

See also: MS-DOS (Microsoft Disk Operating System)   

virtual IP address

An IP address that is shared among the hosts of a Network Load Balancing cluster. A Network Load Balancing cluster might also use multiple virtual IP addresses, for example, in a cluster of multihomed Web servers.

See also: host   IP address   multihomed computer   Network Load Balancing cluster   

A logical link between a backbone area border router and an area border router that is not connected to the backbone.

See also: area border router (ABR)   backbone router   

virtual local area network (VLAN)

A logical grouping of hosts on one or more local area networks (LANs) that allows communication to occur between hosts as if they were on the same physical LAN.

See also: host   local area network (LAN)   

virtual memory

Temporary storage used by a computer to run programs that need more memory than it has. For example, programs could have access to 4 gigabytes (GB) of virtual memory on a computer`s hard drive, even if the computer has only 32 megabytes (MB) of random access memory (RAM). The program data that does not currently fit in the computer`s memory is saved into paging files.

See also: paging file   random access memory (RAM)   Virtual Memory Size   virtual printer memory   

Virtual Memory Size

In Task Manager, the amount of virtual memory, or address space, committed to a process.

See also: Task Manager   virtual memory   

virtual network

A logical network that exists inside Novell NetWare and NetWare-compatible servers and routers but that is not associated with a physical adapter. The virtual network appears to a user as a separate network. On a computer running Windows 2000 Server or on an operating system in the Windows Server 2003 family, programs advertise their location on a virtual network, not a physical network. The internal network number identifies a virtual network inside a computer.

See also: external network number   internal network number   

virtual path identifier (VPI)

A section of the asynchronous transfer mode (ATM) cell header that contains the virtual path address over which the cell is to be routed.

See also: asynchronous transfer mode (ATM)   

virtual printer memory

In a PostScript printer, a part of memory that stores font information. The memory in PostScript printers is divided into two areas: banded memory and virtual memory. The banded memory contains graphics and page-layout information needed to print your documents. The virtual memory contains any font information that is sent to your printer either when you print a document or when you download fonts.

See also: PostScript printer   virtual memory   

virtual private network (VPN)

The extension of a private network that encompasses encapsulated, encrypted, and authenticated links across shared or public networks. VPN connections typically provide remote access and router-to-router connections to private networks over the Internet.

See also: authentication   encryption   remote access   routing   tunnel   

virtual server

In a server cluster, a collection of services that appear to clients as a physical Windows-based server but are not associated with a specific server. A virtual server is typically a resource group that contains all of the resources needed to run a particular application and that can be failed over like any other resource group. All virtual servers must include a Network Name resource and an IP Address resource.

See also: failover   IP Address resource   Network Name resource   resource   server cluster   

virus

A malicious computer program designed specifically to replicate itself and spread from computer to computer. A virus may damage hardware, software, or data.

See also: Trojan horse   

VLAN

See other term: virtual local area network (VLAN)  

VoIP (Voice over Internet Protocol)

A method for sending voice over a local area network (LAN), a wide area network (WAN), or the Internet using TCP/IP packets.

See also: local area network (LAN)   Transmission Control Protocol/Internet Protocol (TCP/IP)   wide area network (WAN)   

volume

An area of storage on a hard disk. A volume is formatted by using a file system, such as file allocation table (FAT) or NTFS, and has a drive letter assigned to it. You can view the contents of a volume by clicking its icon in Windows Explorer or in My Computer. A single hard disk can have multiple volumes, and volumes can also span multiple disks.

See also: disk   drive letter   file allocation table (FAT)   NTFS file system   simple volume   spanned volume   

volume password

An optional, case-sensitive password you can assign to a Macintosh-accessible volume when you configure the volume. To access the volume, a user must type the volume password.

See also: password   volume   

volume set

A volume that consists of disk space on one or more physical disks. A volume set is created by using basic disks and is supported only in Windows NT 4.0 or earlier. Volume sets were replaced by spanned volumes, which use dynamic disks.

See also: basic disk   dynamic disk   partition   spanned volume   volume   

volume shadow copy

A volume that represents a duplicate of the original volume taken at the time the copy began.

See also: crash consistency   differential data   volume   

voluntary tunnel

A tunnel that is initiated by the client. A voluntary tunnel tunnels Point-to-Point Protocol (PPP) over Internet Protocol (IP) from the client to the tunnel server, and then the data is forwarded to the target host by the tunnel server.

See also: client   host   Internet Protocol (IP)   Point-to-Point Protocol (PPP)   tunnel   tunnel server   

VPI

See other term: virtual path identifier (VPI)  

VPN

See other term: virtual private network (VPN)  

VPN server

A computer that accepts virtual private network (VPN) connections from VPN clients. A VPN server can provide a remote access VPN connection or a router-to-router VPN connection.

See also: client   router   server   virtual private network (VPN)