Glossary of Registry Terms

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

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


Active Window Tracking

A window is activated (and optionally brought to the foreground) when the user moves the mouse over it.

asynchronous transfer mode (ATM)

A high-speed, connection-oriented, virtual circuit-based packet switching protocol used to transport many different types of network traffic. ATM packages data in 53-byte, fixed-length cells that can be switched quickly between logical connections on a network.

authentication package

Dynamic-link libraries (DLLs) loaded by the Local Security Authority (LSA) and used for local logon and network authentication. MSV1_0, the default authentication package for Windows 2000, Windows XP, and the Windows Server 2003 family, identifies users by their user names and validates them by their passwords.


black hole router (TCP/IP)

A router that does not return ICMP Destination Unreachable messages when it needs to fragment a TCP packet on which the Don't-Fragment bit is set. TCP must receive Destination Unreachable messages to perform Path MTU Discovery.

browse list

Any list of items that can be browsed, such as a list of servers on a network, or a list of printers displayed in the Add Printer wizard.


code page

A means of providing support for character sets and keyboard layouts for different countries or regions. A code page is a table that relates the binary character codes used by a program to keys on the keyboard or to characters on the display.


Menus, buttons, and help text are those that are associated with a particular point (or context) in a window or dialog box. In Windows, when you right-click a context-senstive point, a menu appears displaying options for that context, or a "What's this" button appears which, when pressed, displays information about the context you clicked. In many dialog boxes, you can display context-sensitive help, that is, information about the context point, by clicking the question mark button on the caption bar and then clicking the context point.

control set

A complete set of the configuration data required to start devices and system services. The system always maintains at least two control sets in the registry. It identifies one as CurrentControlSet and the other as the LastKnownGood control set. The current control set is the one that was most recently used to start the system. The system stores its control set designations in the Select subkey.

cryptographic key cache

A reserved memory space where Message Queuing saves recently used encrypted symmetric keys so that the keys can be used again. Reusing keys makes encrypting and decrypting messages much faster. The cryptographic key cache has two sections, one for keys found in incoming messages and another for keys that are generated for outgoing messages. The size of each section can be adjusted by using the CryptSendKeyCacheSize and CryptReceiveKeyCacheSize entries.

current control set

The control set that was used to start the system this time. Only a successfully started system has a current control set. At startup, the system selects from among the numbered control sets stored in the registry. The number of the control set selected to be the current one appears in the Current entry in the HKLM\SYSTEM\Select subkey. The current control set is stored in the HKLM\SYSTEM\CurrentControlSet subkey.

See also: control set



A situation in which a thread will not relinquish its exclusive access to a critical section.



The means by which Windows learns about a device. Enumerator is a concept is used in Windows Plug and Play. It is a property of a device.


failover time

The amount of time it takes a resource, either individually or in a group, to complete the failover process.

file name completion

A quick search feature of the Windows command processor, Cmd.exe.

  • When you type a path and file name and then press the file name completion character, the command processor searches for all files whose path and file name match your entry.

  • When you type a path and then press the directory name completion character, the command processor searches for all files whose path (but not necessarily the file name) matches your entry.

The command processor displays one of the matching file names each time you type a completion character. To go backward through the list of file names, press SHIFT + completion character.

file system cache

An area of physical memory that holds frequently used pages. It allows applications and services to locate pages rapidly and reduces disk activity.

foreground process / background process

A process moves to the foreground when a user interacts with it; otherwise, it is a background process. This distinction lets the operating system optimize the performance of processes that are most important to the user. The system often assigns higher a processor time priority to foreground processes. As a result, the threads of foreground processes can preempt (interrupt) a running thread of a lower priority process. The threads of foreground processes often receive more processor time each time they run.


global catalog

A directory database that applications and clients can query to locate any object in a forest. The global catalog is hosted on one or more domain controllers in the forest. It contains a partial replica of every domain directory partition in the forest. These partial replicas include replicas of every object in the forest, as follows: the attributes most frequently used in search operations and the attributes required to locate a full replica of the object.

In Microsoft Provisioning System, the Exchange server maintains a list of global catalogs, and it maintains a load balance across global catalogs.

globally unique identifier (GUID)

A 16-byte value generated from the unique identifier on a device, the current date and time, and a sequence number. A GUID is used to identify a particular device or component.


hardware profile

Data that describes the configuration and characteristics of specific computer equipment. This information can be used to configure computers for using peripheral devices.

hot keys

A Windows feature that allows quick activation of specified accessibility features through a combination of keys pressed in unison.

hot tracking

When the cursor moves over an item, highlighting it but not selecting it.

hubbed mode

A mode in which the Address Resolution Protocol/multicast address resolution service (ARP/MARS) provides asynchronous transfer mode (ATM) addresses to requesting clients in the form of a multicast server (MCS) list value. In this mode, ARP/MARS acts as a multicast server, providing active forwarding of all multicast and broadcast traffic destined for IP addresses contained within the ranges specified in the list.

See also: asynchronous transfer mode (ATM); multicast address resolution service (MARS); nonhubbed mode



See definition for: integrated local management interface (ILMI)

Input Method Editor (IME)

A program used to enter the thousands of different characters in written Asian languages with a standard 101-key keyboard. An IME consists of both an engine that converts keystrokes into phonetic and ideographic characters and a dictionary of commonly used ideographic words. As the user enters keystrokes, the IME engine attempts to identify which character or characters that the keystrokes should be converted into.

integrated local management interface (ILMI)

A limited set of Simple Network Management Protocol (SNMP) functions included in the asynchronous transfer mode (ATM) specification for the ATM user network interface (UNI).

See also: asynchronous transfer mode (ATM); Simple Network Management Protocol (SNMP)

interface (TCP/IP)

In TCP/IP, a set of communications functions that permit core elements of the TCP/IP protocol suite to communicate with TCP/IP services. The most commonly known interfaces, the Transport Driver Interface (TDI) and the Network Device Interface (NDIS) are public, and their specifications are available from Microsoft. In addition, there are a number of higher level interfaces available to user-mode applications. The most commonly used are Windows Sockets, RPC, and NetBIOS.



See definition for: iterative query

iterative query

A query made to a DNS server for the best answer the server can provide without seeking further help from other DNS servers. Also called a nonrecursive query.


There are no glossary terms that begin with this letter.



In Registry Editor, a folder that appears in the left pane of the Registry Editor window. A key can contain subkeys and entries. For example, Environment is a key of HKEY_CURRENT_USER.

In IP security (IPSec), a value used in combination with an algorithm to encrypt or decrypt data. Key settings for IPSec are configurable to provide greater security.

See also: registry


Language ID

A 16-bit value which consists of a primary and a secondary language ID. Bits 0-9 make up the primary language ID and bits 10-15 comprise the sub-language ID.

LastKnownGood control set

The control set used most recently to start the system successfully. When the system identifies the LastKnownGood control set, such as ControlSet001, it stores the number of the control set in the LastKnownGood entry in the HKLM\SYSTEM\Select subkey.

See also: control set

Layer Two Tunneling Protocol (L2TP)

An industry-standard Internet tunneling protocol that provides encapsulation for sending Point-to-Point Protocol (PPP) frames across packet-oriented media. For IP networks, L2TP traffic is sent as User Datagram Protocol (UDP) messages. In Microsoft operating systems, L2TP is used in conjunction with Internet Protocol security (IPSec) as a virtual private network (VPN) technology to provide remote access or router-to-router VPN connections. L2TP is described in RFC 2661.


A group of user preference information, such as date and time formatting, represented as a list of values related to the user's language and sublanguage.

Locale ID

A 32-bit value which consists of the language ID in the low word (bits 0-15) and the sorting ID (bits 16-19) and a reserved value (bits 20-31) in the high word.

See also: Language ID


multicast address resolution service (MARS)

A service for resolving multicast IP addresses to the asynchronous transfer mode (ATM) addresses of the clients that have joined that multicast group. MARS can work in conjunction with the multicast server (MCS) and clients to distribute multicast data through point-to-multipoint connections.

See also: asynchronous transfer mode (ATM)



See definition for: Network Driver Interface Specification (NDIS)

Network Driver Interface Specification (NDIS)

A Microsoft/3Com specification establishing a common shared interface for Microsoft operating systems to support protocol-independent transport of multiple network transport protocols (such as TCP/IP, NetBEUI, IPX/SPX, and AppleTalk). NDIS allows more than one transport protocol to be bound and to operate simultaneously over a single network adapter.

nonhubbed mode

A mode in which asynchronous transfer mode (ATM) Address Resolution Protocol/multicast address resolution service (ARP/MARS) does not forward multicast and broadcast traffic for multicast group clients. In this mode, the service returns a dynamic listing of ATM hosts currently registered for the multicast group address to requesting clients. Clients then use this list to initiate and establish their own point-to-multipoint virtual connections with each of the members in the multicast list.

See also: asynchronous transfer mode (ATM); hubbed mode; multicast address resolution service (MARS)

nonpaged pool

Operating system memory that is never paged to disk. Paging is the moving of infrequently used parts of a program's working memory from RAM to another storage medium, usually the hard disk. In Task Manager, the amount of memory used by a process, in kilobytes.

See also: Task Manager


There are no glossary terms that begin with this letter.


paged pool

The system-allocated virtual memory that has been charged to a process and that can be paged. Paging is the moving of infrequently used parts of a program's working memory from random access memory (RAM) to another storage medium, usually the hard disk.

In Task Manager, the amount of system-allocated virtual memory, in kilobytes, used by a process.

See also: Task Manager


A section of shared memory used for interprocess communication. A program can write to a pipe and a program in another process can read the entry and reply. Processes that create pipes are commonly known as pipe servers and processes that read from the pipe are known as pipe clients.


A group of UNIX computers that are designated to receive password synchronization updates from a Windows-based server. When a password changes, the change is sent to one UNIX host in each pod. The UNIX computers that comprise the pod are listed in the value of Hosts.

pool leaks

Application errors that occur when an application allocates, but does not free, pool space.

published printer

A printer that appears in Active Directory. The list of published printers is accessible by using the Add Printer Wizard.


There are no glossary terms that begin with this letter.


raster fonts

Fonts that are stored as bitmaps. Raster fonts are designed with a specific size and resolution for a specific printer and cannot be scaled or rotated. If a printer does not support raster fonts, it will not print them. The five raster fonts are Courier, MS Sans Serif, MS Serif, Small, and Symbol. Also called bit-mapped fonts.

recursive resolution

One of the two process types (iterative and recursive) for DNS name resolution. In this process, a resolver (a DNS client) will request that a DNS server provide a complete answer to a query that does not include pointers to other DNS servers. When a client makes a query and requests that the server use recursive resolution to answer, it effectively shifts the workload of resolving the query from the client to the DNS server. If the DNS server supports and uses recursive resolution, it contacts other DNS servers as necessary (using iterative queries on behalf of the client) until it obtains a definitive answer to the query. This type of resolution allows the client resolver to be small and simple.

See also: iteration; iterative query

referenced entry (TCP/IP ARP cache table)

An ARP cache table entry is considered to be referenced when an outbound IP packet is sent to the address described by the entry.


A database repository for information about a computer's configuration. The registry contains information that Windows continually references during operation, such as:

  • Profiles for each user

  • The programs installed on the computer and the types of documents that each can create

  • Property settings for folders and program icons

  • What hardware exists on the system

  • Which ports are being used

The registry is organized hierarchically as a tree, and it is made up of keys and their subkeys, hives, and entries.

See also: key


scan code

A code number transmitted to an IBM or compatible computer when a key is pressed or released. Each key on the keyboard has a unique scan code.

service group

A group of similar services that are loaded together at startup. Most services that appear in the HKLM\SYSTEM\CurrentControlSet\Services subkey are part of a service group. The system loads one service group at a time. Services that are not in a group are loaded after all service groups are loaded.

Simple Network Management Protocol (SNMP)

A network protocol used to manage TCP/IP networks. In Windows, the SNMP service is used to provide status information about a host on a TCP/IP network.


One or more well-connected (highly reliable and fast) TCP/IP subnets. A site allows administrators to configure Active Directory access and replication topology to take advantage of the physical network.


See definition for: Simple Network Management Protocol (SNMP)

sorting ID

A code which dictates the correct order for sorting the characters of a language. The sorting ID is used in conjunction with a locale ID to distinguish between default sorts and alternate sorts for locales which have more than one sorting order.


Any node within a tree, along with any selection of connected descendant nodes.

The highest level of the registry (for example, HKEY_LOCAL_MACHINE).

See also: key; registry

SYN flooding

A malicious attempt to impair a server that occurs when a computer sends the server numerous Transmission Control Protocol (TCP) connection requests that contain fictitious IP addresses. As a result, the resources of the server are occupied by futile attempts to send acknowledgments to the fictitious IP addresses. The term SYN refers to the synchronize sequence number message that is used to initialize a TCP connection. Also known as a SYN attack.

See also: SYN flooding attack protection

SYN flooding attack protection

A Transmission Control Protocol (TCP) feature that detects symptoms of SYN flooding and responds by reducing the resources (memory and time) a server spends on connection requests that it cannot acknowledge.

See also: SYN flooding


Task Manager

A tool that provides information about programs and processes running on the computer. Using Task Manager, you can end or run programs, end processes, and display a dynamic overview of your computer's performance.


A unit of measure used in typesetting and desktop publishing, equal to one-twentieth of a printer's point (1/1440 inch). The twip notation begins with a dash (-), which, in this context, indicates a twip unit, not a negative value.



See definition for: Universal Naming Convention (UNC)

UNC provider

Interprets names in Universal Naming Convention format.


See definition for: user-to-network interface

Universal Naming Convention (UNC)

A convention for naming files and other resources beginning with two backslashes (\), indicating that the resource exists on a network computer. UNC names conform to the \\servername\sharename syntax, where servername is the server's name and sharename is the name of the shared resource. The UNC name of a directory or file can also include the directory path after the share name, by using the following syntax: \\servername\sharename\directory\filename.

user-to-network interface

The interface and signaling protocol used to establish connections between ATM users or end stations and an ATM switch or network. The ATM Call Manager component of Windows ATM Services support UNI.


virtual machine

A program that provides an independent operating system environment within another operating system. A virtual machine permits the user to run programs that are native to a different operating system.


There are no glossary terms that begin with this letter.


There are no glossary terms that begin with this letter.


There are no glossary terms that begin with this letter.


There are no glossary terms that begin with this letter.