Windows Glossary “Windows Dictionary” (C)

cable modem
A device that enables a broadband connection to the Internet by using cable television infrastructure. Access speeds vary greatly, with a maximum throughput of 10 megabits per second (Mbps).
cache
For DNS and WINS, a local information store of resource records for recently resolved names of remote hosts. Typically, the cache is built dynamically as the computer queries and resolves names. It also helps optimize the time required to resolve queried names.

cache file
A file used by the Domain Name System (DNS) server to preload its names cache when service is started. Also known as the root hints file because DNS uses resource records stored in this file to help locate root servers that provide referral to authoritative servers for remote names. For Windows DNS servers, the cache file is named Cache.dns and is located in the %SystemRoot%\System32\Dns folder.

caching
The process of temporarily storing recently used data values in a special pool in memory for quicker subsequent access. For DNS, typically the ability of the DNS server to store information learned about the DNS namespace during the resolution of DNS queries. (For example, the DNS server can cache DNS records received from other DNS servers.) Caching is also available through the DNS Client service as a way for DNS clients to keep a cache of information learned during recent queries.

caching resolver
A client-side DNS name resolution service that performs caching of recently learned DNS domain name information. The caching resolver service provides system-wide access to DNS-aware programs for resource records obtained from DNS servers during processing of name queries. Cached data is used for a limited period of time and aged according to the active Time-to-Live (TTL) value. You can set the TTL individually for each resource record (RR). Otherwise, it defaults to the minimum TTL set in the SOA RR for the zone.

callback number
The number that a remote access server uses to call back a user. This number can be preset by the administrator or specified by the user at the time of each call, depending on how the administrator configures the user's callback options. The callback number should be the number of the phone line to which the user's modem is connected.

callback security
A form of network security in which a remote access server calls a user back at a preset number after the user has made an initial connection and has been authenticated.

called subscriber ID (CSID) string
A string that specifies the called subscriber ID transmitted by the receiving fax machine when receiving an inbound fax. This string is usually a combination of the fax or telephone number and the name of the business. It is often the same as the transmitter subscriber ID.

canonical (CNAME) resource record
A resource record used to map an alternate alias name to a primary canonical DNS domain name used in the zone.

canonical name
An object's distinguished name presented with the root first and without the LDAP attribute tags (such as: CN=, DC=). The segments of the name are delimited with forward slashes (/). For example,
CN=MyDocuments,OU=MyOU,DC=Microsoft,DC=Com
is presented as
microsoft.com/MyOU/MyDocuments
in canonical form.

cartridge font
A font contained in a plug-in cartridge and used to add fonts to laser, ink-jet, or high-end dot-matrix printers. Cartridge fonts are distinguished both from internal fonts, which are contained in ROM in the printer and are always available, and from downloadable (soft) fonts, which reside on disk and which can be sent to the printer as needed.

cascading hubs
A network configuration in which hubs are connected to other hubs.

catalog
For Indexing Service, a collection of all index information and stored properties for a particular group of file system directories. By default, Indexing Service indexes the System and Web catalogs on your hard drive.

CD-R
Recordable compact disc. Data can be copied to the CD on more than one occasion; however, data cannot be erased from the CD.

CD-RW
Rewritable compact disc. Data can be copied to the CD on more than one occasion and can be erased.

certificate
A digital document that is commonly used for authentication and secure exchange of information on open networks, such as the Internet, extranets, and intranets. A certificate securely binds a public key to the entity that holds the corresponding private key. Certificates are digitally signed by the issuing certification authority and can be issued for a user, a computer, or a service. The most widely accepted format for certificates is defined by the ITU-T X.509 version 3 international standard.

certificate revocation list (CRL)
A document maintained and published by a certification authority that lists certificates that have been revoked.

certificate store
Typically, a permanent storage where certificates, certificate revocation lists, and certificate trust lists are stored.

certificate template
A Windows construct that profiles certificates (that is, it prespecifies the format and content) based on their intended usage. When requesting a certificate from a Windows enterprise certification authority (CA), certificate requestors are, depending on their access rights, able to select from a variety of certificate types that are based on certificate templates, such as User and Code Signing.

certificate trust list (CTL)
A signed list of root certification authority certificates that an administrator considers reputable for designated purposes, such as client authentication or secure e-mail.

certification authority (CA)
An entity responsible for establishing and vouching for the authenticity of public keys belonging to users (end entities) or other certification authorities. Activities of a certification authority can include binding public keys to distinguished names through signed certificates, managing certificate serial numbers, and certificate revocation.

certification hierarchy
A model of trust for certificates in which certification paths are created by means of the establishment of parent-child relationships between certification authorities.

certification path
An unbroken chain of trust, consisting of certificates from trusted certificate authorities, from a specific certificate to the root certification authority in a certification hierarchy.

Challenge Handshake Authentication Protocol (CHAP)
A challenge-response authentication protocol for PPP connections documented in RFC 1994 that uses the industry-standard Message Digest 5 (MD5) one-way encryption scheme to hash the response to a challenge issued by the remote access server.

channel
A path or link through which noncontrol information passes between two devices. A single Basic Rate Interface (BRI) connection, for example, has one physical connection but two channels for exchanging information between devices. This is often called a bearer channel, implying a channel that carries information.
On the Internet, a Web site designed to deliver content from the Internet to your computer, similar to subscribing to a favorite Web site.

CHAP (Challenge Handshake Authentication Protocol)
An authentication protocol used by Microsoft remote access and Network Connections. Using CHAP, a remote access client can send its authentication credentials to a remote access server in a secure form. Microsoft has created a Windows-specific variant of CHAP called MS-CHAP.

character mode
A display mode in which the monitor can display letters, numbers, and other text characters, but no graphical images or character formatting (italics, superscript, and so on).

child object
An object that resides in another object. A child object implies relation. For example, a file is a child object that resides in a folder, which is the parent object.

Class A IP address
A unicast IP address that ranges from 1.0.0.1 through 126.255.255.254. The first octet indicates the network, and the last three octets indicate the host on the network.

Class B IP address
A unicast IP address that ranges from 128.0.0.1 through 191.255.255.254. The first two octets indicate the network, and the last two octets indicate the host on the network.

Class C IP address
A unicast IP address that ranges from 192.0.0.1 to 223.255.255.254. The first three octets indicate the network, and the last octet indicates the host on the network. Network Load Balancing provides optional session support for Class C IP addresses (in addition to support for single IP addresses) to accommodate clients that make use of multiple proxy servers at the client site.

classical IP over ATM (CLIP)
A proposed Internet standard, described in RFC 2225, that allows IP communication directly on the ATM layer, bypassing an additional protocol (such as Ethernet or Token Ring) in the protocol stack.

clear
To turn off an option by removing the X or check mark from a check box. You clear a check box by clicking it, or by selecting it and then pressing the SPACEBAR.

client
Any computer or program connecting to, or requesting the services of, another computer or program. Client can also refer to the software that enables the computer or program to establish the connection.
For a local area network (LAN) or the Internet, a computer that uses shared network resources provided by another computer (called a server).

client application
A Windows-based application that can display and store linked or embedded objects. For distributed applications, the application that imitates a request to a server application.

client request
A service request from a client computer to a server computer or, for Network Load Balancing, a cluster of computers. Network Load Balancing forwards each client request to a specific host within the cluster according to the system administrator's load-balancing policy.

ClipBook Server
A system service that supports ClipBook Viewer, which allows pages to be seen by remote ClipBooks.

cluster
In data storage, the smallest amount of disk space that can be allocated to hold a file. All file systems used by Windows organize hard disks based on clusters, which consist of one or more contiguous sectors. The smaller the cluster size, the more efficiently a disk stores information. If no cluster size is specified during formatting, Windows picks defaults based on the size of the volume. These defaults are selected to reduce the amount of space that is lost and the amount of fragmentation on the volume. A cluster is also called an allocation unit.
In computer networking, a group of independent computers that work together to provide a common set of services and present a single-system image to clients. The use of a cluster enhances the availability of the services and the scalability and manageability of the operating system that provides the services.

cluster adapter
The adapter that, when using multiple network adapters in each host of a Network Load Balancing cluster, handles the network traffic for cluster operations (the traffic for all hosts in the cluster). This adapter is programmed with the host's cluster IP address.

Cluster Administrator
An application that is used to configure a cluster and its nodes, groups, and resources. Cluster Administrator can run on any member of the trusted domain regardless of whether the computer is a cluster node.

Cluster Administrator extension
A software component that implements the Cluster Administrator extension application programming interface (API) for allowing Cluster Administrator to configure a new resource type.

Cluster API
A collection of functions that are implemented by the cluster software and used by a cluster-aware client or server application, a cluster management application, or a Resource DLL. The Cluster API is used to manage the cluster, cluster objects, and the cluster database.

cluster disk
A disk on a shared bus connected to the cluster nodes, which all the cluster nodes can access (though not at the same time).

Cluster service
The essential software component that controls all aspects of server cluster operation and manages the cluster database. Each node in a server cluster runs one instance of the Cluster service.

cluster-aware application
An application that can run on a cluster node and that can be managed as a cluster resource. Cluster-aware applications use the Cluster API to receive status and notification information from the server cluster.

cluster-unaware application
An application that can run on a cluster node and be managed as a cluster resource but that does not support the Cluster API.

Cluster.exe
An alternative to using Cluster Administrator to administer clusters from the command prompt. You can also call Cluster.exe from command scripts to automate many cluster administration tasks.

Cmd Show Override, with
When checked, opens the DDE server application as specified by the integer in value. Possible values are 1 (normal), 2 (minimized), 3 (maximized), and 10 (application default).
When cleared, the DDE server application opens.

CMYK color space
Multidimensional color space consisting of the cyan, magenta, yellow, and black intensities that make up a given color. Commercial color printing devices generally use this system of four-color process inks.

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.

codec
Hardware that can convert audio or video signals between analog and digital forms (coder/decoder); hardware or software that can compress and uncompress audio or video data (compression/decompression); or the combination of coder/decoder and compression/decompression. Generally, a codec compresses uncompressed digital data so that the data uses less memory.

color depth
The number of colors per pixel your monitor and graphics adapter support.

color gamut
The particular range of colors that a device is able to produce. A device such as a scanner, monitor, or printer can produce a unique range of colors, which is determined by the characteristics of the device itself.

color management
Process of producing accurate, consistent color among a variety of input and output devices. A color management system (CMS) maps colors between devices such as scanners, monitors, and printers; transforms colors from one color space to another (for example, RGB to CMYK); and provides accurate on-screen or print previews.

color profile
A profile that contains the data needed for translating the values of a color gamut. This data includes information about color, hue, saturation, and brightness.

color space
A set of three values that defines how a color can be represented on computer devices such as monitors, scanners, and printers. For example, in the LAB color space, the terms luminance or whiteness (L), redness-greenness (A), and yellowness-blueness (B) are used; in the HVC system, the terms are hue (H), value (V), and chroma (C). Color space refers to the three-dimensional space that is defined by the respective values, such as L, A, and B.

command prompt window
A window displayed on the desktop used to interface with the MS-DOS operating system. MS-DOS commands are typed at an entry point identified by a blinking cursor.

common groups
Groups that appear in the program list on the Start menu for all users who log on to the computer. Only administrators can create or change common groups.

communication port
A port on a computer that allows asynchronous communication of one byte at a time. A communication port is also called a serial port.

communication settings
Operating parameters, such as bits per second (bps) and modem type, that apply to serial ports on a computer.

community name
A name used to group SNMP hosts. This name is placed in SNMP messages sent between SNMP-managed devices such as Windows 2000-based server computers and SNMP management stations. Typically, all hosts belong to Public, which is the standard name for a common community of all SNMP hosts.

compatibility mode
A feature of a computer or operating system that allows it to run programs written for a different system. Programs often run slower in compatibility mode.

Complementary Metal Oxide Semiconductor (CMOS)
A specific type of semiconductor technology that requires very little power. The term has been popularized to mean a small storage area where your system keeps track of certain hardware parameters, such as the size of your hard disk, the number of serial ports your computer has, etc. CMOS is also called Setup RAM.

Compression Control Protocol (CCP)
A protocol used in the negotiation process in a PPP connection. Compression Control Protocol is one type of Network Control Protocol (NCP). NCPs are used to establish and configure different network protocol parameters for IP, IPX, and NetBEUI.

computer account
An account that is created by a domain administrator and uniquely identifies the computer on the domain. The Windows computer account matches the name of the computer joining the domain.

computer administrator
A user who manages a computer. The computer administrator makes system-wide changes to the computer, including installing programs and accessing all files on the computer, and can create, change and delete the accounts of other users.

Computer Browser service
A service that maintains an up-to-date list of computers and provides the list to applications when requested. The Computer Browser service provides the computer lists displayed in the My Network Places, Select Computer, and Select Domain dialog boxes and (for Windows 2000 Server only) in the Server Manager window.

Computer Management
A component you can use to view and control many aspects of the computer configuration. Computer Management combines several administration utilities into a single console tree, providing easy access to a local or remote computers administrative properties and tools.

computer quota
For Message Queuing, the storage size limit for messages on a computer, based on the total size of the messages. When a computer quota is reached, Message Queuing can no longer send messages to that computer until one or more messages are removed from queues. Message Queuing enforces the computer quota before it enforces the queue quota on a computer.

connect
To assign a drive letter, port, or computer name to a shared resource so that you can use it.

connected, authenticating user
A user's status when a telephone connection has been established but authentication has not yet taken place. The user may be trying to prove security clearance, or the system may be idle. If this condition occurs, followed by the Waiting for Call phase, then the user was unable to provide a correct user name or password. If this phase is repeated, followed by the Waiting for Call phase, an unauthorized attempt to access the network may be under way.

connected, user authenticated
A user's status when a telephone connection has been established and the user has entered a correct user name and password. If the user has callback permission and has requested callback, the connection is followed by the calling-back phase. If the calling-back phase is followed by a waiting-for-call phase, then the server was unable to reach the user at the specified number. The user may have supplied an inaccurate callback number (in the case of set-by-caller callback), or an unauthorized attempt to access the network may be under way (in the case of preset-to callback).

connector application
For Message Queuing, an application that enables Message Queuing computers to communicate with computers that use other messaging systems.

connector queue
For Message Queuing, a queue created on servers running a connector application. You can use the connector application to exchange messages with computers that are running other message-queuing products.

console tree
The left pane in a Microsoft Management Console (MMC) that displays the items contained in the console. By default it is the left pane of a console window, but it can be hidden. The items in the console tree and their hierarchical organization determine the capabilities of a console.

constant bit rate (CBR)
An ATM service type that supports constant bandwidth allocation. This service type is used for voice and video transmissions that require little or no cell loss and rigorous timing controls during transmission.

container object
An object that can logically contain other objects. For example, a folder is a container object.

convergence
The process of stabilizing a system after changes occur in the network. For routing, if a route becomes unavailable, routers send update messages throughout the internetwork, reestablishing information about preferred routes.
For Network Load Balancing, a process by which hosts exchange messages to determine a new, consistent state of the cluster and to elect the host with the highest host priority, known as the default host. During convergence, a new load distribution is determined for hosts that share the handling of network traffic for specific TCP or UDP ports.

copy backup
A backup that copies all selected files but does not mark each file as having been backed up (in other words, the archive attribute is not cleared). Copying is useful if you want to back up files between normal and incremental backups because copying does not affect these other backup operations.

count limit
For Process Control, the maximum number of active processes in a process group. You can configure this in the Process Control snap-in.

CPU Time
In Task Manager, the total processor time, in seconds, used by a process since it started.

CPU Usage
In Task Manager, the percentage of time that a process used the CPU since the last update. On the Task Manager Process tab, the column heading is CPU.

crash consistency
A feature of shadow copy backups that ensures all files are backed up, regardless of their state.

CRC errors
Errors caused by the failure of a cyclic redundancy check. A CRC error indicates that one or more characters in the data packet received were found garbled on arrival.

credentials
A set of information that includes identification and proof of identification that is used to gain access to local and network resources. Examples of credentials are user names and passwords, smart cards, and certificates.

CRL distribution point
An optional extension in an X.509v3 certificate that identifies how information is obtained. Also, a directory entry or other distribution source for certificate revocation lists.

cross-reference object
Objects in which Active Directory stores information about directory partitions and external directory services. An example of an external directory service is another LDAP-compliant directory.

CryptoAPI
An application programming interface (API) that is provided as part of Microsoft Windows. CryptoAPI provides a set of functions that allow applications to encrypt or digitally sign data in a flexible manner while providing protection for the user's sensitive private key data. Actual cryptographic operations are performed by independent modules known as cryptographic service providers (CSPs).

cryptographic service provider (CSP)
The code that performs authentication, encoding, and encryption services that Windows-based applications access through the CryptoAPI. A CSP is responsible for creating keys, destroying them, and using them to perform a variety of cryptographic operations. Each CSP provides a different implementation of the CryptoAPI. Some provide stronger cryptographic algorithms, while others contain hardware components, such as smart cards.

cryptography
The processes, art, and science of keeping messages and data secure. Cryptography is used to enable and ensure confidentiality, data integrity, authentication (entity and data origin), and nonrepudiation.

custom file type
Typically, files with extensions that have been created for special kinds of files. Custom file types are not tracked by the system registry.