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This site contains terms and definitions from many IBM software and hardware products as well as general computing terms.


A special 10-bit character used to indicate the beginning of a transmission word that performs Fibre Channel control and signaling functions. The first seven bits of the character are the comma pattern. See also comma.

See Apache Kafka.

A business practice that endorses continuous improvement and encourages feedback from all team members.


  1. Chinese characters or ideograms used in Japanese writing. The characters may have different meanings from their Chinese counterparts. See also Hiragana, Katakana.
  2. A graphic character set consisting of symbols used in Japanese ideographic alphabets. Each character is represented by 2 bytes.

A Japanese phonetic syllabary used primarily for foreign names and place names and words of foreign origin. See also Hiragana, Kanji.

See kilobit.

See kilobyte.

See knowledge-based authentication.

See kilobits per second.

See key distribution center.


  1. A TCP/IP mechanism where a small packet is sent across the network at predefined intervals to determine whether the socket is still working correctly.
  2. Pertaining to the amount of time that elapses before a message is sent to verify a connection.

keepalive message
In Internet communications, a message sent among nodes when no data traffic has been detected for a given period of time. This communication ensures the vitality of the session by keeping the link "alive."

See key-encrypting key.

A network authentication protocol that is based on symmetric key cryptography. Kerberos assigns a unique key, called a ticket, to each user who logs on to the network. The ticket is embedded in messages that are sent over the network. The receiver of a message uses the ticket to authenticate the sender.

Kerberos client
In Kerberos, an application or system that gets a service ticket for a Kerberos service.

Kerberos master machine
In Kerberos, the host machine on which the Kerberos database resides.

Kerberos master password
In Kerberos, the password required to change or access the Kerberos database.

Kerberos principal
In Kerberos, a service or user that is known to the Kerberos system. See also principal name.

Kerberos realm
In Kerberos, a set of clients that share the same Kerberos database.

Kerberos ticket
A transparent application mechanism that transmits the identity of an initiating principal to its target. A simple ticket contains the identity of the principal, a session key, a timestamp, and other information, which are sealed using the secret key of the target.


  1. The part of an operating system that performs basic functions, such as allocating hardware resources.
  2. The part of an operating system that contains programs for such tasks as input/output, management and control of hardware, and the scheduling of user tasks. See also kernel address space.
  3. In OSI, a session-layer functional unit that supports the basic session services required to establish connections, transfer normal data, and release connections.

kernel address space
The address space containing support for z/OS UNIX services. See also kernel.

kernel-based virtual machine (KVM)
An open source virtualization software for Linux that is based on hardware virtualization extensions (Intel VT-X and AMD-V) and a modified version of QEMU.

kernel device driver
See device head.

kernel domain
Major component of CICS providing a consistent linkage and recovery environment for CICS. The application programmer has no external interface to kernel linkage.

kernel dump
See system dump.

kernel image
A compiled operating system kernel, either loaded in memory or saved to persistent storage, for example, on an installation medium.

Kernel Linkage
A component of CICSPlex SM that is responsible for building data structures and managing the interfaces between the other CICSPlex SM components. The environment built by Kernel Linkage is known as the method call environment.

kernel mode
The state in which a process runs kernel code. See also user mode.

kernel module

  1. A distinct part of an operating system kernel that provides a specific support or function. For example, kernel modules can be device drivers or support programs for file systems. Kernel modules are either built into the kernel or are compiled as separate object files that can be dynamically loaded into the kernel, as needed.
  2. A piece of code that can be loaded into the kernel upon demand to extend functionality without requiring to reboot the system.

kernel parameter
The variables that specify how the kernel allocates certain system resources.

kernel tap (K-TAP)
An agent for Linux and UNIX-based systems, which monitors access to a database from the local system.

kernel thread
A one-to-one mapping between program threads and process threads where each thread is assigned to a machine task.


  1. The placement of characters such that their bounding boxes (character boxes) overlap. This allows for a more natural-looking spacing between characters.
  2. The adjustment of horizontal space between individual characters in a line of text. Adjustments in kerning are especially important in large display and headline text lines. Without kerning adjustments, many letter combinations can look awkward. The objective of kerning is to create visually equal spaces between all letters so that the eye can move smoothly along the text.

kerning track
A straight-line graph that associates vertical font size with white-space adjustment. The result of this association is used to scale fonts.

kerning track intercept
The X-intercept of a kerning track for a given vertical font size or white-space adjustment value.

Kettle API
The API that is used to access the Pentaho data transformation engine that is capable of doing many different functions, including reading, manipulating, and writing data to and from various data sources.

kettle transformation
An ETL job item that extracts data from business object tables and loads the data into a fact table.


  1. A column or an ordered collection of columns that is identified in the description of a table, index, or referential constraint. The same column can be part of more than one key.
  2. In sorting, a string of weights which can be used to compare characters or character strings.
  3. A column or an ordered collection of columns that is identified in the description of an index, unique constraint, or referential constraint. An index key can also be an expression, an ordered collection of expressions, or an ordered collection of columns and expressions. See also composite key.
  4. A cryptographic mathematical value that is used to digitally sign, verify, encrypt, or decrypt a message. See also key table, private key, public key.
  5. Information that characterizes and uniquely identifies the real-world entity that is being tracked by a monitoring context.
  6. One or more characters within an item of data that are used to uniquely identify a record and establish its order with respect to other records. See also alternate-index record.
  7. A button on a keyboard or key pad.

key analysis
A data analysis that evaluates data tables to find primary, foreign, and natural key candidates.

key attribute
An attribute that is used in warehouse aggregation to identify rows of data that represent the same object.

key authentication
See authentication.

An input device consisting of various keys that allows the user to input data, control cursor and pointer locations, and control the dialog with the workstation.

keyboard grabbing
An active grab of the keyboard by a client so that key events are sent to that client rather than the client to which the events would normally have been sent.

keyboard mapping
A list that establishes a correspondence between keys on the keyboard and characters displayed on a display screen, or action taken by a program, when that key is pressed.

keyboard profile
In System i Access, a file that defines the way characters and functions are mapped to keys on the keyboard when the personal computer is emulating a host session.

keyboard remapping
A facility that allows users to change the key assignments on the keyboard that they are using for emulation.

keyboard shift
In DDS, a characteristic that can be specified for a field in a display file that automatically shifts the display station keyboard to control what the display station user can enter into the field. In IDDU and DDS, the keyboard shift can also be specified in database files, but only applies when these fields are referred to in a display file.

keyboard shortcut
A key or combination of keys that a user can press to perform an action that is available from a menu.

keyboard style
In System i Access, the keyboard key assignments that are changed to match a particular keyboard type or user-defined arrangement.

keyboard traversal
An X widget resource that allows users to move the keyboard focus and activate user interface components using a key sequence rather than a mouse.

keyboard type
The physical key arrangement and assignments for the keyboard shipped from the factory.

keyboard video mouse console (KVM console)
A console that provides user control to multiple computers from a single keyboard, monitor, and mouse.

key certificate
A combination of an ASCII-encoded certificate and an ASCII-encoded PKCS5 encrypted private key.

key certificate file
A file that is stored on the client system that contains an encrypted message to identify the client and enable client/server authentication during secure connections.

A password management system for Apple software. A keychain acts as a secure storage container for passwords that are used by multiple applications and services.

key class
In EJB query language, a class that is used to create or find an entity bean. It represents the identity of the entity bean, corresponding to the primary-key columns of a row in a relational database.

In computer input devices, the unique numeric value generated when a key is pressed.

key column
In an ODM table, a column that forms the unique (non-repeatable) key to the table. For example, if the key columns of a scheduling application are DepartmentName, Workday and Shift, no two rows in the table can contain the same DepartmentName, Workday and Shift.

key database
In security, a storage object, either a file or a hardware cryptographic card, where identities and private keys are stored for authentication and encryption purposes. Some key databases also contain public keys. See also stash file.

key database file
See also keystore file.

key distribution center (KDC)
A network service that provides tickets and temporary session keys. The KDC maintains a database of principals (users and services) and their associated secret keys. It is composed of the authentication server and the ticket granting ticket server.

key drive
See flash drive.

keyed compliance
A requirement whereby the user must have a license key (code) from the software provider to be able to change the usage limit or the expiration date of the license information.

keyed data queue
An i5/OS data queue that contains individual pieces of data (messages) that are associated with a key value. Messages can be received from a keyed data queue by specifying the key value or a relational operator. The system-recognized identifier for the object type is *DTAQ.

keyed direct retrieval
A type of record access that uses relative record number, exact key, approximate key, or generic key.

Keyed-Hashing Message Authentication Code
A mechanism for message authentication that uses cryptographic hash functions.

keyed sequence
An order in which records are retrieved that is based on the contents of key fields in records. See also arrival sequence.

keyed sequence access path
An access path to a database file that is arranged according to the contents of key fields contained in the individual records.

keyed sequential access
In the Virtual Storage Access Method (VSAM), the retrieval or storage of a data record in its key or relative-record sequence, relative to the previously retrieved or stored record as defined by the sequence set of an index.

keyed sequential retrieval
A type of record access that uses keyed direct retrieval to recover subsequent records implicitly in key or relative record-number sequence without specifying another key or relative record number.

key effect
The effect that results when a key on a keyboard is actuated, depending on the level of force, and possibly by a concurrent operation of a qualifier key or keys. The key effect may be the generation of a graphic character or of a control function (see ISO/IEC 9995-1).

key-encrypting key (KEK)
A key that is used exclusively for encrypting and decrypting keys. See also data-encrypting key.

key entry area
In AFP Utilities, an area shown at the lower part of the image area for entering the parameters for an element.

key exchange protocol
A protocol governing how two parties exchange keys to use in securing a transaction. Once keys have been exchanged, data can be encrypted at the sender’s end and decrypted at the receiver’s end.

key expression
An expression that specifies the value that one or more key fields in a data item must have in order to be retrieved in the IPL.

key field

  1. A field that uniquely identifies a data item in a data type.
  2. A field in a data file that contains the values that Gentran Server for Windows uses to determine the trading partnership code.
  3. See sequence field.
  4. The field in a database segment used to store segment occurrences in sequential ascending order. A key field is also a search field. See also search field.
  5. The portion of a record that is used (possibly with other key fields) to locate a data record in a key file See also alternate key.
  6. A field used to arrange the records of a particular type within a file member.
  7. In EJB query language, a container-managed field in an entity bean that corresponds to one of the primary-key columns of a row in a relational database. Each key field is a member of the entity bean key class.

key field level specification
Data description specification coded on the lines following the last field specification. Key field level specifications are permitted only for physical files or logical files.

key file

  1. See key ring.
  2. In computer security, a file that contains public keys, private keys, trusted roots, and certificates.

key frame
A static image from a camera that is usually smaller than the actual video size. A key frame might contain more visual information about an event or alert such as a bounding box, or a track of motion.

key function
When used on a flat collection, a function that returns a reference to the key of an element.

Keyhole Markup Language (KML)
An XML grammar and file format for modeling and storing geographic features such as points, lines, images, and polygons.

key identifier

  1. The key used to indicate how the information for the signing key is included in the WS-Security header of the message.
  2. The unique name associated with the key for a thread in a process.

key label
A user-defined name that identifies the encryption key that can be retrieved from the key server.

key length
A measure of the size of the data that makes up a key, and determines how robust the key is. Longer keys, such as 128 bit, are considered to be harder to crack than shorter keys (48 bit).

key locator
A mechanism that retrieves the key for XML signing, XML digital signature verification, XML encryption, and XML decryption.

keylock feature
A security feature in which a lock and key can be used to restrict the use of the display station.

keylock switch
A switch on the control panel that can be set to one of four different positions to establish the power-on and power-off modes allowed for the system.

key mapping file
A file that defines the names and locations of installation and configuration files that are distributed automatically to client workstations.

Key Metrics
A portal component that provides a view of multiple metrics in a single view. The view contains a list of the metrics and attributes of the metrics, such as actual values, threshold values, and percentage of actual to threshold.

key of reference
In COBOL, the key, either prime or alternate, currently being used to access records within an indexed file.

A physical grouping of keys such as the numeric key pad and the cursor key pad on a keyboard or the buttons on a telephone.

keypad mapping
The process of assigning special alphanumeric characters to the keys on a telephone keypad so that the telephone can be used as a computer terminal keyboard.

key pair
In computer security, a public key and a private key. When the key pair is used for encryption, the sender uses the receiver's public key to encrypt the message, and the recipient uses their private key to decrypt the message. When the key pair is used for signing, the signer uses their private key to encrypt a representation of the message, and the recipient uses the sender's public key to decrypt the representation of the message for signature verification.

key pair certificate
A certificate that uses the pairing of a private key and public key for security.

key performance indicator (KPI)

  1. A quantifiable measure that is designed to track one of the critical success factors of a business process.
  2. A metric that is computed from performance data that indicates a level of compliance against expectations. For example, the acknowledgment response time to an order, an order fill rate, or an on time shipment rate.
  3. A measurable quantity against which specific performance criteria can be set when a service level agreement is written.

The periodic recording of system information and control blocks on the system log - also the data so recorded.

key policy
A single, key-protection transform that the initiating key server offers to the responding key server. A key policy governs Phase I negotiations.

key product
A product that is not being substantially redesigned or rewritten. New products will be classified as flagship or non-key. Existing key products will be reclassified as flagship if they are undergoing substantial re-engineering. See also flagship product, legacy product, non-key product.

key range
The two key fields signifying a range of records to be processed sequentially. The range of records is selected by specifying either key values that bound the records to be selected or an individual key value for which all matching records should be selected in a shared index.

key repository
A store for digital certificates and their associated private keys.

key ring

  1. In computer security, a file that contains public keys, private keys, trusted roots, and certificates.
  2. See key file.

key ring file
A binary file that is protected by a password and stores one or more certificates on the server hard drives. There are two types of key ring files: server and CA.

key schedule
In Cryptographic Support, sixteen 8-byte keys created by the Data Encryption Algorithm from the supplied cryptographic key that are used to encrypt or decrypt the supplied data.

key sequence
The collating sequence of data records, determined by the value of the key field in each of the data records. It can be the same as, or different from, the entry sequence of the records. See also entry sequence.

key-sequenced data set (KSDS)
A VSAM file or data set whose records are loaded in key sequence and controlled by an index.

key server

  1. See encryption key server.
  2. A server that negotiates the values that determine the characteristics of a dynamic virtual private network (VPN) connection that is established between two endpoints.

key set
An unordered flat collection that uses keys and does not allow duplicate elements.

keys help
A choice in the help pull-down that gives a user a list of all the shortcut key assignments for the current application.


  1. A repository that contains password information.
  2. See key database.
  3. A repository of security certificates.
  4. In security, a file or a hardware cryptographic card where identities and private keys are stored, for authentication and encryption purposes. Some keystores also contain trusted or public keys. See also certificate signing request, keytool, truststore.

keystore file
A key ring that contains both public keys that are stored as signer certificates and private keys that are stored in personal certificates. See also key database file.

keystore storepass
A password that is required to access a keystore file.

Additional specification of the entry within a naming service.

keystroke interface
The part of the Front End Programming Interface that allows a front-end application to specify a sequence of keystroke-like commands, which is used to define input to a back-end application.

An encoding of a symbol on a keycap on a keyboard.

key system
In telephony, the type of telephone system that provides telephones with more than one line for users. Outside lines appear directly on the telephones instead of being routed through an operator and transferred, as in PBX systems.

keytab file
A file on the service's host system that contains entries each of which contains the service principal's name and encrypted secret key.

key table

  1. In the Kerberos protocol, a file that contains service principal names and secret keys. The secret keys should be known only to the services that use the key table file and to the key distribution center (KDC). See also key.
  2. See keytab file.

key/think time
In capacity planning, the time between interactive transactions such as typing, thinking, idle time, and so on. As an interactive user's proficiency with the application improves, the user's key/think time is likely to reduce, which can result in an increase in the observed throughput.

A utility used for creating SSL encryption keys and managing the keystores where they are maintained. See also keystore.

key translation
In Cryptographic Support, the conversion of a data encrypting key from encryption under a previous key-encrypting key to encryption under another key-encrypting key.

key-value pair
Information that is expressed as a paired set of parameters. For example, if you want to express that the specific sport is football, this data can be expressed as key=sport and value=football. See also tag group.


  1. A word that a customer enters in a website when searching for an item.
  2. One of the predefined words of a programming language, artificial language, application, or command. See also keyword operand, operand, parameter, positional operand.
  3. A word that is used to conduct searching operations.
  4. A list of strings that can be used by a customer using the web channel application when searching for a category.
  5. See reserved word.
  6. A statement or group of statements that one can reuse in test scripts.
  7. A symbol that identifies a parameter in job control language (JCL).

keyword driven testing
A scripting technique that uses data files to contain not only test data and expected results, but also keywords related to the application being tested. The keywords are interpreted by special supporting scripts that are called by the control script for the test. (ISTQB) See also data driven testing.

keyword functions
The result of processing DDS keywords in a record format specified on an operation.

keyword instruction
In REXX, one or more clauses, the first of which starts with a keyword that identifies the instruction. Some keyword instructions affect the flow of control, while others provide services to the programmer. CALL, DO, and PARSE are examples of keyword instructions.

keyword intelligence system (KIS)
An analytics engine that is used to help marketers analyze keyword data and optimize their content for search.

keyword operand
An operand that consists of a keyword followed by one or more values (such as DSNAME=HELLO). See also definition statement, keyword, positional operand.

keyword parameter
A parameter that consists of a keyword followed by one or more values. See also operand, positional parameter.

keyword search
The standard search method where the user supplies words and candidate documents are returned.

keywords field
A multiple-choice field that lets users make selections by clicking, rather than typing, an entry. Keywords fields can display in several formats, including a drop-down list box, a check box, and a radio button.

See kibibyte.

kibibyte (KiB)
A base-2 unit of measurement that is equal to 1,024 bytes (2 to the 10th power). See also kilobyte.

To automate and facilitate unattended installation and configuration of a Red Hat Linux operating system.

In UNIX operating systems, to terminate a process.

kill character
A character that deletes a line of characters entered after a prompt.

killer app
A computer program that proves to be so popular and valuable that it drives the success of whatever technology that it is associated with. For example, Lotus 1-2-3 drove the sale of the IBM PC.

kill threshold
A threshold that restarts the system. See also throttle threshold.

kilobit (Kb)

  1. For disk storage capacity and communications volume, 1000 bits.
  2. For processor storage, real and virtual storage, and channel volume, 2 to the power of 10 or 1024 bits.

kilobits per second (kbps)
A measure of bandwidth on a data transmission medium, where 1 kbps = 1000 bits per second. This contrasts with units of storage where 1 Kb = 1024 bits (note upper case K). See also gigabits per second, megabits per second.

kilobyte (KB)
For processor storage, real and virtual storage, and channel volume, 2 to the power of 10 or 1,024 bytes. For disk storage capacity and communications volume, 1,000 bytes. See also kibibyte.

kilovolt-ampere (kVA)
A unit of power.

kind test
A form of a node test that can select nodes based on their kind and name. See also node test.

See keyword intelligence system.


  1. A collection of kit components.
  2. A collection of catalog entries that are ordered as a single SKU. See also bundle, prebuilt kit.

kit component
A meta-package that is used to install other components. Kit components support the installation of the following dependencies: kit component dependencies on other kit components, OS package dependencies on packages in an OS distribution, and kit dependencies on packages within the kit.

kit item
An individual item that comprises various components.

kit library
A repository of kits.

kit line
A line item that belongs to a higher-level kit; for example, a bed is one of the kit lines in an order for a bedroom set.

The process of picking components from a parts list or bill of materials (BOM) and assembling them into a new item or a higher level assembly.

See knowledge management.

See Keyhole Markup Language.

knock out (KO)
An answer consequence type that signals to the system not to execute the next step in a process.

knockout question
A question that is asked of candidates at the beginning of an application process to assess their suitability for a position. See also default question.

knowledge asset
A document external to the scope of the product that contains information associated to existing metadata.

knowledge base

  1. See software knowledge base.
  2. See corpus.
  3. A collection of data that may be interpreted as a set of facts and rules considered true in a possible world.

knowledge-based authentication (KBA)
A method of authentication whereby a user proves their identity by correctly answering questions from a knowledge base. See also challenge-response authentication.

knowledge capture
The process of acquiring knowledge from various sources for use in knowledge management. For example, in social business, knowledge capture takes place when an expert shares a strategy in a social forum, where it can then be compiled and used again later. See also knowledge management.

knowledge center
See IBM Knowledge Center.

knowledge graph
A model that consolidates typed entities, their relationships, their properties, and hierarchical taxonomies to represent an organization of concepts for a given domain. After the knowledge graph store is loaded with input from structured and unstructured data sources, users and applications can access the knowledge graph to explore key elements of knowledge for a specific domain, explore interactions, and discover additional relationships.

knowledge management (KM)
Efficient, effective use of enterprise knowledge to achieve common objectives across a corporation. See also knowledge capture.

See knock out.

Kohonen network
A neural network that can be used to cluster a data set into distinct groups. When processing is complete, records that are similar should be close together on the output map, while records that are different will be far apart. See also neural network.

Korean double-byte character set
An IBM-defined double-byte character set for Korean, consisting of Korean non-Hangeul/non-Hanja set, Hangeul set, Hanja set and up to 1,880 user-definable characters.

Korean Hangeul character set
A subset of the Korean DBCS, consisting of 2672 Hangeul characters and 52 Jamo characters.

Korean Hanja character set
A subset of the Korean DBCS, consisting of 5265 Hanja characters.

Korean non-Hangeul/non-Hanja character set
A subset of the Korean DBCS, consisting of non-Hangeul/non-Hanja characters, such as Greek, Russian, Roman numeric, alphanumeric and related symbols, Katakana, Hiragana, and special symbols. There are 940 characters in this set.

Korn shell (ksh)

  1. An interactive command interpreter and a command programming language.
  2. A command interpreter developed for UNIX, which forms the basis for the z/OS shell.

See key performance indicator.

KPI context
A container for key performance indicators (KPIs) and their associated triggers and events.

KPI model
The part of the monitor model that contains the KPI contexts, which in turn contain key performance indicators and their associated triggers and events.

KPI policy
A policy that determines if an incoming event is a KPI event update, then sends it for processing to generate a KPI update or an alert depending on parameters.

KPI value
A numeric value that ranges from 0-100 and indicates key performance indicator reliability. Performance is considered reliable if the value is less than or equal to the configured performance tolerance. If the actual performance is always within tolerance, then the KPI value is 100. Otherwise, the KPI value is 0. Many KPI values are calculated over time to give an average rating.

See thousands of power-on hours.

See key-sequenced data set.

See Korn shell.

See kernel tap.

See kilovolt-ampere.

See kernel-based virtual machine.

KVM console
See keyboard video mouse console.