half duplex
Adjective. Describes a system that allows communication between two endpoints where only one may transmit at a time. SEE ALSO simplex; full duplex.
Hamming code
A class of binary linear codes used for parity calculation that can detect up to two simultaneous bit errors, rather than just odd numbers of errors. Named for Richard Hamming. Used in computer memory (RAM) and telecommunications for validating data transmission.
hash
Alternate form: hashing
hash key
Alternate form: hashed key
SEE key, hash.
hash partitioning
SEE partitioning, hash.
Health Insurance Portability and Accountability Act, The (HIPAA)
A law enacted by the U.S. Congress in 1996. Title I of HIPAA protects health insurance coverage for workers and their families when they change or lose their jobs. Title II requires the establishment of national standards for electronic health care transactions and national identifiers for providers, health insurance plans, and employers. Title II also addresses the security and privacy of health data. The standards are meant to encourage use of electronic data interchange in US healthcare.
heat map
SEE chart, heat map.
heaven and hell chart
help desk
SEE call center.
heterogeneous
Adjective. Describes multiple members in a set that have differences in nature or structure. Opposite of homogeneous.
heuristics
“Rules of thumb” and approximation methods for obtaining a goal, a high quality solution, or improved performance. It sacrifices completeness to increase efficiency, as some potential solutions would not be practicable or acceptable due to their 'rareness' or 'complexity'. This method may not always find the best solution, but it will find an acceptable solution within a reasonable timeframe for problems that will require almost infinite or longer than acceptable times to compute.
hexadecimal
A numbering system using a base of 16, using letters A through F to represent 10 through 15 decimal. A byte is generally 8 binary digits, so that 1 hexadecimal representation represents 4 binary digits. Core dumps are expressed in hexadecimal for example.
hierarchical data model
hierarchical database
Hierarchical Query Language (HQL)
A high-level language on a hierarchical data structure, similar to SQL on a multi-file data structure.
hierarchical relationship
SEE relationship, hierarchical.
hierarchical structure
hierarchical taxonomy
hierarchy
high availability
A protocol and associated execution that ensures a certain relative degree of computing-system operational continuity in any down-time event.
histogram
A chart that shows quantities of data points that occur within various numeric ranges.
historical database
SEE database, historical.
historical revisionism
The reinterpretation of historical data based on new data, validated or invalidated assumptions about the data, or different perspectives on the environment that generated the data.
homogeneous
Adjective. Describes multiple members in a set that have no differences in nature or structure. Opposite of heterogeneous.
homogeneous nodes
A set of nodes conforming to the same definition (or of the same type).
homonym
A term that has the same or nearly same spelling or sound as another term, but has a different meaning. Contrast with synonym.
horizontal abstraction
horizontal partitioning
host-driven
Adjective. Describes a processing method in which the host computer controls the session. A host-driven session typically includes terminal emulation, front ending, or client/server types of connections. The host determines what is displayed on the desktop, receives user input from the desktop, and determines how the application responds to the input.
hot backup
SEE backup, hot.
house of quality chart
householding
Consolidating related names and addresses into groups.
How
Zachman Framework column name, matches Process Transformations.
human interface
An interface from a system to a human that enables the human to interact with and receive information from that system. SEE ALSO interface.
Hybrid OLAP (HOLAP)
SEE OnLine Analytical Processing, Hybrid.
hype-cycle chart
SEE chart, hype-cycle.
hyperbolic tree
hypercube
An OLAP product that stores all data in a single data cube which has all the application dimensions applied to it.
hyperlink
A one-way reference from one electronic document to another. Most frequently implemented as navigational links from one web page to another.
hypertext
Electronically stored text data organized into documents and logical sections that can be accessed randomly via hyperlinks as well as sequentially.
Hypertext Markup Language (HTML)
A tag set used to create a web page document; a subset of SGML (standard generalized markup language). The tags or elements tell the browser how to display the information. The tags are used to “mark,” in a hierarchical format, the different components of the document.
HyperText Transfer Protocol (HTTP)
A system of communicating between a web browser application and a document stored on a web server.