IT Glossary - H - ITU Online IT Training
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IT Glossary
Key Terms To Know In The IT Industry

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High-Order Function

A function that does at least one of the following: takes one or more functions as arguments (i.e., procedural parameters), returns a function as its result.

You will find this term commonly used in Programming

High-Pass Filter

In computing and signal processing, a filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with lower frequencies.

You will find this term commonly used in Multimedia, Audio Processing

High-Performance Parallel Interface (HIPPI)

A computer bus for the transfer of large blocks of data at speeds suitable for supercomputers and complex scientific applications.

You will find this term commonly used in Networking, Hardware

HMAC (Hash-Based Message Authentication Code)

A specific type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. It is used to verify both the data integrity and the authenticity of a message.

You will find this term commonly used in Security, Cryptography

HMAC Authentication

A technique for verifying the integrity and authenticity of a message with a secret key, using Hash-Based Message Authentication Code.

You will find this term commonly used in Security, Cryptography

Holographic Storage

A type of data storage technology that uses the three dimensions of space for data storage instead of the two-dimensional surfaces of conventional storage media.

You will find this term commonly used in Hardware, Storage

Home Page

The initial or main web page of a website or a browser.

You will find this term commonly used in Web Development

Homogeneous Network

A network environment in which all the computers and devices run on the same operating system or platform, often simplifying management and compatibility issues.

You will find this term commonly used in Networking

Homomorphic Encryption

A form of encryption that allows computation on ciphertexts, generating an encrypted result which, when decrypted, matches the result of operations performed on the plaintext.

You will find this term commonly used in Cryptography

Honeynet

A network set up with intentional vulnerabilities; its purpose is to invite attack, so that an attacker's activities and techniques can be studied and that information used to increase network security.

You will find this term commonly used in Security, Cybersecurity

Honeypot

A security mechanism set to detect, deflect, or, in some manner, counteract attempts at unauthorized use of information systems. Typically, it consists of a computer, data, or a network site that appears to be part of a network but is actually isolated and monitored.

You will find this term commonly used in Security, Cybersecurity

Horizontal Scaling

The process of adding more machines or setting up a cluster of machines to share the load more efficiently.

You will find this term commonly used in Cloud Computing, Systems Design

Host

A computer or other device connected to a computer network; often, it is a computer that manages network resources. For example, a file server is a host that stores files, and a web server is a host that stores websites.

You will find this term commonly used in Networking

Host File

A computer file used by an operating system to map hostnames to IP addresses.

You will find this term commonly used in Networking

Host Header

A type of HTTP header that specifies the domain name of the server (website) to which the request is being sent. It is used for routing requests to multiple domains hosted on a single IP address.

You will find this term commonly used in Networking, Web Development

Host Intrusion Prevention System (HIPS)

A security solution that monitors a single host for suspicious activity by analyzing events occurring within that host.

You will find this term commonly used in Security, Cybersecurity

Host Operating System

In virtualization, the OS that runs on the physical hardware and hosts the virtual machines.

You will find this term commonly used in Operating Systems, Virtualization

Host-Based Security System (HBSS)

A framework used in information security management that secures individual devices from threats, often including antivirus, firewall, and intrusion detection systems.

You will find this term commonly used in Security, Cybersecurity

Host-to-Host Communication

In networking, the process by which two hosts (computers, servers, etc.) communicate with each other over a network.

You will find this term commonly used in Networking

Hosted Application

Software as a Service (SaaS) that is accessed over the internet and hosted in a cloud environment, rather than on-premises.

You will find this term commonly used in Cloud Computing, Software as a Service

Hosted Database

A database that is hosted on a remote server, allowing users to access it over the Internet, typically managed by a third-party service provider.

You will find this term commonly used in Cloud Computing, Databases

Hosted Git

A service that provides Git repository hosting which is accessible over the internet. Popular hosted Git services include GitHub, GitLab, and Bitbucket.

You will find this term commonly used in Software Development

Hosted Service

A service provided over the Internet or through a dedicated network.

You will find this term commonly used in Cloud Computing, Networking

Hosted Services

Web services or applications that are hosted by a provider, often in the cloud, allowing customers to access software over the internet.

You will find this term commonly used in Cloud Computing

Hostname

The unique name by which a device is known on a network, used to identify the device in various forms of electronic communication.

You will find this term commonly used in Networking

Hot Deployment

The process of adding new components (such as software updates or new configurations) to a running system without needing to restart it.

You will find this term commonly used in Software Development

Hot Fix

A quick repair job for a piece of programming during the software maintenance process.

You will find this term commonly used in Software Development, Security

Hot Standby

A redundancy approach where a backup system runs simultaneously with the primary system and can take over immediately without loss of service if the primary system fails.

You will find this term commonly used in Systems Design, Networking

Hot Swapping

Replacing or adding components without stopping or shutting down the system.

You will find this term commonly used in Hardware, Computing

Hotfix

A quick repair job for a piece of programming during the software maintenance process.

You will find this term commonly used in Software Development

Hotlink Protection

A security measure used to prevent other websites from directly linking to files (as images, video, etc.) on your website, which can consume bandwidth and server resources.

You will find this term commonly used in Web Development, Security

Hotspot

A physical location where people may obtain Internet access, typically using Wi-Fi, via a wireless local area network (WLAN) with a router connected to an internet service provider.

You will find this term commonly used in Networking

Hotspot Shielding

The practice of securing a wireless network hotspot to protect it from unauthorized access or to ensure privacy and data integrity for its users.

You will find this term commonly used in Networking, Security

HPC (High Performance Computing)

The use of supercomputers and parallel processing techniques for solving complex computational problems.

You will find this term commonly used in Computing, Research

HSM (Hardware Security Module)

A physical computing device that safeguards and manages digital keys for strong authentication and provides crypto processing.

You will find this term commonly used in Security, Cryptography

HTML (HyperText Markup Language)

The standard markup language used for creating web pages and web applications.

You will find this term commonly used in Web Development

HTML Editor

Software for creating and editing HTML code. It can be a simple text editor or a complex integrated development environment (IDE).

You will find this term commonly used in Web Development

HTML Form

A section of a document containing normal content, markup, special elements called controls (checkboxes, radio buttons, menus, etc.), and labels on those controls.

You will find this term commonly used in Web Development

HTML Injection

A type of security vulnerability in which an attacker can inject HTML code into a webpage viewed by other users, potentially leading to cross-site scripting (XSS) attacks.

You will find this term commonly used in Security, Web Development

HTML Parsing

The process of converting HTML documents into a structured format that a computer can understand and manipulate.

You will find this term commonly used in Web Development

HTML5

The latest major revision of the HTML standard, offering new features for presenting content on the World Wide Web.

You will find this term commonly used in Web Development

HTML5 Canvas

An HTML element used to draw graphics and animations directly on a web page via scripting (usually JavaScript).

You will find this term commonly used in Web Development

HTML5 WebSockets

A technology providing full-duplex communication channels over a single TCP connection, enabling web applications to maintain a persistent connection with a server for real-time data transfer.

You will find this term commonly used in Web Development, Networking

HTTP (HyperText Transfer Protocol)

The protocol used for transmitting hypermedia documents, such as HTML. It is the foundation of any data exchange on the Web.

You will find this term commonly used in Networking, Web Development

HTTP Authentication

A method for a web server to secure restricted resources by requiring user verification, using headers to authenticate requests.

You will find this term commonly used in Web Development, Security

HTTP Basic Authentication

A method for an HTTP user agent to provide a user name and password when making a request. It is a simple authentication scheme built into the HTTP protocol.

You will find this term commonly used in Web Development, Security

HTTP Caching

The mechanism by which HTTP responses are stored for re-use, reducing the need to send the same data multiple times over the network.

You will find this term commonly used in Web Development, Networking

HTTP Compression

A capability that can be built into web servers and web clients to improve transfer speed and bandwidth utilization.

You will find this term commonly used in Web Development, Networking

HTTP Cookie

A small piece of data sent from a website and stored on the user's computer by the user's web browser while the user is browsing.

You will find this term commonly used in Web Development, Security

HTTP Flood

A type of Distributed Denial of Service (DDoS) attack where the attacker sends numerous HTTP GET or POST requests to a web server, intending to overwhelm it and make it unavailable to handle legitimate requests.

You will find this term commonly used in Security, Cybersecurity

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