Half-duplex data transmission means that data can be transmitted in both directions on a signal carrier, but not at the same time. 

Haml (HTML Abstraction Markup Language) is a lightweight markup language that is used to describe the XHTML of any web document without the use of traditional inline coding. It is designed to address many of the flaws in traditional templating engines, as well as making markup as elegant as it can be. Haml functions as a replacement for inline page templating systems such as PHP, RHTML, and ASP.

A computer that can conveniently be stored in a pocket (of sufficient size) and used while you're holding it. 

A language that allows the text portions of Web pages to be presented on cellular telephones and personal digital assistants (PDA) via wireless access. 

A typedef supplied in the Windows headers files. A typedef can be thought of as an alias or pseudonym. In the Windows registry, a handle represents an open instance of a basic operating system object with which applications interact. 

A full-featured portable computer that is slightly larger than a PDA, but much smaller than a laptop. It offers hardware, software, performance, and display capabilities.

Haptics is a tactile feedback that applies touch (tactile) sensation and control to interaction with computer applications. Haptic sensations are created in consumer devices by actuators, or motors, which create a vibration.  Those vibrations are managed and controlled by embedded software, and integrated into device user interfaces and applications via the embedded control software APIs.

The mechanism that controls the positioning, reading, and writing of the hard disk, which furnishes the largest amount of data storage for the PC. It is often shortened as 'hard drive'.

A hard drive overwriter is a program or utility that repeatedly overwrites the data on a computer's hard drive with gibberish. By overwriting the entire hard drive with gibberish, the user ensures that their information remains inaccessible.

A mechanical device that physically destroys old hard drives in such a way that the data they contain cannot be recovered. At a minimum, this involves severing every track on every platter in a drive.

A technology that encrypts the data stored on a hard drive using sophisticated mathematical functions. Data on an encrypted hard drive cannot be read by anyone who does not have access to the appropriate key or password.

In information technology, hardware is the physical aspect of computers, telecommunications, and other devices such as cables, connectors, power supply units, and peripheral devices such as the keyboard, mouse, audio speakers, and printers.

A layer of programming that allows a computer operating system to interact with a hardware device at a general or abstract level rather than at a detailed hardware level. 

A differently in managed services and grid computing contexts. In managed services, HaaS is similar to licensing. In grid computing, HaaS is a pay-as-you-go model.

A hardware-based method of turning multiple servers into a cluster (a group of servers that acts like a single system). As a rule, a hardware cluster is created by installing a number of blade servers on the machine that will control the cluster.

A hardware description language (HDL) is a specialized computer language used to program the structure, design and operation of electronic circuits, and most commonly, digital logic circuits. It also allows for the compilation of an HDL program into a lower level specification of physical electronic components, such as the set of masks used to create an integrated circuit. A hardware description language looks much like a programming language such as C; it is a textual description consisting of expressions, statements and control structures. One important difference between most programming languages and HDLs is that HDLs explicitly include the notion of time. HDLs form an integral part of electronic design automation (EDA) systems, especially for complex circuits, such as microprocessors.