Letter H
Haiku             A newer and updated version of the BeOS operating system.

Hard disk         A high capacity and high speed self-enclosed disk. Usually mounted
                  internally in computers to store and load programs and data.
                  Can range between 10MB and 10GB! Also known as HDD.


Hard drive        Similar to hard disks but also contain circuitry to control the
                  hard disk.


Hardware          The physical components that make up a computer system.


Hayes             A Hayes Compatible Modem uses AT commands to control the functions
                  of a modem. The majority of modems are hayes compatible.
				  
HBA               Host Bus Adapter. Refers to SCSI-2 type adapters.

HDCP              High bandwidth Digital Content Protection. A form of Digital Rights
                  Management (DRM) protection to control audio/video content over
                  DVI or HDMI interfaces. 

HD-DVD            High Definition DVD by Toshiba. See also DVD-HD and Bluray.

HDMI              High Definition Multimedia Interface. A video/audio interface to 
                  transmit uncompressed encrypted digital streams such as video
                  from Set Top Boxes, Blu-ray or HD-DVD Discs.

HDTV              High Definition Television. See HD DVD.

Hex               Hexadecimal. Numbering system containing 16 digits for numbers
                  0 to 15. i.e. 0 to 9 and A to F.  Uses Base 16.

HLS               HTTP Live Streaming. Video streaming protocol developed by Apple in 2009
                  which is widely supported. It support adaptive-bitrate steaming, the H.265 codec,
                  latency can be high.

HomeRF            A wireless network protocol running as 1.2Mb/sec but has a longer
                  range than WiFi does. Version 2 now does 10Mb/sec.

HTML              HyperText Markup Language. Document format for hyperlinked files
                  containing text, graphics and sound. Extensively used on the World
                  Wide Web. See W3C Website.

HTTP/HTTPS        HyperText Transfer Protocol (Secure). Used on the World Wide Web to
                  transmit and display html pages between the server and the client.
                  HTTPS uses SSL/TLS certificates to encrypt web traffic.
                  
HUB               Device which allows multiple PCs connect to network via one point
                  or allow multiple USB devices to connect to one USB Port on a PC/Mac.
                  
HyperThreading    Ability to run blocks of code (thread) in parallel with other code for
                  maximum performance. Developed by Intel.

Hyper-V           Hyper-Virtualisation. Microsoft's server virtualisation technology to
                  allow multiple logical or virtual servers run on a physical host.