Computer/System Terms - H
hard disk drive (HDD) - (Sealed units used for nonvolatile data storage in today's computer systems, containing rigid, circular platters (disks), usually constructed of aluminum or glass, which cannot bend or flex.)
hard error rates (HERs) - (The rate of memory chip errors caused by a flaw, physical damage, or other event, where the chip becomes damaged and experiences a permanent failure (hard fail). Fixing this type of failure normally requires replacement of the failed component.)
Hardware Abstraction Layer (HAL) - (In Windows NT and its derivatives, the component of the operating system responsible for low-level interaction with the CPU and closely-related hardware.)
Hardware Compatability List (HCL) - (List of hardware components or brands which are compatible with other components, devices, or brands.)
hardware security module (HSM) - (A physical computing device that safeguards and manages digital keys for strong authentication and provides cryptoprocessing - an HSM traditionally comes in the form of a plug-in card or an external device that attaches directly to a computer or network server.)
Harrison-Ruzzo-Ullman model (HRU) - (A security access model used by software designers which relies on a finite set of procedures to edit the access rights of a subject.)
Hash(ed) Message Authentication Code (HMAC) - (A process that incorporates a secret (symmetric) key in the hashing process, so that a given message produces a unique hash using that particular symmetric key. Integrity and authenticity can be ensured by the hash value, since a message hash value produced without the key will not match the hash value produced when the key is incorporated.)
head disk assembly (HDA) - (Hard disk drive (HDD) unit which contains the read-write heads and the spinning disks (platters) which hold the recorded data.)
Health Information for Economic and Clinical Health Act of 2009 (HITECH Act) - (Federal legislation, enacted as Title XIII of the American Recovery and Reinvestment Act (ARRA) of 2009, which expanded medical information privacy safeguards and established the Office of Civil Rights (OCR) within the Department of Health and Human Services (HHS) - strengthened the enforcement powers of HIPAA data protection rules and added a breach notification requirement.)
Health Insurance Portability and Accountability Act of 1996 (HIPAA) - (federal legislation designed to make health insurance portable by protecting health care coverage when workers change jobs - also provided for additional safeguards relating to protected health information (PHI) requiring physicians and other healthcare providers who conduct electronic transactions to adopt certain security measures to safeguard PHI in electronic form.)
heads per cylinder (HPC) - (Formula or method for measuring the number of heads in relation to a cylinder. HPC is used in the context of the structure or design of the hard disk assembly used to read, write, and store data. The head is the part of a disk drive that reads and writes information magnetically. Individual hard disks are called platters. When multiple platters are used, the tracks on each platter which correspond to, and align with, the tracks on the other platters are collectively known as cylinders.)
heating, ventilation, and air conditioning (HVAC) -
heatsink - (A special attachment for a chip that draws heat away from the chip, serving as a form of "radiator" for cooling PC processor systems.)
Hertz (Hz) -
Heterogeneous Systems Architecture (HSA) - (Type of processor architecture which allows the Central Processing Unit (CPU) to share memory with the Graphics Processing Unit (GPU), where conventional design separated CPU system memory from GPU memory.)
Hewlett-Packard (HP) - (A leading manufacturer of computers and printers, headquartered in Palo Alto, California.)
Hierarchical File System (HFS) - (The file system used by the Macintosh Operating System. Generally, a hierarchical file system is a file system that allows subdirectories or folders to belong to a higher-level subdirectory or folder.)
hierarchical storage management (HSM) - (Type of backup storage system which includes storage media devices of varying speed and cost, such as optical discs, magnetic discs, and tapes. The faster media holds the files that are accessed more often, and the seldom-used files are stored on the slower, or near-line devices. The goal is to reduce costs by using fewer hard drives, which are expensive.)
High Assurance Internet Protocol Encryptor (HAIPE) - (An encryption device which provides a secure gateway that allows two users to exchange data over an untrusted or lower-classification network.)
High Availability (HA) - (A term applied to a system or network that must be kept at a significantly high and reliable level of availability for its users - requires technologies and processes that provide redundancy, fault tolerance, and fai lover capabilities.)
High-bit-rate digital subscriber line (HDSL) - (Type of high-speed connection technology used to connect a home or business to the service provider's central office (digital subscriber line) using regular copper phone wire.)
High-Consequence Event (HCE) - (Adverse events deemed most significant in terms of the severity of impact - often used in the context of cyber events.)
High Definition Audio (HDA) - (An Intel standard for audio recordings released in 2004, with higher-quality and greater channel capabilities than earlier standards. Also known by its development code-name "Azalia.")
High Definition Multimedia Interface (HDMI) - (A standard interface and cable connector for carrying digitized audio and video.)
high-density digital versatile disc (HD DVD) - (A high-density optical disc formerly marketed by Toshiba, but discontinued in 2008, when the Blu-ray disc (BD) became the market standard.)
High Dynamic Range (HDR) - (An image capable of displaying a wide range of values, from the brightest whites to the darkest blacks.)
High-level Data Link Control (HDLC) - (A framing protocol that is used mainly for device-to-device communication, such as two routers communicating over a wide-area network (WAN) link.)
High-level (or logical) formatting (HLF) - (Type of hard disk formatting done by the operating system (OS) which involves the creation of a table of contents for managing files and data on the disk. Low-level, or physical, formatting, involves changes to the disk done at the factory during manufacture.)
high memory area (HMA) - (Area of extended memory - the first 64KB - which can be accessed by a PC processor in real mode (type of processor function).)
High-performance Media Access Technology (HighMAT) - (A set of standards co-developed by Microsoft and Matsushita (Panasonic) for CDs and DVDs that are created on personal computers but played back on consumer electronic devices, such as CD players and DVD-equipped television sets.)
High-Speed Downlink Packet Access (HSDPA) - (wireless broadband)
high speed packet access (HSPA) - (mobile broadband)
High-Speed Serial Interface (HSSI) - (An interface used to connect multiplexers and routers to high-speed communications services such as ATM (asynchronous transfer mode) and frame relay.)
Home Agent (HA) - (In the area of mobile communications, a router with additional capabilities beyond those of a standard router, which keeps track of mobile nodes (MNs) (devices that can move from one network to another) it manages within the its local network, until they move to another network, at which time it forwards packets to the new network.)
Home Location Register (HLR) - (In cellular phone and mobile device systems, the database used by the mobile switching center (MSC) containing subscriber and service information.)
Home Theater Personal Computer (HTPC) -
Homeland Security Presidential Directive (HSPD) - (Presidential directive relating to Homeland Security, probably considered a form of national security directive. Presidential directives are interpretations or clarifications of laws, which are issued by the President without congressional input, considered to be part of the President's lawmaking power but which, in contrast to executive orders and proclamations, do not have to be published in the Federel Register. In contrast to statutes and legislation, directives do not involve Congressional action or input.)
Host (or Host-Based) Intrusion Detection System (HIDS) - (An intrusion detection system, usually software-base, installed on a host as an application, which monitors the internal resources of a system for malicious activiy, which can include packet inspection of potentially malicious packets, along with network monitoring.)
Host Protected Area (HPA) - (A hidden area of the hard drive literally situated past the reported end of the hard drive, normally used to store and protect recovery software or diagnostics but which can be accessed for recovery if there are problems with the boot program.)
hue, saturation, brightness (HSB) - (colors)
human intelligence (HUMINT) - (Information collected by and from hummans such as information collected via social engineering face-to-face, over the phone, or even eavesdropping in a public place.)
human interface device (HID) - (A device or component which allows a person to interact, or communicate with, a computer or system, such as a mouse or keyboard.)
human-machine interface (HMI) - (Device or position, such as a user station or workstation, where a person interacts or communicates with a system through a computer or device - entering data or issuing commands, and working with data.)
Human Resources (HR) - (Department within an organization which deals with employees and employment issues, such as maintaining records of employees - dates of employment, personnel investigations, pay rates, evaluations, payroll, pension and benefits, and terminations - and advising on compliance with laws and regulations, as well as conducting job searches, and anticipating future employee requirements.)
hybrid fiber/coax (coaxial cable) network (HFC) - (Network that connects all the cable TV customers in a neighborhood.)
Hyper-Threading Technology (HT) - (instruction processing)
HyperText Markup Language (HTML) -
HyperText Transfer Protocol (HTTP) - (An Internet protocol used to send web page files from their source location to the requesting user/viewer.)
HyperText Transfer Protocol Secure (HTTPS) -
Hypertext Transfer Protocol over Secure Sockets Layer (HTTPS) -