Haskell Programming Language, simply called Haskell in most cases, is a standardized pure functional programming language with non-strict semantics, named after the logician Haskell Curry. Haskell was designed by a committee from the functional programming community in April 1990. It features static polymorphic typing, higher-order functions, user-defined algebraic data types, and pattern-matching list comprehensions. Innovations include a class system, systematic operator overloading, a functional I/O system, functional arrays, and separate compilation.

Helper application is an external viewer program launched to display content retrieved using a web browser. These applications commonly let you see and hear video and audio files, as well as view specialized text files or virtual reality models. Windows Media Player, QuickTime, Shockwave, CosmoPlayer, and RealAudio are examples of helper applications. Another common term for these programs is "plug ins," because they supplement the capabilities of your browser, and only run when they are needed to display files.

Heterogeneous systems, in software context, refer to systems that have different aspects such as the interface, the implementation, the data, etc. Two systems in a family are heterogeneous to the extent that they are incompatible in some way. One may represent information differently or not include certain functionality or adopt different security policies. If everything between two systems are the same and interoperate, they are homogeneous. Federating or integrating homogeneous systems is presumably simpler than federating heterogeneous systems.

Hex editor is a tool used to create and modify binary files.

High-level language, also known as high-level programming language, is a programming language that, in comparison to low-level programming languages, may be more abstract, easier to use, or more portable across platforms. Examples include languages such as C, FORTRAN, or Pascal that enables a programmer to write programs that are more or less independent of a particular type of computer.

The High Level Architecture (HLA) is a general purpose architecture for distributed computer simulation systems. Using HLA, computer simulations can communicate to other computer simulations regardless of the computing platforms. Communication between simulations is managed by a runtime infrastructure (RTI).

High Level Assembly (HLA) is an assembly language developed by Randall Hyde which can use high level language constructs to aid x86 assembly programmer beginners and advanced assembly developers alike. It fully supports advanced data types and object-oriented assembly language programming. It uses a syntax loosely based on several high-level languages, such as C/C++, Ada, Modula-2, and Pascal, to allow the creation of readable assembly language programs, and to allow High-level language (HLL) programmers to learn HLA as rapidly as possible.

Hybrid multiprocessing(HMP) refers to a kind of multitasking which provides some elements of symmetric multiprocessing, using add-on IBM software called MP/2. IBM OS/2 supports HMP.

The Hoard memory allocator, or Hoard, is a memory allocator for Linux, Solaris, Microsoft Windows and other operating systems. Hoard can improve the performance of multithreaded applications by providing fast, scalable memory management functions (malloc and free). In particular, it reduces contention for the heap (the central data structure used in dynamic memory allocation) caused when multiple threads allocate or free memory, and avoids the false sharing that can be introduced by memory allocators. At the same time, Hoard has low fragmentation.

Homogeneous systems, in software context, refer to the systems if they have the same aspects like the same interface, the same implementation, that can interoperate, can share data, etc. Otherwise, they are heterogeneous, which may represent information differently or not include certain functionality or adopt different security policies. Federating or integrating homogeneous systems is presumably simpler than federating heterogeneous systems.