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S3 (programming Language)
S3 is a structured, imperative high-level computer programming language. It was developed by the UK company International Computers Limited (ICL) for its 2900 Series mainframes. It is a system programming language with syntax influenced by ALGOL 68 but with data types and operators aligned to those offered by the 2900 Series. It was the implementation language of the operating system VME. Annotated Example A rare example of an S3 program available in the public domain is the implementation of Kermit developed at the South-West Universities Regional Computer Centre, and archived in the Columbia University archive of Kermit implementations. The examples below are selected highlights of the main module (kmt_main_module). The program starts with a module identification, and comments which we quote by way of acknowledgment to the authors: MODULE KMT_MAIN_MODULE; @ Version 1.01 @ @------------------------------------------------------- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structured Programming
Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making specific disciplined use of the structured control flow constructs of selection ( if/then/else) and repetition ( while and for), block structures, and subroutines. It emerged in the late 1950s with the appearance of the ALGOL 58 and ALGOL 60 programming languages, with the latter including support for block structures. Contributing factors to its popularity and widespread acceptance, at first in academia and later among practitioners, include the discovery of what is now known as the structured program theorem in 1966, and the publication of the influential " Go To Statement Considered Harmful" open letter in 1968 by Dutch computer scientist Edsger W. Dijkstra, who coined the term "structured programming". Structured programming is most frequently used with deviations that allow for clearer programs in some particular cases, such as whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Higher-order Function
In mathematics and computer science, a higher-order function (HOF) is a function that does at least one of the following: * takes one or more functions as arguments (i.e. a procedural parameter, which is a parameter of a procedure that is itself a procedure), * returns a function as its result. All other functions are ''first-order functions''. In mathematics higher-order functions are also termed '' operators'' or '' functionals''. The differential operator in calculus is a common example, since it maps a function to its derivative, also a function. Higher-order functions should not be confused with other uses of the word "functor" throughout mathematics, see Functor (other). In the untyped lambda calculus, all functions are higher-order; in a typed lambda calculus, from which most functional programming languages are derived, higher-order functions that take one function as argument are values with types of the form (\tau_1\to\tau_2)\to\tau_3. General examples * ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First-class Function
In computer science, a programming language is said to have first-class functions if it treats function (programming), functions as first-class citizens. This means the language supports passing functions as arguments to other functions, returning them as the values from other functions, and assigning them to variables or storing them in data structures. Some programming language theorists require support for anonymous functions (function literals) as well. b) -> [a] -> [b] map f [] = [] map f (x:xs) = f x : map f xs Languages where functions are not first-class often still allow one to write higher-order functions through the use of features such as function pointers or Delegate (CLI), delegates. In the language C (programming language), C: void map(int (*f)(int), int x[], size_t n) There are a number of differences between the two approaches that are ''not'' directly related to the support of first-class functions. The Haskell sample operates on List (computing), lists, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment Variable
An environment variable is a user-definable value that can affect the way running processes will behave on a computer. Environment variables are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process. They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and macOS. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems, including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names. Design In all Unix and Unix-like systems, as well as on Windows, each process has its own separate set of environment vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia University
Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church (Manhattan), Trinity Church in Manhattan, it is the oldest institution of higher education in New York (state), New York and the fifth-First university in the United States, oldest in the United States. Columbia was established as a Colonial colleges, colonial college by royal charter under George II of Great Britain. It was renamed Columbia College (New York), Columbia College in 1784 following the American Revolution, and in 1787 was placed under Trustees of Columbia University in the City of New York, a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved to its current location in Morningside Heights and renamed Columbia University. Columbia is organized into twenty schoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kermit (protocol)
Kermit is a computer file transfer and management protocol and a set of communications software tools primarily used in the early years of personal computing in the 1980s. It provides a consistent approach to file transfer, terminal emulation, script programming, and character set conversion across many different computer hardware and operating system platforms. Technical The Kermit protocol supports text and binary file transfers on both full-duplex and half-duplex 8-bit and 7-bit serial connections in a system- and medium-independent fashion, and is implemented on hundreds of different computer and operating system platforms. On full-duplex connections, a sliding window protocol is used with selective retransmission which provides excellent performance and error recovery characteristics. On 7-bit connections, locking shifts provide efficient transfer of 8-bit data. When properly implemented, as in the Columbia University Kermit Software collection, its authors claim perfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICL VME
VME (''Virtual Machine Environment'') is a mainframe operating system developed by the UK company International Computers Limited (ICL, now part of the Fujitsu group). Originally developed in the 1970s (as VME/B, later VME 2900) to drive ICL's then new 2900 Series mainframes, the operating system is now known as OpenVME incorporating a Unix subsystem, and runs on ICL Series 39 and Trimetra mainframe computers, as well as industry-standard x64 servers. Origins The development program for the New Range system started on the merger of International Computers and Tabulators (ICT) and English Electric Computers in 1968. One of the fundamental decisions was that it would feature a new operating system. A number of different feasibility and design studies were carried out within ICL, the three most notable being: * VME/B (originally System B), targeted at large processors such as the 2970/2980 and developed in Kidsgrove, Staffordshire and West Gorton, Manchester * VME/K ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Programming Language
A system programming language is a programming language used for system programming; such languages are designed for writing system software, which usually requires different development approaches when compared with application software. Edsger Dijkstra referred to these languages as machine oriented high order languages, or mohol. Proceedings published 1974. General-purpose programming languages tend to focus on generic features to allow programs written in the language to use the same code on different platforms. Examples of such languages include ALGOL and Pascal. This generic quality typically comes at the cost of denying direct access to the machine's internal workings, and this often has negative effects on performance. System languages, in contrast, are designed not for compatibility, but for performance and ease of access to the underlying hardware while still providing high-level programming concepts like structured programming. Examples include ESPOL and SPL, bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperative Programming
In computer science, imperative programming is a programming paradigm of software that uses Statement (computer science), statements that change a program's state (computer science), state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program consists of command (computing), commands for the computer to perform. Imperative programming focuses on describing ''how'' a program operates step by step (with general order of the steps being determined in source code by the placement of statements one below the other), rather than on high-level descriptions of its expected results. The term is often used in contrast to declarative programming, which focuses on ''what'' the program should accomplish without specifying all the details of ''how'' the program should achieve the result. Procedural programming Procedural programming is a type of imperative programming in which the program is built from one or more procedures (also termed s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICL 2900 Series
The ICL 2900 Series was a range of mainframe computer systems announced by the British manufacturer International Computers Limited on 9 October 1974. The company had started development under the name "New Range" immediately on its formation in 1968. The range was not designed to be compatible with any previous machines produced by the company, nor for compatibility with any competitor's machines: rather, it was conceived as a ''synthetic option'', combining the best ideas available from a variety of sources. In marketing terms, the 2900 Series was superseded by Series 39 in the mid-1980s; however, Series 39 was essentially a new set of machines implementing the 2900 Series architecture, as were subsequent ICL machines branded "Trimetra". Origins When ICL was formed in 1968 as a result of the merger of International Computers and Tabulators (ICT) with English Electric Leo Marconi and Elliott Automation, the company considered several options for its future product line. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Language
A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually defined by a formal language. Languages usually provide features such as a type system, Variable (computer science), variables, and mechanisms for Exception handling (programming), error handling. An Programming language implementation, implementation of a programming language is required in order to Execution (computing), execute programs, namely an Interpreter (computing), interpreter or a compiler. An interpreter directly executes the source code, while a compiler produces an executable program. Computer architecture has strongly influenced the design of programming languages, with the most common type (imperative languages—which implement operations in a specified order) developed to perform well on the popular von Neumann architecture. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
