Larch Family
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Larch Family
The Larch family of formal specification languages are intended for the precise specification of computing systems. They allow the clean specification of computer programs and the formulation of proofs about program behavior. The Larch family was developed primarily in the United States in the 1980s and 1990s, involving researchers at Xerox PARC, DEC Systems Research Center (DEC/SRC), Massachusetts Institute of Technology (MIT), and other places. Unlike the Z notation, the Larch family has one language for algebraic specification of abstract data types (the ''Larch Shared Language'' (LSL)), and a separate ''interface language'' tailored to each language in which programs are to be written, such as C, Modula-3, Smalltalk, etc. The Larch project also developed tools to support the use of formal specifications, including the Larch Prover (LP). See also * Formal methods In computer science, formal methods are mathematically rigorous techniques for the specification, development, ...
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Specification Language
A specification language is a formal language in computer science used during systems analysis, requirements analysis, and systems design to describe a system at a much higher level than a programming language, which is used to produce the executable code for a system.Joseph Goguen "One, None, A Hundred Thousand Specification Languages" Invited Paper, IFIP Congress 1986 pp 995-1004 Overview Specification languages are generally not directly executed. They are meant to describe the ''what'', not the ''how''. Indeed, it is considered as an error if a requirement specification is cluttered with unnecessary implementation detail. A common fundamental assumption of many specification approaches is that programs are modelled as algebraic or model-theoretic structures that include a collection of sets of data values together with functions over those sets. This level of abstraction coincides with the view that the correctness of the input/output behaviour of a program takes precedence ...
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Computer Program
A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program in its human-readable form is called source code. Source code needs another computer program to execute because computers can only execute their native machine instructions. Therefore, source code may be translated to machine instructions using the language's compiler. ( Assembly language programs are translated using an assembler.) The resulting file is called an executable. Alternatively, source code may execute within the language's interpreter. If the executable is requested for execution, then the operating system loads it into memory and starts a process. The central processing unit will soon switch to this process so it can fetch, decode, and then execute each machine instruction. If the source code is requested for execution, ...
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Mathematical Proof
A mathematical proof is an inferential argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. The argument may use other previously established statements, such as theorems; but every proof can, in principle, be constructed using only certain basic or original assumptions known as axioms, along with the accepted rules of inference. Proofs are examples of exhaustive deductive reasoning which establish logical certainty, to be distinguished from empirical arguments or non-exhaustive inductive reasoning which establish "reasonable expectation". Presenting many cases in which the statement holds is not enough for a proof, which must demonstrate that the statement is true in ''all'' possible cases. A proposition that has not been proved but is believed to be true is known as a conjecture, or a hypothesis if frequently used as an assumption for further mathematical work. Proofs employ logic expressed in mathematical symbols ...
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Springer Science+Business Media
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in Berlin, it expanded internationally in the 1960s, and through mergers in the 1990s and a sale to venture capitalists it fused with Wolters Kluwer and eventually became part of Springer Nature in 2015. Springer has major offices in Berlin, Heidelberg, Dordrecht, and New York City. History Julius Springer founded Springer-Verlag in Berlin in 1842 and his son Ferdinand Springer grew it from a small firm of 4 employees into Germany's then second largest academic publisher with 65 staff in 1872.Chronology
". Springer Science+Business Media.
In 1964, Springer expanded its business internationally, o ...
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United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ...
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Xerox PARC
PARC (Palo Alto Research Center; formerly Xerox PARC) is a research and development company in Palo Alto, California. Founded in 1969 by Jacob E. "Jack" Goldman, chief scientist of Xerox Corporation, the company was originally a division of Xerox, tasked with creating computer technology-related products and hardware systems. Xerox PARC has been at the heart of numerous revolutionary computer developments, including laser printing, Ethernet, the modern personal computer, GUI (graphical user interface) and desktop paradigm, object-oriented programming, ubiquitous computing, electronic paper, a-Si (amorphous silicon) applications, the computer mouse, and VLSI ( very-large-scale integration) for semiconductors. Unlike Xerox's existing research laboratory in Rochester, New York, which focused on refining and expanding the company's copier business, Goldman's “Advanced Scientific & Systems Laboratory” aimed to pioneer new technologies in advanced physics, materials science, and ...
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DEC Systems Research Center
The Systems Research Center (SRC) was a research laboratory created by Digital Equipment Corporation (DEC) in 1984, in Palo Alto, California. DEC SRC was founded by a group of computer scientists, led by Robert Taylor, who left the Computer Science Laboratory (CSL) of Xerox PARC after an internal power struggle. SRC survived the takeover of DEC by Compaq in 1998. It was renamed to "Compaq Systems Research Center". When Compaq was acquired by Hewlett-Packard in 2002, SRC was merged with other HP corporate research labs and relocated there. After Taylor's retirement, the lab was directed by Roy Levin and then by Lyle Ramshaw. Some of the important developments made at SRC include the Modula-3 programming language; the snoopy cache, used in the first multiprocessor workstation, the Firefly, built from MicroVAX 78032 microprocessors; the first multi-threaded Unix system, Taos; the first user interface editor; early networked window systems, Trestle. AltaVista was jointly develo ...
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Massachusetts Institute Of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the most prestigious and highly ranked academic institutions in the world. Founded in response to the increasing industrialization of the United States, MIT adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. MIT is one of three private land grant universities in the United States, the others being Cornell University and Tuskegee University. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River, and encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory, the Bates Center, and the Haystack Observatory, as well as affiliated laboratories such as the Broad and Whitehead Institutes. , 98 ...
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Z Notation
The Z notation is a formal specification language used for describing and modelling computing systems. It is targeted at the clear specification of computer programs and computer-based systems in general. History In 1974, Jean-Raymond Abrial published "Data Semantics". He used a notation that would later be taught in the University of Grenoble until the end of the 1980s. While at EDF ( Électricité de France), working with Bertrand Meyer, Abrial also worked on developing Z. The Z notation is used in the 1980 book ''Méthodes de programmation''. Z was originally proposed by Abrial in 1977 with the help of Steve Schuman and Bertrand Meyer. It was developed further at the Programming Research Group at Oxford University, where Abrial worked in the early 1980s, having arrived at Oxford in September 1979. Abrial has said that Z is so named "Because it is the ultimate language!" although the name "Zermelo" is also associated with the Z notation through its use of Zermelo–Fraenkel ...
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Algebraic Specification
Algebraic specification is a software engineering technique for formally specifying system behavior. It was a very active subject of computer science research around 1980. Overview Algebraic specification seeks to systematically develop more efficient programs by: # formally defining types of data, and mathematical operations on those data types # abstracting implementation details, such as the size of representations (in memory) and the efficiency of obtaining outcome of computations # formalizing the computations and operations on data types # allowing for automation by formally restricting operations to this limited set of behaviors and data types. An algebraic specification achieves these goals by defining one or more data types, and specifying a collection of functions that operate on those data types. These functions can be divided into two classes: # Constructor functions: Functions that create or initialize the data elements, or construct complex elements from simpler ...
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Abstract Data Type
In computer science, an abstract data type (ADT) is a mathematical model for data types. An abstract data type is defined by its behavior (Semantics (computer science), semantics) from the point of view of a ''User (computing), user'', of the data, specifically in terms of possible values, possible operations on data of this type, and the behavior of these operations. This mathematical model contrasts with data structures, which are concrete representations of data, and are the point of view of an implementer, not a user. Formally, an ADT may be defined as a "class of objects whose logical behavior is defined by a set of values and a set of operations"; this is analogous to an algebraic structure in mathematics. What is meant by "behaviour" varies by author, with the two main types of formal specifications for behavior being ''axiomatic (algebraic) specification'' and an ''abstract model;'' these correspond to axiomatic semantics and operational semantics of an abstract machine, r ...
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C (programming Language)
C (''pronounced like the letter c'') is a General-purpose language, general-purpose computer programming language. It was created in the 1970s by Dennis Ritchie, and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted CPUs. It has found lasting use in operating systems, device drivers, protocol stacks, though decreasingly for application software. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the measuring programming language popularity, most widely used programming languages, with C compilers avail ...
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