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Flex Machine
The Flex Computer System was developed by Michael Foster and Ian Currie of Royal Signals and Radar Establishment (RSRE) in Malvern, England, during the late 1970s and 1980s. It used a tagged storage scheme to implement a capability architecture, and was designed for the safe and efficient implementation of strongly typed procedures. The hardware was custom and microprogrammable, with an operating system, (modular) compiler, editor, garbage collector and filing system all written in ALGOL 68RS. There were (at least) two incarnations of Flex, implemented using hardware with writable microcode. The first was supplied by Logica to an RSRE design, and the second used an ICL PERQ. The microcode alone was responsible for storage allocation, deallocation and garbage collection. This immediately precluded a whole class of errors arising from the misuse (deliberate or accidental) of pointers. A notable feature of Flex was the tagged, write-once filestore. This allowed arbitrary code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Signals And Radar Establishment
The Royal Signals and Radar Establishment (RSRE) was a scientific research establishment within the Ministry of Defence (MoD) of the United Kingdom. It was located primarily at Malvern in Worcestershire, England. The RSRE motto was ''Ubique Sentio'' (Latin for "I sense everywhere"). History RSRE was formed in 1976 by an amalgamation of previous research organizations; these included the Royal Radar Establishment (RRE), itself derived from the World War II-era Telecommunications Research Establishment, the Signals Research and Development Establishment (SRDE) in Christchruch, Dorset, and the Services Electronic Research Laboratory (SERL) at Baldock. Beginning in 1979, the SRDE and SERL moved to Malvern to join the RRE's location.EdsRobert Budand Philip Gummett, ''Cold War Hot Science: Applied Research in Britain's Defence Laboratories 1945-1990'', Harwood, 1999 There were several out-stations in Worcestershire, including the ex-RAF airfields at Defford and Pershore and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activation Record
In computer science, a call stack is a Stack (abstract data type), stack data structure that stores information about the active subroutines of a computer program. This kind of stack is also known as an execution stack, program stack, control stack, run-time stack, or machine stack, and is often shortened to just "the stack". Although maintenance of the call stack is important for the proper functioning of most software, the details are normally hidden and automatic in high-level programming languages. Many computer instruction sets provide special instructions for manipulating stacks. A call stack is used for several related purposes, but the main reason for having one is to keep track of the point to which each active subroutine should return control when it finishes executing. An active subroutine is one that has been called, but is yet to complete execution, after which control should be handed back to the point of call. Such activations of subroutines may be nested to any le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capability Systems
A capability is the ability to execute a specified course of action or to achieve certain outcomes. As it applies to human capital, capability represents performing or achieving certain actions/outcomes in terms of the intersection of capacity and ability. Capability may also refer to: Engineering * Capability (systems engineering), the ability to execute a specified course of action * Capability management, integrative management function in the defense sector Computing * Capability-based addressing, scheme used by some computers to control access to memory * Capability-based security, concept in the design of secure computing systems Economics * Capability Maturity Model, a development model * Capability Maturity Model Integration, a process improvement training and appraisal program * Dynamic capabilities, theory in organizational sciences * Capability management in business, capacity, materials, and expertise an organization needs in order to perform core functions * Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computers Designed In The United Kingdom
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a nominally complete computer that includes the hardware, operating system (main software), and peripheral equipment needed and used for full operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster. A broad range of industrial and consumer products use computers as control systems. Simple special-purpose devices like microwave ovens and remote controls are included, as are factory devices like industrial robots and computer-aided design, as well as general-purpose devices like personal computers and mobile devices like smartphones. Computers power the Internet, which links bil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PS-algol
PS-algol is an orthogonally persistent programming language. PS-algol was an extension of the language S-algol implemented by the University of St Andrews and the University of Edinburgh, Scotland. S-algol was designed by Ron Morrison and extended by Pete Bailey, Fred Brown, Paul Cockshott, Ken Chisholm, and Al Dearle. These extensions were additional standard functions that provide a persistent heap that survives termination of PS-algol programs. PS-algol was the world's first fully implemented persistent programming language, and had many users both in academia and, notably, in International Computers Limited (ICL) research labs. History PS-algol was conceived by chance, when Ron Morrison was on sabbatical at the University of Edinburgh and met Malcolm Atkinson. Atkinson had been experimenting with persistent programming languages and was struggling to find a coherent model for a persistent Pascal variant. Morrison, whose interest in general-purpose programming had led to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ten15
Ten15 is an algebraically specified abstract machine. It was developed by Foster, Currie et al. at the Royal Signals and Radar Establishment at Malvern, Worcestershire, during the 1980s. It arose from earlier work on the Flex machine, which was a capability computer implemented via microcode. Ten15 was intended to offer an intermediate language common to all implementations of the Flex architecture for portability purposes. It had the side effect of making the benefits of that work available on modern processors lacking a microcode facility. Ten15 served as an intermediate language for compilers, but with several unique features, some of which have still to see the light of day in everyday systems. Firstly, it was strongly typed, yet wide enough in application to support most languages — C being an exception, chiefly because C deliberately treats an array similar to a pointer to the first element of that array. This ultimately led to Ten15's development into TDF, which in turn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Radar Establishment Automatic Computer
The Royal Radar Establishment Automatic Computer (RREAC) was an early solid-state computer in 1962. It was made with transistors; many of Britain's previous experimental computers used the thermionic valve, also known as a vacuum tube. History Background Britain had built the world's first electronic computer, the Colossus computer, during the war at Bletchley Park in late 1943 and early 1944, and the world's first stored-program computer, the Manchester Baby, on 21 June 1948. The Germans had built the electro-mechanical Z3 in 1941 in Berlin, which used relays. The world's first digital computing device was the Atanasoff–Berry computer in 1942. ENIAC was built in 1946 at the Moore School of Electrical Engineering at the University of Pennsylvania. ENIAC and Colossus both claim to be the world's first electronic computer. Electronic Delay Storage Automatic Calculator (EDSAC) ran its first programs on 6 May 1949 at the University of Cambridge Mathematical Laboratory about a mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEE Proceedings E - Computers And Digital Techniques (IEEE)
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IEE may stand for: * Industrial Electronic Engineers, an aerospace display manufacturer * Initial Environmental Evaluation, a preliminary environmental impact assessment * Institute for Energy Efficiency, a research institute at the University of California, Santa Barbara * Institute for Energy & Environment, at New Mexico State University * Institution of Electrical Engineers, a British professional organisation now part of the Institution of Engineering and Technology * Instituto de Estudos Empresariais, a Brazilian non-profit * Intuitive Ethical Extrovert, in socionics * Intelligent Energy Europe, CIP Operational programme See also * Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remote Procedure Call
In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure (subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction. That is, the programmer writes essentially the same code whether the subroutine is local to the executing program, or remote. This is a form of client–server interaction (caller is client, executor is server), typically implemented via a request–response message-passing system. In the object-oriented programming paradigm, RPCs are represented by remote method invocation (RMI). The RPC model implies a level of location transparency, namely that calling procedures are largely the same whether they are local or remote, but usually, they are not identical, so local calls can be distinguished from remote calls. Remote calls are usually orde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garbage Collection (computer Science)
In computer science, garbage collection (GC) is a form of automatic memory management. The ''garbage collector'' attempts to reclaim memory which was allocated by the program, but is no longer referenced; such memory is called '' garbage''. Garbage collection was invented by American computer scientist John McCarthy around 1959 to simplify manual memory management in Lisp. Garbage collection relieves the programmer from doing manual memory management, where the programmer specifies what objects to de-allocate and return to the memory system and when to do so. Other, similar techniques include stack allocation, region inference, and memory ownership, and combinations thereof. Garbage collection may take a significant proportion of a program's total processing time, and affect performance as a result. Resources other than memory, such as network sockets, database handles, windows, file descriptors, and device descriptors, are not typically handled by garbage collection, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malvern, Worcestershire
Malvern is a spa town and civil parish in Worcestershire, England. It lies at the foot of the Malvern Hills, a designated Area of Outstanding Natural Beauty. The centre of Malvern, Great Malvern, is a historic conservation area, which grew dramatically in Victorian times due to the natural mineral water springs in the vicinity, including Malvern Water. At the 2011 census it had a population of 29,626. It includes Great Malvern on the steep eastern flank of the Malvern Hills, as well as the former independent urban district of Malvern Link. Many of the major suburbs and settlements that comprise the town are separated by large tracts of open common land and fields, and together with smaller civil parishes adjoining the town's boundaries and the hills, the built up area is often referred to collectively as The Malverns. Archaeological evidence suggests that Bronze Age people had settled in the area around 1000 BC, although it is not known whether these settlements were permane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weak Reference
In computer programming, a weak reference is a reference that does not protect the referenced object from collection by a garbage collector, unlike a strong reference. An object referenced ''only'' by weak references – meaning "every chain of references that reaches the object includes at least one weak reference as a link" – is considered '' weakly reachable,'' and can be treated as unreachable and so may be collected at any time. Some garbage-collected languages feature or support various levels of weak references, such as C#, Java, Lisp, OCaml, Perl, Python and PHP since the version 7.4. Uses Weak references have a number of common uses. When using reference counting garbage collection, weak references can break reference cycles, by using a weak reference for a link in the cycle. When one has an associative array (mapping, hash map) whose keys are (references to) objects, for example to hold auxiliary data about objects, using weak references for the keys avoids keeping the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
