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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] |
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] |
TenDRA Distribution Format
The abstract machine TDF (originally the Ten15 Distribution Format, but more recently redefined as the TenDRA Distribution Format) evolved at the Royal Signals and Radar Establishment in the UK as a successor to Ten15. Its design allowed support for the C programming language. TDF is the basis for the Architecture Neutral Distribution Format The Architecture Neutral Distribution Format (ANDF) in computing is a technology allowing common "shrink wrapped" binary application programs to be distributed for use on conformant Unix systems, translated to run on different underlying hardware .... External links A Guide to the TDF Specification, Issue 4.0(retrieved on 24 October 2007) {{compu-stub Executable file formats History of computing in the United Kingdom Malvern, Worcestershire Science and technology in Worcestershire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TenDRA Compiler
The TenDRA Compiler is a C/C++ compiler for POSIX-compatible operating systems available under the terms of the BSD license. It was originally developed by the Defence Evaluation and Research Agency (DERA) in the United Kingdom. In the beginning of 2002 TenDRA was actively developed again by Jeroen Ruigrok van der Werven and offered as a BSD-licensed open source project through the website tendra.org. In the third quarter of 2002 the one-man effort was expanded to a small team. The TDF technology behind TenDRA has an academic history dating back to work on algebraic code validation in the 1970s. In August 2003 TenDRA split into two projects, TenDRA.org and Ten15.org. Both projects seemed to have disappeared from the web around 2006–2007, but actually they are still active. The goals of TenDRA.org are: *to continuously produce correct code, *to ensure code correctness through various means, and *to continuously improve the performance of the compiler and resulting code, unl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Architecture Neutral Distribution Format
The Architecture Neutral Distribution Format (ANDF) in computing is a technology allowing common "shrink wrapped" binary application programs to be distributed for use on conformant Unix systems, translated to run on different underlying hardware platforms. ANDF was defined by the Open Software Foundation and was expected to be a "truly revolutionary technology that will significantly advance the cause of portability and open systems", but it was never widely adopted. As with other OSF offerings, ANDF was specified through an open selection process. OSF issued a Request for Technology for architecture-neutral software distribution technologies in April, 1989. Fifteen proposals were received, based on a variety of technical approaches, including obscured source code, compiler intermediate languages, and annotated executable code. The technology of ANDF, chosen after an evaluation of competing approaches and implementations, was Ten15 Distribution Format, later renamed TenDRA Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abstract Machine
An abstract machine is a computer science theoretical model that allows for a detailed and precise analysis of how a computer system functions. It is analogous to a mathematical function in that it receives inputs and produces outputs based on predefined rules. Abstract machines vary from literal machines in that they are expected to perform correctly and independently of hardware. Abstract machines are “machines” because they allow step-by-step execution of programmes; they are “ abstract” because they ignore many aspects of actual ( hardware) machines. A typical abstract machine consists of a definition in terms of input, output, and the set of allowable operations used to turn the former into the latter. They can be used for purely theoretical reasons as well as models for real-world computer systems. In the theory of computation, abstract machines are often used in thought experiments regarding computability or to analyse the complexity of algorithms. This use of abstr ... [...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] |
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] |
Capability-based Addressing
In computer science, capability-based addressing is a scheme used by some computers to control access to memory as an efficient implementation of capability-based security. Under a capability-based addressing scheme, pointers are replaced by protected objects (called capabilities) that can be created only through the use of privileged instructions which may be executed only by either the kernel or some other privileged process authorised to do so. Thus, a kernel can limit application code and other subsystems access to the minimum necessary portions of memory (and disable write access where appropriate), without the need to use separate address spaces and therefore require a context switch when an access occurs. Practical implementations Two techniques are available for implementation: *Require capabilities to be stored in a particular area of memory that cannot be written to by the process that will use them. For example, the Plessey System 250 required that all capabilities be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcode
In processor design, microcode (μcode) is a technique that interposes a layer of computer organization between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. Microcode is a layer of hardware-level instructions that implement higher-level machine code instructions or internal finite-state machine sequencing in many digital processing elements. Microcode is used in general-purpose central processing units, although in current desktop CPUs, it is only a fallback path for cases that the faster hardwired control unit cannot handle. Microcode typically resides in special high-speed memory and translates machine instructions, state machine data, or other input into sequences of detailed circuit-level operations. It separates the machine instructions from the underlying electronics so that instructions can be designed and altered more freely. It also facilitates the building of complex multi-step instructions, while red ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ian Currie (computer Scientist)
Ian or Iain is a name of Scottish Gaelic origin, derived from the Hebrew given name (Yohanan, ') and corresponding to the English name John. The spelling Ian is an Anglicization of the Scottish Gaelic forename ''Iain''. It is a popular name in Scotland, where it originated, as well as other English-speaking countries. The name has fallen out of the top 100 male baby names in the United Kingdom, having peaked in popularity as one of the top 10 names throughout the 1960s. In 1900, Ian was the 180th most popular male baby name in England and Wales. , the name has been in the top 100 in the United States every year since 1982, peaking at 65 in 2003. Other Gaelic forms of "John" include "Seonaidh" ("Johnny" from Lowland Scots), "Seon" (from English), "Seathan", and "Seán" and "Eoin" (from Irish). Its Welsh counterpart is Ioan, its Cornish equivalent is Yowan and Breton equivalent is Yann. Notable people named Ian As a first name (alphabetical by family name) *Ian Agol (born 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination. Virtual machines differ and are organized by their function, shown here: * '' System virtual machines'' (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs. * Process virtual machines are designed to execute computer programs in a platform-independent environment. Some virtual machine emulators, such as QEMU and video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Languages
A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Construction language – all forms of communication by which a human can specify an executable problem solution to a computer ** Command language – a language used to control the tasks of the computer itself, such as starting programs ** Configuration language – a language used to write configuration files ** Programming language – a formal language designed to communicate instructions to a machine, particularly a computer ** Query language – a language used to make queries in databases and information systems ** Transformation language – designed to transform some input text in a certain formal language into a modified output text that meets some specific goal * Data exchange language – a language that is domain-independent and can be used for data from any kind of discipline; examples: JSON, XML * Markup language – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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