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RC 4000 Multiprogramming System
The RC 4000 Multiprogramming System (also termed Monitor or RC 4000 depending on reference) is a discontinued operating system developed for the RC 4000 minicomputer in 1969. For clarity, this article mostly uses the term Monitor. Overview The RC 4000 Multiprogramming System is historically notable for being the first attempt to break down an operating system into a group of interacting programs communicating via a message passing kernel. RC 4000 was not widely used, but was highly influential, sparking the microkernel concept that dominated operating system research through the 1970s and 1980s. Monitor was created largely by one programmer, Per Brinch Hansen, who worked at Regnecentralen where the RC 4000 was being designed. Leif Svalgaard participated in implementing and testing Monitor. Brinch Hansen found that no existing operating system was suited to the new machine, and was tired of having to adapt existing systems. He felt that a better solution was to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regnecentralen
Regnecentralen (RC) was the first Denmark, Danish computer company, founded on October 12, 1955. Through the 1950s and 1960s, they designed a series of computers, originally for their own use, and later to be sold commercially. Descendants of these systems sold well into the 1980s. They also developed a series of high-speed paper tape machines, and produced Data General Nova machines under license. Genesis What would become RC began as an advisory board formed by the Danish ''Akademiet for de Tekniske Videnskaber'' (''Academy of Applied Sciences'') to keep abreast of developments in modern electronic Computer, computing devices taking place in other countries. After several years in the advisory role, in 1952 they decided to form a computing service bureau for Danish government, military and research uses. Led by Niels Ivar Bech, the group was also given the details of the BESK machine being designed at the Swedish Mathematical Center (Matematikmaskinnämndens Arbetsgrupp). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Input/output
In computing, input/output (I/O, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. Inputs are the signals or data received by the system and outputs are the signals or data sent from it. The term can also be used as part of an action; to "perform I/O" is to perform an input or output operation. are the pieces of hardware used by a human (or other system) to communicate with a computer. For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations. Any interaction with the system by a interactor is an input and the reaction the system responds is called the output. The designation of a device as either input or output depends on perspective. Mice a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Association For Computing Machinery
The Association for Computing Machinery (ACM) is a US-based international learned society for computing. It was founded in 1947 and is the world's largest scientific and educational computing society. The ACM is a non-profit professional membership group, claiming nearly 110,000 student and professional members . Its headquarters are in New York City. The ACM is an umbrella organization for academic and scholarly interests in computer science ( informatics). Its motto is "Advancing Computing as a Science & Profession". History In 1947, a notice was sent to various people: On January 10, 1947, at the Symposium on Large-Scale Digital Calculating Machinery at the Harvard computation Laboratory, Professor Samuel H. Caldwell of Massachusetts Institute of Technology spoke of the need for an association of those interested in computing machinery, and of the need for communication between them. ..After making some inquiries during May and June, we believe there is ample interest to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Operating Systems
This article presents a timeline of events in the history of computer operating systems from 1951 to the current day. For a narrative explaining the overall developments, see the History of operating systems. 1950s * 1951 ** LEO I 'Lyons Electronic Office' was the commercial development of EDSAC computing platform, supported by British firm J. Lyons and Co. * 1955 ** MIT's Tape Director operating system made for UNIVAC 1103 The UNIVAC 1103 or ERA 1103, a successor to the UNIVAC 1101, was a computer system designed by Engineering Research Associates and built by the Remington Rand corporation in October 1953. It was the first computer for which Seymour Cray was cred ... * 1955 ** GM-NAA I/O, General Motors Operating System made for IBM 701 * 1956 ** GM-NAA I/O for IBM 704, based on General Motors Operating System * 1957 ** Atlas Supervisor (University of Manchester, Manchester University) (''Atlas computer project start'') ** BESYS (Bell Labs), for IBM 704, later IBM 7090 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
THE Multiprogramming System
The THE multiprogramming system or THE OS was a computer operating system designed by a team led by Edsger W. Dijkstra, described in monographs in 1965-66 (Jun 14, 1965) and published in 1968. Dijkstra never named the system; "THE" is simply the abbreviation of "Technische Hogeschool Eindhoven", then the name (in Dutch) of the Eindhoven University of Technology of the Netherlands. The THE system was primarily a batch system that supported multitasking; it was not designed as a multi-user operating system. It was much like the SDS 940, but "the set of processes in the THE system was static". The THE system apparently introduced the first forms of software-based paged virtual memory (the Electrologica X8 did not support hardware-based memory management), freeing programs from being forced to use physical locations on the drum memory. It did this by using a modified ALGOL compiler (the only programming language supported by Dijkstra's system) to "automatically generate call ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L4 Microkernel Family
L4 is a family of second-generation microkernels, used to implement a variety of types of operating systems (OS), though mostly for Unix-like, ''Portable Operating System Interface'' (POSIX) compliant types. L4, like its predecessor microkernel L3, was created by German computer scientist Jochen Liedtke as a response to the poor performance of earlier microkernel-based OSes. Liedtke felt that a system designed from the start for high performance, rather than other goals, could produce a microkernel of practical use. His original implementation in hand-coded Intel i386-specific assembly language code in 1993 sparked intense interest in the computer industry. Since its introduction, L4 has been developed to be cross-platform and to improve security, isolation, and robustness. There have been various re-implementations of the original binary L4 kernel application binary interface (ABI) and its successors, including ''L4Ka::Pistachio'' (Karlsruhe Institute of Technology), ''L4/MIPS' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jochen Liedtke
Jochen Liedtke (26 May 1953 – 10 June 2001) was a German computer scientist, noted for his work on microkernel operating systems, especially in creating the L4 microkernel family. Vita Education In the mid-1970s Liedtke studied for a diploma degree in mathematics at the Bielefeld University. His thesis project was to build a compiler for the programming language ELAN, which had been launched for teaching programming in German schools. The compiler was written in ELAN. Post grad After his graduation in 1977, he remained at Bielefeld and worked on an Elan environment for the Zilog Z80 microprocessor. This required a runtime system (environment), which he named Eumel ("Extendable Multiuser Microprocessor ELAN-System", but also a colloquial north-German term for likeable fool. Eumel grew into a complete multi-tasking, multi-user operating system supporting orthogonal persistence, which started shipping (by whom? to whom?) in 1980 and was later ported to Zilog Z8000, Motoro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copy-on-write
Copy-on-write (COW), sometimes referred to as implicit sharing or shadowing, is a resource-management technique used in computer programming to efficiently implement a "duplicate" or "copy" operation on modifiable resources. If a resource is duplicated but not modified, it is not necessary to create a new resource; the resource can be shared between the copy and the original. Modifications must still create a copy, hence the technique: the copy operation is deferred until the first write. By sharing resources in this way, it is possible to significantly reduce the resource consumption of unmodified copies, while adding a small overhead to resource-modifying operations. In virtual memory management Copy-on-write finds its main use in sharing the virtual memory of operating system processes, in the implementation of the fork system call. Typically, the process does not modify any memory and immediately executes a new process, replacing the address space entirely. Thus, it would be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Management Unit
A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit having all memory references passed through itself, primarily performing the translation of virtual memory addresses to physical addresses. An MMU effectively performs virtual memory management, handling at the same time memory protection, cache control, bus arbitration and, in simpler computer architectures (especially 8-bit systems), bank switching. Overview Modern MMUs typically divide the virtual address space (the range of addresses used by the processor) into pages, each having a size which is a power of 2, usually a few kilobytes, but they may be much larger. The bottom bits of the address (the offset within a page) are left unchanged. The upper address bits are the virtual page numbers. Page table entries Most MMUs use an in-memory table of items called a "page table", containing one "page table entry" (PTE) per page, to map virtual page numbers to ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Real-time Computing
Real-time computing (RTC) is the computer science term for hardware and software systems subject to a "real-time constraint", for example from event to system response. Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines". Ben-Ari, Mordechai; "Principles of Concurrent and Distributed Programming", ch. 16, Prentice Hall, 1990, , page 164 Real-time responses are often understood to be in the order of milliseconds, and sometimes microseconds. A system not specified as operating in real time cannot usually ''guarantee'' a response within any timeframe, although ''typical'' or ''expected'' response times may be given. Real-time processing ''fails'' if not completed within a specified deadline relative to an event; deadlines must always be met, regardless of system load. A real-time system has been described as one which "controls an environment by receiving data, processing them, and returning the results sufficiently quic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batch Processing
Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically be run at scheduled times as well as being run contingent on the availability of computer resources. History The term "batch processing" originates in the traditional classification of methods of production as job production (one-off production), batch production (production of a "batch" of multiple items at once, one stage at a time), and flow production (mass production, all stages in process at once). Early history Early computers were capable of running only one program at a time. Each user had sole control of the machine for a scheduled period of time. They would arrive at the computer with program and data, often on punched paper cards and magnetic or paper tape, and would load their program, run and debug it, and carry off their ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
