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L2 (operating System)
EUMEL (pronounced ''oimel'' for Extendable Multi User Microprocessor ELAN System and also known as L2 for Liedtke 2) is an operating system (OS) which began as a runtime system (environment) for the programming language ELAN. It was created in 1979 by Jochen Liedtke at the Bielefeld University. EUMEL initially ran on the 8-bit Zilog Z80 processor. It later was ported to many different computer architectures. More than 2000 Eumel systems shipped, mostly to schools and also to legal practices as a text processing platform. EUMEL is based on a virtual machine using a bitcode and achieves remarkable performance and function. Z80-based EUMEL systems provide full multi-user multi-tasking operation with virtual memory management and complete isolation of one process against all others. These systems usually execute ELAN programs faster than equivalent programs written in languages such as COBOL, BASIC, or Pascal, and compiled into Z80 machine code on other operating systems. One of the ... [...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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bielefeld University
Bielefeld University (german: Universität Bielefeld) is a university in Bielefeld, Germany. Founded in 1969, it is one of the country's newer universities, and considers itself a "reform" university, following a different style of organization and teaching than the established universities. In particular, the university aims to "re-establish the unity between research and teaching", and so all its faculty teach courses in their area of research. The university also stresses a focus on interdisciplinary research, helped by the architecture, which encloses all faculties in one great structure. It is among the first of the German universities to switch some faculties (e.g. biology) to Bachelor/ Master-degrees as part of the Bologna process. Bielefeld University has started an extensive multi-phase modernisation project, which is to be completed by 2025. A total investment of more than 1 billion euros has been planned for this undertaking. Campus The university is located i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthogonal Persistence
In computer science, persistence refers to the characteristic of state of a system that outlives (persists more than) the process that created it. This is achieved in practice by storing the state as data in computer data storage. Programs have to transfer data to and from storage devices and have to provide mappings from the native programming-language data structures to the storage device data structures. Picture editing programs or word processors, for example, achieve state persistence by saving their documents to files. Orthogonal or transparent persistence Persistence is said to be "orthogonal" or "transparent" when it is implemented as an intrinsic property of the execution environment of a program. An orthogonal persistence environment does not require any specific actions by programs running in it to retrieve or save their state. Non-orthogonal persistence requires data to be written and read to and from storage using specific instructions in a program, resulting in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crash (computing)
In computing, a crash, or system crash, occurs when a computer program such as a software application or an operating system stops functioning properly and exits. On some operating systems or individual applications, a crash reporting service will report the crash and any details relating to it (or give the user the option to do so), usually to the developer(s) of the application. If the program is a critical part of the operating system, the entire system may crash or hang, often resulting in a kernel panic or fatal system error. Most crashes are the result of a software bug. Typical causes include accessing invalid memory addresses, incorrect address values in the program counter, buffer overflow, overwriting a portion of the affected program code due to an earlier bug, executing invalid machine instructions (an illegal opcode), or triggering an unhandled exception. The original software bug that started this chain of events is typically considered to be the cause ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persistence (computer Science)
In computer science, persistence refers to the characteristic of state of a system that outlives (persists more than) the process that created it. This is achieved in practice by storing the state as data in computer data storage. Programs have to transfer data to and from storage devices and have to provide mappings from the native programming-language data structures to the storage device data structures. Picture editing programs or word processors, for example, achieve state persistence by saving their documents to files. Orthogonal or transparent persistence Persistence is said to be "orthogonal" or "transparent" when it is implemented as an intrinsic property of the execution environment of a program. An orthogonal persistence environment does not require any specific actions by programs running in it to retrieve or save their state. Non-orthogonal persistence requires data to be written and read to and from storage using specific instructions in a program, resulting i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine Code
In computer programming, machine code is any low-level programming language, consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). Each instruction causes the CPU to perform a very specific task, such as a load, a store, a jump, or an arithmetic logic unit (ALU) operation on one or more units of data in the CPU's registers or memory. Early CPUs had specific machine code that might break backwards compatibility with each new CPU released. The notion of an instruction set architecture (ISA) defines and specifies the behavior and encoding in memory of the instruction set of the system, without specifying its exact implementation. This acts as an abstraction layer, enabling compatibility within the same family of CPUs, so that machine code written or generated according to the ISA for the family will run on all CPUs in the family, including future CPUs. In general, each architecture family (e.g. x86, ARM) has it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal (programming Language)
Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named in honour of the French mathematician, philosopher and physicist Blaise Pascal. Pascal was developed on the pattern of the ALGOL 60 language. Wirth was involved in the process to improve the language as part of the ALGOL X efforts and proposed a version named ALGOL W. This was not accepted, and the ALGOL X process bogged down. In 1968, Wirth decided to abandon the ALGOL X process and further improve ALGOL W, releasing this as Pascal in 1970. On top of ALGOL's scalars and arrays, Pascal enables defining complex datatypes and building dynamic and recursive data structures such as lists, trees and graphs. Pascal has strong typing on all objects, which means that one type of data cannot be converted to or interpreted as another without explicit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BASIC
BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College in 1963. They wanted to enable students in non-scientific fields to use computers. At the time, nearly all computers required writing custom software, which only scientists and mathematicians tended to learn. In addition to the program language, Kemeny and Kurtz developed the Dartmouth Time Sharing System (DTSS), which allowed multiple users to edit and run BASIC programs simultaneously on remote terminals. This general model became very popular on minicomputer systems like the PDP-11 and Data General Nova in the late 1960s and early 1970s. Hewlett-Packard produced an entire computer line for this method of operation, introducing the HP2000 series in the late 1960s and continuing sales into the 1980s. Many early video games trace their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COBOL
COBOL (; an acronym for "common business-oriented language") is a compiled English-like computer programming language designed for business use. It is an imperative, procedural and, since 2002, object-oriented language. COBOL is primarily used in business, finance, and administrative systems for companies and governments. COBOL is still widely used in applications deployed on mainframe computers, such as large-scale batch and transaction processing jobs. However, due to its declining popularity and the retirement of experienced COBOL programmers, programs are being migrated to new platforms, rewritten in modern languages or replaced with software packages. Most programming in COBOL is now purely to maintain existing applications; however, many large financial institutions were still developing new systems in COBOL as late as 2006. COBOL was designed in 1959 by CODASYL and was partly based on the programming language FLOW-MATIC designed by Grace Hopper. It was created ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Text Processing
In computing, the term text processing refers to the theory and practice of automating the creation or manipulation of electronic text. ''Text'' usually refers to all the alphanumeric characters specified on the keyboard of the person engaging the practice, but in general ''text'' means the abstraction layer immediately above the standard character encoding of the target text. The term ''processing'' refers to automated (or mechanized) processing, as opposed to the same manipulation done manually. Text processing involves computer commands which invoke content, content changes, and cursor movement, for example to * search and replace * format * generate a processed report of the content of, or * filter a file or report of a text file. The text processing of a regular expression is a virtual editing machine, having a primitive programming language that has named registers (identifiers), and named positions in the sequence of characters comprising the text. Using these, the "text ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Architecture
In computer engineering, computer architecture is a description of the structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, the description may include the instruction set architecture design, microarchitecture design, logic design, and implementation. History The first documented computer architecture was in the correspondence between Charles Babbage and Ada Lovelace, describing the analytical engine. When building the computer Z1 (computer), Z1 in 1936, Konrad Zuse described in two patent applications for his future projects that machine instructions could be stored in the same storage used for data, i.e., the Stored-program computer, stored-program concept. Two other early and important examples are: * John von Neumann's 1945 paper, First Draft of a Report on the EDVAC, which described an organization of logical elements; and *Alan M. Turing, Alan Turing's mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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