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SeL4
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 created attention by being 20 times faster than Mach. The follow-up publication two years later was considered so influential that it won the 2015 ACM SIGOPS Hall of Fame Award. 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 L4 kernel application ...
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Microkernel
In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, thread (computing), thread management, and inter-process communication (IPC). If the hardware provides multiple Protection ring, rings or CPU modes, the microkernel may be the only software executing at the most privileged level, which is generally referred to as kernel mode, supervisor or kernel mode. Traditional operating system functions, such as device drivers, protocol stacks and file systems, are typically removed from the microkernel itself and are instead run in user space. In terms of the source code size, microkernels are often smaller than monolithic kernels. The MINIX 3 microkernel, for example, has only approximately 12,000 lines of code. History Microkernels trace their roots back to Danish computer pioneer Per Brinch ...
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Computer Security
Computer security (also cybersecurity, digital security, or information technology (IT) security) is a subdiscipline within the field of information security. It consists of the protection of computer software, systems and computer network, networks from Threat (security), threats that can lead to unauthorized information disclosure, theft or damage to computer hardware, hardware, software, or Data (computing), data, as well as from the disruption or misdirection of the Service (economics), services they provide. The significance of the field stems from the expanded reliance on computer systems, the Internet, and wireless network standards. Its importance is further amplified by the growth of smart devices, including smartphones, televisions, and the various devices that constitute the Internet of things (IoT). Cybersecurity has emerged as one of the most significant new challenges facing the contemporary world, due to both the complexity of information systems and the societi ...
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RISC-V
RISC-V (pronounced "risk-five") is an open standard instruction set architecture (ISA) based on established reduced instruction set computer (RISC) principles. The project commenced in 2010 at the University of California, Berkeley. It transferred to the RISC-V Foundation in 2015, and from there to RISC-V International, a Swiss non-profit entity, in November 2019. Similar to several other RISC ISAs, e.g. Amber (processor), Amber (ARMv2)(2001), SuperH#J_Core, J-Core(2015), OpenRISC(2000), or OpenSPARC(2005), RISC-V is offered under royalty-free open-source licenses. The documents defining the RISC-V instruction set architecture (ISA) are offered under a Creative Commons license or a BSD licenses, BSD License. Mainline support for RISC-V was added to the Linux 5.17 kernel in 2022, along with its toolchain. In July 2023, RISC-V, in its 64-bit computing, 64-bit variant called riscv64, was included as an official architecture of Linux distribution Debian, in its Debian version histor ...
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ARM Architecture
ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of reduced instruction set computer, RISC instruction set architectures (ISAs) for central processing unit, computer processors. Arm Holdings develops the ISAs and licenses them to other companies, who build the physical devices that use the instruction set. It also designs and licenses semiconductor intellectual property core, cores that implement these ISAs. Due to their low costs, low power consumption, and low heat generation, ARM processors are useful for light, portable, battery-powered devices, including smartphones, laptops, and tablet computers, as well as embedded systems. However, ARM processors are also used for desktop computer, desktops and server (computing), servers, including Fugaku (supercomputer), Fugaku, the world's fastest supercomputer from 2020 to 2022. With over 230 billion ARM chips produced, , ARM is the most widely used ...
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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. Career 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, ...
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POSIX
The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers. As of POSIX 2024, the standard is aligned with the C17 language standard. Name Originally, the name "POSIX" referred to IEEE Std 1003.1-1988, released in 1988. The family of POSIX standards is formally designated as IEEE 1003 and the ISO/IEC standard number is ISO/ IEC 9945. The standards emerged from a project that began in 1984 building on work from related activity in the ''/usr/group'' association. Richard Stallman suggested the name ''POSIX'' to the IEEE instead of the former ''IEEE-IX''. Th ...
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Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ...
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Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like Application software, application is one that behaves like the corresponding List of POSIX commands, Unix command or Unix shell, shell. Although there are general Unix philosophy, philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like. Some well-known examples of Unix-like operating systems include Linux, FreeBSD and OpenBSD. These systems are often used on servers as well as on personal computers and other devices. Many popular applications, such as the Apache HTTP Server, Apache web server and the Bash (Unix shell), Bash shell, are also designed to be used on Unix-like systems. Definition The Open ...
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Computer Scientist
A computer scientist is a scientist who specializes in the academic study of computer science. Computer scientists typically work on the theoretical side of computation. Although computer scientists can also focus their work and research on specific areas (such as algorithm and data structure development and design, software engineering, information theory, database theory, theoretical computer science, numerical analysis, programming language theory, compiler, computer graphics, computer vision, robotics, computer architecture, operating system), their foundation is the theoretical study of computing from which these other fields derive. A primary goal of computer scientists is to develop or validate models, often mathematical, to describe the properties of computational systems (Processor (computing), processors, programs, computers interacting with people, computers interacting with other computers, etc.) with an overall objective of discovering designs that yield useful ...
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Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total population of over 84 million in an area of , making it the most populous member state of the European Union. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The Capital of Germany, nation's capital and List of cities in Germany by population, most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic peoples, Germanic tribes have inhabited the northern parts of modern Germany since classical ...
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BSD Licenses
BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses. BSD is both a license and a class of license (generally referred to as BSD-like). The modified BSD license (in wide use today) is very similar to the license originally used for the BSD version of Unix. The BSD license is a simple license that merely requires that all code retain the BSD license notice if redistributed in source code format, or reproduce the notice if redistributed in binary format. The BSD license (unlike some other licenses e.g. GPL) does not require that source code be distributed at all. Terms In addition to ...
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