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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 management, and inter-process communication (IPC). If the hardware provides multiple rings or CPU modes, the microkernel may be the only software executing at the most privileged level, which is generally referred to as 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 Hansen and his tenure in Danish computer compan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach Kernel
Mach () is a kernel developed at Carnegie Mellon University by Richard Rashid and Avie Tevanian to support operating system research, primarily distributed and parallel computing. Mach is often considered one of the earliest examples of a microkernel. However, not all versions of Mach are microkernels. Mach's derivatives are the basis of the operating system kernel in GNU Hurd and of Apple's XNU kernel used in macOS, iOS, iPadOS, tvOS, and watchOS. The project at Carnegie Mellon ran from 1985 to 1994, ending with Mach 3.0, which is a true microkernel. Mach was developed as a replacement for the kernel in the BSD version of Unix, so no new operating system would have to be designed around it. Mach and its derivatives exist within a number of commercial operating systems. These include all using the XNU operating system kernel which incorporates an earlier non-microkernel Mach as a major component. The Mach virtual memory management system was also adopted in 4.4BSD by the BSD dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach (kernel)
Mach () is a kernel developed at Carnegie Mellon University by Richard Rashid and Avie Tevanian to support operating system research, primarily distributed and parallel computing. Mach is often considered one of the earliest examples of a microkernel. However, not all versions of Mach are microkernels. Mach's derivatives are the basis of the operating system kernel in GNU Hurd and of Apple's XNU kernel used in macOS, iOS, iPadOS, tvOS, and watchOS. The project at Carnegie Mellon ran from 1985 to 1994, ending with Mach 3.0, which is a true microkernel. Mach was developed as a replacement for the kernel in the BSD version of Unix, so no new operating system would have to be designed around it. Mach and its derivatives exist within a number of commercial operating systems. These include all using the XNU operating system kernel which incorporates an earlier non-microkernel Mach as a major component. The Mach virtual memory management system was also adopted in 4.4BSD by the BSD de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid Kernel
A hybrid kernel is an operating system Kernel (computer science), kernel architecture that attempts to combine aspects and benefits of microkernel and monolithic kernel architectures used in computer operating systems. Overview The traditional kernel categories are monolithic kernels and microkernels (with nanokernels and exokernels seen as more extreme versions of microkernels). The "hybrid" category is controversial, due to the similarity of hybrid kernels and ordinary monolithic kernels; the term has been dismissed by Linus Torvalds as simple marketing. The idea behind a hybrid kernel is to have a kernel structure similar to that of a microkernel, but to implement that structure in the manner of a monolithic kernel. In contrast to a microkernel, all (or nearly all) operating system services in a hybrid kernel are still in kernel space. There are none of the reliability benefits of having services in user space, as with a microkernel. However, just as with an ordinary monolithic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mono-kernel
A monolithic kernel is an operating system architecture where the entire operating system is working in kernel space. The monolithic model differs from other operating system architectures (such as the microkernel architecture) in that it alone defines a high-level virtual interface over computer hardware. A set of primitives or system calls implement all operating system services such as process management, concurrency, and memory management. Device drivers can be added to the kernel as modules. Loadable modules Modular operating systems such as OS-9 and most modern monolithic operating systems such as OpenVMS, Linux, BSD, SunOS, AIX, and MULTICS can dynamically load (and unload) executable modules at runtime. This modularity of the operating system is at the binary (image) level and not at the architecture level. Modular monolithic operating systems are not to be confused with the architectural level of modularity inherent in server-client operating systems (and its derivat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monolithic Kernel
A monolithic kernel is an operating system architecture where the entire operating system is working in kernel space. The monolithic model differs from other operating system architectures (such as the microkernel architecture) in that it alone defines a high-level virtual interface over computer hardware. A set of primitives or system calls implement all operating system services such as process management, concurrency, and memory management. Device drivers can be added to the kernel as modules. Loadable modules Modular operating systems such as OS-9 and most modern monolithic operating systems such as OpenVMS, Linux, BSD, SunOS, AIX, and MULTICS can dynamically load (and unload) executable modules at runtime. This modularity of the operating system is at the binary (image) level and not at the architecture level. Modular monolithic operating systems are not to be confused with the architectural level of modularity inherent in server-client operating systems (and its derivat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MINIX 3
Minix 3 is a small, Unix-like operating system. It is published under a BSD-3-Clause license and is a successor project to the earlier versions, Minix 1 and 2. The project's main goal is for the system to be fault-tolerant by detecting and repairing its faults on the fly, with no user intervention. The main uses of the system are envisaged to be embedded systems and education. , Minix 3 supports IA-32 and ARM architecture processors. It can also run on emulators or virtual machines, such as Bochs, VMware Workstation, Microsoft Virtual PC, Oracle VirtualBox, and QEMU. A port to PowerPC architecture is in development. The distribution comes on a live CD and does not support live USB installation. Minix 3 is believed to have inspired the Intel Management Engine (ME) OS found in Intel's Platform Controller Hub, starting with the introduction of ME 11, which is used with Skylake and Kaby Lake processors. It was debated that Minix could have been the most widely used OS on x86/AM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Richard Rashid
Richard Farris Rashid is the founder of Microsoft Research, which he created in 1991. Between 1991 and 2013, as its chief research officer and director, he oversaw the worldwide operations for Microsoft Research which grew to encompass more than 850 researchers and a dozen labs around the world. Before joining Microsoft in 1991, Rashid had been the developer of the Mach kernel during his tenure as a professor of computer science at Carnegie Mellon University. The Mach multiprocessor operating system kernel developed by Rashid has had a lasting influence in the design of modern operating systems, including the design of Windows NT, and remains at the core of several operating systems such as NeXTSTEP, GNU Hurd, macOS, iOS, OSF/1, and Tru64 UNIX. Rashid's Mach kernel pioneered the concepts of microkernel architecture and its impact can be traced in today's computing landscape with hundreds of millions of people still using Mach based operating systems thirty years after its creati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per Brinch Hansen
Per Brinch Hansen (13 November 1938 – 31 July 2007) was a Danish-American computer scientist known for his work in operating systems, concurrent programming and parallel and distributed computing. Biography Early life and education Per Brinch Hansen was born in Frederiksberg, an enclave surrounded by Copenhagen, Denmark. His father, Jørgen Brinch Hansen, worked as a civil engineer, becoming a leading expert in soil mechanics, and later accepting a professorship at Technical University of Denmark. His mother, Elsebeth Brinch Hansen (née Ring), was the daughter of Danish composer Oluf Ring and worked as a hairdresser before marrying. Brinch Hansen attended Skt. Jørgens Gymnasium and then studied electrical engineering at Technical University of Denmark where he sought an area to pursue that "was still in its pioneering phase" on the belief that "If a subject was being taught, it was probably already too late to make fundamental contributions." After a seven-week student ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protection Ring
In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (by improving fault tolerance) and malicious behavior (by providing computer security). Computer operating systems provide different levels of access to resources. A protection ring is one of two or more hierarchical ''levels'' or ''layers'' of privilege within the architecture of a computer system. This is generally hardware-enforced by some CPU architectures that provide different CPU modes at the hardware or microcode level. Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered zero) to least privileged (least trusted, usually with the highest ring number). Ring 0 is the level with the most privileges and allows direct interaction with the physical hardware such as certain CPU functionality and chips on the motherboard. Special call gates between rings are provided to allow an outer ring to acces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exec (Amiga)
Exec is the kernel of AmigaOS. It is a 13 KB multitasking microkernel which enabled pre-emptive multitasking in as little as 256 KB of memory (as supplied with the first Amiga 1000s). Exec provided functions for multitasking, memory management, and handling of interrupts and dynamic shared libraries. It acts as a scheduler for tasks running on the system, providing pre-emptive multitasking with prioritized round-robin scheduling. Exec also provides access to other libraries and high-level inter-process communication via message passing. Other comparable microkernels have had performance problems because of the need to copy messages between address spaces. Since the Amiga has only one address space, Exec message passing is quite efficient. The only fixed memory address in the Amiga software (address 4) is a pointer to exec.library, which can then be used to access other libraries. Exec was designed and implemented by Carl Sassenrath. Exec Unlike newer modern operating ... [...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] |
