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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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach (kernel)
Mach () is an operating system 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, not requiring a new operating system to be designed around it. Mach and its derivatives exist within several 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach Kernel
Mach () is an operating system 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, not requiring a new operating system to be designed around it. Mach and its derivatives exist within several 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 4.4BS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid Kernel
A hybrid kernel is an operating system Kernel (operating system), kernel whose architecture attempts to combine aspects and benefits of microkernel and monolithic kernel architectures used in 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 user space and kernel space, kernel space. There are none of the reliability benefits of having services in user space and kernel space, user space, as with a microke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mono-kernel
A monolithic kernel is an operating system architecture with the entire operating system running in kernel space. The monolithic model differs from other architectures such as the microkernel 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 loadable kernel modules. Examples *Most BSD kernels **FreeBSD **OpenBSD **NetBSD *Linux kernel ** Android *Other Unix/Unix-like kernels **AIX **Oracle Solaris *MS-DOS **Windows 9x *OpenVMS *Palm OS (version ≤ 5.0) Loadable modules Modular operating systems such as OS-9 and most modern monolithic-kernel operating systems such as OpenVMS, Linux, FreeBSD, NetBSD, DragonFly BSD, Solaris, and AIX can dynamically load (and unload) executable kernel modules at runtime. This modularity of the operating system is at the binary (ima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monolithic Kernel
A monolithic kernel is an operating system software architecture, architecture with the entire operating system running in kernel space. The monolithic model differs from other architectures such as the microkernel 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 (computing), process management, Concurrency (computer science), concurrency, and memory management. Device drivers can be added to the kernel as loadable kernel modules. Examples *Most BSD kernels **FreeBSD **OpenBSD **NetBSD *Linux kernel **Android (operating system), Android *Other Unix/Unix-like kernels **AIX **Oracle Solaris *MS-DOS **Windows 9x *OpenVMS *Palm OS (version ≤ 5.0) Loadable modules Modular operating systems such as OS-9 and most modern monolithic-kernel operating systems such as OpenVMS, Linux kernel, Linux, FreeBSD, NetBSD, DragonFly BSD, Oracle Solaris, Solaris, and AIX can d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OSFMK
OSF/1 is a variant of the Unix operating system developed by the Open Software Foundation during the late 1980s and early 1990s. OSF/1 is one of the first operating systems to have used the Mach kernel developed at Carnegie Mellon University, and is probably best known as the native Unix operating system for DEC Alpha architecture systems. In 1994, after AT&T had sold UNIX System V to Novell and the rival Unix International consortium had disbanded, the Open Software Foundation ceased funding of research and development of OSF/1. The Tru64 UNIX variant of OSF/1 was supported by HP until 2012. Background In 1988, during the so-called "Unix wars", Digital Equipment Corporation (DEC) joined with IBM, Hewlett-Packard, and others to form the Open Software Foundation (OSF) to develop a version of Unix named OSF/1. The aim was to compete with System V Release 4 from AT&T Corporation and Sun Microsystems, and it has been argued that a primary goal was for the operating system to be fr ... [...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 third generation computer 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 solut ... [...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. Biography Rashid was born in Fort Madison, Iowa, and is the son of Farris Rashid and Ramona Wright Rashid. Rashid graduated from Stanford University in 1974 with degrees in mathematics and comparative literature. He then received a Master of Science and a Ph.D. in computer science from the University of Rochester, finishing in 1980. While at Rochester, he and Gene Ball wrote what is probably one of the earliest networked multiplayer computer games, '' Alto Trek'', for Xerox Alto computers. 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 opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per Brinch Hansen
Per Brinch Hansen (13 November 1938 – 31 July 2007) was a Denmark, Danish-United States, American computer scientist known for his work in operating systems, Concurrent computing, concurrent Computer programming, programming and Parallel computing, parallel and distributed computing. Biography Early life and education Per Brinch Hansen was born in Frederiksberg, an enclave surrounded by Copenhagen, Denmark. His father, :de:Jørgen Brinch Hansen, 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 w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel Mode
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). On most operating systems, Ring 0 is the level with the most privileges and interacts most directly with the physical hardware such as certain CPU functionality (e.g. the control registers) and I/O controllers. Special mechanisms are provided ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
