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XNU
XNU ("X is Not Unix") is the computer operating system (OS) kernel developed at Apple Inc. since December 1996 for use in the Mac OS X (now macOS) operating system and released as free and open-source software as part of the Darwin OS, which, in addition to being the basis for macOS, is also the basis for Apple TV Software, iOS, iPadOS, watchOS, visionOS, and tvOS. XNU was originally developed by NeXT for the NeXTSTEP operating system. It was a hybrid kernel derived from version 2.5 of the Mach kernel developed at Carnegie Mellon University, which incorporated the bulk of the 4.3BSD kernel modified to run atop Mach primitives, along with an application programming interface (API) in Objective-C for writing drivers named DriverKit. After Apple acquired NeXT, the kernel was updated with code derived from OSFMK 7.3 from OSF, and the FreeBSD project, and the DriverKit was replaced with new API on a restricted subset of C++ (based on Embedded C++) named IOKit. By keeping the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin (operating System)
Darwin is the core Unix-like operating system of macOS, iOS, watchOS, tvOS, iPadOS, audioOS, visionOS, and bridgeOS. It previously existed as an independent open-source software, open-source operating system, first released by Apple Inc. in 2000. It is composed of code derived from NeXTSTEP, FreeBSD and other BSD operating systems, Mach (kernel), Mach, and other free software projects' code, as well as code developed by Apple. Darwin's unofficial mascot is Hexley the Platypus. Darwin is mostly POSIX-compatible, but has never, by itself, been certified as compatible with any version of POSIX. Starting with Mac OS X Leopard, Leopard, macOS has been certified as compatible with the Single UNIX Specification version 3 (SUSv3). History The heritage of Darwin began with Unix derivatives supplemented by aspects of NeXT's NeXTSTEP operating system (later, since version 4.0, known as OPENSTEP), first released in 1989. After Apple bought NeXT in 1996, it announced it would base its nex ... [...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] |
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] |
Kernel (operating System)
A kernel is a computer program at the core of a computer's operating system that always has complete control over everything in the system. The kernel is also responsible for preventing and mitigating conflicts between different processes. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the use of common resources, such as CPU, cache, file systems, and network sockets. On most systems, the kernel is one of the first programs loaded on startup (after the bootloader). It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit. The critical code of the kernel is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nukernel
NuKernel is a microkernel that was developed at Apple Computer during the early 1990s. It was the basis for the Copland operating system. It was written from scratch and designed using concepts from the Mach 3.0 microkernel, with extensive additions for soft real-time scheduling to improve multimedia performance. Only one NuKernel version was released, with a Copland alpha release. Development ended in 1996 with the cancellation of Copland. The External Reference Specification (ERS) for NuKernel is contained in its entirety in its patent. The one-time technical lead for NuKernel, Jeff Robbin, was one of the leaders of iTunes and the iPod. Apple's NuKernel is not the microkernel in BeOS, nukernel. See also *XNU, the microkernel in Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MacOS
macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. Within the market of Desktop computer, desktop and laptop computers, it is the Usage share of operating systems#Desktop and laptop computers, second most widely used desktop OS, after Microsoft Windows and ahead of all Linux distributions, including ChromeOS and SteamOS. , the most recent release of macOS is MacOS Sequoia, macOS 15 Sequoia, the 21st major version of macOS. Mac OS X succeeded classic Mac OS, the primary Mac operating systems, Macintosh operating system from 1984 to 2001. Its underlying architecture came from NeXT's NeXTSTEP, as a result of NeXT#1997–2006: Acquisition by Apple, Apple's acquisition of NeXT, which also brought Steve Jobs back to Apple. The first desktop version, Mac OS X 10.0, was released on March 24, 2001. Mac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of The Berkeley Software Distribution
The history of the Berkeley Software Distribution began in the 1970s when University of California, Berkeley received a copy of Unix. Professors and students at the university began adding software to the operating system and released it as BSD to select universities. Since it contained proprietary Unix code, it originally had to be distributed subject to AT&T licenses. The bundled software from AT&T was then rewritten and released as free software under the BSD license. However, this resulted in a lawsuit with Unix System Laboratories, the AT&T subsidiary responsible for Unix. Eventually, in the 1990s, the final versions of BSD were publicly released without any proprietary licenses, which led to many descendants of the operating system that are still maintained today. 1BSD (PDP-11) The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the operating system, allowing researchers at universities to modify and extend Unix. The operating system ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPadOS
iPadOS is a mobile operating system developed by Apple for its iPad line of tablet computers. It was given a name distinct from iOS, the operating system used by Apple's iPhones to reflect the diverging features of the two product lines, such as multitasking. It was introduced as iPadOS 13, reflecting its status as the successor to iOS 12 for the iPad, and first released to the public on September 24, 2019. Major versions of iPadOS are released annually; the current stable version, iPadOS 18.5, was released to the public on May 12, 2025. History The first iPad was introduced on January 10, 2010, and ran iPhone OS 3.2, which added support for the larger device to the operating system, previously only used on the iPhone and its smaller counterpart, the iPod Touch. This shared operating system was rebranded as iOS with the release of iOS 4 in June 2010. The operating system initially had rough feature parity running on the iPhone, iPod Touch, and iPad, with variations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X86-64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit extension of the x86 instruction set architecture, instruction set. It was announced in 1999 and first available in the AMD Opteron family in 2003. It introduces two new operating modes: 64-bit mode and compatibility mode, along with a new four-level paging mechanism. In 64-bit mode, x86-64 supports significantly larger amounts of virtual memory and physical memory compared to its 32-bit computing, 32-bit predecessors, allowing programs to utilize more memory for data storage. The architecture expands the number of general-purpose registers from 8 to 16, all fully general-purpose, and extends their width to 64 bits. Floating-point arithmetic is supported through mandatory SSE2 instructions in 64-bit mode. While the older x87 FPU and MMX registers are still available, they are generally superseded by a set of sixteen 128-bit Processor register, vector registers (XMM registers). Each of these vector registers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TvOS
tvOS (formerly Apple TV Software) is an operating system developed by Apple for the Apple TV, a digital media player. In the first-generation Apple TV, Apple TV Software was based on Mac OS X. The software for the second-generation and later Apple TVs is based on the iOS operating system and has many similar frameworks, technologies, and concepts. The second- and third-generation Apple TV have several built-in applications, but do not support third-party applications. On September 9, 2015, Apple announced the fourth-generation Apple TV, with support for third-party applications. Apple also changed the name of the Apple TV operating system to tvOS, adopting the camel case nomenclature that they were using for their other operating systems, iOS and watchOS. The latest version, tvOS 18, was released on September 16, 2024. History On October 30, 2015, the fourth-generation Apple TV became available; it shipped with tvOS 9.0. On November 9, 2015, tvOS 9.0.1 was released, pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VisionOS
visionOS is a mixed reality operating system derived primarily from iPadOS and its core frameworks (including UIKit, SwiftUI, ARKit and RealityKit), and MR-specific frameworks for foveated rendering and real-time interaction. It was developed by Apple Inc. exclusively for its Apple Vision Pro mixed reality headset. It was unveiled on June 5, 2023, at Apple's WWDC23 event alongside the reveal of the Apple Vision Pro. The software released on February 2, 2024, shipping with the Apple Vision Pro. History Apple has reportedly been working on and conceptualizing visionOS throughout the 2010s and early 2020s. Internally codenamed Borealis, it was officially revealed to the public at Apple's WWDC23 event alongside the Vision Pro. Apple stated the two would release in early 2024. App Store guidelines for the operating system similarly state that developers should refer to visionOS software as "spatial computing experiences" or "vision apps", and avoid the use of terms such as "a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
