 Hexley, the mascot of OpenDarwin OpenDarwin is a freely available, multi-platform BSD / Mach 3.0-based UNIX-like operating system. Picture of Hexley. ...
Picture of Hexley. ...
Berkeley Software Distribution (BSD) is the UNIX derivative distributed by the University of California, Berkeley starting in the 1970s. ...
Mach is an operating system kernel developed at Carnegie-Mellon University to support operating system research, primarily distributed and parallel computation. ...
A Unix-like operating system is one that behaves in a manner similar to a UNIX system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ...
In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ...
The goal of the OpenDarwin project, founded in April 2002, is to create an independent branch of the Darwin operating system that increases collaboration between Apple developers and the open source community. Apple benefits from the project because development in OpenDarwin is often incorporated into Darwin releases; and the open source community benefits since it is given complete control over its own operating system. April is the fourth month of the year in the Gregorian Calendar and one of four with the length of 30 days. ...
2002 is a common year starting on Tuesday of the Gregorian calendar. ...
Hexley, the mascot of Darwin Unix-like, filiation on Unixs systems. ...
Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ...
The mascot of OpenDarwin is Hexley the platypus. Mascots at the Mascot Olympics in Orlando, FL. A mascot is something, typically an animal or human character used to represent a group with a common identity, such as a school, professional sports team, or corporation. ...
Hexley Hexley is the mascot of the open source operating system, Darwin, which is the core of Mac OS X. Hexley is a cartoon platypus that usually wears a cap which resembles a daemons horns and carries a trident, similar to the BSD Daemon. ...
Binomial name Ornithorhynchus anatinus (Shaw, 1799) The platypus (Ornithorhynchus anatinus) is a small, half-aquatic mammal endemic to the eastern part of Australia, and one of the four extant monotremes, the only mammals that lay eggs instead of giving birth to live young (the other three are echidnas). ...
Kernel design
Like most modern kernels, OpenDarwin's is a hybrid, containing features of both monolithic and microkernels, attempting to make the best use of both technologies, such as the message passing capability of microkernels enabling larger portions of the OS to benefit from protected memory, as well as retaining the speed of monolithic kernels for certain critical tasks. In computer science, the kernel is the fundamental part of an operating system. ...
Memory protection is a system that prevents one process from corrupting the memory of another process running on the same computer at the same time. ...
The design allows many parts of the kernel to be migrated out into userland, whereby they will be more easily debugged as they will be smaller, isolated programs, instead of being small parts entwined in a larger chunk of code. The migration of select kernel code into userspace has the additional benefit of making the system more robust; if a userspace driver crashes, it will not crash the kernel.
The kernel xnu, is derived from a number of sources, particularly Mach 3.0 and FreeBSD 5.x. XNU is the name of the kernel used in the open source Darwin computer operating system, that Apple uses as the foundation of its Mac OS X operating system. ...
Mach is an operating system kernel developed at Carnegie-Mellon University to support operating system research, primarily distributed and parallel computation. ...
A rendering of the BSD daemon by Poul-Henning Kamp FreeBSD is a free, open source, Unix-like operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through 386BSD and 4. ...
Mach The core of the xnu kernel, Mach provides kernel threads, message-passing (used in inter-process communication), protected memory, virtual memory management, real-time support, kernel debugging support and console I/O. A thread in computer science is short for a thread of execution or a sequence of instructions. ...
The expression Inter-process communication (IPC) describes the exchange of data between one process and another, either within the same computer or over a network. ...
BSD The BSD portion of the kernel provides the POSIX API (BSD system calls), the process model, basic security policies, user ids, permissions, the networking code, the virtual filesystem code (including a filesystem independant journalling layer), cryptographic framework, System V IPC, and some of the locking primitives. POSIX is the collective name of a family of related standards specified by the IEEE to define the application program interface for software designed to run on variants of the Unix OS. They are formally designated as IEEE 1003 and the international standard name is ISO/IEC 9945. ...
API redirects here. ...
AT&T UNIX System V was one of the versions of the UNIX operating system. ...
I/O Kit This is the device driver framework, written in a subset of C++. Due to it's object-oriented design, device drivers can be written more quickly using less code as features common to any class of driver is provided within the framework itself. The I/O Kit is multi-threaded, SMP safe, and allows for hot pluggable devices and automatic and dynamic device configuration. A device driver, often called a driver for short, is a computer program that enables another program, typically, an operating system (e. ...
C++ (pronounced see plus plus) is a general-purpose computer programming language. ...
Object-oriented programming (OOP) is a computer programming paradigm in which a software system is modeled as a set of objects that interact with each other. ...
SMP is a Three letter abbreviation which can refer to the following: In computing: Symmetric multiprocessing, the use of multiple CPUs. ...
Many drivers can be written to run from user-space, which further enhances the stability of the system; if a userspace driver crashes, it will not crash the kernel.
Protecting shared resources In order to run safely on multiprocessor machines, access to shared resources (files, data structures etc.) must be serialized so that threads or processes do not attempt to modify the same resource at the same time. Atomic operations, spinlocks, critical sections, mutexes and serializing tokens are all possible methods that can be used to prevent concurrent access. Like both Linux and FreeBSD 5, OpenDarwin employs a fine-grained mutex model to achieve higher performance on multiprocessor systems. (disputed — see talk page) busy waiting is now its own page. ...
Mutual exclusion (often abbreviated to mutex) algorithms are used in concurrent programming to avoid the concurrent use of un-shareable resources by pieces of computer code called critical sections. ...
Multiprocessing is traditionally known as the use of multiple concurrent processes in a system as opposed to a single process at any one instant. ...
Supported processors Currently, OpenDarwin runs on x86 (Intel and AMD) based computers, as well as PowerPC based machines, both single processor and SMP models. x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ...
Intel Corporation (NASDAQ: INTC) (founded 1968) is a U.S.-based multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ...
Advanced Micro Devices, Inc. ...
PowerPC is a RISC microprocessor architecture created by the 1991 Apple-IBM-Motorola alliance, known as AIM. Originally intended for workstations, PowerPC CPUs have since become popular embedded and high-performance processors as well. ...
SMP is a Three letter abbreviation which can refer to the following: In computing: Symmetric multiprocessing, the use of multiple CPUs. ...
Development and distribution
Version management The OpenDarwin developers use a version control system called CVS to manage changes to the OpenDarwin source code. Many of the OpenDarwin developers are Apple employees, whereas others are not. It should be noted that the OpenDarwin project is fully independant of Apple, and has complete control over it's own code, though they generally try to stay compatible with Apple's own software. The Concurrent Versions System (CVS), also known as the Concurrent Versioning System, implements a version control system: it keeps track of all work and all changes in a set of files, typically the implementation of a software project, and allows several (potentially widely separated) developers to collaborate. ...
Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ...
Quality control Like most modern operating systems, OpenDarwin employs a built-in kernel debugger to help the developers find kernel bugs.
Releases
The current version OpenDarwin 8.2 corresponds to Mac OS X v10.4.2. Mac OS X is the latest version of the Mac OS, the operating system software for Macintosh computers. ...
See also Hexley, the mascot of Darwin Unix-like, filiation on Unixs systems. ...
Mac OS X is the latest version of the Mac OS, the operating system software for Macintosh computers. ...
External links - OpenDarwin community development site
- DarwinPorts project
- OpenDarwin's Bugzillla database
- Hexley, the Darwin mascot
- irc.freenode.net #opendarwin
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