Kernel (operating system)The kernel is a computer program at the core of a computer's operating system and generally has complete control over everything in the system. 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 utilization of common resources e.
Operating systemAn operating system (OS) is system software that manages computer hardware and software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, peripherals, and other resources.
OS/2OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 relative to Microsoft's new Windows 3.1 operating environment, the two companies severed the relationship in 1992 and OS/2 development fell to IBM exclusively. The name stands for "Operating System/2", because it was introduced as part of the same generation change release as IBM's "Personal System/2 (PS/2)" line of second-generation personal computers.
Linux kernelThe Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally written in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU operating system, which was written to be a free (libre) replacement for Unix. Linux is provided under the GNU General Public License version 2 only, but it contains files under other compatible licenses.
Mobile operating systemA mobile operating system is an operating system for smartphones, tablets, smartwatches, smartglasses, or other non-laptop personal mobile computing devices. While computers such as typical/mobile laptops are "mobile", the operating systems used on them are generally not considered mobile ones, as they were originally designed for desktop computers that historically did not have or need specific mobile features. This line distinguishing mobile and other forms has become blurred in recent years, due to the fact that newer devices have become smaller and more mobile unlike hardware of the past.
MacOSmacOS (ˌmækoʊˈɛs; previously OS X and originally Mac OS X) is an operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and laptop computers, it is the second most widely used desktop OS, after Microsoft Windows and ahead of Linux (including ChromeOS). macOS succeeded the classic Mac OS, a Mac operating system with nine releases from 1984 to 1999.
Comparison of operating systemsThese tables provide a comparison of operating systems, of computer devices, as listing general and technical information for a number of widely used and currently available PC or handheld (including smartphone and tablet computer) operating systems. The article "Usage share of operating systems" provides a broader, and more general, comparison of operating systems that includes servers, mainframes and supercomputers.
ReactOSReactOS is a free and open-source operating system for amd64/i686 personal computers intended to be binary-compatible with computer programs and device drivers developed for Windows Server 2003 and later versions of Microsoft Windows. ReactOS has been noted as a potential open-source drop-in replacement for Windows and for its information on undocumented Windows APIs. ReactOS has been in development since 1996. , it is still considered feature-incomplete alpha software, and is therefore recommended by the developers only for evaluation and testing purposes.
Mac OS X LeopardMac OS X Leopard (version 10.5) is the sixth major release of macOS, Apple's desktop and server operating system for Macintosh computers. Leopard was released on October 26, 2007 as the successor of Mac OS X 10.4 Tiger, and is available in two editions: a desktop version suitable for personal computers, and a server version, Mac OS X Server. It retailed for 129forthedesktopversionand499 for Server. Leopard was superseded by Snow Leopard (version 10.6) in 2009. Monolithic kernelA 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.
Usage share of operating systemsThe usage share of operating systems is the percentage of computing devices that run each operating system (OS) at any particular time. All such figures are necessarily estimates because data about operating system share is difficult to obtain. There are few reliable primary sources and no agreed methodologies for its collection. Operating systems are used in the vast majority of computers, from embedded devices to supercomputers.
Loadable kernel moduleIn computing, a loadable kernel module (LKM) is an that contains code to extend the running kernel, or so-called base kernel, of an operating system. LKMs are typically used to add support for new hardware (as device drivers) and/or s, or for adding system calls. When the functionality provided by an LKM is no longer required, it can be unloaded in order to free memory and other resources.
Embedded operating systemAn embedded operating system is an operating system for embedded computer systems. Embedded operating systems are computer systems designed to increase functionality and reliability for achieving a specific task. Depending on the method used for Computer multitasking, this type of operating system might be considered a real-time operating system (RTOS). All embedded systems contain a processor and software. There must be a place for embedded software to store the executable and temporary storage for run-time data processing.
Technical features new to Windows VistaWindows Vista (formerly codenamed Windows "Longhorn") has many significant new features compared with previous Microsoft Windows versions, covering most aspects of the operating system. In addition to the new user interface, security capabilities, and developer technologies, several major components of the core operating system were redesigned, most notably the audio, print, display, and networking subsystems; while the results of this work will be visible to software developers, end-users will only see what appear to be evolutionary changes in the user interface.
Mac OS 8Mac OS 8 is an operating system that was released by Apple Computer on July 26, 1997. It includes the largest overhaul of the classic Mac OS experience since the release of System 7, approximately six years before. It places a greater emphasis on color than prior versions. Released over a series of updates, Mac OS 8 represents an incremental integration of many of the technologies which had been developed from 1988 to 1996 for Apple's overly ambitious OS named Copland.
User space and kernel spaceA modern computer operating system usually segregates virtual memory into user space and kernel space. Primarily, this separation serves to provide memory protection and hardware protection from malicious or errant software behaviour. Kernel space is strictly reserved for running a privileged operating system kernel, kernel extensions, and most device drivers. In contrast, user space is the memory area where application software and some drivers execute. The term user space (or userland) refers to all code that runs outside the operating system's kernel.
CentOSCentOS (ˈsɛntɒs, from Community Enterprise Operating System; also known as CentOS Linux) is a discontinued Linux distribution that provided a free and open-source community-supported computing platform, functionally compatible with its upstream source, Red Hat Enterprise Linux (RHEL). In January 2014, CentOS announced the official joining with Red Hat while staying independent from RHEL, under a new CentOS governing board. The first CentOS release in May 2004, numbered as CentOS version 2, was forked from RHEL version 2.
Real-time operating systemA real-time operating system (RTOS) is an operating system (OS) for real-time computing applications that processes data and events that have critically defined time constraints. An RTOS is distinct from a time-sharing operating system, such as Unix, which manages the sharing of system resources with a scheduler, data buffers, or fixed task prioritization in a multitasking or multiprogramming environment. Processing time requirements need to be fully understood and bound rather than just kept as a minimum.
Inferno (operating system)Inferno is a distributed operating system started at Bell Labs and now developed and maintained by Vita Nuova Holdings as free software under the MIT License. Inferno was based on the experience gained with Plan 9 from Bell Labs, and the further research of Bell Labs into operating systems, languages, on-the-fly compilers, graphics, security, networking and portability. The name of the operating system, many of its associated programs, and that of the current company, were inspired by Dante Alighieri's Divine Comedy.
Windows VistaWindows Vista is a major release of the Windows NT operating system developed by Microsoft as the direct successor to Windows XP, which was released in 2001. At the time, this 5-year gap was the longest time span between successive releases of Microsoft's Windows desktop operating systems. Development was finished on November 8, 2006, and over the following three months, it was released in stages to computer hardware and software manufacturers, business customers, and retail channels.
