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Mknod
In Unix-like operating systems, a device file, device node, or special file is an interface to a device driver that appears in a file system as if it were an ordinary file. There are also special files in DOS, OS/2, and Windows. These special files allow an application program to interact with a device by using its device driver via standard input/output system calls. Using standard system calls simplifies many programming tasks, and leads to consistent user-space I/O mechanisms regardless of device features and functions. Overview Device files usually provide simple interfaces to standard devices (such as printers and serial ports), but can also be used to access specific unique resources on those devices, such as disk partitions. Additionally, device files are useful for accessing system resources that have no connection with any actual device, such as data sinks and random number generators. There are two general kinds of device files in Unix-like operating systems, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like Application software, application is one that behaves like the corresponding List of POSIX commands, Unix command or Unix shell, shell. Although there are general Unix philosophy, philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like. Some well-known examples of Unix-like operating systems include Linux, FreeBSD and OpenBSD. These systems are often used on servers as well as on personal computers and other devices. Many popular applications, such as the Apache HTTP Server, Apache web server and the Bash (Unix shell), Bash shell, are also designed to be used on Unix-like systems. Definition The Open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reserved Word
In a programming language, a reserved word (sometimes known as a reserved identifier) is a word that cannot be used by a programmer as an identifier, such as the name of a variable, function, or label – it is "reserved from use". In brief, an ''identifier'' starts with a letter, which is followed by any sequence of letters and digits (in some languages, the underscore '_' is treated as a letter). In an imperative programming language and in many object-oriented programming languages, apart from assignments and subroutine calls, keywords are often used to identify a particular statement, e.g. if, while, do, for, etc. Many languages treat keywords as reserved words, including Ada, C, C++, COBOL, Java, and Pascal. The number of reserved words varies widely from one language to another: C has about 30 while COBOL has about 400. A few languages do not have any reserved words; Fortran and PL/I identify keywords by context, while Algol 60 and Algol 68 generally use stroppin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chroot
chroot is a shell (computer), shell command (computing), command and a system call on Unix and Unix-like operating systems that changes the apparent root directory for the current running process and its Child process, children. A program that is run in such a modified environment cannot name (and therefore normally cannot access) files outside the designated directory tree. The term ''chroot'' may refer to the system call or the command-line interface, command-line utility. The modified environment is called a chroot jail. History The chroot system call was introduced during development of Version 7 Unix in 1979. One source suggests that Bill Joy added it on 18 March 1982 – 17 months before Berkeley Software Distribution, 4.2BSD was released – in order to test its installation and build system. All versions of BSD that had a kernel have chroot(2). An early use of the term "jail" as applied to chroot comes from William Cheswick, Bill Cheswick creating a Honeypot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Udev
udev (userspace ) is a device manager for the Linux kernel. As the successor of devfsd and hotplug, udev primarily manages device nodes in the directory. At the same time, udev also handles all user space events raised when hardware devices are added into the system or removed from it, including firmware loading as required by certain devices. Rationale It is an operating system's kernel that is responsible for providing an abstract interface of the hardware to the rest of the software. Being a monolithic kernel, the Linux kernel does exactly that: device drivers are part of the Linux kernel, and make up more than half of its source code. Hardware can be accessed through system calls or over their device nodes. To be able to deal with peripheral devices that are hotplug-capable in a user-friendly way, a part of handling all of these hotplug-capable hardware devices was handed over from the kernel to a daemon running in user-space. Running in user space serves security a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
User Space
A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides 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, typically with one address space per process. Overview The term user space (or userland) refers to all code that runs outside the operating system's kernel. User space usually refers to the various programs and libraries that the operating system uses to interact with the kernel: software that performs input/output, manipulates file system objects, application software, etc. Each user space process usually runs in its own virtual memory space, and, unless explici ... [...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] |
DragonFly BSD
DragonFly BSD is a free and open-source Unix-like operating system forked from FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and FreeBSD developer between 1994 and 2003, began working on DragonFly BSD in June 2003 and announced it on the FreeBSD mailing lists on 16 July 2003. Dillon started DragonFly in the belief that the techniques adopted for threading and symmetric multiprocessing in FreeBSD 5 would lead to poor performance and maintenance problems. He sought to correct these anticipated problems within the FreeBSD project. Due to conflicts with other FreeBSD developers over the implementation of his ideas, his ability to directly change the codebase was eventually revoked. Despite this, the DragonFly BSD and FreeBSD projects still work together, sharing bug fixes, driver updates, and other improvements. Dillon named the project after photographing a dragonfly in his yard, while he was still working on FreeBSD. Intended as the log ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FreeBSD
FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable home-class hardware, and has since continuously been the most commonly used BSD-derived operating system. FreeBSD maintains a complete system, delivering a kernel, device drivers, userland utilities, and documentation, as opposed to Linux only delivering a kernel and drivers, and relying on third-parties such as GNU for system software. The FreeBSD source code is generally released under a permissive BSD license, as opposed to the copyleft GPL used by Linux. The project includes a security team overseeing all software shipped in the base distribution. Third-party applications may be installed using the pkg package management system or from source via FreeBSD Ports. The project is supported and promoted by the FreeBSD Foundation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual File System
A virtual file system (VFS) or virtual filesystem switch is an abstract layer on top of a more concrete file system. The purpose of a VFS is to allow client applications to access different types of concrete file systems in a uniform way. A VFS can, for example, be used to access local and network storage devices transparently without the client application noticing the difference. It can be used to bridge the differences in Windows, classic Mac OS/macOS and Unix filesystems, so that applications can access files on local file systems of those types without having to know what type of file system they are accessing. A VFS specifies an interface (or a "contract") between the kernel and a concrete file system. Therefore, it is easy to add support for new file system types to the kernel simply by fulfilling the contract. The terms of the contract might change incompatibly from release to release, which would require that concrete file system support be recompiled, and possibly m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Vista
Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft Windows. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on November 8, 2006, and over the following two months, it was released in stages to business customers, original equipment manufacturers (OEMs), and retail channels. On January 30, 2007, it was released internationally and was made available for purchase and download from the Windows Marketplace; it is the first release of Windows to be made available through a digital distribution platform. Development of Windows Vista began in 2001 under the codename "Longhorn"; originally envisioned as a minor successor to Windows XP, it feature creep, gradually included numerous new features from the then-next major release of Windows codenamed "Blackc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YouTube
YouTube is an American social media and online video sharing platform owned by Google. YouTube was founded on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim who were three former employees of PayPal. Headquartered in San Bruno, California, it is the second-most-visited website in the world, after Google Search. In January 2024, YouTube had more than 2.7billion monthly active users, who collectively watched more than one billion hours of videos every day. , videos were being uploaded to the platform at a rate of more than 500 hours of content per minute, and , there were approximately 14.8billion videos in total. On November 13, 2006, YouTube was purchased by Google for $1.65 billion (equivalent to $ billion in ). Google expanded YouTube's business model of generating revenue from advertisements alone, to offering paid content such as movies and exclusive content produced by and for YouTube. It also offers YouTube Premium, a paid subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
