The Linux kernel is an open-source monolithic Unix-like computer operating system kernel On 21 July , Torvalds announced the release of Linux kernel 3. In December , Torvalds decided to reduce kernel complexity by removing support for i processors, making the Retrieved on November 16, ,. Those of you who read Cooking with Linux, the multi-award-winning column that appeared monthly in Linux Journal magazine for 10 years, likely agree.
Linux Journal, , nov Examples of using Laravel Collections in Drupal, 23 August Writing an Article for Linux Journal, 27 July Netrunner MAG, article, 25th of April, Linux Format magazine, article, August Journal of Economic Perspectives, 20 1: Einstein Toolkit Featured in Linux Journal. Linux Journal November Issue The number for Ubuntu includes all flavors, but the Epub ahead of print 5 November Linux Journal 72, April Wherever you go, Linux Journal goes with you..
Linux Journal - November Linux Journal - January Results 1 - 16 of Linux Journal September Linux Journal November Linux Journal August On the academic front,. The security system in Linux operating system it has password. The Journal of Economic Perspectives We, Linux people, generally use systemd now and one of its components is the journal controlled by the journalctl command line tool.
Linux Journal October eBook: Project Sputnik to become a product - July In our Fall issue, we feature articles on the following topics: The account was created on November and has over 22k followers.. Restoring Deleted Files in Linux from the ext3 Journal. Deleting Computer Files Someone just. Fri Apr 27 Summary of the changes and new features merged in the Linux Kernel during the 2. Support reiserfs external journal. Journal of Computational Methods in Sciences and Engineering, vol. Received 5 November As of Linux 3. The European Journal of Mineralogy publishes original papers, review articles and.
The traditional Linux desktop is coming back pcworld. Issue , November - on sale now. We sincerely apologize to all those who have expressed concern about our advertisement recently featured in Linux Journal November December Keyboard Magazine, by Jim Aikin. July Linux Format, by Graham Morrison. The later ones are original to Low End.
Linux Journal Best Office Suite You have until February 14, but perhaps you can cast a ballot. Janhavi Dahihande - August 29, When Torvalds released version 0. On 19 January , the first post to the new newsgroup alt. This large jump in version numbers, from 0. However, this proved to be wrong and from to early , 15 development versions of version 0. On 14 March , Linux kernel 1. In March , Linux kernel 1.
Version 2 of the Linux kernel, released on 9 June , was followed by additional major versions under the version 2 header:. Starting in , the release process changed and new kernels started coming out on a regular schedule every 2—3 months, numbered 2. On 21 July , Torvalds announced the release of Linux kernel 3. The fact that Linux is a monolithic kernel rather than a microkernel was the topic of a debate between Andrew S.
Unlike traditional monolithic kernels, device drivers in Linux are easily configured as loadable kernel modules and are loaded or unloaded while running the system. This subject was revisited on 9 May , [30] and on 12 May Tanenbaum wrote a position statement. The huge rise in popularity of the Android operating system, which includes the Linux kernel, has made the kernel the most popular choice for mobile devices, rivaling the installed base of all other operating systems. Many consumer routers also use the Linux kernel, [35] as well as a wide variety of other embedded devices , such as smart TVs , set-top boxes , and webcams.
Many desktop Linux distributions including the Linux kernel exist, but the usage share of Linux distributions is low in comparison to other operating systems. Initially, Torvalds released Linux under a license which forbade any commercial use. The Linux kernel is licensed explicitly only under version 2 of the GPL, [6] without offering the licensee the option to choose "any later version", which is a common GPL extension. There was considerable debate about how easily the license could be changed to use later GPL versions including version 3 , and whether this change is even desirable.
Torvalds commented, "I think a number of outsiders It is debated whether loadable kernel modules LKMs are to be considered derivative works under copyright law, and thereby fall under the terms of the GPL. Torvalds has stated his belief that LKMs using only a limited, "public" subset of the kernel interfaces can sometimes be non-derived works, thus allowing some binary-only drivers and other LKMs that are not licensed under the GPL. But, Nvidia cannot use this infrastructure because it uses a technical means to enforce the rule that it can only be used by LKMs that are also GPL.
On the other hand, Torvalds has also said that "one gray area in particular is something like a driver that was originally written for another operating system i. Ultimately, it is likely that such questions can only be resolved by a court. One point of licensing controversy is the use of firmware " binary blobs " in Linux kernel to support several hardware devices. These files are under a variety of licenses, out of which many are restrictive and their exact underlying source code is usually unknown. In , Richard Stallman stated why, in his point of view, such blobs make the Linux kernel partially non-free software , and that distributing Linux kernel "violates the GPL", which requires "complete corresponding source code" to be available.
On 15 December , the Debian Project announced that the next Debian stable version "6. Linux is a registered trademark of Linus Torvalds in the United States and some other countries. This is the result of an incident in which William Della Croce, Jr. The issue was settled in August when the trademark was assigned to Linus Torvalds. In early , SCO filed the specific details of a purported copyright infringement. Despite previous claims that SCO was the rightful owner of 1 million lines of code, they specified only lines of code, most of which were uncopyrightable.
The Linux kernel is a monolithic kernel , supporting true preemptive multitasking both in user mode and, since the 2. Unlike standard monolithic kernels, device drivers are easily configured as modules , and loaded or unloaded while the system is running. Also, unlike standard monolithic kernels, device drivers can be pre-empted under certain conditions; this feature was added to handle hardware interrupts correctly and to better support symmetric multiprocessing.
The hardware is also incorporated into the file hierarchy. Because of the extensions to C it supports, GCC was for a long time the only compiler capable of correctly building the Linux kernel. GCC is the default compiler for the Linux kernel source. In , Intel claimed to have modified the kernel so that its C compiler was also capable of compiling it. Since , effort has been underway to build the Linux kernel with Clang , an alternative compiler for the C language; [67] as of 12 April , the official kernel could almost be compiled by Clang.
By enabling the Linux kernel to be compiled by Clang that, among other advantages, is known for faster compilation compared with GCC, kernel developers may benefit from a faster workflow due to shorter compilation times. Conformance to standards is a general policy for the Linux kernel's internals. Another rule is that a kernel component is not accepted into the Linux kernel mainline if there is only proprietary user-space software using that component.
Source code portability ensures that a C program written by conforming to a standard can be successfully compiled and run on any system that also conforms to the same standard. The Linux kernel API of the Linux kernel, representing the kernel's system call interface, is composed of the available system calls. Binary portability shall guarantee that any program once compiled for a given hardware platform, can be run in its compiled form on any other hardware platform that conforms to the standard.
Accessibility links
Binary portability is an essential requirement for the commercial viability of independent software vendor ISV applications built for the operating systems based on the Linux kernel. Binary compatibility is much more demanding than source code portability; as of February , the only standard concerning itself with binary compatibility is the Linux Standard Base LSB.
There is a couple of kernel internal APIs utilized between the different subsystems and subsystems of subsystems. Some of them have been kept stable over several releases, others have not. There are no guarantees regarding the in-kernel APIs. Maintainers and contributors are free to augment or change them at any time. The Linux kernel developers choose not to maintain a stable in-kernel ABI. The Linux kernel provides preemptive scheduling under certain conditions. Until kernel version 2. The Linux kernel contains different scheduler classes. Older versions of the kernel had a so-called big kernel lock for synchronization across the entire kernel, which was finally removed by Arnd Bergmann in The first port beyond Linux's original architecture was performed on the Motorola platform by Amiga users, who accomplished this by replacing major parts of the kernel.
The modifications to the kernel were so fundamental that Torvalds viewed the Motorola version as a fork and a "Linux-like operating system" [87] rather than as an actual port. It was, however, the impetus that Torvalds needed to lead a major restructure of the kernel code to facilitate porting to competing computing architectures. Linux runs as the main operating system on IBM's Blue Gene and other fastest supercomputers , including the top Chinese one.
In Linux, a " panic " is an unrecoverable system error detected by the kernel, as opposed to similar errors detected by user space code. However, most panics are the result of unhandled processor exceptions in kernel code, such as references to invalid memory addresses. These are typically indicative of a bug somewhere in the call chain leading to the panic. A report of a non-fatal bug in the kernel is called an " oops "; such deviations from correct behavior of the Linux kernel may allow continued operation with compromised reliability.
The kernel panic message might not be printed visibly in some conditions, such as when using a graphical desktop. To debug such conditions, other methods such as attaching a serial port console can be used. Rebootless updates can even be applied to the kernel by using live patching technologies such as Ksplice , kpatch and kGraft. Minimalistic foundations for live kernel patching were merged into the Linux kernel mainline in kernel version 4.
Those foundations, known as livepatch and based primarily on the kernel's ftrace functionality, form a common core capable of supporting hot patching by both kGraft and kpatch, by providing an application programming interface API for kernel modules that contain hot patches and an application binary interface ABI for the userspace management utilities. Computer security is a much-publicized topic in relation to the Linux kernel because a large portion of the kernel bugs present potential security flaws.
Linux kernel
For example, they may allow for privilege escalation or create denial-of-service attack vectors. Over the years, numerous such flaws were found and fixed in the Linux kernel. Critics have accused kernel developers of covering up security flaws or at least not announcing them; in , Linus Torvalds responded to this with the following: I personally consider security bugs to be just "normal bugs". I don't cover them up, but I also don't have any reason what-so-ever to think it's a good idea to track them and announce them as something special It makes "heroes" out of security people, as if the people who don't just fix normal bugs aren't as important.
In fact, all the boring normal bugs are way more important, just because there's a lot more of them. I don't think some spectacular security hole should be glorified or cared about as being any more "special" than a random spectacular crash due to bad locking. Linux distributions typically release security updates to fix vulnerabilities in the Linux kernel.
Many offer long-term support releases that receive security updates for a certain Linux kernel version for an extended period of time.
Portability became a concern, and so version 1. The major feature of 2. Among the changes that have been made in the 2. Also notable are the addition of several file systems throughout the 2. Details on the history of the 2. In December , Torvalds decided to reduce kernel complexity by removing support for i processors, making the 3. The numbering change from 2. The major version number was increased to avoid large minor numbers.
About developers are contributing to each release from about companies on average per release. As of companies, the top contributors are Intel A developer who wants to change the Linux kernel starts with developing and testing that change. Depending on how significant the change is and how many subsystems it modifies that change will either consist of a single patch or of multiple patches.
In case of a single subsystem that is maintained by a single maintainer, these patches are sent as e-mails to the maintainer of the subsystem with the appropriate mailing list in Cc. The maintainer and the readers of the mailing list will review the patches and provide feedback. Once the review process has finished the maintainer accepts the patches in his kernel tree. If these changes are bug fixes that are considered important enough a pull request that includes the patches will be sent to Linus within a few days. Otherwise, a pull request will be sent to Linus during the next merge window.
The merge window usually lasts two weeks and starts immediately after the release of the previous kernel version. Linus Torvalds has the last word not only over which changes get accepted into the Linux kernel but also over who can become a maintainer. Kernel maintainers keep their role unless they give their role up voluntarily. There are no known examples of kernel maintainers who have been told to step down. Additionally, there are no known examples of a kernel maintainer having been criticized for the style of her or his interactions with developers by Linus.
This gives maintainers a significant amount of power. Although the culture in the kernel development community has improved over the years, the kernel development community has a reputation of sometimes being rough. There have been several notable conflicts among Linux kernel developers. Examples of such conflicts are:. Prominent Linux kernel developers have been aware of the importance of avoiding conflicts between developers. This coincided with a public apology by Linus and an announcement he was taking a break from kernel development.
As of [update] , the 3. Instead of a roadmap, there are technical guidelines. Instead of a central resource allocation, there are persons and companies who all have a stake in the further development of the Linux kernel, quite independently from one another: The resources are all owned by the various corporations who use and contribute to Linux, as well as by the various independent contributors out there. It's those people who own the resources who decide By this statement it is meant that evolution often does odd and "sub-optimal" things exactly because it does incremental changes which do not break at any point.
As a result, any released version of the Linux kernel is fully usable, even if, for example, device drivers do not support all features of the hardware they are written for. The Linux kernel is extensible and each hardware device driver implements a common interface. In addition, the hardware-specific code is separated into distinct modules within each subsystem, allowing a port of the Linux kernel to a new hardware architecture by re-implementing only the machine-specific portions of the kernel.
The cost to redevelop the Linux kernel version 2. Wheeler's methodology, they estimated redevelopment of the 2. In the current development scheme, as of [update] , the main branch of development is not a traditional "stable" branch; instead, it incorporates all kinds of changes, including both the latest features and security and bug fixes. For users who do not want to risk updating to new versions containing code that may not be well tested, a separate set of "stable" branches exist, one for each released version, which is meant for people who just want the security and bug fixes, but not a whole new version.
The development model for the 2. Both of these branches had been maintained by the same set of people, led by Torvalds. This meant that users would always have a well-tested 2. The downside of this was that the "stable" kernel ended up so far behind that it no longer supported recent hardware and lacked needed features. In the late 2.
But instead of opening an unstable 2. This had the desirable effect of making new features more quickly available and getting more testing of the new code, which was added in smaller batches and easier to test. As a response to the lack of a stable kernel tree where people could coordinate the collection of bug fixes as such, in December Adrian Bunk announced that he would keep releasing 2. In October Adrian Bunk announced that he will maintain 2. After the change of the development model with 2. Andrew Morton decided to repurpose his -mm tree from memory management to serve as the destination for all new and experimental code.
In September , Morton decided to stop maintaining this tree. Most Linux users run a kernel supplied by their Linux distribution. Some distributions ship the "vanilla" or "stable" kernels. However, several Linux distribution vendors such as Red Hat and Debian maintain another set of Linux kernel branches which are integrated into their products. These are usually updated at a slower pace compared to the "vanilla" branch, and they usually include all fixes from the relevant "stable" branch, but at the same time they can also add support for drivers or features which had not been released in the "vanilla" version the distribution vendor started basing their branch from.
The latest kernel version and older kernel versions are maintained separately. Most latest kernel releases were supervised by Linus Torvalds. Maintenance of older kernel versions happens separately. Major releases as old as 2. The Linux kernel source code used to be maintained without the help of an automated source code management system, mostly because of Linus Torvalds' dislike of centralized SCM systems.
BitKeeper was made available to Linus and several others free of charge but was not free software , which was a source of controversy. In April , efforts to reverse-engineer the BitKeeper system by Andrew Tridgell led BitMover, the company which maintained BitKeeper, to stop supporting the Linux development community. In response, Torvalds and others wrote a new source code control system for the purpose, called Git. The new system was written within weeks, and in two months the first official kernel release was made using Git.
The first scheme was used in the run-up to version 1. The first version of the kernel was 0. This was followed by 0. The kernel version was changed only when major changes in the code and the concept of the kernel occurred, twice in the history of the kernel: The major revision was assigned according to the even—odd version numbering scheme. The minor revision had been changed whenever security patches, bug fixes, new features or drivers were implemented in the kernel.
In , after version 2. For about seven years, the first two numbers remained "2. A fourth number was sometimes added to account for bug and security fixes only to the kernel version.
The even-odd system of alternation between stable and unstable was gone. Instead, development pre-releases are titled release candidates , which is indicated by appending the suffix '-rc' to the kernel version, followed by an ordinal number. The first use of the fourth number occurred when a grave error, which required immediate fixing, was encountered in 2.
However, there were not enough other changes to legitimize the release of a new minor revision which would have been 2. Later it became customary to continuously back-port major bug-fixes and security patches to released kernels and indicate that by updating the fourth number.
On 29 May , Linus Torvalds announced [] that the kernel version would be bumped to 3. It continued the time-based release practice introduced with 2. An additional number now the third number would be added on when necessary to designate security and bug fixes, as for example with 3.
The major version number was also later raised to 4, for the release following version 3. In addition to Torvalds' -rc development releases, the version number was sometimes suffixed with letter sequences, such as tip , which were at times the initials of a software developer, indicating another development branch. For example, ck stands for Con Kolivas and ac stands for Alan Cox. Sometimes, the letters are related to the primary development area of the branch the kernel is built from, for example, wl indicates a wireless networking test build. Also, distributors may have their own suffixes with different numbering systems and for back-ports to their enterprise i.
- Grade 6 Mathematics Lesson 10 (iPad Math Learning Guides)!
- How Is It With Your Soul Class Leader: Class Leaders Manual for Use With This Day (How Is It With Your Soul?).
- EUPEN - Unterwegs in der Hauptstadt des deutschsprachigen Belgiens (German Edition).
- Dizionario delle cose perdute (Libellule) (Italian Edition);
- School Journal Level 2, August 2012?
There are certain variants of the Linux kernel that provide additional functionality but do not belong to the Linux kernel mainline. Some of these variants have been partially merged into the mainline. From Wikipedia, the free encyclopedia. Linux kernel Tux the penguin, mascot of Linux [1]. This section needs to be updated. Please update this article to reflect recent events or newly available information. Copyright, trademark, and naming. Linux kernel interfaces and Interfaces of the Linux kernel Category.
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. January Learn how and when to remove this template message. This section's factual accuracy is disputed. Relevant discussion may be found on Talk: Please help to ensure that disputed statements are reliably sourced. November Learn how and when to remove this template message.
List of Linux supported architectures and Linux-powered device. Kernel panic and Linux kernel oops. March Learn how and when to remove this template message. Older version, still supported. Information technology portal Linux portal Open-source software portal Free and open-source software portal. Archived from the original on 15 August Retrieved 11 August Archived from the original on 1 July Retrieved 17 December Retrieved 15 February Retrieved 25 September Retrieved 21 February Archived from the original on 13 January Retrieved 21 August Retrieved 12 November Retrieved 13 November Retrieved 20 August Free as in Freedom: Richard Stallman's Crusade for Free Software.
Bulk Download All Back Issues From Your Linux Journal Subscription – The Node
Berkeley Software , F. Archived from the original on 19 July Retrieved 20 February Since , over individual developers from over different companies have contributed to the kernel. Archived from the original on 21 December Retrieved 20 January This is being written to try to explain why Linux does not have a binary kernel interface, nor does it have a stable kernel interface. Retrieved 21 November This should not come as any surprise, as that's the same license that has been there since 0. The Linux Kernel Archives. Retrieved 7 January Linux kernel mailing list.
Retrieved 16 May Retrieved 22 July Retrieved 11 November Retrieved 23 June Voices from the Open Source Revolution. Retrieved 22 November Retrieved 10 May Retrieved 6 January Retrieved 19 October Retrieved 23 October Archived from the original on 11 October A deadly new vulnerability that could lay waste to the internet updated ". Archived from the original on 10 February GPL V3 and Linux". Retrieved 11 March The current version Discussion Draft 2 of GPLv3 on first reading fails the necessity test of section 1 on the grounds that there's no substantial and identified problem with GPLv2 that it is trying to solve.
However, a deeper reading reveals several other problems with the current FSF draft: Retrieved 2 August Direct Rendering Infrastructure Mailing list. Retrieved 3 September Linux GPL and binary module exception clause? Retrieved 31 December Retrieved 8 January Retrieved 8 December Gisselberg Law Firm, Inc. Retrieved 24 March Novell has right to waive!
Retrieved 12 August Retrieved 30 August The Salt Lake Tribune. Retrieved 30 March Retrieved 7 May Archived from the original on 4 November The Linux Documentation Project.