Linux Guide | Part 2

Linux Guide | Part 2

Linux – Legal Aspects – Licensing Terms

Initially, Torvalds has distributed Linux under a license which forbade any commercial exploitation. This was soon changed by the GNU General Public License (GPL) since version 0.12. This license allows the distribution and sale of possibly changed versions of Linux or not, but requires that all copies are distributed under the same license, accompanied by the complete corresponding source code.

Torvalds has described licensing under the GPL as “the best thing I ever did.”

Linux – GNU General Public License Version # 3

Currently, Linux is licensed only under version 2 of the GPL, and, unlike many other software under the GPL, with no option to use a later version, and there is more controversy about how easy it could be modified to use Later versions of the GPL, such as version 3, and even if this is desirable. Specifically Indicated Torvalds himself upon the release of version 2.4.0 That his own code is only under version 2. However, the terms of the GPL state that if no version is specified, then any version may be used, as shown by Alan Cox, few Linux developers specify a particular version of the GPL. In July 2006, a survey of 29 key developers of Linux indicated that 28 preferred GPLv2 to the then current draft of GPLv3. Torvalds commented, “I think a number of outsiders… believed that I personally was the only odd man out because I was so publicly not a fan of GPLv3.”

Linux – Loadable kernel modules and firmware

It is argued that modules from the core (in English: LKMs) should be considered derivative work under U.S. copyright law, and therefore falls under the GPL. Torvalds stated his belief that modules that use a limited subset, and public interfaces of the core may sometimes not be derived works, and thus allowing some binary modules and other modules that are not licensed under the GPL. Many Linux contributors disagree with this interpretation, however, even Torvalds agrees that many modules are clearly derived works, and sure enough, he writes that “the core modules ARE derivative ‘by default.” In contrast, Torvalds also said that “a gray area in particular is something like a driver that was originally written for another operating system (e.g., clearly is not a derivative work of Linux in origin). THIS is a gray area, and _esta_ is the area that I believe that some modules can not be considered as derivative works, simply because they were not designed for Linux and not dependent on any specific operating goals. ” proprietary graphics drivers in particular, are widely discussed. Finally, it is likely that such issues can only be resolved by a court.

One point of controversy over the licensing, is that Linux makes use of “smearing binary” firmware to support hardware devices. These files are distributed under a wide variety of licenses, many restrictive, and its fundamental exact source is unknown. Richard Stallman argues that these blots make Linux partially non-free software, and deploy Linux may be a violation of the GPL, which requires “complete corresponding source code” is available. In response, the FSFLA started to project, Linux-libre, to create a Completely Free kernel without proprietary objects, WHICH IS used by some distributions Completely Free.

Linux Trademark

Linux is a trademark of Linus Torvalds in the United States and certain other countries. This is the result of an incident in which William Della Croce, Jr., who was not involved in the Linux project, registered the name and then asked for royalties for its use. Several supporters of the Linux part of a legal counsel and filed a lawsuit against Della Croce, who agreed in 1998 to designate the record to Torvalds.

Linux – SCO Litigation

In March 2003, the SCO Group (SCO) filed a lawsuit against IBM claiming that IBM had infringed copyrights that SCO says it has about the source code of Unix, by contributing portions of that code to Linux. Additionally, SCO sent letters to several companies warning that their use of Linux without a license from SCO may be a violation of copyright law, and told the press that they would sue individual users of Linux. IBM has pledged to defend its consumer Linux on their behalf. This process has generated controversy by SCO against Novell, DaimlerChrysler (partially dismissed in July 2004), and AutoZone, and retaliatory processed by Red Hat and others against SCO.

In early 2007 the SCO met the specific details of the object infringed. Despite earlier assertions that the SCO was the rightful owner of one million lines of code, it specifies 326 lines of code, most of whom were ineligible for copyright. In September 2007, the court in the Novell case ruled that SCO did not own the truth of the Unix copyrights to begin with, although the Court of Appeals for the Tenth U.S. Circuit ruled in September 2009 that the question of who was the owner of itself copyright was for the jury to decide. The case was decided on March 30, 2010, favoring Novell.

Linux Specifications

Linux supports multitasking in advance (in both user mode and kernel mode), virtual memory, shared libraries, demand loading, executable copy-on-write shared memory management, the set of Internet protocols, and execution in line.

Linux Architecture

Linux is a monolithic kernel. device drivers and kernel extensions run in kernel space (ring 0 on many CPU architectures), with full access to the hardware, although some exceptions are implemented in user space. The graphics system that most people use with Linux will not run in the nucleus, in contrast to that found in Microsoft Windows.

Preemptive Kernel-mode allows device drivers to be anticipated under certain conditions. This feature was added to handle hardware interrupts correctly and improve support for symmetric multiprocessing (in English: SMP). Preemptive also improves latency, increasing responsiveness and making Linux more suitable for real time applications.

Kernel panic

On Linux, a “panic” is an unrecoverable system error detected by the nucleus in contrast to similar errors found by code in user space. It is possible for kernel code to indicate such a condition by calling the panic function located in the file header file sys / system.h. However, most panics are the result of an untreated processor exception in kernel code, such as references to an invalid address in memory. Typically these are indicators of a malfunction somewhere in the call chain leading to panic. They can also mean a hardware failure, like a cell RAM failure or errors in arithmetic functions on the processor caused by defective processor, damaged / overheated, or a slight error.

Kernel Oops

A bug report in the nucleus called kerneloops is received automatically by the software kerneloops or by extending the kernel oops ABRT. Kerneloops.org gathers these statistics and publishes reports on its website.

Tanenbaum-Torvalds Debate

The fact that Linux is a monolithic kernel rather than a microkernel was the topic of debate between Andrew Tanenbaum-Torvalds S. Tanenbaum and Linus Torvalds. The debate began in 1992, and on Linux kernel architectures in general discussion group on Usenet comp.os.minix. Tanenbaum argued that micronuclei are superior to monolithic kernels, and therefore Linux was obsolete. Unlike traditional monolithic kernels, device drivers are easily configured as loadable modules, and are loaded or unloaded while running the system. This subject was revisited in May 9, 2006, and on May 12, 2006 Tanenbaum wrote a statement.

Continued…

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