GNU General Public License
The GNU General Public License is a widely-used free software license, which guarantees end users the freedom to run, study and modify the software. The license was written by Richard Stallman of the Free Software Foundation for the GNU Project, grants the recipients of a computer program the rights of the Free Software Definition; the GPL is a copyleft license, which means that derivative work can only be distributed under the same license terms. This is in distinction to permissive free software licenses, of which the BSD licenses and the MIT License are widely-used examples. GPL was the first copyleft license for general use; the GPL license family has been one of the most popular software licenses in the free and open-source software domain. Prominent free-software programs licensed under the GPL include the Linux kernel and the GNU Compiler Collection. David A. Wheeler argues that the copyleft provided by the GPL was crucial to the success of Linux-based systems, giving the programmers who contributed to the kernel the assurance that their work would benefit the whole world and remain free, rather than being exploited by software companies that would not have to give anything back to the community.
In 2007, the third version of the license was released to address some perceived problems with the second version that were discovered during its long-time usage. To keep the license up to date, the GPL license includes an optional "any version" clause, allowing users to choose between the original terms or the terms in new versions as updated by the FSF. Developers can omit it; the GPL was written by Richard Stallman in 1989, for use with programs released as part of the GNU project. The original GPL was based on a unification of similar licenses used for early versions of GNU Emacs, the GNU Debugger and the GNU C Compiler; these licenses contained similar provisions to the modern GPL, but were specific to each program, rendering them incompatible, despite being the same license. Stallman's goal was to produce one license that could be used for any project, thus making it possible for many projects to share code; the second version of the license, version 2, was released in 1991. Over the following 15 years, members of the free software community became concerned over problems in the GPLv2 license that could let someone exploit GPL-licensed software in ways contrary to the license's intent.
These problems included tivoization, compatibility issues similar to those of the Affero General Public License—and patent deals between Microsoft and distributors of free and open-source software, which some viewed as an attempt to use patents as a weapon against the free software community. Version 3 was developed to attempt to address these concerns and was released on 29 June 2007. Version 1 of the GNU GPL, released on 25 February 1989, prevented what were the two main ways that software distributors restricted the freedoms that define free software; the first problem was that distributors may publish binary files only—executable, but not readable or modifiable by humans. To prevent this, GPLv1 stated that copying and distributing copies or any portion of the program must make the human-readable source code available under the same licensing terms; the second problem was that distributors might add restrictions, either to the license, or by combining the software with other software that had other restrictions on distribution.
The union of two sets of restrictions would apply to the combined work, thus adding unacceptable restrictions. To prevent this, GPLv1 stated that modified versions, as a whole, had to be distributed under the terms in GPLv1. Therefore, software distributed under the terms of GPLv1 could be combined with software under more permissive terms, as this would not change the terms under which the whole could be distributed. However, software distributed under GPLv1 could not be combined with software distributed under a more restrictive license, as this would conflict with the requirement that the whole be distributable under the terms of GPLv1. According to Richard Stallman, the major change in GPLv2 was the "Liberty or Death" clause, as he calls it – Section 7; the section says that licensees may distribute a GPL-covered work only if they can satisfy all of the license's obligations, despite any other legal obligations they might have. In other words, the obligations of the license may not be severed due to conflicting obligations.
This provision is intended to discourage any party from using a patent infringement claim or other litigation to impair users' freedom under the license. By 1990, it was becoming apparent that a less restrictive license would be strategically useful for the C library and for software libraries that did the job of existing proprietary ones; the version numbers diverged in 1999 when version 2.1 of the LGPL was released, which renamed it the GNU Lesser General Public License to reflect its place in the philosophy. Most "GPLv2 or any version" is stated by users of the license, to allow upgrading to GPLv3. In late 2005, the Free Software Foundation announced work on version 3 of the GPL. On 16 January 2006, the first "discussion draft" of GPLv3 was published, the public consultation began; the public consultation was planned for ni
A music tracker is a type of music sequencer software for creating music. The music is represented as discrete musical notes positioned in several channels at discrete chronological positions on a vertical timeline. A music tracker's user interface is number based. Notes, parameter changes and other commands are entered with the keyboard into a grid of fixed time slots as codes consisting of letters and hexadecimal digits. Separate patterns have independent timelines. Trackers departed from using module files, adding other options both to the sound synthesis and to the sequencing becoming general purpose sequencers with a different user interface. Music trackers like DefleMask and FamiTracker are used to create chiptunes; the term tracker derives from Ultimate Soundtracker written by Karsten Obarski and released in 1987 by EAS Computer Technik for the Commodore Amiga. Ultimate Soundtracker was a commercial product, but soon shareware clones such as NoiseTracker appeared as well; the general concept of step-sequencing samples numerically, as used in trackers, is found in the Fairlight CMI sampling workstation of the early 1980s.
Some early tracker-like programs appeared for the MSX and Commodore 64, before 1987, such as Sound Monitor, but these did not feature sample playback, instead playing notes on the computer's internal synthesizer. Programs like Rock Monitor supported additional sample playback with short drum samples loaded in RAM memory; the first trackers supported four pitch and volume modulated channels of 8-bit PCM samples, a limitation derived from the Amiga's Paula audio chipset and the commonplace 8SVX format used to store sampled sound. However, since the notes were samples, the limitation was less important than those of synthesizing music chips. During the 1990s, tracker musicians gravitated to the PC as software production in general switched from the Amiga platform to the PC. Although the IBM and compatibles lacked the hardware sound processing capabilities of the Amiga, with the advent of the Sound Blaster line from Creative, PC audio began to approach CD Quality with the release of the SoundBlaster 16.
Another sound card popular on the PC tracker scene was the Gravis Ultrasound, which continued the hardware mixing tradition, with 32 internal channels and onboard memory for sample storage. For a time, it offered unparalleled sound quality and became the choice of discerning tracker musicians. Understanding that the support of tracker music would benefit sales, Gravis gave away some 6000 GUS cards to participants. Coupled with excellent developer documentation, this gesture prompted the GUS to become an integral component of many tracking programs and software; the balance was redressed with the introduction of the Sound Blaster AWE32 and its successors, which featured on-board RAM and wavetable mixing. The responsibility for audio mixing passed from hardware to software, which enabled the use of more and more channels. From the typical 4 MOD channels of the Amiga, the limit had moved to 7 with TFMX players and 8, first with Oktalyzer and with the vastly more popular OctaMED 32 with ScreamTracker 3 and FastTracker 2 on the PC and on to 64 with Impulse Tracker and MED SoundStudio.
An Amiga tracker called Symphonie Pro supported 256 channels. As such, hardware mixing did not last; as processors got faster and acquired special multimedia processing abilities and companies began to push Hardware Abstraction Layers, like DirectX, the AWE and GUS range became obsolete. DirectX, WDM and, now more ASIO, deliver high-quality sampled audio irrespective of hardware brand. There was a split off from the sample based trackers taking advantage of the OPL2/OPL3 chips of the Sound Blaster series. Adlib Tracker II, Reality Adlib Tracker v2 and others survived to this day. All Sound Tracker was able to combine both the FM synthesis of the OPL chips and the sample based synthesis of the EMU-8000 chips in the Sound Blaster AWE series of cards as well as MIDI output to any additional hardware of choice. Tracker music could be found in computer games of the late 1990s and early 2000s, such as the Unreal series, Deus Ex, Crusader: No Remorse, Jazz Jackrabbit and Uplink. Tracker software continues to develop.
Some of the early Amiga trackers such as ProTracker and OctaMED have received various updates for porting to other platforms. ProTracker having resumed development in 2004, with plans for releasing version 5 to Windows and AmigaOS, but only version 4.0 beta 2 for AmigaOS has been released. Other cross-platform trackers include Renoise, MilkyTracker and SunVox. Buzz, OpenMPT, Renoise and others offer features undreamed-of back in the day. In 2005, FamiTracker, a tracker for the NES and Famicom, was released; as of version 0.5 beta, it is so far the only tracker for the system with full expansion audio support including the Sunsoft 5B. During 2007, Renoise and OpenMPT were presented in Computer Music Magazine as professional and inexpensive alternative to other music production software. In 2010, Modplug Tracker and Renoise were two of the most popular and developed trackers. Four new trackers, Buzé, SVArTracker, had extended the tracker concept with new features such as piano roll, tickless events, and
The Commodore 64 known as the C64 or the CBM 64, is an 8-bit home computer introduced in January 1982 by Commodore International. It has been listed in the Guinness World Records as the highest-selling single computer model of all time, with independent estimates placing the number sold between 10 and 17 million units. Volume production started in early 1982, marketing in August for US$595. Preceded by the Commodore VIC-20 and Commodore PET, the C64 took its name from its 64 kilobytes of RAM. With support for multicolor sprites and a custom chip for waveform generation, the C64 could create superior visuals and audio compared to systems without such custom hardware; the C64 dominated the low-end computer market for most of the 1980s. For a substantial period, the C64 had between 30% and 40% share of the US market and two million units sold per year, outselling IBM PC compatibles, Apple computers, the Atari 8-bit family of computers. Sam Tramiel, a Atari president and the son of Commodore's founder, said in a 1989 interview, "When I was at Commodore we were building 400,000 C64s a month for a couple of years."
In the UK market, the C64 faced competition from the BBC Micro and the ZX Spectrum, but the C64 was still one of the two most popular computers in the UK. Part of the Commodore 64's success was its sale in regular retail stores instead of only electronics or computer hobbyist specialty stores. Commodore produced many of its parts in-house to control costs, including custom integrated circuit chips from MOS Technology, it has been compared to the Ford Model T automobile for its role in bringing a new technology to middle-class households via creative and affordable mass-production. 10,000 commercial software titles have been made for the Commodore 64 including development tools, office productivity applications, video games. C64 emulators allow anyone with a modern computer, or a compatible video game console, to run these programs today; the C64 is credited with popularizing the computer demoscene and is still used today by some computer hobbyists. In 2011, 17 years after it was taken off the market, research showed that brand recognition for the model was still at 87%.
In January 1981, MOS Technology, Inc. Commodore's integrated circuit design subsidiary, initiated a project to design the graphic and audio chips for a next generation video game console. Design work for the chips, named MOS Technology VIC-II and MOS Technology SID, was completed in November 1981. Commodore began a game console project that would use the new chips—called the Ultimax or the Commodore MAX Machine, engineered by Yash Terakura from Commodore Japan; this project was cancelled after just a few machines were manufactured for the Japanese market. At the same time, Robert "Bob" Russell and Robert "Bob" Yannes were critical of the current product line-up at Commodore, a continuation of the Commodore PET line aimed at business users. With the support of Al Charpentier and Charles Winterble, they proposed to Commodore CEO Jack Tramiel a true low-cost sequel to the VIC-20. Tramiel dictated. Although 64-Kbit dynamic random-access memory chips cost over US$100 at the time, he knew that DRAM prices were falling, would drop to an acceptable level before full production was reached.
The team was able to design the computer because, unlike most other home-computer companies, Commodore had its own semiconductor fab to produce test chips. The chips were complete by November, by which time Charpentier and Tramiel had decided to proceed with the new computer; the product was code named the VIC-40 as the successor to the popular VIC-20. The team that constructed it consisted of Yash Terakura, Shiraz Shivji, Bob Russell, Bob Yannes and David A. Ziembicki; the design and some sample software were finished in time for the show, after the team had worked tirelessly over both Thanksgiving and Christmas weekends. The machine used the same case, same-sized motherboard, same Commodore BASIC 2.0 in ROM as the VIC-20. BASIC served as the user interface shell and was available on startup at the READY prompt; when the product was to be presented, the VIC-40 product was renamed C64. The C64 made an impressive debut at the January 1982 Consumer Electronics Show, as recalled by Production Engineer David A. Ziembicki: "All we saw at our booth were Atari people with their mouths dropping open, saying,'How can you do that for $595?'"
The answer was vertical integration. Commodore had a reputation for announcing products that never appeared, so sought to ship the C64. Production began in spring 1982 and volume shipments began in August; the C64 faced a wide range of competing home computers, but with a lower price and more flexible hardware, it outsold many of its competitors. In the United States the greatest competitors were the Atari 8-bit 400, the Atari 800, the Apple II; the Atari 400 and 800 had been designed to accommodate stringent FCC emissions requirements and so were expensive to