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130-447: ITunes Store is a digital marketplace selling music , music videos , ringtones and alert tones. It was launched by Apple Inc. on April 28, 2003 for macOS , and on October 16, 2003 for Microsoft Windows . It launched as a mobile application with iOS on June 29, 2007. It previously sold mobile applications until the launch of the App Store on July 10, 2008, and e-books until

260-422: A data compression algorithm. Adaptive DPCM (ADPCM) was introduced by P. Cummiskey, Nikil S. Jayant and James L. Flanagan at Bell Labs in 1973. Perceptual coding was first used for speech coding compression, with linear predictive coding (LPC). Initial concepts for LPC date back to the work of Fumitada Itakura ( Nagoya University ) and Shuzo Saito ( Nippon Telegraph and Telephone ) in 1966. During

390-462: A digital system do not result in error unless they are so large as to result in a symbol being misinterpreted as another symbol or disturbing the sequence of symbols. It is, therefore, generally possible to have an entirely error-free digital audio system in which no noise or distortion is introduced between conversion to digital format and conversion back to analog. A digital audio signal may be encoded for correction of any errors that might occur in

520-472: A high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, AT&T licensed the operating system's source code as a trade secret to anyone who asked. As a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of its regional operating companies , and

650-511: A loudspeaker . Digital audio systems may include compression , storage , processing , and transmission components. Conversion to a digital format allows convenient manipulation, storage, transmission, and retrieval of an audio signal. Unlike analog audio, in which making copies of a recording results in generation loss and degradation of signal quality, digital audio allows an infinite number of copies to be made without any degradation of signal quality. Digital audio technologies are used in

780-424: A minimalist functionality, while more elaborate window managers such as FVWM , Enlightenment , or Window Maker provide more features such as a built-in taskbar and themes , but are still lightweight when compared to desktop environments. Desktop environments include window managers as part of their standard installations, such as Mutter (GNOME), KWin (KDE), or Xfwm (xfce), although users may choose to use

910-505: A solution stack such as LAMP . The source code of Linux may be used, modified, and distributed commercially or non-commercially by anyone under the terms of its respective licenses, such as the GNU General Public License (GPL). The license means creating novel distributions is permitted by anyone and is easier than it would be for an operating system such as MacOS or Microsoft Windows . The Linux kernel, for example,

1040-489: A DAC. According to the Nyquist–Shannon sampling theorem , with some practical and theoretical restrictions, a band-limited version of the original analog signal can be accurately reconstructed from the digital signal. During conversion, audio data can be embedded with a digital watermark to prevent piracy and unauthorized use. Watermarking is done using a direct-sequence spread-spectrum (DSSS) method. The audio information

1170-514: A code printed on the Slurpee cup into iTunes Music Store application. Coca-Cola did this in spite of having its own music store, myCoke Music.com, that competed with iTunes Music Store in Europe. myCokeMusic.com ceased business on July 31, 2006. Digital audio In a digital audio system, an analog electrical signal representing the sound is converted with an analog-to-digital converter (ADC) into

1300-466: A competing OS, agrees that "Linux wasn't designed, it evolved", but considers this to be a limitation, proposing that some features, especially those related to security, cannot be evolved into, "this is not a biological system at the end of the day, it's a software system." A Linux-based system is a modular Unix-like operating system, deriving much of its basic design from principles established in Unix during

1430-537: A different sampling rate to a common sampling rate prior to processing. Audio data compression techniques, such as MP3 , Advanced Audio Coding (AAC), Opus , Ogg Vorbis , or FLAC , are commonly employed to reduce the file size. Digital audio can be carried over digital audio interfaces such as AES3 or MADI . Digital audio can be carried over a network using audio over Ethernet , audio over IP or other streaming media standards and systems. For playback, digital audio must be converted back to an analog signal with

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1560-971: A different window manager if preferred. Wayland is a display server protocol intended as a replacement for the X11 protocol; as of 2022 , it has received relatively wide adoption. Unlike X11, Wayland does not need an external window manager and compositing manager. Therefore, a Wayland compositor takes the role of the display server, window manager, and compositing manager. Weston is the reference implementation of Wayland, while GNOME's Mutter and KDE's KWin are being ported to Wayland as standalone display servers. Enlightenment has already been successfully ported since version 19. Additionally, many window managers have been made for Wayland, such as Sway or Hyprland, as well as other graphical utilities such as Waybar or Rofi. Linux currently has two modern kernel-userspace APIs for handling video input devices: V4L2 API for video streams and radio, and DVB API for digital TV reception. Due to

1690-414: A digital signal, typically using pulse-code modulation (PCM). This digital signal can then be recorded, edited, modified, and copied using computers , audio playback machines, and other digital tools. For playback, a digital-to-analog converter (DAC) performs the reverse process, converting a digital signal back into an analog signal, which is then sent through an audio power amplifier and ultimately to

1820-644: A large number of independent labels in order to begin to offer most iTunes music DRM-free. On January 6, 2009, Apple announced that DRM had been removed from 80% of its music catalog in the US. Full DRM-free "iTunes Plus" music availability was achieved in the US on April 7, 2009, coinciding with the introduction of a three-tiered pricing model. This does not apply to songs downloaded using Apple Music , Apple's subscription-based music streaming service. Television episodes, many books, and films are still "FairPlay" DRM-protected. On Super Bowl Sunday , February 1, 2004, Apple launched

1950-453: A phone call from Apple CEO Steve Jobs , who offered his congratulations, as well as a 40 GB 3rd Generation iPod laser-engraved with a message of thanks. Inspired by Pepsi's marketing success with iTunes giveaways, Coca-Cola partnered with 7-Eleven to give away a free iTunes song with every 32 US fl oz (950 ml). Slurpee frozen beverage until July 31, 2005. Songs could be redeemed until August 31, 2005, by entering

2080-404: A place in server installations such as the popular LAMP application stack. The use of Linux distributions in home and enterprise desktops has been growing. Linux distributions have also become popular in the netbook market, with many devices shipping with customized Linux distributions installed, and Google releasing their own ChromeOS designed for netbooks. Linux's greatest success in

2210-498: A popular CLI shell. The graphical user interface (or GUI) used by most Linux systems is built on top of an implementation of the X Window System . More recently, the Linux community has sought to advance to Wayland as the new display server protocol, in place of X11. Many other open-source software projects contribute to Linux systems. Installed components of a Linux system include the following: The user interface , also known as

2340-484: A preview of a show to bonus content to pilot episodes and entire seasons of TV shows (examples of free seasons include HBO's The Weight of the Nation and ABC's Pan-Am ). Some networks, such as ABC and NBC, have their own pages of "Free Season Premieres". While previously the US iTunes Store has offered as many as three free songs each week (the single of the week, Discovery Download, and Canción de la Semana) in recent years,

2470-506: A promotion with Pepsi in which they gave away 100 million songs, through tokens on selected soft drink bottle caps. Unfortunately for Apple, Pepsi failed to properly distribute the bottles to major metropolitan areas until only weeks before the promotion ended, despite a one-month extension of the deadline by Apple. The promotion was repeated beginning January 31, 2005, with 200 million songs available, and an iPod Mini given away every hour. On July 1, 2004, Apple announced that, starting with

2600-522: A range of digital transmission applications such as the integrated services digital network (ISDN), cordless telephones and cell phones . Digital audio is used in broadcasting of audio. Standard technologies include Digital audio broadcasting (DAB), Digital Radio Mondiale (DRM), HD Radio and In-band on-channel (IBOC). Digital audio in recording applications is stored on audio-specific technologies including CD, DAT, Digital Compact Cassette (DCC) and MiniDisc . Digital audio may be stored in

2730-481: A significant business around Linux distributions. The free software licenses , on which the various software packages of a distribution built on the Linux kernel are based, explicitly accommodate and encourage commercialization; the relationship between a Linux distribution as a whole and individual vendors may be seen as symbiotic . One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer

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2860-515: A similar function with Hi8 tapes. Formats like ProDigi and DASH were referred to as SDAT (stationary-head digital audio tape) formats, as opposed to formats like the PCM adaptor-based systems and Digital Audio Tape (DAT), which were referred to as RDAT (rotating-head digital audio tape) formats, due to their helical-scan process of recording. Like the DAT cassette, ProDigi and DASH machines also accommodated

2990-587: A slight profit. The store also offers hundreds of movie trailers and music videos, in an attempt to boost soundtrack sales. In the conference, Steve Jobs reiterated that a subscription service is still not in the interest of customers and reported that only 5 million of the 100 million songs offered in the Pepsi giveaway campaign were redeemed, which he blamed on technical problems in Pepsi distribution. According to an Apple press release dated August 10, 2004, iTunes Music Store

3120-447: A software update which automatically allowed 3G and EDGE users to access the store's full functionality for files smaller than 10 megabytes (MB). The iOS 3.0 update added the ability to download movies, TV shows, audiobooks, iTunes U, and ringtones on mobile devices, in addition to the previously available songs and podcasts. On February 18, 2010, Apple increased the 10 MB 3G download limit to 20 MB. In March 2012, Apple increased

3250-493: A specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks. Another business model is to give away the software to sell hardware. This used to be the norm in the computer industry, with operating systems such as CP/M , Apple DOS , and versions of the classic Mac OS before 7.6 freely copyable (but not modifiable). As computer hardware standardized throughout

3380-442: A specified sampling rate and converts at a known bit resolution. CD audio , for example, has a sampling rate of 44.1  kHz (44,100 samples per second), and has 16-bit resolution for each stereo channel. Analog signals that have not already been bandlimited must be passed through an anti-aliasing filter before conversion, to prevent the aliasing distortion that is caused by audio signals with frequencies higher than

3510-420: A standard audio file formats and stored on a Hard disk recorder , Blu-ray or DVD-Audio . Files may be played back on smartphones, computers or MP3 player . Digital audio resolution is measured in audio bit depth . Most digital audio formats use either 16-bit, 24-bit, and 32-bit resolution. Linux This is an accepted version of this page Linux ( / ˈ l ɪ n ʊ k s / , LIN -uuks )

3640-972: A system's software from one central location. A distribution is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, Debian being a well-known example. Others maintain a community version of their commercial distributions, as Red Hat does with Fedora , and SUSE does with openSUSE . In many cities and regions, local associations known as Linux User Groups (LUGs) seek to promote their preferred distribution and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. Many Internet communities also provide support to Linux users and developers. Most distributions and free software / open-source projects have IRC chatrooms or newsgroups . Online forums are another means of support, with notable examples being Unix & Linux Stack Exchange , LinuxQuestions.org and

3770-402: A user may interact with the application; however, certain extensions of the X Window System are not capable of working over the network. Several X display servers exist, with the reference implementation, X.Org Server , being the most popular. Server distributions might provide a command-line interface for developers and administrators, but provide a custom interface for end-users, designed for

3900-453: A vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions. Many developers of open-source software agree that the Linux kernel was not designed but rather evolved through natural selection . Torvalds considers that although

4030-540: A week: in the United States, this rental costs 99 cents. Movie rentals are still not available in all countries but they are available in many countries including the United States, Mexico, the United Kingdom, Canada, Australia, India and New Zealand. There is a weekly promotion in which one to three songs are available to download for free to logged-in users. Free downloads are available on Tuesdays, and remain free until

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4160-544: Is a family of open-source Unix-like operating systems based on the Linux kernel , an operating system kernel first released on September 17, 1991, by Linus Torvalds . Linux is typically packaged as a Linux distribution (distro), which includes the kernel and supporting system software and libraries — many of which are provided by the GNU Project — to create a complete operating system. Many Linux distributions use

4290-531: Is divided into genres (Alternative, Classical, Jazz, Soundtrack, etc.), and there are a number of links to other sections of the store under the Quick Links header. These include Recommended for You, Complete My Album, iTunes LP, as well as thematic sections, such as iTunes Festival sections. In November 2006, Apple created a category for Latino and Hispanic content, "iTunes Latino". Telemundo and Mun2 made some of their popular programs available for purchase, becoming

4420-562: Is licensed under the GPLv2, with an exception for system calls that allows code that calls the kernel via system calls not to be licensed under the GPL. Because of the dominance of Linux-based Android on smartphones , Linux, including Android, has the largest installed base of all general-purpose operating systems as of May 2022 . Linux is, as of March 2024 , used by around 4 percent of desktop computers . The Chromebook , which runs

4550-462: Is no web-based interface for the iTunes Store with the exception of limited iTunes Preview pages; the desktop application has to be installed to browse the store. While initially a dominant player in digital media, by the mid-2010s, streaming media services were generating more revenue than the buy-to-own model used by the iTunes Store. Currently, iTunes is supported on the macOS ( Leopard and above) and Microsoft Windows operating systems. iTunes

4680-519: Is not available for download on a per song basis, whilst Circus ( Britney Spears ' 2008 album) has two songs that are available for album download only, Rock Me In and Phonography . Some albums on the iTunes store are available only as a "Partial Album" meaning that one or more of the songs on an album's CD release are not available on its iTunes equivalent, often due to differing copyright holders between songs. Some tracks are listed as "Work Only", which means they can only be obtained by purchasing

4810-490: Is speculated that the rebranding came because the functionality of iTunes would be changing in macOS Catalina and therefore the Mastered for iTunes name no longer made sense. There is a policy of censoring profanity in titles on iTunes. This has resulted in a Scunthorpe glitch , by which inoffensive titles are censored due to a coincidental string of letters. If the song has an explicit label, it will be marked "explicit" next to

4940-403: Is that the Linux kernel and other components are free and open-source software. Linux is not the only such operating system, although it is by far the most widely used. Some free and open-source software licenses are based on the principle of copyleft , a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common free software license,

5070-577: Is the Bourne-Again Shell (bash), originally developed for the GNU Project, other shells such as Zsh are also used. Most low-level Linux components, including various parts of the userland , use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks and provides very simple inter-process communication . On desktop systems, the most popular user interfaces are

5200-465: Is then modulated by a pseudo-noise (PN) sequence, then shaped within the frequency domain and put back in the original signal. The strength of the embedding determines the strength of the watermark on the audio data. Pulse-code modulation (PCM) was invented by British scientist Alec Reeves in 1937. In 1950, C. Chapin Cutler of Bell Labs filed the patent on differential pulse-code modulation (DPCM),

5330-468: Is typically built into the firmware and is highly tailored to the system. This includes routers , automation controls, smart home devices , video game consoles , televisions (Samsung and LG smart TVs ), automobiles (Tesla, Audi, Mercedes-Benz, Hyundai, and Toyota), and spacecraft ( Falcon 9 rocket, Dragon crew capsule, and the Ingenuity Mars helicopter). The Unix operating system

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5460-415: Is used on a wide variety of devices including PCs, workstations , mainframes and embedded systems . Linux is the predominant operating system for servers and is also used on all of the world's 500 fastest supercomputers . When combined with Android , which is Linux-based and designed for smartphones , they have the largest installed base of all general-purpose operating systems . The Linux kernel

5590-487: The Free Software Foundation and wrote the GNU General Public License (GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, compilers , text editors , a command-line shell , and a windowing system ) were completed, although low-level elements such as device drivers , daemons , and the kernel , called GNU Hurd , were stalled and incomplete. Minix

5720-736: The GNU toolchain , which includes the GNU Compiler Collection (GCC) and the GNU Build System . Amongst others, GCC provides compilers for Ada , C , C++ , Go and Fortran . Many programming languages have a cross-platform reference implementation that supports Linux, for example PHP , Perl , Ruby , Python , Java , Go , Rust and Haskell . First released in 2003, the LLVM project provides an alternative cross-platform open-source compiler for many languages. Proprietary compilers for Linux include

5850-470: The GUI shells , packaged together with extensive Desktop environments , such as KDE Plasma , GNOME , MATE , Cinnamon , LXDE , Pantheon , and Xfce , though a variety of additional user interfaces exist. Most popular user interfaces are based on the X Window System, often simply called "X". It provides network transparency and permits a graphical application running on one system to be displayed on another where

5980-547: The Nyquist frequency (half the sampling rate). A digital audio signal may be stored or transmitted. Digital audio can be stored on a CD, a digital audio player , a hard drive , a USB flash drive , or any other digital data storage device . The digital signal may be altered through digital signal processing , where it may be filtered or have effects applied. Sample-rate conversion including upsampling and downsampling may be used to change signals that have been encoded with

6110-633: The Red Cross . The store began operations after Apple signed deals with five major record companies: EMI , Universal Music Group , Warner Music Group , Sony Music Entertainment , and Bertelsmann Music Group . Songs from more than 2,000 independent labels were added later, the first being from The Orchard on June 24, 2003. As of April 2020, iTunes offers 60 million songs, including exclusive tracks from numerous artists. Not all artists are available on iTunes, but many holdouts, such as Led Zeppelin and Radiohead , have allowed their music to be sold on

6240-700: The United States was made by Thomas Stockham at the Santa Fe Opera in 1976, on a Soundstream recorder. An improved version of the Soundstream system was used to produce several classical recordings by Telarc in 1978. The 3M digital multitrack recorder in development at the time was based on BBC technology. The first all-digital album recorded on this machine was Ry Cooder 's Bop till You Drop in 1979. British record label Decca began development of its own 2-track digital audio recorders in 1978 and released

6370-417: The iPhone , iPad , Apple TV and iPod Touch . Apple offers three apps, each of which provides access to certain types of content. Other, free content available from the iTunes Store can be accessed from two other iOS apps: Originally, mobile users had to be connected to a Wi-Fi network in order to enter the store, hence its original name: iTunes Wi-Fi Music Store . However, at Macworld 2009, Apple issued

6500-476: The shell , is either a command-line interface (CLI), a graphical user interface (GUI), or controls attached to the associated hardware, which is common for embedded systems. For desktop systems, the default user interface is usually graphical, although the CLI is commonly available through terminal emulator windows or on a separate virtual console . CLI shells are text-based user interfaces, which use text for both input and output. The dominant shell used in Linux

6630-399: The 1970s and 1980s. Such a system uses a monolithic kernel , the Linux kernel, which handles process control, networking, access to the peripherals , and file systems . Device drivers are either integrated directly with the kernel or added as modules that are loaded while the system is running. The GNU userland is a key part of most systems based on the Linux kernel, with Android being

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6760-434: The 1970s, Bishnu S. Atal and Manfred R. Schroeder at Bell Labs developed a form of LPC called adaptive predictive coding (APC), a perceptual coding algorithm that exploited the masking properties of the human ear, followed in the early 1980s with the code-excited linear prediction (CELP) algorithm. Discrete cosine transform (DCT) coding, a lossy compression method first proposed by Nasir Ahmed in 1972, provided

6890-451: The 1980s, it became more difficult for hardware manufacturers to profit from this tactic, as the OS would run on any manufacturer's computer that shared the same architecture. Most programming languages support Linux either directly or through third-party community based ports . The original development tools used for building both Linux applications and operating system programs are found within

7020-518: The 3G download limit to 50 MB, and, in late 2013, Apple increased the limit to 100 MB when they released the final version of iOS 7 for their new iPhones. In the United States, Apple provides technical support for the iTunes Store via email; there is no phone number for issues with iTunes purchases. Most customer service inquiries are handled online, via the Report a Problem link in iTunes. In response to major natural disasters , Apple provides

7150-598: The Czech Republic, Cyprus, Denmark, Estonia, Finland, France, Germany, Greece, Hong Kong, Hungary, India, Indonesia, the Republic of Ireland, Italy, Japan, Laos, Latvia, Lithuania, Luxembourg, Macau, Malaysia, Malta, Mexico, the Netherlands, New Zealand, Norway, Philippines, Poland, Portugal, Puerto Rico, Romania, Russia, Singapore, Slovakia, Slovenia, Spain, Sri Lanka, Sweden, Switzerland, Taiwan, Thailand, Turkey, United Kingdom,

7280-663: The GNU General Public License (GPL), is a form of copyleft and is used for the Linux kernel and many of the components from the GNU Project. Linux-based distributions are intended by developers for interoperability with other operating systems and established computing standards. Linux systems adhere to POSIX, SUS , LSB , ISO , and ANSI standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT. Free software projects, although developed through collaboration , are often produced independently of each other. The fact that

7410-588: The Heart of the Beast by Henry Cow is 16 minutes and 18 seconds, yet is available for individual purchase as of 24 December 2013. Soundtracks also often have many Album Only tracks. Sometimes, the 10-minute restriction works in an artist's favor. Examples of this include Prince's Lovesexy and the deluxe version of Phoenix's Bankrupt! , which both have an album as a single track instead of being separate, (in Prince's case,

7540-460: The Linux kernel, key components that make up a distribution may include a display server (windowing system) , a package manager , a bootloader and the Bash shell . Linux is one of the most prominent examples of free and open-source software collaboration. While originally developed for x86 based personal computers , it has since been ported to more platforms than any other operating system, and

7670-602: The Linux kernel-based ChromeOS , dominates the US K–12 education market and represents nearly 20 percent of sub-$ 300 notebook sales in the US. Linux is the leading operating system on servers (over 96.4% of the top one million web servers' operating systems are Linux), leads other big iron systems such as mainframe computers , and is used on all of the world's 500 fastest supercomputers (as of November 2017 , having gradually displaced all competitors). Linux also runs on embedded systems , i.e., devices whose operating system

7800-605: The Linux kernel. On July 3, 1991, to implement Unix system calls , Linus Torvalds attempted unsuccessfully to obtain a digital copy of the POSIX standards documentation with a request to the comp.os.minix newsgroup . After not finding the POSIX documentation, Torvalds initially resorted to determining system calls from SunOS documentation owned by the university for use in operating its Sun Microsystems server. He also learned some system calls from Tanenbaum's Minix text. Torvalds began

7930-559: The Macworld 2008 keynote, Steve Jobs , who was Apple's CEO at the time, announced iTunes movie rentals. Movies are available for rent in the iTunes Store on the same day they are released on DVD, though the iTunes Store also offers for rental some movies that are still in theaters. Movie rentals are only viewable for 24 hours (in the US) or 48 hours (in other countries) after users begin viewing them. The iTunes Store also offers one low-priced movie rental

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8060-793: The TV app. Any music in users' iTunes library would transfer to the Music app, which would still offer access to the iTunes Store. The iTunes Store is available on most Apple devices, including the Mac (inside the Music app), the iPhone , the iPad , the iPod touch , and the Apple TV , as well as on Windows (inside iTunes). Video purchases from the iTunes Store are viewable on the Apple TV app on Roku and Amazon Fire TV devices and certain smart televisions. Unlike other Apple media services such as Apple Music or Apple TV+ , there

8190-477: The United States or Vietnam. Apple also offers other payment methods (like PayPal ), which differ from country to country. Residents in other countries can only buy a gift card from a merchant or download free podcasts and previews. In the past, the iTunes Store used Apple's FairPlay digital rights management (DRM) technology. FairPlay was built into the MP4 multimedia file format as an encrypted AAC audio layer, and

8320-399: The artist 9 cents in profit. They also reported that customers were purchasing 2.5 million songs a week which translates to a projected annual run rate of 130 million songs a year. The 50 millionth song was "The Path of Thorns" by Sarah McLachlan . On April 28, 2004, iTunes Music Store marked its first anniversary with 70 million songs sold, clear dominance in the paid online music market and

8450-487: The audio data being recorded to the tape using a multi-track stationary tape head. PCM adaptors allowed for stereo digital audio recording on a conventional NTSC or PAL video tape recorder . The 1982 introduction of the CD by Philips and Sony popularized digital audio with consumers. ADAT became available in the early 1990s, which allowed eight-track 44.1 or 48 kHz recording on S-VHS cassettes, and DTRS performed

8580-466: The basis for the modified discrete cosine transform (MDCT), which was developed by J. P. Princen, A. W. Johnson and A. B. Bradley in 1987. The MDCT is the basis for most audio coding standards , such as Dolby Digital (AC-3), MP3 ( MPEG Layer III), AAC, Windows Media Audio (WMA), Opus and Vorbis ( Ogg ). PCM was used in telecommunications applications long before its first use in commercial broadcast and recording. Commercial digital recording

8710-466: The beginning, it was rather casually hacked on by huge numbers of volunteers coordinating only through the Internet. Quality was maintained not by rigid standards or autocracy but by the naively simple strategy of releasing every week and getting feedback from hundreds of users within days, creating a sort of rapid Darwinian selection on the mutations introduced by developers." Bryan Cantrill , an engineer of

8840-447: The complexity and diversity of different devices, and due to the large number of formats and standards handled by those APIs, this infrastructure needs to evolve to better fit other devices. Also, a good userspace device library is the key to the success of having userspace applications to be able to work with all formats supported by those devices. The primary difference between Linux and many other popular contemporary operating systems

8970-482: The computer can effectively run at a single time. Avid Audio and Steinberg released the first digital audio workstation software programs in 1989. Digital audio workstations make multitrack recording and mixing much easier for large projects which would otherwise be difficult with analog equipment. The rapid development and wide adoption of PCM digital telephony was enabled by metal–oxide–semiconductor (MOS) switched capacitor (SC) circuit technology, developed in

9100-498: The consumer market is perhaps the mobile device market, with Android being the dominant operating system on smartphones and very popular on tablets and, more recently, on wearables . Linux gaming is also on the rise with Valve showing its support for Linux and rolling out SteamOS , its own gaming-oriented Linux distribution, which was later implemented in their Steam Deck platform. Linux distributions have also gained popularity with various local and national governments, such as

9230-498: The decision was made to standardize on AAC instead of the more popular MP3 format on the supposition that it offers better quality compared to other codecs at similar bit rates. Mastered for iTunes (MFiT) is a procedure developed by Apple specifically for mastering engineers to follow. This set of tools allows engineers to audition Apple's proprietary encoding during the mastering process to take into account how music will eventually interact with Apple's encoding. In addition to auditioning

9360-464: The design of Unix served as a scaffolding, "Linux grew with a lot of mutations – and because the mutations were less than random, they were faster and more directed than alpha-particles in DNA ." Eric S. Raymond considers Linux's revolutionary aspects to be social, not technical: before Linux, complex software was designed carefully by small groups, but "Linux evolved in a completely different way. From nearly

9490-502: The development of 386BSD , from which NetBSD , OpenBSD and FreeBSD descended, predated that of Linux. Linus Torvalds has stated on separate occasions that if the GNU kernel or 386BSD had been available at the time (1991), he probably would not have created Linux. While attending the University of Helsinki in the fall of 1990, Torvalds enrolled in a Unix course. The course used a MicroVAX minicomputer running Ultrix , and one of

9620-527: The development of the Linux kernel on Minix and applications written for Minix were also used on Linux. Later, Linux matured and further Linux kernel development took place on Linux systems. GNU applications also replaced all Minix components, because it was advantageous to use the freely available code from the GNU Project with the fledgling operating system; code licensed under the GNU GPL can be reused in other computer programs as long as they also are released under

9750-476: The development of the components of the system and free software. An analysis of the Linux kernel in 2017 showed that well over 85% of the code was developed by programmers who are being paid for their work, leaving about 8.2% to unpaid developers and 4.1% unclassified. Some of the major corporations that provide contributions include Intel , Samsung , Google , AMD , Oracle , and Facebook . Several corporations, notably Red Hat, Canonical , and SUSE have built

9880-570: The early 1970s. This led to the development of PCM codec-filter chips in the late 1970s. The silicon-gate CMOS (complementary MOS) PCM codec-filter chip, developed by David A. Hodges and W.C. Black in 1980, has since been the industry standard for digital telephony. By the 1990s, telecommunication networks such as the public switched telephone network (PSTN) had been largely digitized with VLSI (very large-scale integration ) CMOS PCM codec-filters, widely used in electronic switching systems for telephone exchanges , user-end modems and

10010-409: The electrical audio signal is amplified and then converted back into physical waveforms via a loudspeaker . Analog audio retains its fundamental wave-like characteristics throughout its storage, transformation, duplication, and amplification. Analog audio signals are susceptible to noise and distortion, due to the innate characteristics of electronic circuits and associated devices. Disturbances in

10140-466: The encoder, there is also a tool (called afclip) that processes the audio file and creates a text file for audio clips. Because of this special encoding process, extra attention must be paid to headroom and inter-sample peaking while mastering. In August 2019, it was announced that the Mastered for iTunes program would be rebranded as Apple Digital Masters. With the rebranding, the high resolution masters are now available with Apple Music through streaming. It

10270-461: The entire piece of work (within the album); the tracks cannot be bought as singles. Works are generally pieces of classical music: symphonies, string quartets, etc., in multiple movements. In September 2009, Apple introduced the iTunes LP format (known pre-launch by the code name "Cocktail") which features visual, interactive content alongside album tracks and lyrics. When entering the US music store, there are multiple sections one can visit. Music

10400-427: The facility for donations to be made through the iTunes Store. Unlike other iTunes purchases, donations made to charitable organizations through this system are not subject to the 30% handling fee Apple usually charges. iTunes donation pages were set up following the 2010 Haiti earthquake , the 2011 Japanese earthquake and ensuing tsunami, and 2012's Hurricane Sandy . In all of these cases, donations were redirected to

10530-546: The federal government of Brazil . Linus Torvalds is the lead maintainer for the Linux kernel and guides its development, while Greg Kroah-Hartman is the lead maintainer for the stable branch. Zoë Kooyman is the executive director of the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise

10660-871: The first 18 hours, the iTunes store sold about 275,000 tracks, and more than 1 million tracks were sold in its first 5 days. When released for Windows in October 2003, iTunes was downloaded more than 1 million times in the first 3 days, selling more than 1 million songs in that period. On December 15, 2003, Apple announced that it had sold 25 million songs. In January 2004 at the Macworld Conference & Expo in San Francisco, Steve Jobs announced (Sellers, 2004) that an unnamed person had purchased US$ 29,500 worth of music. On March 15, 2004, Apple announced that iTunes Music Store customers had purchased and downloaded 50 million songs from iTunes Music Store. A song sold on iTunes gives

10790-399: The first European digital recording in 1979. Popular professional digital multitrack recorders produced by Sony/Studer ( DASH ) and Mitsubishi ( ProDigi ) in the early 1980s helped to bring about digital recording's acceptance by the major record companies. Machines for these formats had their own transports built-in as well, using reel-to-reel tape in either 1/4", 1/2", or 1" widths, with

10920-596: The first Hispanic television content in the store. It offers music, music videos, audiobooks, podcasts and television shows in Spanish in a single concentrated area. The brief descriptions given to the content are in Spanish as well as several subcategories. Gibraltarian flamenco metal band Breed 77 released an exclusive album called Un Encuentro to coincide with the launch of "iTunes Latino". It features 11 songs, all from previous albums, but all sung in Spanish. In 2012, Apple created Mastered for iTunes. When iTunes launched,

11050-466: The first version of the Linux kernel on the Internet . Like GNU and 386BSD, Linux did not have any Unix code and therefore avoided any current legal issues . Desktop Linux distributions include a windowing system such as X11 or Wayland and a desktop environment such as GNOME , KDE Plasma or Xfce . Distributions intended for servers may not have a graphical user interface at all or include

11180-481: The five major record labels to offer their content through iTunes. The iTunes Music Store (later iTunes Store) was introduced by Jobs at a special Apple music event in April 2003. Music could be purchased in the iTunes application, and purchases were playable in iTunes or on the iPod . The store was initially available to Mac computers, and was later expanded to Microsoft Windows in October 2003 when iTunes for Windows

11310-526: The following Tuesday, when the store gets refreshed with new content. Some artists choose to have select songs available for no charge. This is not available at all iTunes Stores. Some iTunes television programs have begun the same technique to encourage brand loyalty, although those stay longer. In fact, the iTunes Store has a "Free TV Episodes" page where free episodes are organized by length, either as "featurettes" (shorter than 15 minutes) or full-length episodes (longer than 15 minutes). Free content can vary from

11440-429: The higher-quality rate of 256 kbit/s . Previously, this model, known as "iTunes Plus", had been available only for music from EMI and some independent labels. Users can sample songs by listening to previews, ninety seconds in length, or thirty seconds for short tracks. In addition, the iTunes Store offers apps, which are applications used for various purposes (games, productivity, news, etc.) that are compatible with

11570-440: The iPod Touch, iPhone, and iPad, although some apps are specifically for the iPhone or iPad only. Some apps cost money (called "Paid Apps") and some are free (called "Free Apps"). Developers can decide which prices they want to charge for apps, from a pre-set list of pricing tiers, from free to several hundred dollars. When someone downloads an App, 70 percent of the purchase goes to the developer(s), and 30 percent goes to Apple. At

11700-495: The iTunes Store also come with album artwork (Artwork is embedded in the metadata). Artwork can be obtained for songs not purchased from the store for free if the user has an iTunes Store account. Purchased songs do not come with lyrics, nor does iTunes provide a service for acquiring the missing lyrics. However, several third-party applications exist to locate and automatically add lyrics to the user's music. Some albums purchased on iTunes came with booklets. The first instance of this

11830-399: The iTunes Store in recent years. New songs are added to iTunes catalog on a daily basis, and the iTunes Store is updated each Tuesday. Downloaded songs come with song information (name, artist, album) already filled out, though iTunes provides a free service by Gracenote to do this for songs not purchased from the store, although they must be imported with iTunes. Songs that have an entry in

11960-632: The introduction of the iTunes Store, individual songs were all sold for the same price, though Apple introduced multiple prices in 2007. Music in the store is in the Advanced Audio Coding (AAC) format, which is the MPEG-4 -specified successor to MP3 . Originally, songs were only available with DRM and were encoded at 128  kbit / s . At the January 2009 Macworld Expo, Apple announced that all iTunes music would be made available without DRM, and encoded at

12090-551: The issue as being more of a threat than music piracy . On July 5, 2005, Apple announced a promotion counting down to half a billion songs sold. Originally only Mac OS X users who had a US billing address could buy songs with the service, but Steve Jobs announced plans to support both Windows and non-American users. The Windows version of iTunes and support for the Windows platform from iTunes Music Store were announced on October 16, 2003, with immediate availability. Beginning in 2004,

12220-401: The launch of the iBooks Store on March 31, 2010. It also used to facilitate the downloading of podcasts which later became integrated into Apple Podcasts , as well as the provision to buy and rent films and TV shows which has since become integrated into Apple TV . The iTunes Store opened as part of then-CEO Steve Jobs ' push to open a digital marketplace for music. When it launched, it was

12350-516: The mid-1990s in the supercomputing community, where organizations such as NASA started to replace their increasingly expensive machines with clusters of inexpensive commodity computers running Linux. Commercial use began when Dell and IBM , followed by Hewlett-Packard , started offering Linux support to escape Microsoft 's monopoly in the desktop operating system market. Today, Linux systems are used throughout computing, from embedded systems to virtually all supercomputers , and have secured

12480-399: The most common form of music consumption. An analog audio system converts physical waveforms of sound into electrical representations of those waveforms by use of a transducer , such as a microphone . The sounds are then stored on an analog medium such as magnetic tape , or transmitted through an analog medium such as a telephone line or radio . The process is reversed for reproduction:

12610-415: The music industry distributed and sold music by selling physical copies in the form of records and cassette tapes . With digital audio and online distribution systems such as iTunes , companies sell digital sound files to consumers, which the consumer receives over the Internet. Popular streaming services such as Apple Music , Spotify , or YouTube , offer temporary access to the digital file, and are now

12740-441: The notable exception. The GNU C library , an implementation of the C standard library , works as a wrapper for the system calls of the Linux kernel necessary to the kernel-userspace interface, the toolchain is a broad collection of programming tools vital to Linux development (including the compilers used to build the Linux kernel itself), and the coreutils implement many basic Unix tools . The GNU Project also develops Bash ,

12870-578: The obligatory 44.1 kHz sampling rate, but also 48 kHz on all machines, and eventually a 96 kHz sampling rate. They overcame the problems that made typical analog recorders unable to meet the bandwidth (frequency range) demands of digital recording by a combination of higher tape speeds, narrower head gaps used in combination with metal-formulation tapes, and the spreading of data across multiple parallel tracks. Unlike analog systems, modern digital audio workstations and audio interfaces allow as many channels in as many different sampling rates as

13000-462: The only legal digital catalog of music to offer songs from all five major record labels , which played a part in its success and influenced the music downloading business. Music streaming services began to overtake music downloading, with Apple launching Apple Music on June 30, 2015. Steve Jobs saw the opportunity to open a digital marketplace for music due to the rising popularity of easily downloadable tracks. In 2002, Jobs made an agreement with

13130-501: The operating system to their specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. A distribution is responsible for the default configuration of the installed Linux kernel, general system security, and more generally integration of the different software packages into a coherent whole. Distributions typically use a package manager such as apt , yum , zypper , pacman or portage to install, remove, and update all of

13260-453: The recording, manipulation, mass-production, and distribution of sound, including recordings of songs , instrumental pieces, podcasts , sound effects, and other sounds. Modern online music distribution depends on digital recording and data compression . The availability of music as data files, rather than as physical objects, has significantly reduced the costs of distribution as well as making it easier to share copies. Before digital audio,

13390-455: The required texts was Operating Systems: Design and Implementation by Andrew S. Tanenbaum . This textbook included a copy of Tanenbaum's Minix operating system. It was with this course that Torvalds first became exposed to Unix. In 1991, he became curious about operating systems. Frustrated by the licensing of Minix, which at the time limited it to educational use only, he began to work on his operating system kernel, which eventually became

13520-562: The sale of the 95 millionth song, an iPod would be given away to the buyer of each 100 thousandth song, for a total of 50 iPods. The buyer of the 100 millionth song would receive a PowerBook , iPod, and US$ 10,000 gift certificate to iTunes Music Store. Ten days later, on July 11, Apple announced that 100 million songs had been sold through iTunes Music Store. The 100 millionth song was titled "Somersault ( Dangermouse Remix)" by Zero 7 , purchased by Kevin Britten of Hays, Kansas . He then received

13650-412: The same or a compatible license. Torvalds initiated a switch from his original license, which prohibited commercial redistribution, to the GNU GPL. Developers worked to integrate GNU components with the Linux kernel, creating a fully functional and free operating system. Linus Torvalds had wanted to call his invention " Freax ", a portmanteau of "free", "freak", and "x" (as an allusion to Unix). During

13780-648: The service has become available in a number of countries other than the United States: To buy files through the store, a user must install the proprietary digital media player iTunes to access the store. This software is available only for certain versions of the Macintosh or Windows operating systems. A user must also pay with an iTunes gift card or a credit card with a billing address in Australia, Austria, Belgium, Brunei, Bulgaria, Brazil, Cambodia, Canada, Colombia,

13910-441: The software licenses explicitly permit redistribution, however, provides a basis for larger-scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution. Many Linux distributions manage a remote collection of system software and application software packages available for download and installation through a network connection. This allows users to adapt

14040-403: The song title. If a song is marked "explicit" it is unavailable for purchase if "restrict explicit content" is checked under the parental controls preference. Often there will be a "clean" mark next to the title of some songs, meaning the lyrics have been censored, and is available to purchase on all accounts. Generally if a song is marked "clean" there is an explicit version available as well. In

14170-569: The start of his work on the system, some of the project's makefiles included the name "Freax" for about half a year. Initially, Torvalds considered the name "Linux" but dismissed it as too egotistical. To facilitate development, the files were uploaded to the FTP server ( ftp.funet.fi ) of FUNET in September 1991. Ari Lemmke, Torvalds' coworker at the Helsinki University of Technology (HUT) who

14300-400: The storage or transmission of the signal. This technique, known as channel coding , is essential for broadcast or recorded digital systems to maintain bit accuracy. Eight-to-fourteen modulation is the channel code used for the audio compact disc (CD). If an audio signal is analog, a digital audio system starts with an ADC that converts an analog signal to a digital signal. The ADC runs at

14430-506: The store has instead replaced the three aforementioned categories with a unified "Single of the Week" banner, with the week's single being from a new up-and-coming artist. In 2015, Apple discontinued the "Single of the Week" program. App prices are set by the developer; they can be free of charge or charged at 99 cents plus any number of dollars. The iTunes Store allows users to purchase and download items directly to portable Apple devices, such as

14560-524: The track was the album, while in Phoenix's case, it was a collection of demos and outtakes) forcing the buyer to buy the album itself. Movie soundtracks normally include songs owned by many different labels, making licensing more complex. For example, Forrest Gump: The Soundtrack includes songs from Peacock Records , Argo Records , and Capitol Records , among many others. Greatest Hits by Red Hot Chili Peppers has only one song, " Higher Ground ", that

14690-471: The use case of the system. This custom interface is accessed through a client that resides on another system, not necessarily Linux-based. Several types of window managers exist for X11, including tiling , dynamic , stacking , and compositing . Window managers provide means to control the placement and appearance of individual application windows, and interact with the X Window System. Simpler X window managers such as dwm , ratpoison , or i3wm provide

14820-489: The use of DRM on music, raising points about the future of the protection and announced the company's support for ending the use of DRM. Although the open letter initially caused mixed industry reactions, Apple signed a deal with EMI , a record label , the following month in order to offer iTunes customers a purchase option called "iTunes Plus", for a higher-quality, DRM-free version of all of EMI's tracks. In January 2009, Apple signed deals with all major record labels as well as

14950-559: The various distribution-specific support and community forums, such as ones for Ubuntu , Fedora, Arch Linux , Gentoo , etc. Linux distributions host mailing lists ; commonly there will be a specific topic such as usage or development for a given list. There are several technology websites with a Linux focus. Print magazines on Linux often bundle cover disks that carry software or even complete Linux distributions. Although Linux distributions are generally available without charge, several large corporations sell, support, and contribute to

15080-511: The word "Linux" in their name, but the Free Software Foundation uses and recommends the name " GNU/Linux " to emphasize the use and importance of GNU software in many distributions, causing some controversy . Thousands of distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian , Fedora Linux , Arch Linux , and Ubuntu , while commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise . Other than

15210-429: The word "Linux" should be pronounced, he included an audio guide with the kernel source code. However, in this recording, he pronounces Linux as /ˈlinʊks/ ( LEEN -uuks ) with a short but close front unrounded vowel , instead of a near-close near-front unrounded vowel as in his newsgroup post. The adoption of Linux in production environments, rather than being used only by hobbyists, started to take off first in

15340-445: Was conceived and implemented in 1969, at AT&T 's Bell Labs , in the United States by Ken Thompson , Dennis Ritchie , Douglas McIlroy , and Joe Ossanna . First released in 1971, Unix was written entirely in assembly language , as was common practice at the time. In 1973, in a key pioneering approach, it was rewritten in the C programming language by Dennis Ritchie (except for some hardware and I/O routines). The availability of

15470-446: Was created by Andrew S. Tanenbaum , a computer science professor, and released in 1987 as a minimal Unix-like operating system targeted at students and others who wanted to learn operating system principles. Although the complete source code of Minix was freely available, the licensing terms prevented it from being free software until the licensing changed in April 2000. Although not released until 1992, due to legal complications ,

15600-510: Was designed by Linus Torvalds , following the lack of a working kernel for GNU , a Unix -compatible operating system made entirely of free software that had been undergoing development since 1983 by Richard Stallman . While a separate working Unix-compatible system called Minix was later released, its license was not entirely free at the time. The first entirely free Unix for personal computers, 386BSD , did not appear until 1992, by which time Torvalds had already built and publicly released

15730-548: Was known to run passably well in Linux on x86 -based computers using the Wine compatibility layer; however, by December 2011, this was no longer the case. Users without iTunes installed can see a content database (but not hear or view the content itself) using the iTunes Preview service, which runs inside their internet browser. This service also allows users to watch trailers for upcoming film releases. Should they choose to purchase any media, they will be redirected to iTunes. Following

15860-459: Was later originally developed, it represented the first successful commercial attempt at distributing a primarily single-user microcomputer that ran a Unix operating system. With Unix increasingly "locked in" as a proprietary product, the GNU Project , started in 1983 by Richard Stallman , had the goal of creating a "complete Unix-compatible software system" composed entirely of free software . Work began in 1984. Later, in 1985, Stallman started

15990-471: Was launched. In April 2008, the iTunes Store was the largest music vendor in the United States, and in February 2010, it was the largest music vendor in the world. The iTunes Store's revenues in the first quarter of 2011 totaled nearly US$ 1.4 billion. By May 28, 2014, the store had sold 35 billion songs worldwide. In 2016, it was reported that music streaming services had overtaken digital downloads in sales. It

16120-510: Was one of the volunteer administrators for the FTP server at the time, did not think that "Freax" was a good name, so he named the project "Linux" on the server without consulting Torvalds. Later, however, Torvalds consented to "Linux". According to a newsgroup post by Torvalds, the word "Linux" should be pronounced ( / ˈ l ɪ n ʊ k s / LIN -uuks ) with a short 'i' as in 'print' and 'u' as in 'put'. To further demonstrate how

16250-495: Was pioneered in Japan by NHK and Nippon Columbia and their Denon brand, in the 1960s. The first commercial digital recordings were released in 1971. The BBC also began to experiment with digital audio in the 1960s. By the early 1970s, it had developed a 2-channel recorder, and in 1972 it deployed a digital audio transmission system that linked their broadcast center to their remote transmitters. The first 16-bit PCM recording in

16380-518: Was released from its obligation not to enter the computer business; freed of that obligation, Bell Labs began selling Unix as a proprietary product, where users were not legally allowed to modify it. Onyx Systems began selling early microcomputer-based Unix workstations in 1980. Later, Sun Microsystems , founded as a spin-off of a student project at Stanford University , also began selling Unix-based desktop workstations in 1982. While Sun workstations did not use commodity PC hardware, for which Linux

16510-521: Was reported that iTunes-style digital download sales had dropped 24% as streaming continued to increase. In April 2018, the iTunes app was added to the Microsoft Windows 10 app store. Beginning in the spring of 2019, the iTunes app became available on Samsung Smart TVs. In October 2019, with the release of macOS Catalina , iTunes was split into separate Music , TV , and Podcasts apps. Apple's storefront for movies and television shows moved inside

16640-413: Was the first store to have a catalog of more than one million songs. Also, iTunes Music Store at that point maintained a 70 percent market share of legal music downloads. The emerging monopoly of the store was criticized in 2011 by Mike Lang of Miramax for "effectively strangling the industry". He says that because the music industry has allowed too few content providers, it is now suffering. Lang views

16770-432: Was the release of the album How to Dismantle an Atomic Bomb by rock band U2 . Some songs are available from the store by "Album Only", meaning the song can only be acquired through the purchase of the entire album, whereas most songs can be downloaded separately from the album they belong to. Songs above 10 minutes in length are by default Album Only songs. However, this is not universally true; for example, Living in

16900-637: Was used by the company to protect copyrighted works sold through the store, allowing only authorized devices to play the content. The restrictions imposed by FairPlay, mainly limited device compatibility, sparked criticism, with a lawsuit alleging antitrust violation that was eventually closed in Apple's favor, and various successful efforts to remove the DRM protection from files, with Apple continually updating its software to counteract such projects. In February 2007, an open letter by Steve Jobs , Apple's then- CEO , discussed

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