One comment: No wireless. Less space than a nomad. Lame.

Rob “CmdrTaco” Malda introduced the iPod to the Slashdot crowd with a statement rivalled only by Bill Gates’ quip “640 KB should be enough for anybody”.

Since that post in 2001, Apple’s iPod quickly became one of the most successful products in consumer electronics history. While its success largely derives from its “hip” factor and stylish design, the iPod’s integration with the iTunes music application and the iTunes Music Store has made the device a favorite among music listeners.

The iPod is a single component of Apple’s larger music platform

The iPod is a single component of Apple’s larger music platform.

The hub of the platform is the iTunes desktop digital music player. The iTunes application is only one of many in a long series of digital music library applications. iTunes began existence as a classic MacOS application called SoundJam. When Apple began developing and promoting their digital hub strategy, Apple purchased SoundJam and rechristened it iTunes. Prior to the introduction of the iPod, iTunes was simply another Mac MP3 program.

Both the music store and music sharing functionality are visible in this instance of iTunes

In 2001, Apple released the iPod. The device differed from other portable digital music players because of the tight integration with iTunes. Since other portable digital music players connected to applications other than those provided by the devices’ vendors, no other player was as tightly coupled with a desktop application as the iPod. While this close integration created a disadvantage where the iPod depends fully upon iTunes, Apple used the opportunity to craft the iPod as an extension to desktop-bound audio collections. Users can create static and dynamic playlists in iTunes, and the iPod synchronizes itself with those lists upon connection to the host computer.

While the iPod and iTunes originated as Mac-only products, in 2003, Apple expanded its strategy and ported iTunes to Windows and added USB functionality to the iPod. This opened the product’s market to Windows users. In short order, the iPod and iTunes dominated the market for portable hardware players and digital music applications.

Apple made the iTunes Music Store a success by striking new deals with copyright holders and leveraging the tight integration with iTunes

Later in 2003, Apple expanded the iTunes platform by introducing the iTunes Music Store. Previous online music stores had struggled with balancing copyright protection and user convenience. But Apple made the iTunes Music Store a success by striking new deals with copyright holders and leveraging the tight integration with iTunes. Furthermore, the iTunes Music Store is only accessible from within iTunes and iTunes (via Quicktime) is the only desktop application legally allowed to play protected tracks purchased from Apple’s online store. While critics had initially predicted the failure of the online music store, due to the difficulties inherent with Digital Rights Management (DRM) technology, the store succeeded and flourished due to the fine balance that Apple was able to maintain, between copyright holders and users. Apple is capable of maintaining this balance because it controls all levels of the technology platform used to acquire and play the protected tracks.

In 2004, Apple further expanded the iTunes music platform with the introduction of AirPort Express base stations

In 2004, Apple further expanded the iTunes music platform with the introduction of AirPort Express base stations. The Airport Express device is a smaller version of Apple’s Airport wireless access hardware. The Airport Express had also improved upon the older designs by including a dedicated USB hub, for printers and audio output ports, allowing connection between standard stereo equipment and wireless networks. To communicate with the Airport Express audio features, iTunes was given new functionality that sent audio to local Airport Express units. With this feature, iTunes users can use connected stereo devices to listen to their protected audio tracks. In addition to the analog stereo output port, Apple also integrated a digital 5.1 surround sound output into the device. (However there are currently no applications or content that can use the 5.1 surround sound feature as Apple has restricted access to third-party developers’.)

While Apple continued to expand the iTunes platform every year since its release, numerous third-party developers also created applications that integrate and interoperate with iTunes. Creative examples include music quiz applications that use the users’ local iTunes libraries as a source for questions, and applications that assist users creating and refining metadata by providing connectivity to new data sources.

While Apple continues to restrict developer access to the Airport Express peripherals, it documented iTunes XML and AppleScript dictionaries for third-party developers to use when extending the iTunes platform. Furthermore, due to the efforts of persistent developers, undocumented portions of the platform (notably, music sharing protocols) are now better understood. Developers use this knowledge, official and otherwise, to create new applications that take advantage of the iTunes platform.

Programming with iTunes—XML, AppleScript, and Windows

Out of all the components in the Apple music platform, the iTunes application offers the most options for interested developers.

Out of all the components in the Apple music platform, the iTunes application offers the most options for interested developers

An XML file provides access to most of the iTunes metadata. Other applications can control iTunes with AppleScript (on the Mac) or the iTunes COM SDK (on Windows). Client and server applications can communicate with iTunes using the Digital Audio Access Protocol (DAAP). Finally, protected AAC files purchased from the online music store can be played using Apple’s Quicktime API.

The location and contents of the iTunes XML file

Writing applications that can read the iTunes library XML file provides the easiest route for adding new functionality. This file is located at the root of a user’s music collection and is named “iTunes Music Library.xml”. This file uses an Apple subset of XML. It begins with metadata about the iTunes application and continues with a list of track entries and playlist definitions. The individual track entries contain metadata like creators, albums titles, and genres. The file also contains automatically generated metadata such as the last play date and local file locations. With the exception of album cover art, metadata encoded in individual tracks is also part of the XML file and is accessible to applications that read that file. Following the song entries, the file contains XML descriptions of the local playlists.

In addition to making its metadata available via XML, iTunes have also provided a rich AppleScript dictionary. MacOS X applications use AppleScript to automate common tasks or to control other applications. Users write AppleScripts in an English-like syntax that is designed for nonprogrammers.

AppleScript also provides access to frameworks such as Cocoa, allowing users to write standard GUI applications entirely in AppleScript

AppleScript also provides access to frameworks such as Cocoa, allowing users to write standard GUI applications entirely in AppleScript. Furthermore, AppleScripts can be invoked from the command line or developed interactively with a bundled AppleScript interpreter called Script Editor. This application is a specialized environment for developing and testing AppleScript code. Developers access locally installed applications’ AppleScript dictionaries from Script Editor. Using the iTunes dictionary, developers can discover the functions that the iTunes application provides via AppleScript.