IPhone OS
Encyclopedia
iOS is Apple's mobile operating system
. Originally developed for the iPhone
, it has since been extended to support other Apple, Inc. devices such as the iPod Touch
, iPad
, and Apple TV. Apple, Inc. does not license iOS for installation on third-party hardware. , Apple, Inc.'s App Store contained more than 500,000 iOS applications, which have collectively been downloaded more than 18 billion times. It had a 26% share of the smartphone
operating system units sold in the last quarter of 2010, behind both Google's Android and Nokia
's Symbian
. In May 2010 in the USA, it accounted for 59% of mobile web data consumption (including use on both the iPod Touch and the iPad).
The user interface
of iOS is based on the concept of direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. The response to user input is immediate and provides a fluid interface. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multitouch interface. Internal accelerometer
s are used by some applications to respond to shaking the device (one common result is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode).
iOS is derived from Mac OS X
, with which it shares the Darwin
foundation, and is therefore a Unix-like
operating system by nature.
In iOS, there are four abstraction layer
s: the Core OS layer, the Core Services
layer, the Media layer, and the Cocoa Touch
layer. The current version of the operating system (iOS 5.0.1) uses roughly 770 megabytes of the device's storage, varying for each model.
on January 9, 2007, and released in June of that year. At first, Apple marketing literature did not specify a separate name for the operating system, stating simply that the "iPhone runs OS X".
Initially, third-party applications were not supported. Steve Jobs argued that developers could build web applications that "would behave like native apps on the iPhone". On October 17, 2007, Apple announced that a native Software Development Kit (SDK) was under development and that they planned to put it "in developers' hands in February". On March 6, 2008, Apple released the first beta, along with a new name for the operating system: "iPhone OS".
The previous September, Apple had released the iPod touch, which had most of the non-phone capabilities of the iPhone. Apple also sold more than one million iPhones during the 2007 holiday season. On January 27, 2010, Apple announced the iPad, featuring a larger screen than the iPhone and iPod touch, and designed for web browsing, media consumption, and reading iBooks
.
In June 2010, Apple rebranded iPhone OS as "iOS". The trademark "IOS" had been used by Cisco
for over a decade for its operating system, IOS
, used on its routers. To avoid any potential lawsuit, Apple licensed the "IOS" trademark from Cisco.
(which owned IOS
), the same company with which Apple had earlier settled a dispute over the "iPhone" trademark.
Apple released iOS 4 on June 21, 2010, three days before the iPhone 4
, in an effort to reduce the strain on Apple's servers. iOS 4 was the first version of the OS to be a free upgrade on the iPod touch; Apple had charged $4.99 for earlier upgrades. Apple previously announced that iPad users with 3.x software would receive a free upgrade to the next major (4.x) release.
iOS 4.0.1 included a fix to the reception signal strength indicator(s). It was released on July 15, 2010, the day before Apple hosted a press conference to discuss its response to the widely publicized iPhone antenna issues. Apple also released iOS 3.2.1 for the iPad which tweaked the tablet's Wi-Fi connectivity, video playback, and copy-and-paste for PDF attachments, among other updates.
iOS 4.1 for the iPhone and iPod touch was released on September 8, 2010; the update fixed some bugs reported by users, improved battery life and added several new features:
iOS 4.1 also updated carrier settings which (at that time in the United States, AT&T
8.0 only). At the same time, TV show rentals became available on the iTunes US Store
.
iPad 2 is currently the only iOS device with the Photo Booth
app. iOS 4.2.5 was released as a demo version for the CDMA version of the iPhone 4
. This iPhone 4 variant was released for Verizon Wireless
customers in the US on February 10, 2011, but pre-ordering was available for qualified Verizon Wireless Customers on February 3. The version released with the phone, 4.2.6, has some slight UI changes specifically for the CDMA version of the phone, including a "Personal Hotspot" switch in the Settings app, a service which has to be activated by the carrier in order for the feature to be usable. This became available for purchase from Verizon as a separate plan, as is currently possible on other smartphones.
iOS 4.3 was released to the public on March 9, 2011, two days before the iPad 2
was available in the United States
. In addition to earlier features, the public release of iOS 4.3 included many new features such as a Nitro JavaScript engine in Safari
, making Safari run up to twice as fast according to Apple. iTunes Home Sharing also received a major revision in iOS 4.3; it allows users to connect to their home Wi-Fi
networks and stream content from iOS devices to speakers, TVs and other devices, or vice versa. Personal Hotspot for iPhone 4 is a new feature to GSM iPhones (previously released with the Verizon CDMA iPhone) that allows the user to create a Wi-Fi
network with an iPhone 4 and provide Internet access for up to five other devices on Verizon Wireless
, three on AT&T.. In addition, the side button on the iPad is now customizable, with users able to use it either as a system sound mute or as a screen rotation lock. iOS 4.3 was not released for CDMA iPhones, which stayed on 4.2.x versions until they were upgraded to iOS 5 with the rest of the iOS line on October 12, 2011.
iOS 5.0 and its features were announced on June 6 at the WWDC 2011 keynote address. The update was released at 6pm GMT on October 12, 2011. iOS 5 introduced the iCloud
service and the Notification Center
, as well as improvements to native apps such as Camera. The operating system also features new applications, such as the "Reminders" app and "Newsstand", an application that lets you buy newspapers and magazines. Newsstand is the first native application to run on the homescreen. "iMessage
" is an application that allows iPod touch, iPhone, and iPad users to communicate, much like a chat service only used between these devices. The iMessage feature has been integrated into the "Messages" application on the iPhone. The iPod application on the iPhone and iPad has now been split into the Music and Video application, just as it had been on the iPod touch. iOS 5 also brings long-awaited Hindi
virtual keyboard. According to Apple, the new OS has over 200 new features.
iOS 5 introduced a restriction over previous versions. Previously, it had been possible to install an app that allowed printing to (almost) any WiFi printer from any app that supported printing to the Apple air printer. iOS 5.0 (and later) have deliberately disabled the ability of printer support apps to work and it is now only possible to print to an air printer. There are workarounds for some (but not all) apps.
Many upgrading users have complained because the upgrade erases contacts, messages, music, apps, and all game progress.
") displays application
icons and a dock at the bottom of the screen where users can pin their most frequently used apps. The home screen appears whenever the user switches on the device or presses the "Home" button (a physical button on the device). The screen has a status bar across the top to display data, such as time, battery level, and signal strength. The rest of the screen is devoted to the current application.
Since iOS version 3.0, a Spotlight Search function has been available on the home screen, allowing users to search through media, applications, emails, contacts and similar files.
is activated through the Settings app.
All of the utilities, such as voice memos, clock, calculator, and compass are in one folder called "Utilities" in 4.0. Many of the included applications are designed to share data (e.g., a phone number can be selected from an email and saved as a contact or dialed for a phone call).
The iPod touch retains the same applications that are present by default on the iPhone, with the exception of the Phone, Messages, Compass and Camera (before the 4th generation) apps. The "iPod" App present on the iPhone is split into two apps, on the iPod touch: Music, and Videos. The bottom row of applications is also used to delineate the iPod touch's main purposes: Music, Videos, Safari, and App Store (Dock Layout was changed in 3.1 Update). For the 4th Generation iPod touch, it includes FaceTime and Camera, and the dock layout had changed to Music, Mail, Safari, Video. As of iOS 5.0, "iMessage" will be available on all iOS devices running iOS 5. iMessage is effectively a version of the iPhone Messages app that sends free text or multimedia messages to other iOS devices (similar to BlackBerry Messenger
).
The iPad comes with the same applications as the iPod touch excluding Stocks, Weather, Clock, Calculator, and the Nike + iPod app. Separate music and video apps are provided, as on the iPod touch, although (as on the iPhone) the music app is named "iPod". Although, that was changed in iOS 5 to "Music", to match the other devices in the family. In iOS 5, the iPod app will be replaced by Music and Video apps on all devices. Most of the default applications are completely rewritten to take advantage of the iPad's larger display. The default dock layout includes Safari, Mail, Photos and Music.
was limited to a selection of the applications Apple included on the devices. Apple worried that running multiple third-party applications simultaneously would drain batteries too quickly. Starting with iOS 4, on 3rd-generation and newer iOS devices, multitasking is supported through seven background APIs
:
multiplayer "social gaming network" released by Apple. It allows users to "invite friends to play a game, start a multiplayer game through matchmaking, track their achievements, and compare their high scores on a leader board."
Game Center was announced during an iOS 4 preview event hosted by Apple on April 8, 2010. A preview was released to registered Apple developers in August. It was released on September 8, 2010 with iOS 4.1 on iPhone 4, iPhone 3GS and iPod touch 2nd generation through 4th generation. Game Center made its public debut on the iPad with iOS 4.2.1. There will be no support for the iPhone 3G
and original iPhone
. However, Game Center is unofficially available on the iPhone 3G via a hack.
web browser
supports web application
s as with other web browsers. Authorized third-party native applications
are available for devices running iOS 2.0 and later through Apple's App Store.
(SDK) would be made available to third-party developers in February 2008. The SDK was released on March 6, 2008, and allows developers to make applications for the iPhone and iPod touch, as well as test them in an "iPhone simulator". However, loading an application onto the devices is only possible after paying an iPhone Developer Program fee.
Since the release of Xcode 3.1
, Xcode is the development environment for the iOS SDK. iPhone applications, like iOS and Mac OS X, are written in Objective-C
.
Developers are able to set any price above a set minimum for their applications to be distributed through the App Store, of which Apple will take 30% of the revenue (the other 70% goes to the developer). Alternately, they may opt to release the application for free and need not pay any costs to release or distribute the application except for the membership fee.
); however, with each iOS update the jailbreak appears to no longer work.
Since the arrival of the App Store and third-party applications, the focus of the jailbreaking community has shifted. A major focus of jailbreaking is allowing theming, using emulators
and community-made tweaks like multitasking, Adobe Flash player, accessing the iPhone file system, and customizing the SpringBoard further. Multitasking is only natively supported on 3rd-generation and newer iOS devices, and applications on the official App Store are not allowed to modify the look of the OS, hence the need for jailbreaking.
advocates such as the Electronic Frontier Foundation
, computer engineer and activist Brewster Kahle
, Internet-law specialist Jonathan Zittrain
, and the Free Software Foundation
who protested the iPad's introductory event and have targeted the iPad with their "Defective by Design
" campaign. Competitor Microsoft
, via a PR spokesman, has also criticized Apple's control over its platform.
At issue are restrictions imposed by the design of iOS, namely DRM
intended to lock purchased media to Apple's platform, the development model (requiring a yearly subscription to distribute apps developed for the iOS), the centralized approval process for apps, as well as Apple's general control and lockdown of the platform itself. Particularly at issue is the ability for Apple to remotely disable or delete apps at will.
Some in the tech community have expressed concern that the locked-down iOS represents a growing trend in Apple's approach to computing, particularly Apple's shift away from machines that hobbyists can "tinker with" and note the potential for such restrictions to stifle software innovation.
However, there are some outside of Apple who have voiced support for the iOS closed model. Facebook
developer Joe Hewitt, who had previously protested against Apple's control over its hardware as a "horrible precedent", has subsequently argued the locked apps in the iPad are akin to web applications and provide added security.
Mobile operating system
A mobile operating system, also known as a mobile OS, mobile software platform or a handheld operating system, is the operating system that controls a mobile device or information appliance—similar in principle to an operating system such as Windows, Mac OS X, or Linux distributions that controls a...
. Originally developed for the iPhone
IPhone
The iPhone is a line of Internet and multimedia-enabled smartphones marketed by Apple Inc. The first iPhone was unveiled by Steve Jobs, then CEO of Apple, on January 9, 2007, and released on June 29, 2007...
, it has since been extended to support other Apple, Inc. devices such as the iPod Touch
IPod Touch
The iPod Touch is a portable media player, personal digital assistant, handheld game console, and Wi-Fi mobile device designed and marketed by Apple Inc. The iPod Touch adds the multi-touch graphical user interface to the iPod line...
, iPad
IPad
The iPad is a line of tablet computers designed, developed and marketed by Apple Inc., primarily as a platform for audio-visual media including books, periodicals, movies, music, games, and web content. The iPad was introduced on January 27, 2010 by Apple's then-CEO Steve Jobs. Its size and...
, and Apple TV. Apple, Inc. does not license iOS for installation on third-party hardware. , Apple, Inc.'s App Store contained more than 500,000 iOS applications, which have collectively been downloaded more than 18 billion times. It had a 26% share of the smartphone
Smartphone
A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...
operating system units sold in the last quarter of 2010, behind both Google's Android and Nokia
Nokia
Nokia Corporation is a Finnish multinational communications corporation that is headquartered in Keilaniemi, Espoo, a city neighbouring Finland's capital Helsinki...
's Symbian
Symbian
Symbian is a mobile operating system and computing platform designed for smartphones and currently maintained by Accenture. The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user...
. In May 2010 in the USA, it accounted for 59% of mobile web data consumption (including use on both the iPod Touch and the iPad).
The user interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
of iOS is based on the concept of direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. The response to user input is immediate and provides a fluid interface. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multitouch interface. Internal accelerometer
Accelerometer
An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...
s are used by some applications to respond to shaking the device (one common result is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode).
iOS is derived from Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
, with which it shares the Darwin
Darwin (operating system)
Darwin is an open source POSIX-compliant computer operating system released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, and other free software projects....
foundation, and is therefore a Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating system by nature.
In iOS, there are four abstraction layer
Abstraction layer
An abstraction layer is a way of hiding the implementation details of a particular set of functionality...
s: the Core OS layer, the Core Services
Core Services
Core Services are a set of Mac OS X and iOS application programming interfaces that architecturally are underneath Carbon, Cocoa and Cocoa Touch. In addition to Core Foundation, it also encompasses other APIs including Grand Central Dispatch, Blocks, CFNetwork, CarbonCore, OSServices, and...
layer, the Media layer, and the Cocoa Touch
Cocoa Touch
Cocoa Touch is an API for building software programs to run on the iPhone, iPod Touch, and iPad from Apple Inc.Cocoa Touch provides an abstraction layer of iOS, the operating system for the iPhone, iPod Touch, and iPad. Cocoa Touch is based on the Mac OS X Cocoa API toolset and, like it, is...
layer. The current version of the operating system (iOS 5.0.1) uses roughly 770 megabytes of the device's storage, varying for each model.
History
The operating system was unveiled with the iPhone at the Macworld Conference & ExpoMacworld Conference & Expo
Produced by Boston-based IDG World Expo, Macworld | iWorld is a trade-show with conference tracks dedicated to the Apple Macintosh platform. It is held annually in the United States, usually during the second week of January...
on January 9, 2007, and released in June of that year. At first, Apple marketing literature did not specify a separate name for the operating system, stating simply that the "iPhone runs OS X".
Initially, third-party applications were not supported. Steve Jobs argued that developers could build web applications that "would behave like native apps on the iPhone". On October 17, 2007, Apple announced that a native Software Development Kit (SDK) was under development and that they planned to put it "in developers' hands in February". On March 6, 2008, Apple released the first beta, along with a new name for the operating system: "iPhone OS".
The previous September, Apple had released the iPod touch, which had most of the non-phone capabilities of the iPhone. Apple also sold more than one million iPhones during the 2007 holiday season. On January 27, 2010, Apple announced the iPad, featuring a larger screen than the iPhone and iPod touch, and designed for web browsing, media consumption, and reading iBooks
IBooks
iBooks is an e-book application by Apple Inc. It was announced in conjunction with the iPad on January 27, 2010, and was released for the iPhone and iPod Touch in mid-2010, as part of the iOS 4 update. At that time, it was described by Apple as being available only in the United States...
.
In June 2010, Apple rebranded iPhone OS as "iOS". The trademark "IOS" had been used by Cisco
Cisco
Cisco may refer to:Companies:*Cisco Systems, a computer networking company* Certis CISCO, corporatised entity of the former Commercial and Industrial Security Corporation in Singapore...
for over a decade for its operating system, IOS
Cisco IOS
Cisco IOS is the software used on the vast majority of Cisco Systems routers and current Cisco network switches...
, used on its routers. To avoid any potential lawsuit, Apple licensed the "IOS" trademark from Cisco.
Version history
Apple licensed the trademark for "iOS" from Cisco SystemsCisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...
(which owned IOS
Cisco IOS
Cisco IOS is the software used on the vast majority of Cisco Systems routers and current Cisco network switches...
), the same company with which Apple had earlier settled a dispute over the "iPhone" trademark.
Apple released iOS 4 on June 21, 2010, three days before the iPhone 4
IPhone 4
The iPhone 4 is a touchscreen slate smartphone developed by Apple Inc. It is the fourth generation iPhone, and successor to the iPhone 3GS. It is particularly marketed for video calling , consumption of media such as books and periodicals, movies, music, and games, and for general web and e-mail...
, in an effort to reduce the strain on Apple's servers. iOS 4 was the first version of the OS to be a free upgrade on the iPod touch; Apple had charged $4.99 for earlier upgrades. Apple previously announced that iPad users with 3.x software would receive a free upgrade to the next major (4.x) release.
iOS 4.0.1 included a fix to the reception signal strength indicator(s). It was released on July 15, 2010, the day before Apple hosted a press conference to discuss its response to the widely publicized iPhone antenna issues. Apple also released iOS 3.2.1 for the iPad which tweaked the tablet's Wi-Fi connectivity, video playback, and copy-and-paste for PDF attachments, among other updates.
iOS 4.1 for the iPhone and iPod touch was released on September 8, 2010; the update fixed some bugs reported by users, improved battery life and added several new features:
- Game Center, which allows gamers to play multiplayer games online, upload high scores and unlock achievements (though Apple removed Game Center from the iPhone 3GIPhone 3GThe iPhone 3G is the second generation of iPhone designed and marketed by Apple Inc.. It was the successor to the original iPhone, and is succeeded by the iPhone 3GS. Introduced on June 9, 2008 at the WWDC 2008 at the Moscone Center, San Francisco...
because of reports of slow performance) - The ability to toggle spell checking on and off
- HDR photography (iPhone 4 and 4S only)
- PingITunes PingiTunes Ping, also known simply as Ping, is a software-based, music-oriented social networking and recommender system service developed and operated by Apple. It was announced and launched on 1 September 2010 as part of the tenth major release of iTunes...
, a social music network and discovery tool
iOS 4.1 also updated carrier settings which (at that time in the United States, AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
8.0 only). At the same time, TV show rentals became available on the iTunes US Store
ITunes Store
The iTunes Store is a software-based online digital media store operated by Apple. Opening as the iTunes Music Store on April 28, 2003, with over 200,000 items to purchase, it is, as of April 2008, the number-one music vendor in the United States...
.
iPad 2 is currently the only iOS device with the Photo Booth
Photo Booth
Photo Booth is a small software application for taking photos and videos with an iSight camera by Apple Inc. for Mac OS X and iOS .-Photo Booth:...
app. iOS 4.2.5 was released as a demo version for the CDMA version of the iPhone 4
IPhone 4
The iPhone 4 is a touchscreen slate smartphone developed by Apple Inc. It is the fourth generation iPhone, and successor to the iPhone 3GS. It is particularly marketed for video calling , consumption of media such as books and periodicals, movies, music, and games, and for general web and e-mail...
. This iPhone 4 variant was released for Verizon Wireless
Verizon Wireless
Cellco Partnership, doing business as Verizon Wireless, is one of the largest mobile network operators in the United States. The network has 107.7 million subscribers as of 2011, making it the largest wireless service provider in America....
customers in the US on February 10, 2011, but pre-ordering was available for qualified Verizon Wireless Customers on February 3. The version released with the phone, 4.2.6, has some slight UI changes specifically for the CDMA version of the phone, including a "Personal Hotspot" switch in the Settings app, a service which has to be activated by the carrier in order for the feature to be usable. This became available for purchase from Verizon as a separate plan, as is currently possible on other smartphones.
iOS 4.3 was released to the public on March 9, 2011, two days before the iPad 2
IPad 2
The iPad 2 is the second and current generation of the iPad, a tablet computer designed, developed and marketed by Apple. It serves primarily as a platform for audio-visual media including books, periodicals, movies, music, games, presentations and web content, and is available in black or white...
was available in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. In addition to earlier features, the public release of iOS 4.3 included many new features such as a Nitro JavaScript engine in Safari
Safari (web browser)
Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the...
, making Safari run up to twice as fast according to Apple. iTunes Home Sharing also received a major revision in iOS 4.3; it allows users to connect to their home Wi-Fi
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
networks and stream content from iOS devices to speakers, TVs and other devices, or vice versa. Personal Hotspot for iPhone 4 is a new feature to GSM iPhones (previously released with the Verizon CDMA iPhone) that allows the user to create a Wi-Fi
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
network with an iPhone 4 and provide Internet access for up to five other devices on Verizon Wireless
Verizon Wireless
Cellco Partnership, doing business as Verizon Wireless, is one of the largest mobile network operators in the United States. The network has 107.7 million subscribers as of 2011, making it the largest wireless service provider in America....
, three on AT&T.. In addition, the side button on the iPad is now customizable, with users able to use it either as a system sound mute or as a screen rotation lock. iOS 4.3 was not released for CDMA iPhones, which stayed on 4.2.x versions until they were upgraded to iOS 5 with the rest of the iOS line on October 12, 2011.
iOS 5.0 and its features were announced on June 6 at the WWDC 2011 keynote address. The update was released at 6pm GMT on October 12, 2011. iOS 5 introduced the iCloud
ICloud
iCloud is a cloud storage and cloud computing service from Apple Inc. announced on June 6, 2011 at the Apple Worldwide Developers Conference . The service allows users to store data such as music files on remote computer servers for download to multiple devices such as iPhones, iPods, iPads, and...
service and the Notification Center
Notification Center
Notification Center is a feature in iOS in which the user can see alerts from applications on the device. It was developed by Apple Inc. and released with iOS 5 on October 12, 2011.-Features:...
, as well as improvements to native apps such as Camera. The operating system also features new applications, such as the "Reminders" app and "Newsstand", an application that lets you buy newspapers and magazines. Newsstand is the first native application to run on the homescreen. "iMessage
IMessage
iMessage is an instant messenger application developed by Apple for iOS 5. iMessage was released on October 12, 2011 to the general public.-History:iMessage was announced by Scott Forstall at his keynote speech on June 6, 2011 at the WWDC 2011...
" is an application that allows iPod touch, iPhone, and iPad users to communicate, much like a chat service only used between these devices. The iMessage feature has been integrated into the "Messages" application on the iPhone. The iPod application on the iPhone and iPad has now been split into the Music and Video application, just as it had been on the iPod touch. iOS 5 also brings long-awaited Hindi
Hindi
Standard Hindi, or more precisely Modern Standard Hindi, also known as Manak Hindi , High Hindi, Nagari Hindi, and Literary Hindi, is a standardized and sanskritized register of the Hindustani language derived from the Khariboli dialect of Delhi...
virtual keyboard. According to Apple, the new OS has over 200 new features.
iOS 5 introduced a restriction over previous versions. Previously, it had been possible to install an app that allowed printing to (almost) any WiFi printer from any app that supported printing to the Apple air printer. iOS 5.0 (and later) have deliberately disabled the ability of printer support apps to work and it is now only possible to print to an air printer. There are workarounds for some (but not all) apps.
Many upgrading users have complained because the upgrade erases contacts, messages, music, apps, and all game progress.
Home screen
The home screen (rendered by "SpringBoardSpringboard
A springboard or diving board is used for diving and is a board that is itself a spring, i.e. a linear flex-spring, of the cantilever type....
") displays application
Application software
Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...
icons and a dock at the bottom of the screen where users can pin their most frequently used apps. The home screen appears whenever the user switches on the device or presses the "Home" button (a physical button on the device). The screen has a status bar across the top to display data, such as time, battery level, and signal strength. The rest of the screen is devoted to the current application.
Since iOS version 3.0, a Spotlight Search function has been available on the home screen, allowing users to search through media, applications, emails, contacts and similar files.
Folders
With iOS 4 came the introduction of a simple folder system. When applications are in "jiggle mode", any two can be dragged on top of each other to create a folder, and from then on, more apps can be added to the folder using the same procedure, up to 12 on iPhone and iPod touch and 20 on iPad. A title for the folder is automatically selected by the type of applications inside, but the name can also be edited by the user.Notification Center
In the iOS 5 update, the notifications feature has been completely redesigned. Notifications now collate in a window which can be dragged down from the top of the screen. And if you touch a received notification, you go to the application that sent the notification.Included applications
The iOS home screen contains these default "apps". Some of these applications are hidden by default and accessed by the user through the Settings app or another method—for instance, Nike+iPodNike+iPod
The Nike+iPod Sports Kit is a device which measures and records the distance and pace of a walk or run. The Nike+iPod consists of a small accelerometer attached to or embedded in a shoe, which communicates with either the Nike+ Sportband, a receiver plugged into an iPod Nano, or directly with a...
is activated through the Settings app.
| Name | Use | First appearance | ||
|---|---|---|---|---|
| iPhone | iPod touch | iPad | ||
| Phone | Telephone Telephone The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other... , FaceTime FaceTime FaceTime is a video calling software application and related protocol developed by Apple for supported mobile devices running the iOS, in addition to Macintosh computers running Mac OS X 10.6.6 and higher... video calling Videotelephony Videotelephony comprises the technologies for the reception and transmission of audio-video signals by users at different locations, for communication between people in real-time.... |
1.0 (FaceTime 4.0) | FaceTime 4.1 | FaceTime 4.3 |
| Mail Mail (application) Mail is an email program included with Apple Inc.'s Mac OS X operating system. Originally developed by NeXT as NeXTMail, a part of their NeXTSTEP operating system, it was adapted, following Apple's acquisition of NeXT, to become OS X's Mail application.Mail uses the SMTP, POP3, and IMAP protocols,... |
E-mail client E-mail client An email client, email reader, or more formally mail user agent , is a computer program used to manage a user's email.The term can refer to any system capable of accessing the user's email mailbox, regardless of it being a mail user agent, a relaying server, or a human typing on a terminal... |
1.0 | 1.1.3 | 3.2 |
| Safari Safari (web browser) Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the... |
Web browser Web browser A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content... |
|||
| Music Music Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture... (formerly iPod) |
Portable media player Portable media player A portable media player or digital audio player, is a consumer electronics device that is capable of storing and playing digital media such as audio, images, video, documents, etc. the data is typically stored on a hard drive, microdrive, or flash memory. In contrast, analog portable audio... |
| Name | Use | Version included | ||
|---|---|---|---|---|
| iPhone | iPod touch | iPad | ||
| Messages | Text messaging Text messaging Text messaging, or texting, refers to the exchange of brief written text messages between fixed-line phone or mobile phone and fixed or portable devices over a network... , MMS Multimedia Messaging Service Multimedia Messaging Service, or MMS, is a standard way to send messages that include multimedia content to and from mobile phones. It extends the core SMS capability that allowed exchange of text messages only up to 160 characters in length.The most popular use is to send photographs from... , iMessage IMessage iMessage is an instant messenger application developed by Apple for iOS 5. iMessage was released on October 12, 2011 to the general public.-History:iMessage was announced by Scott Forstall at his keynote speech on June 6, 2011 at the WWDC 2011... instant messaging Instant messaging Instant Messaging is a form of real-time direct text-based chatting communication in push mode between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet... |
1.0 (MMS 3.0, iMessage 5.0) | iMessage 5.0 | iMessage 5.0 |
| Calendar | Calendar Calendar A calendar is a system of organizing days for social, religious, commercial, or administrative purposes. This is done by giving names to periods of time, typically days, weeks, months, and years. The name given to each day is known as a date. Periods in a calendar are usually, though not... |
1.0 | 3.2 | |
| Photos | Photo viewer | 1.0 (Video viewer 2.0) | 3.2 | |
| Camera | Camera Camera A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images... , Camcorder Camcorder A camcorder is an electronic device that combines a video camera and a video recorder into one unit. Equipment manufacturers do not seem to have strict guidelines for the term usage... |
1.0 Video recording and auto-focus iPhone 3GS (3.0) onwards 720p HD video iPhone 4 (4.0) HDR High dynamic range imaging In image processing, computer graphics, and photography, high dynamic range imaging is a set of techniques that allows a greater dynamic range between the lightest and darkest areas of an image than current standard digital imaging techniques or photographic methods... iPhone 4 (4.1) Crop, red eye fix, auto enhance and photo rotate (5.0) |
4.1 (4th generation only) Crop, red eye fix, auto enhance and photo rotate (5.0)(4th generation only) |
4.3 (iPad 2 only) Crop, red eye fix, auto enhance and photo rotate (5.0) (iPad 2 only) |
| YouTube YouTube YouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos.... |
YouTube YouTube YouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos.... video streamer |
1.0 | 3.2 | |
| FaceTime FaceTime FaceTime is a video calling software application and related protocol developed by Apple for supported mobile devices running the iOS, in addition to Macintosh computers running Mac OS X 10.6.6 and higher... |
Video calling Videotelephony Videotelephony comprises the technologies for the reception and transmission of audio-video signals by users at different locations, for communication between people in real-time.... |
4.0 (iPhone 4, via Phone app) |
4.1 (4th generation) |
4.3 (iPad 2) |
| Stocks | Yahoo! Finance Yahoo! Finance Yahoo! Finance is a service from Yahoo! that provides financial information. It is the top financial news and research website in the United States, with more than 23 million visitors in February 2010, according to comScore.... |
1.0 | ||
| Maps | Google Maps Google Maps Google Maps is a web mapping service application and technology provided by Google, free , that powers many map-based services, including the Google Maps website, Google Ride Finder, Google Transit, and maps embedded on third-party websites via the Google Maps API... |
1.0 (Assisted GPS Assisted GPS Assisted GPS, generally abbreviated as A-GPS or aGPS, is a system which can, under certain conditions, improve the startup performance, or time-to-first-fix of a GPS satellite-based positioning system. It is used extensively with GPS-capable cellular phones as its development was accelerated by... 2.0) |
1.0 | 3.2 |
| Weather | Yahoo! Yahoo! Yahoo! Inc. is an American multinational internet corporation headquartered in Sunnyvale, California, United States. The company is perhaps best known for its web portal, search engine , Yahoo! Directory, Yahoo! Mail, Yahoo! News, Yahoo! Groups, Yahoo! Answers, advertising, online mapping ,... Weather |
1.0 | ||
| Voice Memos | Voice recorder | 3.0 | ||
| Notes | A simple note-taking program | 1.0 | 3.2 | |
| Newsstand Newsstand (Apple) Newsstand is an iOS App which can download and display Newspapers and Magazines. It was included in iOS Versions after 5.0.... |
A newspaper and magazine store | 5.0 | ||
| Reminders | A to-do list application | 5.0 | ||
| Clock | World clock World clock A world clock, often called a "Worldtime Clock", is a clock which displays the time for many places around the world.The display can take various forms:... , stopwatch Stopwatch A stopwatch is a handheld timepiece designed to measure the amount of time elapsed from a particular time when activated to when the piece is deactivated. A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stopclock.The timing functions... , alarm clock Alarm clock An alarm clock is a clock that is designed to make a loud sound at a specific time. The primary use of these clocks is to awaken people from their night's sleep or short naps; they are sometimes used for other reminders as well. To stop the sound, a button or handle on the clock is pressed; but... and timer Timer A timer is a specialized type of clock. A timer can be used to control the sequence of an event or process. Whereas a stopwatch counts upwards from zero for measuring elapsed time, a timer counts down from a specified time interval, like an hourglass.Timers can be mechanical, electromechanical,... |
1.0 | ||
| Calculator | Calculator Calculator An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic... (includes scientific version) |
1.0 (Scientific calculator 2.0) |
||
| Settings | Settings | 1.0 | 3.2 | |
| iTunes ITunes iTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad.... |
Access to the iTunes Music Store and iTunes Podcast Directory | 1.1 | 3.2 | |
| App Store | To buy iOS apps | 2.0 | 3.2 | |
| Compass | Compass Compass A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined... |
3.0 (iPhone 3GS IPhone 3GS -Camera:The iPhone 3GS features an improved 3 megapixel camera manufactured by OmniVision. In addition to the higher megapixel count, it also features auto-focus, auto white balance and auto macro and is capable of capturing VGA video... onwards) |
||
| Contacts | Address/phone book | 1.0 (integrated in Phone app) (Separate application for 2.0) |
1.1 | 3.2 |
| Nike + iPod | Records the distance and pace of a walk or run; can connect to Nike + iPod sensor | 3.0 (iPhone 3GS onwards) |
2.2.1+ (2nd Generation onwards) |
|
| Game Center Game Center Game Center is an online multiplayer social gaming network released by Apple. It allows users to invite friends to play a game, start a multiplayer game through matchmaking, track their achievements, and compare their high scores on a leader board.-History:... |
Allows the user to play multiplayer games with other users, track in game achievements and view leaderboards. | 4.1 (iPhone 3GS onwards) |
4.1 (2nd Generation onwards) |
4.2 (4.2.1 to public) |
| Photo Booth Photo Booth Photo Booth is a small software application for taking photos and videos with an iSight camera by Apple Inc. for Mac OS X and iOS .-Photo Booth:... |
A camera application with added special effects | 4.3 (iPad 2) |
||
| Siri Siri (software) Siri is an intelligent software assistant and knowledge navigator functioning as a personal assistant application for iOS. The application uses a natural language user interface to answer questions, make recommendations, and perform actions by delegating requests to a set of web services... |
Voice control assistant | 5.0 (iPhone 4S Only) |
||
All of the utilities, such as voice memos, clock, calculator, and compass are in one folder called "Utilities" in 4.0. Many of the included applications are designed to share data (e.g., a phone number can be selected from an email and saved as a contact or dialed for a phone call).
The iPod touch retains the same applications that are present by default on the iPhone, with the exception of the Phone, Messages, Compass and Camera (before the 4th generation) apps. The "iPod" App present on the iPhone is split into two apps, on the iPod touch: Music, and Videos. The bottom row of applications is also used to delineate the iPod touch's main purposes: Music, Videos, Safari, and App Store (Dock Layout was changed in 3.1 Update). For the 4th Generation iPod touch, it includes FaceTime and Camera, and the dock layout had changed to Music, Mail, Safari, Video. As of iOS 5.0, "iMessage" will be available on all iOS devices running iOS 5. iMessage is effectively a version of the iPhone Messages app that sends free text or multimedia messages to other iOS devices (similar to BlackBerry Messenger
Blackberry Messenger
BlackBerry Messenger is a proprietary Internet-based instant messenger application included on BlackBerry devices which allows messaging between BlackBerry users.It was developed by Research In Motion , maker of the BlackBerry device...
).
The iPad comes with the same applications as the iPod touch excluding Stocks, Weather, Clock, Calculator, and the Nike + iPod app. Separate music and video apps are provided, as on the iPod touch, although (as on the iPhone) the music app is named "iPod". Although, that was changed in iOS 5 to "Music", to match the other devices in the family. In iOS 5, the iPod app will be replaced by Music and Video apps on all devices. Most of the default applications are completely rewritten to take advantage of the iPad's larger display. The default dock layout includes Safari, Mail, Photos and Music.
Multitasking
Before iOS 4, multitaskingComputer multitasking
In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...
was limited to a selection of the applications Apple included on the devices. Apple worried that running multiple third-party applications simultaneously would drain batteries too quickly. Starting with iOS 4, on 3rd-generation and newer iOS devices, multitasking is supported through seven background APIs
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
:
- Background audio - application continues to run in the background as long as it is playing audio or video content
- Voice over IP - application is suspended when a phone call is not in progress
- Background location - application is notified of location changes
- Push notificationsApple Push Notification ServiceThe Apple Push Notification Service is a service created by Apple Inc. that was launched together with iOS 3.0 on June 17, 2009. It uses push technology through a constantly-open IP connection to forward notifications from the servers of third party applications to the Apple devices; such...
- Local notifications - application schedules local notifications to be delivered at a predetermined time
- Task completion - application asks the system for extra time to complete a given task
- Fast app switching - application does not execute any code and may be removed from memory at any time
Switching applications
Double-clicking the home button activates the application switcher. A scrollable dock-like interface appears from the bottom, moving the contents of the screen up. Choosing an icon switches to an application. To the far left are icons which function as music controls, and a rotation lock. Holding the icons briefly makes them "jiggle" (similarly to the homescreen) and allows the user to force quit the applications.Game Center
Game Center is an onlineInternet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
multiplayer "social gaming network" released by Apple. It allows users to "invite friends to play a game, start a multiplayer game through matchmaking, track their achievements, and compare their high scores on a leader board."
Game Center was announced during an iOS 4 preview event hosted by Apple on April 8, 2010. A preview was released to registered Apple developers in August. It was released on September 8, 2010 with iOS 4.1 on iPhone 4, iPhone 3GS and iPod touch 2nd generation through 4th generation. Game Center made its public debut on the iPad with iOS 4.2.1. There will be no support for the iPhone 3G
IPhone 3G
The iPhone 3G is the second generation of iPhone designed and marketed by Apple Inc.. It was the successor to the original iPhone, and is succeeded by the iPhone 3GS. Introduced on June 9, 2008 at the WWDC 2008 at the Moscone Center, San Francisco...
and original iPhone
IPhone (original)
The iPhone—retroactively labeled the original iPhone, iPhone 2G, or iPhone EDGE—was the first generation of iPhone designed and marketed by Apple Inc. and was succeeded by the iPhone 3G. It was announced on January 9, 2007 after months of rumors and speculation. It was introduced in the United...
. However, Game Center is unofficially available on the iPhone 3G via a hack.
Development
The applications must be written and compiled specifically for iOS and the ARM architecture. The SafariSafari (web browser)
Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the...
web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
supports web application
Web application
A web application is an application that is accessed over a network such as the Internet or an intranet. The term may also mean a computer software application that is coded in a browser-supported language and reliant on a common web browser to render the application executable.Web applications are...
s as with other web browsers. Authorized third-party native applications
Machine code
Machine code or machine language is a system of impartible instructions executed directly by a computer's central processing unit. Each instruction performs a very specific task, typically either an operation on a unit of data Machine code or machine language is a system of impartible instructions...
are available for devices running iOS 2.0 and later through Apple's App Store.
SDK
On October 17, 2007, in an open letter posted to Apple's "Hot News" weblog, Steve Jobs announced that a software development kitSoftware development kit
A software development kit is typically a set of software development tools that allows for the creation of applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar platform.It may be something as simple...
(SDK) would be made available to third-party developers in February 2008. The SDK was released on March 6, 2008, and allows developers to make applications for the iPhone and iPod touch, as well as test them in an "iPhone simulator". However, loading an application onto the devices is only possible after paying an iPhone Developer Program fee.
Since the release of Xcode 3.1
Xcode
Xcode is a suite of tools, developed by Apple, for developing software for Mac OS X and iOS. Xcode 4.2, the latest major version, is available on the Mac App Store for free for Mac OS X 10.7 , and on the Apple Developer Connection website for free to registered developers Xcode is a suite of tools,...
, Xcode is the development environment for the iOS SDK. iPhone applications, like iOS and Mac OS X, are written in Objective-C
Objective-C
Objective-C is a reflective, object-oriented programming language that adds Smalltalk-style messaging to the C programming language.Today, it is used primarily on Apple's Mac OS X and iOS: two environments derived from the OpenStep standard, though not compliant with it...
.
Developers are able to set any price above a set minimum for their applications to be distributed through the App Store, of which Apple will take 30% of the revenue (the other 70% goes to the developer). Alternately, they may opt to release the application for free and need not pay any costs to release or distribute the application except for the membership fee.
Jailbreaking
iOS has been subject to a variety of different hacks centered on adding functionality not supported by Apple. Before the 2008 debut of the App Store, the primary reason for jailbreaking was to install third-party native applications. Apple said it would not design software updates specifically to break these native apps (other than applications that perform SIM unlockingSIM lock
A SIM lock, simlock, network lock or subsidy lock is a capability built into GSM phones by mobile phone manufacturers. Network providers use this capability to restrict the use of these phones to specific countries and network providers...
); however, with each iOS update the jailbreak appears to no longer work.
Since the arrival of the App Store and third-party applications, the focus of the jailbreaking community has shifted. A major focus of jailbreaking is allowing theming, using emulators
Video game console emulator
A video game console emulator is a program that allows a computer or modern console to emulate a different video game console's behavior. Emulators are most often used to play older video games on personal computers and modern video game consoles, but they are also used to play games translated...
and community-made tweaks like multitasking, Adobe Flash player, accessing the iPhone file system, and customizing the SpringBoard further. Multitasking is only natively supported on 3rd-generation and newer iOS devices, and applications on the official App Store are not allowed to modify the look of the OS, hence the need for jailbreaking.
Digital rights management
The closed and proprietary nature of iOS has garnered criticism, particularly by digital rightsDigital rights
The term digital rights describes the permissions of individuals legitimately to perform actions involving the use of a computer, any electronic device, or a communications network...
advocates such as the Electronic Frontier Foundation
Electronic Frontier Foundation
The Electronic Frontier Foundation is an international non-profit digital rights advocacy and legal organization based in the United States...
, computer engineer and activist Brewster Kahle
Brewster Kahle
Brewster Kahle is a computer engineer, internet entrepreneur, activist, and digital librarian.- Biography :Kahle graduated from the Massachusetts Institute of Technology in 1982 with a Bachelor of Science in computer science and engineering, where he was a member of the Chi Phi Fraternity. The...
, Internet-law specialist Jonathan Zittrain
Jonathan Zittrain
Jonathan L. Zittrain is a US professor of Internet law at Harvard Law School and the Harvard Kennedy School, a professor of computer science at the Harvard School of Engineering and Applied Sciences, and a faculty co-director of Harvard's Berkman Center for Internet & Society...
, and the Free Software Foundation
Free Software Foundation
The Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...
who protested the iPad's introductory event and have targeted the iPad with their "Defective by Design
Defective by Design
Defective by Design is an anti-digital rights management initiative by the Free Software Foundation. DRM technology, dubbed "digital restrictions management" by opponents, restricts users’ ability to freely use their purchased movies, music, literature, software, and hardware in ways they are...
" campaign. Competitor Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
, via a PR spokesman, has also criticized Apple's control over its platform.
At issue are restrictions imposed by the design of iOS, namely DRM
Digital rights management
Digital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
intended to lock purchased media to Apple's platform, the development model (requiring a yearly subscription to distribute apps developed for the iOS), the centralized approval process for apps, as well as Apple's general control and lockdown of the platform itself. Particularly at issue is the ability for Apple to remotely disable or delete apps at will.
Some in the tech community have expressed concern that the locked-down iOS represents a growing trend in Apple's approach to computing, particularly Apple's shift away from machines that hobbyists can "tinker with" and note the potential for such restrictions to stifle software innovation.
However, there are some outside of Apple who have voiced support for the iOS closed model. Facebook
Facebook
Facebook is a social networking service and website launched in February 2004, operated and privately owned by Facebook, Inc. , Facebook has more than 800 million active users. Users must register before using the site, after which they may create a personal profile, add other users as...
developer Joe Hewitt, who had previously protested against Apple's control over its hardware as a "horrible precedent", has subsequently argued the locked apps in the iPad are akin to web applications and provide added security.
External links
- iOS Dev Center – on the Apple Developer ConnectionApple Developer ConnectionApple Developer, formerly Apple Developer Connection or ADC, is Apple Inc.'s developer network. It is designed to make available resources to help software developers write software for the Mac OS X and iOS platforms...
website - iOS Reference Library – on the Apple Developer Connection website