The iPhone SDK and the Opening of Apple’s Native Mobile Application Platform

The first iPhone did not launch with a native third-party SDK

In June 2007 Apple announced that third-party developers could build iPhone applications using Web 2.0 standards and Safari rather than a native application kit.^[1] This preserved a controlled security model but limited access to device capabilities and native application frameworks.

The original platform boundary was deliberately narrow

Developers could create rich web applications, but they could not initially ship arbitrary native binaries through a public Apple SDK.

Apple reversed course with the iPhone 2.0 SDK in March 2008

On March 6, 2008 Apple announced the beta iPhone SDK together with iPhone 2.0 software and a formal developer program.^[2] The SDK opened native APIs covering Core OS, Core Services, Media and Cocoa Touch.

Cocoa Touch made the phone a distinct software platform

The SDK exposed multi-touch interaction, animation, accelerometer and location capabilities through mobile-specific frameworks rather than treating the phone as a small desktop computer.

The toolchain integrated development, simulation and profiling

Apple bundled Xcode, Interface Builder, Instruments and an iPhone Simulator as part of the SDK environment.^[2] This gave developers an end-to-end workflow from source editing through debugging and performance analysis.

The simulator lowered the cost of experimentation

Developers could test much of an application without dedicating a physical phone to every edit-build-debug cycle.

Developer interest was immediate

Apple reported more than 100,000 downloads of the beta SDK within four days of its March launch.^[3] By June, the company reported more than 250,000 SDK downloads and highlighted applications from companies in messaging, games, enterprise software and web services.^[4]

A phone became a target for general software companies

The SDK drew developers who had previously built for PCs, consoles, websites and enterprise systems into one mobile platform.

The SDK shipped as part of iPhone 2.0

Apple’s June 2008 iPhone 3G announcement described iPhone 2.0 as including the SDK-created third-party application platform alongside enterprise features and GPS-enabled services.^[5]

Native APIs gave software deeper access to device capabilities

Applications could combine touch interfaces, sensors, networking, media and location in ways web applications of the period could not easily match. This changed the mobile device from a browser-plus-built-ins model into a programmable application platform.^[2]

The SDK was inseparable from Apple’s distribution and signing model

Membership in Apple’s developer program governed device testing and App Store distribution. The platform therefore paired powerful native APIs with centralized code signing, review and distribution rather than the open executable-install model common on desktop systems.^[2]

Why the iPhone SDK belongs in mobile-computing history

The 2008 SDK was the technical opening that allowed outside developers to treat the iPhone as a native computing platform. The transition from web apps in 2007 to Cocoa Touch and Xcode in 2008 changed what mobile software could do and created the development side of the app economy that followed.^[1][3]

RESEARCH / PROVENANCE

Works Cited

5 SOURCES

1. 01
   Apple — iPhone to Support Third-Party Web 2.0 Applications ↗apple.com
2. 02
   Apple — Apple Announces iPhone 2.0 Software Beta ↗apple.com
3. 03
   Apple — iPhone SDK Downloads Top 100,000 ↗apple.com
4. 04
   Apple — iPhone SDK Downloads Top 250,000 ↗apple.com
5. 05
   Apple — Apple Introduces the New iPhone 3G ↗apple.com

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