This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Origins iPhone OS holds much of its origins in NEXTSTEP, an operating system created in the late 1980s by original Apple cofounder Steve Jobs. Developed with a core UNIX base and a mach (micro-) kernel, NEXTSTEP featured several developmental and user interface features that have carried forward into OS X today. NEXT acquired an object oriented, message-passing language built on top of C known as Objective-C for the core of its operating system. After NEXTSTEP was acquired by Apple in the late 1990s, work began on the next Mac operating system with a large basis on NEXTSTEP. Although NEXTSTEP with Steve Jobs at the helm seemed like the perfect match for the company and the future operating system, NEXTSTEP was only acquired after BeOS declined acquisition by Apple. BeOS was created by several former Mac developers and was based on a UNIX-like environment developed in C++. Apple based the development of OS X on a smaller sub-environment known as Darwin, which is based on both FreeBSD and the NEXTSTEP Mach kernel and associated libraries and contains a fair amount of its open-source code. The iPhone OS is able to trace its ancestry back to this operating system layer almost directly, since nearly all of the OS-level features (kernel, services, libraries, etc.) are shared between Mac OS X and the iPhone OS, and both are developed in Objective C. Android can find its origin largely in the Linux kernel. Developed by Linus Torvalds in the early 1990s, the kernel is licensed under the GNU Public License (GPL) and is the basis of many operating systems distributed throughout the world. The use of the GPL requires that nearly all component features which statically or dynamically link with the kernel release source code under the license. Unlike the microkernel used in OS X and iPhone OS which runs only necessary processes in supervisor mode, the Linux kernel is run entirely in supervisor mode. This requires that much of the code executed in normal operation under Linux is run in supervisor mode, allowing for an increased potential for abuse should a single feature of the kernel be exploited by a malicious user. The Android OS is an initiative created by Google after acquiring Android, Inc., a software development company, in 2005. Programs written for Android are run under a Java Virtual Machine using Google-created libraries for both functionality and user interface. Hardware Apple has held tight control over the hardware which runs iPhone OS. There have been several revisions of two specific hardware lines: the iPhone, and the iPod Touch. Recently, an iPhone OS-based tablet computer was released which uses a modified version of the OS with its own distinct libraries and interface paradigms. Unlike Android devices, the iPhone OS does not allow for storage increase after sale, nor does it allow for its storage to be used as a general purpose USB Mass Storage Device. All iPhones support assisted GPS....
View Full Document
This note was uploaded on 07/30/2011 for the course COP 5611 taught by Professor Staff during the Spring '08 term at University of Central Florida.
- Spring '08
- Operating Systems