The Mac Os X Internals Hacker's Handbook Pdf Download Updated

The Mac Os X Internals Hacker's Handbook Pdf Download

We saw in Chapter 1 that Mac OS 10 is a mix of several technologies that differ not just in what they do but likewise in where they came from, which philosophies they represent, and how they are implemented. Nevertheless, Mac OS X presents a cohesive and consistent picture to the cease user. The fact that Apple computers have a well-defined, limited hardware base is conducive to Apple tree's success in maintaining a generally positive user feel despite the underlying software eclecticism seen in Mac Os X.

From a high-level standpoint, Mac Os 10 may be seen every bit consisting of three classes of technologies: those that originated at Apple, those that originated at Side by side, and "everything else." The latter consists mostly of third-party^[1] open source software. On the 1 hand, such confluence makes it somewhat hard to clearly visualize the structure of Mac OS X and might fifty-fifty be a stumbling block for the new Mac OS X programmer. On the other hand, Mac OS X programmers have a rather colorful environs to requite vent to their creative fervors. The end user is the bigger beneficiary, enjoying a range of software that is non seen on whatever other single platform. In item, Mac OS X provides the benefits of a typical Unix system, while maintaining the traditional ease of utilize of a Macintosh. The Mac Os 10 Unix surroundings is standard plenty so that most portable Unix softwaresuch as the GNU suite and X Window applicationsruns hands. Mac Os X is oft dubbed a mass-market Unix arrangement, and however, traditionally non-Unix, mainstream software, such as Microsoft Office and the Adobe Creative Suite, is available natively for Mac OS X. Apple's own software repertoire is wide ranging in that information technology includes offerings such equally the following:

^[1] The other two categories also incorporate open source components.

Everyday applications such every bit those for managing email, instant messaging, and web browsing
"Digital-lifestyle" applications such as those for managing digital photos, music, and movies
"Office" applications for creating presentations, slide shows, and other documents
High-end professional software for blitheness, moving picture editing and effects, music editing and generation, DVD creation, and photography postproduction

This chapter is a whirlwind bout of the high-level architecture of Mac OS X. Nosotros will identify the main technologies that establish Mac OS X and meet how they fit in the overall picture. Manybut not alltopics that are mentioned in this chapter will be discussed in greater detail in subsequent chapters.

Effigy 21 shows a layered view of the important components of the Mac OS X compages. The moving-picture show is approximate since it is impracticalif not impossibleto separate various components into cleanly separated layers. Sometimes there is overlap between the layers. For example, OpenGL is functionally the hardware abstraction layer (HAL) of the graphics subsystem and logically sits atop the graphics hardwarethis is not obvious from Figure 21. As some other example, the BSD application environs, which includes the standard C library, logically sits atop the kernel but is shown alongside other application environments in Effigy 21. In general, the following statements apply to the layered view shown hither.

Lower layers, which are shown closer to the kernel, provide functionality that is more fundamental than that provided by college layers. Typically, higher layers utilize lower layers in their implementation.
A layer may consist of applications, libraries, and frameworks.^[2]

^[ii] In the simplest sense, a framework is a packaged dynamic shared library. We volition discuss frameworks in Section 2.viii.3.
Entities may exist with the aforementioned (or like) name in multiple layers. For example, QuickTime is both an awarding environs and an application service. Similarly, we take a layer named Cadre Services in Effigy 21, merely there is too a similarly named framework (CoreServices.framework). Moreover, many critical components of Mac Os X reside in the /System/Library/CoreServices/ directory.
End users collaborate with the highest layers, whereas developers additionally interact with one or more lower layers, depending on the kind of development they do. For example, a programmer creating an stop-user Cocoa application may not demand^[3] to go any "lower" than the Cocoa application surroundings.

^[iii] In nearly cases, information technology would notwithstanding be to a developer'due south advantage to understand how the system works.

Effigy 21. The high-level architecture of Mac OS 10