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21 Février 2021
The OS X operating system combines a stable core with advanced technologies to help you deliver world-class products on the Mac platform. Knowing what these technologies are, and how to use them, can help streamline your development process, while giving you access to key OS X features.
Apple MacOS 10.14 Mojave, the version of the Mac operating system before the new macOS Catalina, is the last version that supports 32-bit software. With Catalina, only 64-bit software will be. Mac OS X is Apple 's operating system for its line of Macintosh computers. Its interface, known as Aqua, is built on a Unix foundation. Although it has much of the look and feel of the former Mac OS, features such as preemptive multitasking, symmetric multiprocessing, multithreading, and protected memory give Mac OS X improved stability and performance.
This guide introduces you to the range of possibilities for developing Mac software, describes the many technologies you can use for software development, and points you to sources of information about those technologies. It does not describe user-level system features or features that have no impact on software development.
It's helpful to view the implementation of OS X as a set of layers. The lower layers of the system provide the fundamental services on which all software relies. Subsequent layers contain more sophisticated services and technologies that build on (or complement) the layers below.
The lower the layer a technology is in, the more specialized are the services it provides. Generally, technologies in higher layers incorporate lower-level technologies to provide common app behaviors. A good rule of thumb is to use the highest-level programming interface that meets the goals of your app. Here is a brief summary of the layers of OS X.
The Cocoa (Application) layer includes technologies for building an app's user interface, for responding to user events, and for managing app behavior.
The Media layer encompasses specialized technologies for playing, recording, and editing audiovisual media and for rendering and animating 2D and 3D graphics.
The Core Services layer contains many fundamental services and technologies that range from Automatic Reference Counting and low-level network communication to string manipulation and data formatting.
The Core OS layer defines programming interfaces that are related to hardware and networking, including interfaces for running high-performance computation tasks on a computer's CPU and GPU.
The Kernel and Device Drivers layer consists of the Mach kernel environment, device drivers, BSD library functions (libSystem), and other low-level components. The layer includes support for file systems, networking, security, interprocess communication, programming languages, device drivers, and extensions to the kernel.
Relevant Chapters:Cocoa Application Layer, Media Layer, Core Services Layer, Core OS Layer, Kernel and Device Drivers Layer
Using the developer tools and system frameworks, you can develop a wide variety of software for Mac, including the following:
Apps. Apps help users accomplish tasks that range from creating content and managing data to connecting with others and having fun. OS X provides a wealth of system technologies such as app extensions and handoff, that you use to extend the capabilities of your apps and enhance the experience of your users.
Frameworks and libraries. Frameworks and libraries enable code sharing among apps.
Command-line tools and daemons. Command-line tools allow sophisticated users to manipulate data in the command-line environment of the Terminal app. Daemons typically run continuously and act as servers for processing client requests.
App plug-ins and loadable bundles. Plug-ins extend the capabilities of other apps; bundles contain code and resources that apps can dynamically load at runtime.
System plug-ins. System plug-ins, such as audio units, kernel extensions, I/O Kit device drivers, preference panes, Spotlight importers, and screen savers, extend the capabilities of the system.
Relevant Chapter:Creating Software Products for the Mac Platform
The technology stacks on which Cocoa and Cocoa Touch apps are based have many similarities. Some system frameworks are identical (or nearly identical) in each platform, including Foundation, Core Data, and AV Foundation. This commonality of API makes some migration tasks—for example, porting the data model of your Cocoa Touch app—easy.
Other migration tasks are more challenging because they depend on frameworks that reflect the differences between the platforms. For example, porting controller objects and revising the user interface are more demanding tasks because they depend on AppKit and UIKit, which are the primary app frameworks in the Cocoa and CocoaTouch layers, respectively.

Apple provides developer tools and additional information that support your development efforts.
Xcode, Apple's integrated development environment, helps you design, create, debug, and optimize your software. You can download Xcode from the Mac App Store.
For an overview of the developer tools for OS X, see the Xcode Apple Developer webpage. For an overview Xcode functionality, read Xcode Overview.
The OS X Developer Library contains the documentation, sample code, tutorials, and other information you need to write OS X apps. You can access the OS X Developer Library from the Apple Developer website or from Xcode. In Xcode, choose Help > Documentation and API Reference to view documents and other resources in the Organizer window.
In addition to the OS X Developer Library, there are other sources of information on developing different types of software for Mac:
Apple Open Source. Apple makes major components of OS X—including the UNIX core—available to the developer community. To learn about Apple's commitment to Open Source development, visit Open Source Development Resources. To learn more about some specific Open Source projects, such as Bonjour and WebKit, visit Mac OS Forge.
BSD. Berkeley Software Distribution (BSD) is an essential UNIX-based part of the OS X kernel environment. Several excellent books on BSD and UNIX are available in bookstores. But you can also find additional information on any of the websites that cover BSD variants—for example, The FreeBSD Project.
Third-party books. Several excellent books on Mac app development can be found online and in the technical sections of bookstores.
Copyright © 2004, 2015 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2015-09-16
This is the operating system that runs on Macintosh computers. It is pronounced, 'mack-oh-es.' The Mac OS has been around since the first Macintosh was introduced in 1984. Since then, it has been continually updated and many new features have been added to it. Each major OS release is signified by a new number (i.e. Mac OS 8, Mac OS 9).
Since the core of the Mac OS was nearly decades old, Apple decided to completely revamp the operating system. In March of 2001, Apple introduced a completely new version of the Mac OS that was written from the ground up. The company dubbed it 'Mac OS X,' correctly pronounced 'Mac OS 10.' Unlike earlier versions of the Mac OS, Mac OS X is based on the same kernel as Unix and has many advanced administrative features and utilities. Though the operating system is much more advanced than earlier versions of the Mac OS, it still has the same ease-of-use that people have come to expect from Apple software.
What's the big deal about operating systems in the first place? What do they actually do? An operating system is the level of programming that lets you do things with your computer. The operating system interacts with a computer's hardware on a basic level, transmitting your commands into language the hardware can interpret. The OS acts as a platform for all other applications on your machine. Without it, your computer would just be a paperweight.
At its heart, a computer is a number-crunching device. It takes input in the form of zeros and ones -- bits -- and channels them through various circuits and processors. The hardware behaves according to strict rules. We define these rules using things like logic gates, which take input and produce an output in a predictable way. Some simple computers have no need of an operating system because they only perform a specific task. But personal computers need to be more versatile. The operating system allows complex programs to access the capabilities of the hardware to get results. Only the hardware's physical properties and our own imaginations can limit what programs can do.
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You could design an operating system by physically programming it into a computer's circuits. This would require building electrical pathways using millions of logic gates. But such an operating system would be inflexible. How to make a minecraft on mac. That's why operating systems like Mac OS X and Windows are software. Software is more malleable than hardware -- you can make changes through software patches and version updates. To do the same with hardware would mean switching out physical chips and circuit boards.
Operating systems are like the manager for a computer. It's the job of the OS to monitor what software needs and what the hardware can provide. As you run applications on your computer, the OS allocates the resources necessary to complete the task. That can include processing power, memory allocation and computer storage access, among other things. Ideally, the OS will make sure that your computer's hardware is never overtaxed.
The OS also allows programs to run on a computer. Without an OS, a programmer would have to design an application to run on the hardware directly. This isn't very efficient. An operating system acts as an application interface to the hardware. The OS does this through an application program interface (API). Program developers build applications for the API. Assuming the programmer has done a good job at building an application without any serious bugs, it should run just fine on the operating system.

One important part of the Mac computer is the firmware. How to find my startup disk mac. Firmware is a level of programming that exists directly on top of a hardware layer. It's not part of the operating system itself. The Mac firmware is the first stored program that executes when you turn on a Mac computer. Its job is to check the computer's CPU, memory, disk drives and ports for errors. The PC equivalent to the Mac firmware is called BIOS, which stands for basic input-output systems. A second program called a bootloader loads the Mac OS X, assuming there are no errors reported by the firmware.
Next, we'll take a closer look at what makes the Mac OS X tick.