TMoS schrieb:
Hallo Leute
Nur mal rein theoretisch und intressen halber:
Es würde doch sicher funktionieren Darwin und das gesammte OS X auf einem Linuxkernel 4 ppc laufen zulassen, anstatt auf dem FreeBSD kernel.. oder?
Sicher es wäre ein haufen Arbeit, würden sich daraus irgendwelche Vorteile ergeben? Oder kann der FreeBSD kernel alles das Linux kann?
MfG
TMoS
Es gibt keinen BSD-Kernel. Lies selbst.
"
Darwin
Beneath the appealing, easy-to-use interface of Mac OS X is a rock-solid, UNIX-based foundation called Darwin that is engineered for stability, reliability, and performance. Darwin integrates a number of technologies, most importantly Mach 3.0, operating-system services based on FreeBSD 5, high-performance networking facilities, and support for multiple, integrated file systems. Because the design of Darwin is highly modular, you can dynamically add such things as device drivers, networking extensions, and new file systems.
For more information about Darwin, see
Darwin Documentation.
Mach
Mach is at the heart of Darwin because it performs a number of the most critical functions of an operating system. Much of what Mach provides is transparent to applications. It manages processor resources such as CPU usage and memory, handles scheduling, enforces memory protection, and implements a messaging-centered infrastructure for untyped interprocess communication, both local and remote. Mach provides many important advantages to Macintosh computing:
- Protected memory. The stability of an operating system should not depend on all executing applications being good citizens. Even a well-behaved process can accidentally write data into the address space of the system or another process, which can result in the loss or corruption of data or even precipitate system crashes. Mach ensures that an application cannot write in another application’s memory or in the operating system’s memory. By walling off applications from each other and from system processes, Mach makes it virtually impossible for a single poorly behaved application to damage the rest of the system. Best of all, if an application crashes as the result of its own misbehavior, the crash affects only that application and not the rest of the system.
- Preemptive multitasking. With Mach, processes share the CPU efficiently. Mach watches over the computer’s processor, prioritizing tasks, making sure activity levels are at the maximum, and ensuring that every task gets the resources it needs. It uses certain criteria to decide how important a task is and therefore how much time to allocate to it before giving another task its turn. Your process is not dependent on another process yielding its processing time.
- Advanced virtual memory. In Mac OS X, virtual memory is “on” all the time. The Mach virtual memory system gives each process its own private virtual address space. For 32-bit applications, this virtual address space is 4 GB. For 64-bit applications, the theoretical maximum is approximately 18 exabytes, or 18 billion billion bytes. Mach maintains address maps that control the translation of a task’s virtual addresses into physical memory. Typically only a portion of the data or code contained in a task’s virtual address space resides in physical memory at any given time. As pages are needed, they are loaded into physical memory from storage. Mach augments these semantics with the abstraction of memory objects. Named memory objects enable one task (at a sufficiently low level) to map a range of memory, unmap it, and send it to another task. This capability is essential for implementing separate execution environments on the same system.
- Real-time support. This feature guarantees low-latency access to processor resources for time-sensitive media applications.
Mach also enables cooperative multitasking, preemptive threading, and cooperative threading.
BSD
Integrated with Mach is a customized version of the BSD operating system (currently FreeBSD 5). Darwin’s implementation of BSD includes much of the POSIX API, which is available from the application layers of the system. BSD serves as the basis for the file systems and networking facilities of Mac OS X. In addition, it provides several programming interfaces and services, including:
- The process model (process IDs, signals, and so on)
- Basic security policies such as file permissions and user and group IDs
- Threading support (POSIX threads)
- Networking support (BSD sockets)"
Noch mehr Informationen findest Du hier.->
http://developer.apple.com/documentation/MacOSX/Conceptual/OSX_Technology_Overview/index.html
