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An Introduction To And History of Darwin

Posted by timothy on from the evolving dept.

proclus writes "Roberto Donhert of Aqua icon theme fame (screenshot) has written a concise review of Darwin OS. The article covers the origin and evolution of Darwin OS, as well as the various Darwin distributions that are available for PowerPC and x86 architectures. OSnews has the story. The only thing that I would add is the contributions of Torrey Lyons of XonX, who created the XDarwin Xserver that made so much of this possible. BTW, Roberto also has a commentary about the SCO situation running at OSnews."

4 of 82 comments (clear)

  1. more Yves by proclus · · Score: 4, Informative
    Actually, Yves wrote a whole series, which is quite excellent. Here are the links.

    http://www.osxfaq.com/Editorial/open/
    http://www.osxfaq.com/Editorial/open/index2.ws
    http://www.osxfaq.com/Editorial/open/index3.ws
    http://www.osxfaq.com/Editorial/open/index4.ws

    Regards,
    proclus
    http://www.gnu-darwin.org/

  2. Ugh by Anonymous Coward · · Score: 5, Informative
    Um......here are the mistakes just on the first page (not including the odd description of microkernel modules):
    The differences between a Microkernel ... and a Monolithic Kernel ... is that a Monolithic Kernel is a large chunk of code, where a Microkernel consists of small message passing cores or Modules, with several different Daemons...
    The difference between a microkernel and a monolithic kernel is that a microkernel has offloaded most system services to outside the protected boundary.
    The Open Step Develpment Environment ...
    History, Mach, BSD, OpenSTEP ...
    It's ONE word. Capitalized as "OpenStep" or as "OPENSTEP", the former being the standard (the latter being NeXT's later marketspeak).
    [OpenStep] is a true object oriented programming environment developed by Avie Tevanian and others at CMU.
    Avie Tevanian worked on Mach at CMU. It is an operating system kernel. OpenStep was developed much later by developers at NeXT. Had nothing to do with CMU. It is a development library built on top of Objective-C and Display PostScript, and ran on top of several operating systems (Solaris, NT, Mach/BSD). I do not think that Avie worked on OpenStep significantly while he was a NeXT, but I'm not sure.
    1. Re:Ugh by Mneme · · Score: 4, Informative

      But wait, there are more errors

      • In Mach, device drivers are IOKits ( Input-Output kits).
        No. In Darwin there is an Embedded-C++ framework called IOKit for writing device drivers. It doesn't come from Mach (Mach is written in C), it is a masterpiece of design that was written from scatch at Apple, inspired by DriverKit, which was an Objective-C framework with the same intent. (Yes, NeXT put Objective-C in the kernel. At the time, they were running on PC hardware and needed a way to write drivers that minimized developer time.)
      • The differences between a Microkernel, like what is used in Mac OS X and Darwin, and a Monolithic Kernel ... a Microkernel consists of small message passing cores or Modules, with several different Daemons or "servers" that communicate between the modules
        No. Darwin does not use Mach as a microkernel, and neither did NeXT's kernel. Mach is used in Darwin because it provides an excellent core for the OS with a clean API. But given the way it shares its address space with the BSD layer and IOKit, you cannot call the Darwin kernel a Microkernel. Yes, Mach makes it easy to have a chunk of a device driver out in user space, and Apple encourages developers to do this when they can, but some Linux device drivers do that, too.

      In my opinion, IOKit is what makes Darwin special. The way it uses inheritance and its concepts of drivers having different interrelationships on different `planes' (e.g., power, USB topology, code dependencies, etc.) make it easier to write drivers and support things like dynamic device attachment and power management that Linux still struggles with.

  3. Re:What I really want.. by dadragon · · Score: 3, Informative

    There are a bunch at IBM's technical library, and also Motorola's tech library. The Linux ABI is well documented, as are the other BSDs, but not Darwin.

    Here is one, "PowerPC Microprocessor Family: The Programming Environments for 32-Bit Microprocessors"
    Here is one that is PowerPC Linux specific.

    --
    God save our Queen, and Heaven bless The Maple Leaf Forever!