Valid XHTML 1.0!


 

(updates 13., 31. Jul and 23. Apr 2002, see links at bottom)

proceed to Mac OS X special topics

 

Introduction. While commercial grade UNIX servers (predominantly Suns Solaris, HPs HP-UX and IBMs AIX) and in recent time also open source UNIX systems, especially GNU/Linux, rule the real server world, the UNIX desktop world saw in earlier times a certain dominance of Suns SPARC/Solaris systems, which were clearly overtaken by GNU/Linux in the very last years in this regard. Then the newest member of the big UNIX family of enterprise capable operating systems took that pole position away from GNU/Linux (at least for the moment): Mac OS X.

Concepts. Mac OS X is a fully POSIX compliant UNIX, so let us view for the differences to other family members. These are notable, making Mac OS X a somewhat special UNIX flavor. The main differences are:

  • no classic more or less monolithic kernel, but a microkernel (Darwin)

  • it ignores largely the usual /etc directory in favor of the (object-oriented) NetInfo center with its info daemon

  • it doesn't come with a standard X Window System based GUI, but with the so-called Aqua

History. Despite being rather new in the OS scene, none of its components are really new, when you take care to look for them: in the 80' some universities (Carnigie) looked for an object-oriented kernel alternative to more classic, widespread ones, several projects were launched (for example also a GPL microkernel with name Hurd, which lost until now against the GPL Linux kernel especially because of (non-)evolution speed). The free (open source) BSD UNIX framework of commands and so on is even older, inherited from the 1978 introduced and still living (FreeBSD, OpenBSD, NetBSD) systems. Finally, Next(Step) and its successors OpenSTEP and GNUstep are largely involved or used in the Aqua GUI of Mac OS X.

Technical remarks. The object oriented Darwin kernel has the advantage of being hotpluggable regarding completely new kernel modules without recompile, so this resembles more the driver plug in concept of the mob/monopoly OS's then that of more classical kernels like Linux. But it's a little less mature, though rather stable indeed. The also object oriented netinfo configuration system is a homogenous thing to use, but will give any UNIX familiar admin a hard time to learn, because it's so different from the usual /etc configuration (with very few exceptions the existing, rare and small /etc files are respected only in single user mode by Mac OS X!). To round it up, the Aqua GUI is also an object oriented framework like it's anchestors, so limited compatible to NextStep, GNUstep and so on only, but totally incompatible to the UNIX GUI standard X. Either way, it's no real problem (though a little tedious while installing it) to run a current Xfree system (4.2!) on top of Aqua, because it operates on another port and there are no real conflict situations; you can use even rootless mode for it. --- The major drawback of this first fully straightforward realized object oriented UNIX system concept for non-experts is an often rather poor performance, not a new thing for the experienced software developer. A non-objective, classical C-solution (here an OO extension of C is used, the less known Objective-C, compared to C++ or even Java) gives often dramatic performance advantages over such high abstraction layered ones.

Perspectives.Okay, why this new ranking of UNIX flavors on the desktop has emerged: 1. Mac OS X (PowerPC only), 2. GNU/Linux (ia-32 and traces of all other architectures), 3. SPARC/Solaris (ia-32 irrelevant in quantity)? About these three systems: SPARC/Solaris is now for a long time the commercial UNIX leader in terms of distributed systems, and Sun microsystems did never anything else (until the very last time, when they commited to the GNU/Linux community also own contributions) as their own UNIX Solaris run on any of their machines, from the desktop (like the current Blade systems) over workstations (like the UltraSPARC n station machines) to the high-end servers (like the SunFires). The reliable and efficient, but no way cheap hardware prevented it from a wider distribution, though it grabbed some number one positions as mentioned. The PowerPC processors are a little more widely used, running in systems like IBM's UNIX AIX or by the dated and unstable proprietary Mac OS <= 9.22. And there are more Macs out there then IBM AIX systems; and now Apple sells all new Macs with OS X preinstalled as the primary OS! Together with the now usable system and an increasing pool of software both from the classic area and from the UNIX world this has increased the acceptance and distribution of Mac OS X in an explosive manner in the last half year (written in early spring 2002). That GNU/Linux, the first end user UNIX success model, since distributors like the French Mandrake and the German SuSE made it for the first time really easy to install, can't keep up at the moment, despite the ia-32 processors like Intel and AMD chips are by far the mostly used CPUs, is simply due to the infamous monopoly, which is held by a certain Redmond mob, you know. But this will change in the years coming again, and probably the ia-32 and later on the successor ia-64 respective (not equal!) amd-64 will further stay in front regarding number of installed CPUs, so GNU/Linux with its best supported ia-32/64 and amd-64 versions is likely to be the number one installed desktop UNIX again after the termination of the illegal activities of the Redmond mob. But this doesn't threaten the importance and interest in Mac OS X, despite GNU/Linux' second most important platform is the PowerPC too, and maybe we see a port to the last CISC systems from Mac OS X too on the other hand?

Licensing issues.There are open source ingredients with different licenses (especially public BSD and GPL) involved, so you must use the (GPL!) GNU compiler 2.95(.2 (installed) or .3) at now for compiling system components (similar to the open source GNU/Linux system), but there are also a number of proprietary, commercial extensions in the system. This may give Apple a hard time in some situations, especially in the future...

My own contributions. Only started, you will find more material in the future; because I'm now an active Mac OS X user as well as an active GNU/Linux user with my own machines (and with many GNU/Linux boxes to supervise at work too; on Suns Solaris I have also older and recent desktop working experience, by the way). For now that's all:

Internet browsers for Mac OS X [13. Oct 2002]

collected hints and proposals for (UNIX) power users of Mac OS X [23. Apr 2002]

books about and links to Mac OS X [new since 31. Jul 2002]

the system monitor GKrellM [15. Jun 2002]

Search my site:

to UNIX main  to computers & GNU/Linux main  to main

remarks etc. to: stefan.urbat@apastron.lb.shuttle.de

(URL:  http://www.lb.shuttle.de/apastron/macosx.htm)