A well constructed reply. I probably will not be as organized but here goes:

Certainly OSX is becoming a lot more open in some respects. There are clearly some people in Apple that have been trying to make some changes for a while, and I applaud that and hope to see it continue. The fact they ship with a lot of major open source tools makes me happy.

Even on my side of the fence I will go as far as to say there are plenty of tools in OSX to meet most needs of most developers.

Also a window manager is not "low level" in the traditional sense. I could of worded that better. It is however something at a lower level than one can have any control over on OSX. If you choose OSX you _must_ accept Apple's choice of window manager. I on the other hand use Awesome, a tiling window manger with a Lua driven UI which allows me to edit just about anything in the UI and reload it on the fly without logging out. Typically everything runs in a single process that consumes well under 20MB of ram. That's the kind of control that OSX does not offer. Sure it is not "low level" but it sure feels that way on OSX when you can't do anything about it no matter how much you program, it's simply outside of the range of what the platform allows short of hacking binaries or running an XServer on top of the existing OSX desktop.

As for memory management I would expect any novice linux sysadmin _should_ know how to go through and kill all unneeded processes, run headless, build a lean kernel tailored to the hardware etc. I make even interns learn how to do things like these. Any professional sysadmin should also know how to build in extensions like PaX or selinux, and recompile any user-land binaries as needed to to support it. For sensitive systems you can also build a hardened toolchain and compile every single binary on your system through it. This means you can force position-independent executables, stack smashing protection, and compile-time buffer checks, which can prevent a lot of 0days in other people's code that might otherwise work with "virgin" binaries. I do all of the above for all my production systems. I also at least always compile my kernels with Pax which randomizes memory addressing schemes at compile time. This way as well so kernels will map memory the same way for added protection against many 0days which will often assume stock memory mapping.

There are lots of things you can really only do to protect a system, if you have all the code sitting there. In OSX you just have to cross your fingers there are no 0-days in any system processes, or that if there are... that apple gets around to fixing them and deploying them fast.

In regard to ksplice, your right. I said enterprise here for a reason. Most sysadmins won't touch it for most uses. People that do know what they are doing with it however and can't afford downtime make use of tools like these to keep boxes online, and even can justify far more frequent kernel updates than they might ordinarily. In OSX you don't even have the possibility to do such things. Most system level updates require a reboot, period.

in response to OSX running better on non-apple PC hardware than Linux... I am hard pressed to buy that without more detail of your exact issues.

Homebrew... Homebew is neat. Truly a step in the right direction. Every OSX install I do, It is the first thing to go on. It only has perhaps a fraction of a percent of the number of packages in a modern Linux distribution, but it at least has a lot of the important command line tools. I really hope this project matures and gets more community support to bring a wider range of open tools to the table. I used macports for a while but broken packages at every turn made it rather unusable.

Regardless, it is still just a fledgling effort. Personal use? Sure, but I would certainly not trust it for a production system. Many packages are very out of date, or are having to deal with the most recent OSX-compilable builds. It's better... but they have a long way to go yet. I do welcome anything encouraging more open source adoption without the OSX crowd though.