New to MacOSX, enabling dma and other questions


I'm a fairly experienced Linux and Solaris user doing enterprise software development on these platforms with C++/Java/Corba and various sysadmin tasks. I just got my G4/500 Cube and installed OSX. I see no obvious library cache (like under linux) or even $LD_LIBRARY_PATH, I did however see see something called "update_prebinding" run whilst installing the development tools package. I scanned through the manpage quickly, does this only need to be done when installing packages? How about compiling some source and installing that?
Can anyone recommend any documents getting a newbie developer (to OSX) started?
I quickly compiled openssl 0.9.5a, it seemed rather slow compared to my Thunderbird 800/256mb. I noticed quite a bit of cpu (20% - 30%) spend inside the system as opposed to user space. I've also noticed some slowdown while doing disk io intensive operations which leds me to believe the DMA transfers is not enabled? Is there something equivalent to linux's hdparm?
dmesg didn't yield any useful information, I don't want to reboot it remotely, being unsure what the GUI will think of that.
Any tips, hints, suggestions or advice would be much appreciated.