[drmbb]

So, launchd has replaced cron in Tiger (and much of the rc init scripts functionality), but seems to have almost zero documentation. And, some of you may notice, things in your crontab file are just gone - the functions commanded by the crontab entries have been moved to lauchd plist files in /System/Library/LaunchDaemons. Any custom entries or specific tasks you added to crontab are gone, and you'll need to create plist files for them, and put those in /System/Library/LaunchAgents.
P.S. cron is still there, in /usr/sbin, but does not run by default anymore, and Apple is clearly looking to just get rid of it, and the rc init scripts, altogether.
Not smoothly done Apple /forums/ubbthreads/images/graemlins/mad.gif
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[d00d]

Ars Technica had some writeup on the move (which looks to be an improvement). Slashdot had a discussion on it as well (the posts by As Seen On TV are good ones to read).
However, that said, I've seen little documentation elsewhere, but then again, I haven't had a reason to look yet.
I'm curious if launchd is like anacron (in that it forces missed events to be triggered upon the system coming back up).

[jmincey]

There is a man page for this, but I assume you've consulted it and found it wanting already.
I sympathize with your problem. Before I performed a clean install I referred to a log file I had made of all custom changes to UNIX config files. For example, I had a custom script in Panther's /System/Library/StartupItems/Network directory. I had (among other things) changed the default mtu value from 1500 to 1492 for en1. I knew that Tiger would put the kabosh on this and in fact there is no "Network" directory at all any longer. (Instead we have something called "NetworkTime".)
Changes like this are always problematic. And I must confess that Apple's upgrades seem to cause more problems in this regard than updates to other UNIX variants. Apple assures its developers that the APIs will remain stable for a while -- but what of the underlying directory structure?
I had things running in /usr/local/bin (in part for some consistency between Darwin and Linux), but I knew these things would not survive in a Tiger install -- and they didn't.
Sorry I can't shed light on your specific launchd question at this time; this is just a general response to confirm what you are going through.

[drmbb]

Thanks for that d00d. And a good question - it's not clear if launchd rescans it's various plist folders periodically or not, nor if it is somehow logging what's been run, when last, and so forth.
My main complaint is that the installation actually deletes the old entries in crontab, without warning. It's proven a minor matter on my own personal machines, but will be an issue when we move our XServe cluster and lab machines over to Tiger. It should have preserved the old crontab settings, and presented a screen reminder to update those entries to plist files and put them in the appropriate places to run.
Somer of us have a lot of cron tasks to shift over, ya' know /forums/ubbthreads/images/graemlins/tongue.gif
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[Dr-NiKoN]

http://developer.app...stemStartup.pdf

[drmbb]

Thanks, but I'd read that, and it's pretty light on what launchd really is or what it really does. And I only got to that after the installer blew away my old crontab file (why couldn't it simple cp it to crontab.applesaved ?, cripes, it made enough other *.applesaved files, why not keep the old crontab entries ?).
Anyhow, I'm getting launchd figured out now, and we'll be ready when it comes time to upgrade the public machines /forums/ubbthreads/images/graemlins/wink.gif
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[Dr-NiKoN]

Hm, I haven't look at launchd yet, but can't you just start crond from launchd?

[drmbb]

Yes, you could make a plist file to launch cron. But, you'd still have to recreate your old crontab. And since launchd is clearly the future of OS X, and is already running by default, I figure I might as well learn to code up these plist files and "recreate" my cron settings in launchd format.
My beef is that given how fundamental a change this is, it is very poorly documented, and poorly executed in the installation/upgrade process. I'm not against launchd or anything like that - it actually is kind of nice to have one master system for the dozen or so other daemons used traditionally to control automated and periodic processes. But you don't roll something like that out without some blatant notification (during the process of installing Tiger) as you dump the old and bring in the new.
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