Sent a note to Brian Hill asking his thoughts, will post them if and when he responds...jf
On Jan 13, 2006, at 9:37 AM, Profile wrote: > Lee, > > Thanks so much, this is VERY informative, it also is a pleasure to > hear someone of intelligence speak (type). I'll see about > upgrading MacJanitor. > > John R. > > > On Jan 13, 2006, at 9:14 AM, Lee Larson wrote: > >> Yesterday I wrote that Apple has changed the way they do the >> periodic maintenance jobs on Mac OS X. I spent some time last >> night figuring out how it's being done now. Here's what's happening. >> >> The way most Unix systems have done the periodic maintenance from >> time immemorial is to schedule them as cron jobs. The cron daemon >> on a Unix system is a program that runs quietly in the background-- >> that's why it's called a daemon--keeping track of a list of >> commands and times at which to run those commands. Each user can >> have a table of scheduled jobs, called a crontab. The mother of >> all crontabs is the system crontab, that's owned by the operating >> system itself. The system crontab listed the times to run the >> scripts called daily, weekly and monthly, to do periodic maintenance. >> >> The scripts are still there in the latest versions of Mac OS X. >> You just have to look in the /etc directory. The scripts are still >> there, but they are not used. >> >> To tell you what's being done now, I must go off on a tangent. >> >> Unix systems have had a very confusing way of starting things up >> when they are booted. Some things are launched by one set of >> scripts and another set of things are launched by another method >> entirely. (Linux users should think of rc.d and xinetd.) Apple >> wanted to clean this up, so they invented a new traffic cop that's >> the very first program launched by the kernel and called it >> launchd. (The "d" on the end is a clue that launchd is also a >> daemon.) All the startup stuff is handled in one place by launchd. >> Most of the functionality of crond was rolled into launchd, so >> Apple has turned off cron in Tiger. >> >> The new launchd periodically calls a program called periodic to >> handle the rest of the stuff crond used to do. The periodic >> program has its own cleanup scripts in the directory /etc/periodic/ >> daily, /etc/periodic/monthly and /etc/periodic/weekly. (The /etc >> directory is invisible in the Finder because Apple is trying to >> hide the geeky Unix stuff from the proletariat.) >> >> As of version 1.3, MacJanitor calls the periodic program instead >> of the old crond scripts, so it should be safe to use it. (I have >> not tried it.) >> > > > > | The next meeting of the Louisville Computer Society will > | be January 24 at Pitt Academy, 6010 Preston Highway. > | The LCS Web page is <http://www.kymac.org>. > | List posting address: <mailto:macgroup at erdos.math.louisville.edu> > | List Web page: <http://erdos.math.louisville.edu/macgroup> -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/pkcs7-signature Size: 2102 bytes Desc: not available Url : http://www.math.louisville.edu/pipermail/macgroup/attachments/20060113/27cc68d9/attachment.bin
