Lennart Poettering píše v Pá 26. 11. 2010 v 01:27 +0100:
And also, cron does a couple of really nasty things. For example it
wakes up in regular intervals to check if a job is ready to run. It does
so to deal with wallclock time changes/suspends. In systemd we are
working on a different way to solve this, so that we can actually sleep
as long as possible, and don't have to wake up in regular
intervals. Also, this means we can have much more accurate time
specifications, and we don't have to pay a price for it, due to
this. This different design will even allow us to do amazing stuff that
hasn't existed so far, for example, mark cron jobs so that they wake up
the machine from suspend, and similar.
To summarize this: the current logic of cron is not pretty. And it
duplicates process spawning and babysitting which already exists in way
too many daemons, and is actually the more interesting code. systemd
unifies all that code, and the end result will be simpler, more powerful
and less code, since we reuse what already exists anyway. The only thing
we basically add to systemd is a parser for calendar events, and
everything else already exists.
Lennart Poettering - Red Hat, Inc.