Date: Wed, 10 Jan 2001 12:42:14 -0800 (PST) From: Doug Barton <DougB@gorean.org> To: Neil Blakey-Milner <nbm@mithrandr.moria.org> Cc: Dan Langille <dan@langille.org>, <freebsd-hackers@FreeBSD.ORG> Subject: Re: how to test out cron.c changes? (was: cvs commit: src/etc crontab) Message-ID: <Pine.BSF.4.31.0101101223460.91066-100000@dt051n37.san.rr.com> In-Reply-To: <20010110112451.A52255@mithrandr.moria.org>
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Well, we've obviously hit a hot button issue for you here Neil,
for reasons that I don't pretend to understand. Please try to reduce the
amount of emotion that's going into your argument.... It's just a
computer thing after all. :)
On Wed, 10 Jan 2001, Neil Blakey-Milner wrote:
> On Wed 2001-01-10 (21:20), Dan Langille wrote:
> > > > And when you finally realize that everyone else thinks this is a great
> > > > idea,
> >
> > I do not like being included in "everyone". I don't think it's a great idea.
>
> If you didn't miss the comment, I was (and am now) attempting to emulate
> Doug's style.
As I said previously, don't give up your day job.
> (The "I don't like this change, and since nobody
> commented, it must be a terrible thing" style.)
Actually, that's not my postition at all. I have stated clearly
and on several occasions that I oppose this change on its merits. When I
was doing consulting work as a business I got hired to research this exact
issue. I can't tell you who the customer was, unfortunately. The problem
is that while the existing behavior of cron is somewhat confusing for
certain edge cases (like DST, or poorly configured system timekeeping) it
is the only behavior that makes sense for the vast majority of cases. In
addition, while the problems are somewhat confusing to novice admins, the
solutions are well known, and what's more, well documented, particularly
in sources outside the freebsd project. Therefore, changing existing
behavior, especially to something as dramatic as the proposed change is
ill advised.
> These changes have been tested in OpenBSD for 3 years.
With all due respect to our friends in the openbsd project, I
don't consider this a significant factor. Others have expressed reasons
why this may or may not be the case in other threads, I'll leave it to
that.
> The "solution" is _not_ to tell people they're stupid to schedule jobs
> during the changeover.
Woah.... who said anything about people being stupid? What I said
was that novice system admins, all the way down to desktop freebsd
users don't really care about this issue (other than the occasional "how
come my periodic thingy ran twice?" e-mails). More experienced admins,
and/or people who have really time critical jobs will take the appropriate
steps to make sure things happen the way they want. Our current cron is
working exactly as it is (or should be) expected. Therefore, like so many
other parts of the system, the "fix" is user education, rather than
violating POLA in a major way by changing many years of established
behavior.
> It has nothing to do with them. If they want jobs at 2am
> in the morning, that's cool.
What if there is no 2am on a given day? You have defined a fairly
limited problem set wherein your proposed changes are the solution. What
I'm trying to tell you is that the problem set is much larger then what
you're seeing.
> The fact the changeover is a problem is
> cron-specific. It shouldn't be trying to be clever and work with local
> time when local time does weird things like randomly add and remove time
> from existence.
Once again, the current implementation of cron isn't trying to be
clever. It's just doing what it's told, namely running jobs when the
system clock tells it what time it is.
> Again, this change is from OpenBSD. We will synchronise with their
> changes, and perhaps offer them back a patch to ignore what "ultra leet
> sysadmins who rely on broken behaviour because people who don't are
> simply stupid and shouldn't be running FreeBSD anyway!" with an option.
Well, this paragraph is obviously an attempted dig at me, but
you're dramatically misrepresenting my position, as explained above.
Doug
--
"The most difficult thing in the world is to know how to do a thing and
to watch someone else do it wrong without comment."
-- Theodore H. White
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