R help - Nov 2009 - can R scripts detect signals sent by the task scheduler ?

In general, is it possible to run R scripts through cron jobs ?
Is it possible to make  the script detect the system interrupt, save its current
status and then exit so that next time it is rescheduled it can pick up from
where it left ?
Examples, if any, are more then welcome.

Thank you in advance,
Maura



tutti i telefonini TIM!


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On Fri, Nov 20, 2009 at 1:25 PM,  <mauede at alice.it>
wrote:
> In general, is it possible to run R scripts through cron jobs ?
 Yes, the only problem might be if you use anything that needs a
graphics window. In the old days you needed an X11 display to create
png graphics with the png() function, but not any more. I'm not sure
if yo need an X11 system for anything apart from showing graphs. But I
don't know everything.
> Is it possible to make ?the script detect the system interrupt, save its
current status and then exit so that next time it is rescheduled it can pick up
from where it left ?
?Signals:

Interrupting Execution of R
Description:
     On receiving ?SIGUSR1? R will save the workspace and quit.
     ?SIGUSR2? has the same result except that the ?.Last? function and
     ?on.exit? expressions will not be called.

 So if you can send that signal to your process you might be in luck.
However if by 'system interrupt' you mean the SIGQUIT signal, then
I'm
not sure that R can trap interrupts to that extent. You might want to
see if your operating system supports 'checkpointing', in which case
any process can be saved and restarted.

 If by 'system interrupt' you mean SIGKILL (signal 9) then you are very
stuck.

 What is going on in your system? Are you trying to checkpoint if the
machine is shut down?

 Barry

On 20 November 2009 at 14:25, mauede at alice.it wrote:
| In general, is it possible to run R scripts through cron jobs ?
| Is it possible to make  the script detect the system interrupt, save its
current status and then exit so that next time it is rescheduled it can pick up
from where it left ?
| Examples, if any, are more then welcome.

You are conflating a few things here:

  i)    yes, you can run R from cron or task scheduler -- that is how R
        updates webpages on the R site, how CRANberries is updated etc pp
 
  ii)   to a program, it doesn't matter who started it, be it the task
        scheduler or interactive use (modulo correcly setup PATH et al
        variables

  iii)  R and its predecessor systems have stopped and resumed for decades,
        look at help(save.image) or help(save)

  iv)   Snapshotting running applications and resuming them elsewhere is
        an operating system task -- some OSs do this, but typically not
        in consumer grade versions.

Hope this helps, Dirk
    
-- 
Three out of two people have difficulties with fractions.