[CentOS] Reactive systems -- was: Event scheduling

[R P Herrold]

On Fri, 16 Feb 2007, Frank M. Ramaekers wrote:

> Sure I understand that, but If I wanted it to be within 15 
> seconds response, I'd have to check 4times x 60 seconds x 60 
> minutes x 24 hours per day.  Kind of a waste for a file that 
> may or may not be transmitted each day.

push v pull, poll v select -- SGI formerly had 'fam' and the 
fam daemon to make this more economical, and we shipped it in 
centos-2

http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0650&db=bks&fname=/SGI_Developer/books/IIDsktp_IG/sgi_html/ch08.html

 	and

http://oss.sgi.com/projects/fam/

--------------------

If one wanted to enqueue events without polling, use a tail -f 
on the xferlog, and | grep the desired events, feeding those 
to an enqueuer, or just fire off a child as each new item is 
completed -- Such a script can live in the /etc/inittab 
quite happily, and Linux will handle the scheduling for you.

-- Russ Herrold