[comp.unix.internals] Problems with the crontab

cap@ifi.unizh.ch (12/05/90)

We observed the following problems with the cron on a SparcStation1
under SunOS4.0.3:

1) Several times processes are started too early than specified
   (error of several seconds)

2) One time out of approx. 10 times a process is even started TWICE.
   The crontab contains a line that should start a process at the full
   hour saying the time by copying a file to /dev/audio
   Every now and then two such processes are started and we hear an
   interleaving of two time-announcements.

3) Even worse, we have similar problems with our dumps that get started
   via crontab and crash from time to time when two dump processes
   are started.

If someone has made similar observations or has an explanation for this
please E-MAIL to cap@ifi.unizh.ch
(I do not read this group regularly)

THANX a LOT.

-- 
* Dr. Clemens H. CAP           cap@ifi.unizh.ch        Phone +01 257-4326
* Dept. of Computer Science    University of Zurich    Winterthurerstr. 190 
* CH-8057 Zurich, Switzerland  #include<disclaimer.h>  #exclude <flames.h>            
   

cap@ifi.unizh.ch (12/11/90)

In article <1990Dec5.131108.17376@ifi.unizh.ch> cap@ifi.unizh.ch writes:
>
>We observed the following problems with the cron on a SparcStation1
>under SunOS4.0.3:
>
>1) Several times processes are started too early than specified
>   (error of several seconds)
>
>2) One time out of approx. 10 times a process is even started TWICE.
>   The crontab contains a line that should start a process at the full
>   hour saying the time by copying a file to /dev/audio
>   Every now and then two such processes are started and we hear an
>   interleaving of two time-announcements.
>
>3) Even worse, we have similar problems with our dumps that get started
>   via crontab and crash from time to time when two dump processes
>   are started.


I got a lot of answers - and so I am unable to thank everyone individually.
So THANX FOR ALL THE ANSWERS.

Summary:

The problem seems to be a bug in SunOS 4.0.3 which seems to got fixed in
SunOS 4.1.
So ... it's upgrade time 8-) ...

-- 
* Dr. Clemens H. CAP           cap@ifi.unizh.ch        Phone +01 257-4326
* Dept. of Computer Science    University of Zurich    Winterthurerstr. 190 
* CH-8057 Zurich, Switzerland  #include<disclaimer.h>  #exclude <flames.h>            
   

cgh018@tijc02.uucp (Calvin Hayden x2254) (12/21/90)

From article <1990Dec5.131108.17376@ifi.unizh.ch>, by cap@ifi.unizh.ch:
> 
> We observed the following problems with the cron on a SparcStation1
> under SunOS4.0.3:
> 
> 1) Several times processes are started too early than specified
>    (error of several seconds)
> 
> 2) One time out of approx. 10 times a process is even started TWICE.
>    The crontab contains a line that should start a process at the full
>    hour saying the time by copying a file to /dev/audio
>    Every now and then two such processes are started and we hear an
>    interleaving of two time-announcements.
> 
> 3) Even worse, we have similar problems with our dumps that get started
>    via crontab and crash from time to time when two dump processes
>    are started.
> 
> If someone has made similar observations or has an explanation for this
> please E-MAIL to cap@ifi.unizh.ch
> (I do not read this group regularly)
> 
> THANX a LOT.
> 
> -- 
> * Dr. Clemens H. CAP           cap@ifi.unizh.ch        Phone +01 257-4326
> * Dept. of Computer Science    University of Zurich    Winterthurerstr. 190 
> * CH-8057 Zurich, Switzerland  #include<disclaimer.h>  #exclude <flames.h>            
There was a bug in 4.0.3 as I remember.  It is fixed in 4.1.  We
were getting ready to go to 4.1 anyway, so I dont have any information
on the patch (Sun knew of this, so there should be a patch :-) ).  I think
that it was just a new cron binary - actually I just verified that there
was indeed a patch tape from sun, but I dont know the bugid.

I was seeing this on nightly dumps on occasion also.

Hope this helps.

Cal
-- 
Calvin Hayden
Texas Instruments, Johnson City, Tn.    
Voice (615)461-2254
UUCP:  ...mcnc!rti!{olympus,tijc02}!{root,cgh018}