[daip] AIPS 1: TASK ACTIVE problem

[Philip Lah]

Hello Eric,

   unfortunately I do not have much I can add to give a more complete 
description of the problem.  I am using perl scripts to interface with 
AIPS for my data reduction.  For some reason on the new machine I now 
occasionally get the TASK ACTIVE halting my task and stopping my script. 
Years ago I did look at using DOWAIT but I discarded it as an option 
because it did not give the result I wanted with my scripts.

   From your email I now have a suspiscion about what may be going wrong. 
In the perl script that halted prematuraly last night I have multiple 
FITTP commands that run one after another outputting the 25 facets of my 
continuum image.  I am guessing the for one of the runs the FITTP1.$nnnnn 
for the precious run in the /tmp dir had not been removed before the next 
FTTP started, so AIPS decided to halt with the TASK ACTIVE error.  This 
does not always happen as I ran the same script today with no trouble.  I 
suspect that the machine was under higher read/write pressure when the 
problem occured hence the delay in removing the old FITTP1.$nnnnn.  I am 
not sure how to stop this problem from happening again.  Perhaps I should 
have my scripts check for the existance of the FITTP1.$nnnnn before 
deciding to continue.

   Bye
          Philip Lah

On Tue, 1 Nov 2011, Eric Greisen wrote:

> Philip Lah wrote:
>> Hello Eric,
>> 
>>   I am repeatedly encountering a problem with AIPS not completing a task 
>> with the error message
>> 
>> AIPS 1: TASK ACTIVE
>> 
>>   being given.  This usually happens with FITLD or FITTP but does not occur 
>> everytime these tasks are run.  Every so often for reasons unknown to me 
>> AIPS just chooses to stop.  Do you have any idea on the possible causes of 
>> this problem and how to stop this from happening?
>> 
>
> The message above is given when AIPS attempts to start a task and the 
> operating system tells it that a previous task by that name is still running. 
> When you get one of these, there are several things to do:
>
> I will use FITTP for the example:
>
> 1. ps -elf | grep FITTP
>
> 2. ls -l /tmp/FITTP*
>
> The /tmp area gets files named e.g. FITTP1.nnnnn where nnnnn is the process 
> number.  The are you active routine looks at /tmp and then asks the OS if 
> nnnnn is still running.  If /tmp has a FITTP file then do
>    ps -elf | grep nnnnn
>
>
> I do not know what you mean "AIPS just chooses to stop".  Be aware that GO 
> has adverbs - most especially DOWAIT.  If that is TRUE (> 0) then the task 
> will not resume AIPS until it finishes more or less normally or disappears 
> (AIPS detects that and resumes itself).
>
> I guess I need a more complete description of what is going on in order to 
> answer the question properly.
>
> Eric Greisen
>

**************************************************
     Philip Lah
   Postdoctoral Fellow, joint appointment at
   National Centre for Radio Astrophysics
     and
   Australian National University

   Home Page: http://www.mso.anu.edu.au/~plah/

**************************************************