[daip] "ZLOCK - No locks available problem.

[Eric Greisen]

Ishwara Chandra C. H wrote:
> I am running aips on a 64-bit linux machine.
> I am a full time aips user since 1993 and was also
> 'aips manager' for several years - this problem puzzles me.
> 
> My login is aips, which is installed on /home/aips/
> 
> I wanted to load a FITS file.
> setenv DSK /Vstr/vstr/aips
> and in the task say
> DATAIN='DSK:3C321.610U.FITS' ; go fitld -
> It gives this error on the main window:
> go fitld
> ZLOCK: No locks available
> AIPS 1: Resumes
> and in MSGSRV the following error:
> FITLD1: Task FITLD  (release of 31DEC08) begins
> FITLD1: ZTPOPN: DISK DEVICE = DSK:3C321.610U.FITS1 NOT FOUND
> FITLD1: TAPIO: ERROR   2 OPENING FILE
> FITLD1: ALSO COULD NOT OPEN DSK:3C321.610U.FITS
> FITLD1: ERROR      8 OPENING TAPE
> FITLD1: Purports to die of UNNATURAL causes
> 
> I just change the DATAIN path to
> 'FITS:3C321.610U.FITS' ; everything is fine.
> The only difference is FITS is the local disk
> and /Vstr is the nis mounted disk. However
> aips can read and write outside AIPS;
> since it is owned by aips.
> 
> There is nothing wrong with the data area definition.
> I am ABLE to run PRTMSG and write message files to DSK;
> but not to write or read FITS file.
> 
> Does anybody have the clue?
>

The ZLOCK message is the clue I think.  The machine owning /Vstr is 
probably not running suitable daemons --- or allowing them --- for 
remote file locking.  The FITS file reading uses file locking as does 
most of AIPS I/O.  However, simple text file writing as in PRTMSG is 
done via Fortran with no attempt at file locking.

Eric Greisen