20010327: McIDAS-XCD files

>From: Robert Ballentine <address@hidden>
>Organization: SUNY Oswego
>Keywords: 200103270605.f2R654L20289 McIDAS-XCD

Bob,

>   I am accumulating some very large files in my
>mcidas directory. Some of the largest ones are
>listed below: 
>   File Name        Size
>  DD010850.XCD   202711040
>  DD010860.XCD    48520800
>  FOUS14.RAT      33554100
>  HRS.SPL         33558529
>  RAOB.RAT        33554260
>  SAOMETAR.RAP    34780676
>  SAOMETAR.RAT    33554260
>  SYNOPTIC.RAT    33554260
>  TERMFCST.RAT    33554260
> 
>   Are these files growing with time, or are they
>supposed to be this large all the time?

In McIDAS-XCD that is setup to run with the Unidata LDM, data is
ingested into spool files which are then used by decoders.  The DD*.XCD
files are the daily spool files for textual data (DDPLUS+IDS LDM
feeds), and HRS.SPL is the spool file for gridded data.

The DD*.XCD files grow throught the day.  The one that is important to
keep around as far as McIDAS is concerned is the one for the current
day.

The other files that are listed are a fixed size.  The *.R* files are used
for rapid access into the DD*.XCD files.  They are used by XCD decoders
and the weather text listing routines.

>Would it be safe for me to remove/delete any of these files 
>periodically to save space, or would that cause
>mcidas to crash?

The DD*.XCD files should be scoured every night.  When I setup McIDAS
on your machine, I also setup a cron entry to scour these files.  If
they are not being scoured daily, then there is something amiss with
the scouring entry in cron.  I believe that the scouring was setup under
the root account, but I can't remember exactly.  I would say that at
most you should see two DD*.XCD files at any time, and the older one of
the two can be removed with no ill effects.

The other thing that can be done is delete the HRS.SPL file if the
XCD ingestion and decoding of gridded data (model output) is turned
off.  To check this, you should review ~ldm/etc/pqact.conf entries.
Look for an entry like:

HRS     ^.*     PIPE
        xcd_run HRS

If this entry is uncommented, comment it out and then send a HUP signal
to pqact.  This will turn XCD ingestion of gridded data off

>I'm not worried about losing the
>data, but I don't want to screw up mcidas.

Removing "yesterday's" .XCD file will cause no problems.  Removing the
HRS.SPL file will cause no problems if XCD ingestion of gridded data
is truned off (if it isn't, the file will simply be recreated).  Removing
the *.R* files will cause decoding problems.

>   Thanks,

You are welcome.

Tom