DIFAX Source

[Larry Riddle]

We (Scripps Inst of Oceanography) use DIFAX, but do not get it from 
Alden.  We are a customer of Unisys.  This message is NOT an endorsement of 
Unisys.  We have our own, if different, set of problems with 
Unisys.  However, the system is usually reliable.

We pay Unisys $300.00 per year (ie, $25.00 per month, once per year) for 
the service.  There are three major problems.  First, this is a "pull" 
technology system.  My old friend "cron" ftp's to Kennett Square once an 
hour (about 5 minutes past) to get the maps for the previous hour.  Not an 
elegant solution, but it works.

The second problem has to do with reliability.  The the maps are produced 
on some other machine and transferred to the ftp host.  Frequency of 
transfer is unknown.  The problem is that this transfer is periodically 
shutdown (or fails) and they forget to restart it.

The third problem is format.  The maps are created as "pcx" format 
files.  They can be fairly large.  The latest 00Z chart is about 340K.  The 
latest western tropical surface chart is about 600K.  When I print these 
files on my 11x17 inch printer, I get large, crisp, clear maps.

These files would be a lot smaller, with no loss of detail, if they were in 
"gif" format.  They don't seem to be in any hurry to make this 
change.  Remember, Unisys is the patent holder for the compression 
algorithm in gif.  Seems strange.  My connect time (and their consequent 
cpu time) on their ftp host would be much shorter with gif files.

One plus is that their trouble desk is manned 24/7 and I've never called 
there and not spoken with a real human being.  They don't always know how 
to solve problems (or have authority to solve problems), but they can 
usually contact someone who does.  Usually.

Finally, I have had conversations with Mike Porrecha (sp?) who indicated 
(but did NOT promise) that when the NWS shuts DIFAX down, Unisys might 
continue to produce the maps.

This is all "for what it's worth".  I think that, if a bunch of Unidata 
folks transferred their allegiance to Unisys and all started pulling maps 
down, their system would probably choke.  But, it might be a short term 
solution for some of you.

Larry

     ---===---=-=-=-=-=-=-=-=-=-=-=====[\/]=====-=-=-=-=-=-=-=-=-=-=---===---
   -----===(*  Climate's what we expect, but weather's what we get.  *)===-----
  Larry Riddle : Climate Research Division : Scripps Institution of 
Oceanography
      University of California, San Diego : La Jolla, California  92093-0224
      Phone: (858) 534-1869 : Fax: (858) 534-8561 : E-Mail: lriddle at ucsd.edu