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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
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