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>From: Rick Kohrs <address@hidden> >Organization: SSEC >Keywords: 200108091622.f79GMP122796 McIDAS nexradir nexraget Rick, >The caching would explain the difference. What is actually cached? My >batch job goes through several radar sites and I am always seeing >IMGLIST take longer than IMGCOPY. Are things cached based on ID? What the OS caches is up to itself. Since the header portion of each file has to be read to get the information necessary to synthesize an AREA header, that data will get cached by the OS. This information will be used by the IMGCOPY phase as the server _once again_ determines which file contains the information needed, so finding the file to send will be quicker. The actual job of extracting and sending the NEXRAD data back to the client is relatively quick since the file will already be open and seeked to the beginning of data (opening files and seeking in them are heavy weight processes). The actual amount of data that gets sent back in the copy is very small for NEXRAD data especially after it is compressed, so that time is neglegible. The listing of NEXRAD data could be made faster _if_ one could assume that information needed to be sent back for things like IMGLIST were contained in the name of the file. This does not help, however, in something that must be calculated: the resolution at the center of an image. Tom