This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Tom, After perusing the pqact(1) code, I've concluded that a PIPE-ed data-product could be smaller than a FILE-d data-product if the computer were heavily loaded. In order to avoid spending too much time trying to pipe data to a slow decoder, the pqact(1) process sets a timeout alarm. The default timeout is 60 seconds but can be overridden by a command-line option. If the associated SIGALRM is received before the data is written, then pqact(1) will abandon the attempt and log this fact in the LDM logfile. I'm waiting for David to tell me if the LDM logfile contained any relevant messages. Regards, Steve Emmerson