Current Status of LDM/IDD/NOAAport

by Robb Kambic 01/19/2000

A paper on Data Acquisition Issues was presented at the AMS that covered the current IDD configurations and the stresses and strains that new data volumes presents. These increases could be the result from new data streams or the request for more data from the present streams. Currently it is possibly to receive 2 Gigabytes/hour or 17.5 Terabytes/year. None of our sites currently receive the max, 100 sites receive .5 Gigabytes/hour. In the next couple of years our sites will be able to receive 4 Gigabytes/hour, so the current IDD configurations will be pushed to their limits. The solution to this problem is for the sites to obtain the largest bandwidth possible and to obtain the latest hardware and software.

The above data volumes will push the current LDM design to it's limits also, it was designed to handle about 50 Megabytes/hour. A modification in progress will permit the LDM queue to be as large as 2 Gigabytes even with the large number of small products being feed into the queue. This fix should be completed in time for the radar products being inserted into the NOAAport channel 3 in the October time frame. A new design of the LDM will take place during the year with the possibility of a separate queue for each different data feed. This is not the only modification that will be addressed, automatic routing, more feed types, better LDM statistics, also.

A LDM patch was released on 12/30/99 for a Y2K bug in the pqact program. The bug was not discovered until 12/29/99, it caused file names to start with 100 instead of 00 for the year 2000. A binary pqact was created for all supported platforms, a source patch was also released including extra support to get this patch installed before 2000. Most sites installed the patch without a hitch. This bug also appeared in the perl decoders, perl also return 100 instead of 00 for the year 2000.

Currently, work in being done to provide access to the Unidata sites to the Canadian GEM model. The products will be about 20k a piece and total about 17 Megabytes/day. Linda Miller has the details on the aspects of the model.

The IDD has been working well with the same problems of temporary network outages. Many sites need help when outages occur, but UPC can't put in request to check the network problem because UPC is not the customer. The request to the network folks or ISP must come the site having the problem. A support document on how to solve network outages might fill the necessary information gap.

I have been teaching a 1-2 LDM workshop for Anne Wilson and Jeff Weber to bring them up to speed in performing LDM support.

The LDM is going to be used in the receiving and distribution of the Level 2 radar data and the GPS data. At this time the details are uncertain.

The work on the UPC NOAAport card that can supply all four NOAAport channels is almost completed. The next step is too modify the LDM to work with the new card.

The LDM workshop for 2000 is scheduled for: LDM Oct 26-28 (Thu-Sat)

This document is maintained by Robb Kambic<>