LDM Status Report

by

Steve Emmerson

2003-02-18

• The latest LDM is called LDM-6.

• LDM-6 has much better performance than its predecessor, LDM-5, due to the use of non-blocking RPC calls and better connection strategies. In a test sending 200 kilobyte products over a high-bandwidth, high-latency network from the UPC to Belem, Brazil, LDM-6 had 8.4 times better throughput than LDM-5.

• LDM-6 is completly backward-compatible with the previous LDM-5: it can both send to and receive from an LDM-5 with performance that is equal to or better than an LDM-5's.

• A new program by Steve Chiswell has been added. Named rtstats, this program supports the near real-time display of product latencies by the UPC and has allowed Yoksas, Chiswell, and Emmerson to verify and validate the performance of LDM-6.

• LDM-6 has been tested on 12 systems -- including thelma.ucar.edu, motherlode.ucar.edu, papagayo.unl.edu, marzipan.atmos.washington.edu, and atm.geo.nsf.gov.

• We are releasing it now.