# Earthworm Modules:
Findwave Overview

(last revised 30 May 2006)

Findwave is a command line diagnostic program. It attaches to a transport ring and discovers all TRACE_BUF messages on that ring. It then computes some statistics for each SCN, and writes this to a file. This file is rewritten every five seconds, listing the statistics at that time. Findwave also writes the number of distinct SCN's found to stdout.

Findwave attempts to be helpful for configuring WaveServers:

First, it lists the largest packet length (Msg Len Max) found for each SCN - this is suitable for the "Record size" field in wave_serverV.d. Second, it estimates the required tank size for 24 hours of trace data storage. This is computed for each SCN as follows: Find the average time contained in all TRACE_BUF messages seen for this SCN; assume that each message will live in a record of "Max Msg Len" bytes, and compute the number of such records required to store 24 hours of trace data.

Usage: FINDWAVE <ring name> <index size> <days> <file name> <output type>
output type = w for waveserver output, which produces a waveserver
helper file with days = days to save per tank, and index size = the
waveserver index size.
output type = d for SCN debug output, still provide days and index size.

For example:

`findwave WAVE_RING testfile.txt`

`This would result in the file containing:`

`S C N Msg Len Rate Nmsg Mb/day`

`Max Min
` `8028 HNE NP 464 464 100.0 186 40.1
` `8028 HNN NP 464 464 100.0 187 40.1
` `8028 HNZ NP 464 464 100.0 187 40.1
` `PMR BHE AT 2288 1904 20.0 14 8.6
` `PMR BHN AT 2228 1936 20.0 14 8.0`

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