CTDBackup is a simple SIO-CalCOFI developed Windows program that zips and backs up CTD cast files - .hex, .bl, .xmlcon, .mrk, .nav. The utility is run immediately after a CTD cast and data acquisition is stopped. CTDBackup copies all the cast files to our network data server, and creates a zip file which is copied to two locations - flash drive & local backup dir. CTDBackup also creates the sample log (CESL) base file using the cast's .mrk file plus GPS info from either the CTDAtDepth event or .hdr.