>I've been doing some conversions from RM Cobol, and it does have a weird data format. The index and data blocks are interspersed. I think I may still have some pieces of the converter I wrote, and it relies not on the structure being known, but on columns being recognized. From what I know about conversions from Cobol, the structure you may get is obsolete :). That's what happened to me each time I had it, and most of the time I didn't have it.

Sounds like VSAM. http://sciris.shu.edu/Resources/Cs/c2113/c2113n10.htm