Extracting Data from a VERY old unix machine

I do not recognize those kinds of filenames A\G\data.dat and so on (filenames with backslashes in them???) and it's likely to be a proprietary format so I wouldn't expect much from that avenue. You can try running file on these to see if they are in any recognized format just to see...

I would suggest improving the speed of data extraction over ODBC by virtualizing the system. A modern computer will have faster memory, faster disks, and a faster CPU and may be able to extract the data a lot more quickly. You will have to extract a disk image from the old system in order to virtualize it, but hopefully a single sequential pass at reading everything off its disk won't be too slow.

I don't know what the architecture of this system is, but I guess it is x86, which means it might be not too hard to virtualize (depending on how well the SCO OpenServer 6 OS agrees with the virtualization). You will have to use a hypervisor that supports full virtualization (not paravirtualization).

I finally solved the problem, running a query using another tool (not through MS Access or MS Excel) worked massively faster, ended up using DaFT (Database Fishing Tool) to SELECT INTO a text file. Processed all 50 million rows in a few hours.

It seems the dll driver I was using doesn't work well with any MS products.