>We're running Foxpro concurrently with Clipper against some older Clipper DBFS. There's no problem so long as the Clipper App is using a CDX instead of NTX, and you SET CPDIALOG OFF in Foxpro, and finally, if the Clipper App is using the Clipper Descend() function in an Index, you'll have to re-write that index in Clipper, or Foxpro will choke on it.
>(e.g., instead of Descend(Dtos(Date)), you have to come up with some god-awful thing like Str( 99999999 - Val(Dtos(Date()))) )

You could write your own descend function, but it would probably write some wrong values into the cdx file, unless you got the source of it, or can emulate the result, i.e. return the same values of the same length. I suppose it's writing a nine's complement, so a candidate for it would be

function descend (cString)
return chrtran(cString, '0123456789','9876543210')

but then it's just a guess.

Never really tried to write back into Clipper tables, but you can just try on a copy and see if it works.