Perhaps they were .TPUs instead of BGI? BGIs were the graphic drivers IIRC.

dragonwriter · on April 11, 2020

TPUs are closer than BGIs, but still aren't dynamically linked. They are object files which are statically linked into the final exe.

It's possible that the author is thinking of pre-TP4.0 chain files (which were used to get around the 64K memory limit of .COM format before TP switched to generating EXEs.)