Were there other systems of this type?
Quite a while ago, I ended up looking after a system running in the USA (Baltimore) that was written using CBASIC (the DOS version). This used a sort utility, that was called from the CBASIC prog. I will still have a copy of the prog, somewhere with all the source for the complete system.
BUT, I never saw any documentation for it, I don't know much about it, I just left it alone and simply copied the calling routine from parts of the system where it was already working. However, I don't think it was IBM?
For a big dataset, the process was pretty efficient and seemed to work well. But, I seem to remember that for a small dataset, much less so. In such a case I think I decided to replace the SORT util with my own code using QS, which appeared to be much faster.
Geoff