Sorry for the delay, Leslie.

Thank you for all your considered remarks.

> I have been looking through my archives for the QBE specification this 
> afternoon and have not had any luck at this time. I do have a copy of 
> the book "Paradox Queries" by Dan Ehrmann but Bernie wants a Paradox for 
> DOS specification which makes that one too modern.

I think Dan did two books, which I think I have - so, if you want me to 
look up anything, let me know.

>> And, I've always had huge respect for the folks who developed the
>> internal ISAM/B-Tree handling, record locking, etc.
> 
> How it works is nothing special really, in fact quite common back then.

Well, there are standard algos, but real-life implementations can get a 
bit messy - support for Soundex, maintain high-density (balanced) index 
blocks (for faster retrieval, but slower Inserts/Deletes), etc. And I've 
used a few B-Tree libraries that had reproducible bugs in them!

> I co-wrote something similar back in the late 80's which we used in 
> parallel with Btrieve 3.5/4.0.
> 
> I have rewritten that library twice since then as I use it in other 
> applications today. It does super-fast data retrieval (faster than 
> Paradox actually) and does not need an engine like the BDE...

Well Done!!

   - Mike