MS DOS overlay programming

DEC bigots can skip this message safely. :-) I've been working on a TCP/IP stack for my beloved PCjr. There are already TCP/IP stacks that run on it, but that's not the point. Borrowing a page from Tony's book, I decided to write my own so that I could fix the inevitable bugs. Anyway, I'm interested in reducing memory consumption. Any complex code involves tradeoffs between function and performance, and I've been careful, but one thing that is bothering me is the initialization code. I've got a fair amount of code that reads environment variables, talks to the packet driver, and sets up data structures. The nature of the code is that it runs once, and then just sits there consuming memory. Waaay back in history I was a Zbasic user - Zbasic was a fairly nice BASIC dialect/compiler. Zbasic had overlay support, which I used extensively. It wasn't sophisticated, but it did the job. It would be perfect for this code - init everything that I need, and then overlay the init code with the run code. Now 20 years later I'm using Turbo C++ 3.0 for this project, and it has overlay support but it has a more complicated memory manager that goes along with it. I don't have a lot of 'gas' in the code, so going to the VROOOM overlay manager just to overlay my init code is overkill, and will probably require more memory. I was hoping Borland had a simpler mechanism ... Any ideas? The only one I can think of is kind of brute force ... have two apps, one that inits everything and leaves the storage resident, and another that refers to that resident storage. (I was hoping for something simpler in the Borland runtime support.) Mike PS: I'm still looking for a late version of Zbasic .. I had 4.02 and I know that 4.71 was released. I'd love to see what it evolved to, but that's a different topic.