I wrote a fair number of DOS programs. The memory models wern't that bad, at least you had choices... I also wrote code on machines that had 64k address spaces,

I wrote a fair number of DOS programs. The memory models wern't that bad, at least you had choices... I also wrote code on machines that had 64k address spaces, with soft banking. That was worse... What I remember being a huge PITA was memory management on macOS in the system 5/6 time-frame. I vaguly have memories of struggling with locking/unlocking handles.. Heck googling about it, turns up a whole wikipedia article which spends a bit of time describing it in general. https://en.wikipedia.org/wiki/Mac_OS_memory_management https://en.wikipedia.org/wiki/Mac_OS_memory_management Anyway, in dos, .ost little utilities and such worked just fine in tiny (and you could use .com which simplified everything even more). Medium and compact were sort pointless because if you were writing anything you expected to grow beyond 64k then you used a HLL and let the compiler deal with most of the fiddly stuff. IIRC One of the compilers (may have been turboC) had an project/link option which let you cycles through all the memory models, and with a quick rebuild you could check executable sizes or run little benchmarks. I did a fair amount of programming in Turbo Pascal, and I just checked the manual, it basically hid the entire memory model argument, even going so far as to have that "overlay" functionality which was basically a software paging unit for your program which would load groups of methods from disk as necessary. Yah, and I wrote TSR's too... and hacks to take over bios/dos INT calls, etc etc etc. These days it seems any software project that has been around for a few years is orders of magnitude more difficult than the stuff people claim was hard about DOS. Heck there are _network_ drivers in linux that are orders of magnitude more code (and more complex) than DOS or probably the vast majority of DOS applications. People simply didn't write 100 million line DOS programs so dealing with little hardware oddities is simple vs trying to ferret out VM barrier bugs in linux (or whatever).