So, Max finally did it. He found the HW to read our old floppy disks and got our 1985/86 software back and onto proper modern media ;)
And then we both separately tried to get a good old DOS to run. My attempt was in a virtualbox on my PC... Tricky to get the program/files into that DOS box because you can't mount a folder from the host then (DOS doesnt have vbox extensions), nor do you have networking on it... so I had to dreate a disk image file, put the files on that, and mount it as disk 0 ("A:") to the DOS vm. And this worked.
Ladies and Gentlemen ... I give you...
UFOS
Please don't ask me what UFOS stood for... the U was most surely "Unterricht" (=education), but I can't remember wha tthe F would be for. I guess I need to try and find that in the sources.
Speaking of which, we did some wonderful stuff - and remember that was two 17y/o kids in high school working on 4.77MHz PCs with just 2 floppy disk drives, natively in x86 Assembler (Macro Assembler if that makes a difference to you, it doesn't to me, because I always considered the "marco" part a primitive pre-processor, not a different language) .
Core architecture was the base module (a .com file), that would load the various modules from disk when needed, and supply a bunch of common functions (a core library, if you will) as a service interrupt. So when a module wanted to do some windowing/output stuff it would - as was common practice under DOS - load a function code into the AH register (the AH part of the accu, ok) and call INT F0h, like you would do for a DOS or BIOS function.
The rest seems to be pretty awful, not only because of the lack of documentation.
The above-mentioned interrupt handler, utilized a jump table, i.e. use the function code in AH as an index into an array of function addresses to call those functions (pretty cool for 17y/o, right?) but I didn't check any boundaries... I probably thought I wouldn't need to, because only us two boys would ever call this interrupt... pretty stupid. (And when I say I, I'm pretty sure that I wrote this piece of code at that time, and looking at the source, it look remarkably like my code)
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