3 ms·

MS-DOS wasn't that great. Oh, don't get me wrong, it's great at being a singer user, non-reentrant interrupt handler on a painful to program architecture [1].

by spc476 9y ago

MS-DOS wasn't that great. Oh, don't get me wrong, it's great at being a singer user, non-reentrant interrupt handler on a painful to program architecture [1]. A lot of applications skipped using device drivers entirely for things like the keyboard, video and serial I/O (using such made the program run more slowly). Do you know how much work it was to redirect the input/output of an MS-DOS application? It can get pretty insane [2]. [1] You had to pick a memory model to compile against for one thing---tiny, small, medium, compact, large or huge. You had to deal with FAR and NEAR pointers, and it really drove home the point that sizeof(int) != sizeof(long) != sizeof(void *) when writing C on that system. [2] http://boston.conman.org/2015/12/13.1 http://boston.conman.org/2015/12/13.1 More info here: https://github.com/spc476/NaNoGenMo-2015 https://github.com/spc476/NaNoGenMo-2015

StillBored 9y ago
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).

by spc476 9y ago

StillBored 9y ago

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).