Hi, On Wed, May 2, 2018 at 7:07 AM, Eric Auer <e.a...@jpberlin.de> wrote: > >> JEMM386 is basically for 16 bit programs.
Hardware EMS (expanded) on 8086s was before XMS (extended, 286+). But obviously some programs still utilized EMS for many years (e.g. many Borland tools themselves would use it, if available). I think even the game Blackthorne (late '90s) required it. Hence the reliance on EMM386 (using V86 mode). > JEMM386 is for EMS and UMB memory. It is indeed > not a DOS extender. So in a way, you could say > that if your program uses protected mode with a > DOS extender, it will not depend on EMS anyway. VCPI (superset of EMS) was 386+ only and always ring 0 (less secure), so DPMI was meant to improve and replace that. IIRC, only Windows 3.x "standard mode" allowed it. https://en.wikipedia.org/wiki/Virtual_Control_Program_Interface >> As previously told switch to DOS32A > > I totally agree! DOS32A is a drop-in replacement > with improved function for DOS/4G or DOS/4GW, so > if you want to compile programs with Open Watcom > which likes those DOS extenders, then DOS32A is > the version of DOS extender which you want to use! But I think OW 1.9 still only has older 7.x version while latest is 9.1.2. >>> like compile 32-bit programs these uses FreeDOS >>> HIMEMX and JEMM386 on Open Watcom. > > Actually 32-bit programs compiled with Open Watcom > do not need HIMEM or EMM386 to run. Instead, those > two drivers are for making it easier for "classic" > (without protected mode) DOS programs to make use > of additional memory. Most DPMI hosts and DOS extenders try to support several schemes: raw, XMS, VCPI, DPMI. So it should (in theory) work in almost all environments. In other words they provide a simple frontend and handle the others behind the scenes. So DPMI (e.g. CWSDPMI) is exclusively used by DJGPP v2, but when it calls CWSDPMI proper, that handles the allocation from various other available APIs. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
