Hi, On Thu, Mar 8, 2012 at 12:28 PM, Bernd Blaauw <bbla...@home.nl> wrote: > > DOS has no support for over-4GB memory usage, not through 32bit AWE or > PAE, nor 64bit stuff.
CWSDPMI r7 supports (in theory) 4 GB but has some issues (rare bugs) due to low page tables. Anyways, DJGPP's runtime assumes a 2 GB address space anyways, so it would be hard to use more than that anyways, and you'd definitely have to use sbrk() to allocate more than 2 GB at a time. CWS is too busy these days, but who knows what he has up his sleeve for the future. DOS/32A has an experimental PAE build, but I've not tested it. IMO, this is probably the way to go, and I'm surprised that Windows didn't choose it to keep legacy around for a longer amount of time. AMD64 long mode only has "legacy" support for 32-bit. Supposedly there is also some partial 16-bit pmode support, but nobody uses that (AFAICT). However, with latest Intel VT-X (and/or older? incompatible? AMD SVM), there is better support for real mode and big real mode (and/or paged real mode). So, presumably, I guess???, somebody could write a very slim hypervisor atop FreeDOS and somehow be able to access 64-bit. Maybe??? I dunno, very confusing. (I guess? this is what let older Mac OS X kernels access 64-bit via 32-bit. At least, I think? you're able to boot a 64-bit kernel atop a 32-bit VirtualBox if your cpu supports VT-X.) So all hope isn't "necessarily" lost. Although given the unstable nature of the PC marketplace these days, there may be no winner at all (though Windows vs. POSIX seem to be virtually everywhere, for good or bad). ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
