Hi, On Tue, Jun 28, 2016 at 12:56 PM, Abe Mishler <a...@mishlerlabs.com> wrote: > > It's apparent that a well written book might help me come up > to speed on all of these memory modes and managers.
I'm not an expert, but the simple answer is you don't need all of them. Pure XMS (and optional DPMI) should suffice for most uses. Don't overcomplicate it. Don't worry about every feature under the sun unless an app you want to run direly needs it (unlikely). EMS is quite old and rare, and even without EMM386, the amount of conventional memory free should be "good enough" for most existing programs, so you probably don't need UMBs at all. (But see UMBPCI. Or EMS Magic, which reuses conventional memory, which is sometimes better for compatibility.) Besides, you can "JEMM386 LOAD" (and "UNLOAD") later if you (temporarily) need EMS for something (but not for UMBs). Somebody, when preparing FD 1.1, was perhaps overzealous for features when trying to support JEMMEX. But, for the record, VBox is not necessarily bug-free or a primary target (remember that DOS is meant for actual native booting, or at least was before UEFI). So yes, presumably EMM386 (et al.) work better on "real" native hardware than emulators. That can't be avoided, but perhaps it's not wise to recommend (or even include) overcomplicated JEMMEX config lines in future FD versions. (This has been discussed before, so you're not the first one to notice this hanging VBox + JEMMEX behavior.) P.S. Emulators are still (usually) run on top of advanced host OSes. So I'm not sure certain low-level DOS things are directly useful there (software cache, screen saver, ultra DMA). So I wouldn't worry about those either. > My interest is in programming anyways (I'm new to DOS but not programming). > Any suggestions? The officially recommended compilers / languages are C (OpenWatcom) and assembler (NASM). But the DJGPP tree is quite nice too (and includes barely-related offshoots like Free Pascal, FreeBASIC, and more). None of these need EMS or UMBs. So it's unlikely you'll be interested in EMS at all. Stick to real mode (640 kb) or DPMI (2 GB). ------------------------------------------------------------------------------ Attend Shape: An AT&T Tech Expo July 15-16. Meet us at AT&T Park in San Francisco, CA to explore cutting-edge tech and listen to tech luminaries present their vision of the future. This family event has something for everyone, including kids. Get more information and register today. http://sdm.link/attshape _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
