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Originally posted by vmxa1
Well not quite. 2MB of ram is not related to EMS. I suspect that the post of 1mb of EMS is really XMS. I never seen any one with 1MB of EMS and I doubt that it is possible. It has been a long time, but EMS is extented memory above the 640K conventional, but within the 1MB. I don;t think you can allocate 1mb of EMS.
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Well, actually.
1MB of EMS really IS 1MB of EMS, only that usually EMS was run inside XMS space.
EMS demands a 64K frame inside the 384 KB upper memory area (which is called exactly that, UMA or UMB for upper memory blocks). This frame I haven't been able to free on my newest laptop. Grrr. But I digress. That frame acts as a cache for the memory DOS really can't access above 1M. EMS is old tech. Meaning REALLY old tech, like pre-287 tech. True EMS needed special hardware memory boards.
When XMS was invented, that does the same thing (making more than 1M memory available only with a completely different approach,) XMS stubs (like QEMM and EMM386) were made to emulate the older standard EMS. So people could still run their old Lotus-1-2-3 on spanking new 386 machines.
When Simtex programmed MOO and needed more RAM, they had to take EMS, since EMM386 wasn't included in DOS before 6.0 (1994), and anyway, XMS needs a 386 chip, while the old hardware EMS runs fine on a 286.
So yes. 2MB RAM is related to 1MB conventional+UMA and 1MB of EMS, which was almost always emulated by XMS. These days, of course, XMS is emulated by a DOS emulator inside a true flat memory model.
C.
Had to read up on this bit when I experimented with running MOO on my latest PC. It's not something I usually bother to remember...