EMS boards

[Torinde]

I try to make a config emulating a EMS board(s) for running Win3.x in real mode.

When I set ems=emsboard and memsize=128 at DOSbox prompt in MEM I still get XMS = EMS = 128, where I expected EMS to be 32MB (or less) - probably related to #3800.

At ems.cpp I see a few TODO notes, which seems relevant.

What is the difference in behavior between the ems=emsboard and emm386 settings?
Can I have multiple boards for a total of more than 32MB EMS?

Drivers and information about LIM specification and Intel Above Board Plus 8 - memory card using EMM.SYS:

• Conventional memory backfill (to increase it to 640KB for PCs with less)
• Mappable conventional memory (window from inside the first 640KB) - for DESQview, Win2.0
• Expanded memory (window from inside the Upper memory 384KB) - for DOS LIM applications
• up to 14MB per card
• multiple cards, up to 32MB total per PC (what will happen if 4x14MB=56MB are installed?)

EMS4.0 compatible superset 64MB:

• NEC Vadem VG230 (VG330 supports only 16MB) - 286 real mode CPU (datasheet)
• C&T F8680 emulation - 186 with 26-bit addressing #5261

Other variants:

• LIM3.0 (for Win1.x?) Emulate LIM EMS 3.0 compatible expanded memory 86Box/86Box#4054
• LIM3.2
• EEMS
• LIM4.0 16-bit ISA expansion card that can expand up to 32 MB, EMS, UMB, XMS, 8-bit ISA compatible, XT/AT/386/486 [FEATURE REQUEST] Orchid RAMQuest 8/16 86Box/86Box#4528
• LIMulator - EMS on HDD (like Above Disc driver, but supporting the "LIM4.0 compatible superset" of Vadem VG230 or the F8680A approach or a custom DOSbox one for >32MB capacity)
• XMA, JRAM, others? - if a software using those is found

Alternative:

• EMS driver that uses host RAM (or such option in the LIMulator) - maybe based on this
• EMS driver option to use HDD space not managed by DOS (e.g. another partition/unpartitioned area or another HDD, even on additional controller) - that can be useful also on bare metal with (XT-)IDE SSD/RAMdisk.