By enigma (2021-10-21)

HT12MM.SYS is a expanded memory driver for the HT12 chipset.

It allows to emulate EMS memory from XMS memory provided by the BIOS.

HT12MM.SYS works only correctly if Memory Relocation is disabled in BIOS.

While the drivers readme states that it should be the first driver in config.sys
it is better to load HIMEM.SYS first, because HIMEM.SYS provides the High Memory Area (HMA)
that also allows to load DOS high. HT12MM.SYS works also with XMS provided by HIMEM.SYS.

CONFIG.SYS example lines:
DOS=HIGH,UMB
DEVICE=HIMEM.SYS
DEVICE=HT12MM.SYS FULLDISPLAY EXT=2048

The number 2028 refers to 2048 kB (2 MB) of extended memory (XMS).
The remaining memory is made available as expanded memroy (EMS).
