Nine, dos, high, | low, umb|noumb)

Dos s high, umb then dos loads itself into high-end memory (high) and manages upper memory (umb).

Noumb does not manage upper memory.

You should load the device-himem code before writing dos-high and .sys

In order to load a program or driver into upper memory, you must save most of the regular memory by using dos -umb.

You can .sys dos-high, umb anywhere in the config

If hma not avoiable or load down low is displayed, high -end memory cannot be used.