		EMS 4.0 DOCUMENTATION


The EMS (Expanded Memory Specification) Version 4.0 device
driver is a standard MS DOS device driver that gets loaded at boot
time by the CONFIG.SYS file. Because EMS 4.0 is a device driver, it
should look like this in the CONFIG.SYS file:

	DEVICE = EMM412.SYS

Without anything else included in this command line, the EMS
driver will get loaded with the default hardware values of the I/O
address that enables the EMS and the memory address used for
EMS paging. These default values are dependent on the NEAT
implementation of EMS.

To change these default values, as well as add a few extra
features, the EMS device driver command line can look like this:

	DEVICE = EMM412.SYS -Ix -My -Pzz -D

           where,
		I = I/O address to enable EMS pages
		x = 0 ==> 208h
		  = 1 ==> 218h
		  = 5 ==> 258h
		  = 6 ==> 268h
		  = A ==> 2A8h
		  = B ==> 2B8h
		  = E ==> 2E8h

		M = page frame address (address of 64K window)
		y = 1 ==> C0000h
		  = 2 ==> C4000h
		  = 3 ==> C8000h
		  = 4 ==> CC000h
		  = 5 ==> D0000h
                  = 6 ==> D4000h
                  = 7 ==> D8000h
                  = 8 ==> DC000h
                  = 9 ==> E0000h

		P = maximum number of open processes
				(defaults to 64)
                zz = number of processes (64-128)

		D = enable EMS diagnostics

The command line parameters can be in either upper or lower case.


When the EMS driver is first executed, a title and copyright notice
will appear on the screen as follows:

        " EMS Expanded Memory Device Driver 4.0,  Version 1.52 "
	" Copyright (c) Chips and Technologies inc., 1987"

If the EMS driver detects that a previous EMS driver has been loaded, 
it will put this message on the screen:

    " An Expanded Memory Manager has already been installed. "

The EMS driver will then not get loaded into the system.


When the EMS driver gets loaded by MS DOS, an internal check is
done on the EMS configuration in hardware. If the driver detects any
conflicts that would cause EMS to not function properly, the message:

" The EMS setup has been incorrectly specified. No EMS is available. "

will appear on the screen after the EMS copyright notice and EMS will be
disabled. If the EMS hardware is configured properly and the I/O address
is overridden by the command line parameter, the screen will show this
message:
	" The EMS I/O address has been changed. "

If the EMS page frame address is being overridden from the command line,
the following message will appear:

	" The EMS Frame Segment has been changed. "

If the diagnostics option is selected, this message will appear on the
screen:
	" Testing EMS Expanded Memory Page Number: NNN "

The NNN represents the page number currently under test. If the 
diagnostics fail, the EMS will be disabled and the following message 
appears on the screen:
	" Expanded Memory FAILED diagnostics test. "

If the diagnostics pass, or if diagnostics were not specified on the 
command line, the EMS driver has been loaded correctly and EMS is 
enabled. The final message to appear on the screen is:

" There are XXX pages, or YYYY Kbytes of EMS Expanded Memory on the system. "


The system can now be used to support Lotus/Intel/Microsoft EMS 4.0
in the same manner as standard EMS cards.


