From Newsgroup: comp.sys.ibm.ps2.hardware

A bit more detail, but nothing technical, 'natch...

https://www.ibm.com/docs/en/announcements/archive/ENUSZG94-0485

Multiple XGA Support
The minimum system requirements for Multiple XGA software are as follows:

One of the following computer systems:
If you are using Microchannel(*) XGA display adapters, you must use an
IBM or IBM-compatible Microchannel computer with at least two XGA
graphics hardware packages (on the system board or on separate adapters,
or both), one of which must be XGA-2 level.
If you are using ISA XGA-2 display adapters, you must use a
ValuePoint(*) or compatible ISA-bus computer with at least two XGA-2
graphics hardware packages (on the system board or on separate adapters,
or both), one of which must be XGA-2 level.
The Multiple XGA-2 device drivers operate with XGA-1 and XGA-2 adapters installed in your computer or with an XGA-1 or XGA-2 installed on the
system board (instead of a separate adapter), or both. At least one
XGA-2 must be present in the computer either on the system board or on a separate adapter. When the display device drivers are installed in a
computer that contains a mix of XGA-1 and XGA-2 technologies, the
display device drivers will always default to the resolution and color
depth of the lowest level XGA available. If you have a display that is
capable of a high resolution and another display that is not capable of
as high a resolution, selection of the higher resolution will be ignored.
With Multiple XGA support, you can use a maximum of eight displays in
various horizontal and vertical configurations, that is, set up side by
side, stacked, or a combination of both. Depending on the number of
XGA's installed and displays attached, the following configurations of displays are available:

Side by side: 2x1, 3x1, 4x1, 5x1, 6x1, 7x1, 8x1
Stacked: 1x2, 1x3, 1x4, 1x5, 1x6, 1x7, 1x8
Side by side and stacked: 2x2, 2x3, 3x2, 2x4, 4x2
Note: a 1x2 configuration is two displays, one stacked on top of the
other. A 3x1 configuration is three displays, placed side by side.

The following colors and resolutions are available:

COLORS RESOLUTION CHOICES

64K 640x480, 800x600
256 640x480, 800x600, 1024x768, 1104x828
16 1280x960, 1280x1024, 1360x1024
The effective resolution is the number of pixels you have in both the horizontal and vertical directions. The effective resolution is the
result of multiplying the horizontal and vertical resolutions by the
number of XGA's installed and the number of displays attached. For
example, a 4x2 display configuration operating at 1104x828 by 246 colors
will provide an effective resolution of 4416x1656 by 256 colors.
Resolutions other than 640x480 and 1024x768, as well as the 64K color
option, are available only if the system is using all XGA-2's (either on
the system board or on a separate adapter, or both).

Software Requirements
OS/2 2.1 or later versions (OS/2 Desktop or WIN OS/2 session)
DOS with Windows 3.1
DMQS (Display Modem Query/Set) Program files are required by XGA
software shipped with the hardware and by Multiple XGA support.
Compatibility
The IBM Multiple XGA Display Device Drivers will run in any environment
in which the corresponding XGA-2 Device Drivers operate (OS/2 2.1 or
Windows 3.1)
The IBM Multiple XGA Display Device Drivers will support the following products from Nth Graphics which have two complete XGA-2 chip sets on a
single graphics card:
NAT01 - MCA with 1MB or VRAM
NAT02 - ISA with 1MB OF VRAM
NAT03 - MCA with 2MB of VRAM
NAT04 - ISA with 2MB of VRAM
It is possible to install as many as four of these cards in an ISA bus
PC (AT bus) or MCA bus computer to obtain eight accelerated graphics
displays operating in one PC.

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