16-Bit SVGA Graphics Adapter  (250-4056)  Hints & Tips  Faxback Doc. # 2160

Systems with two Display Adapters:

If your system has more than one display board, only one can be a color dis-
play adapter. The Super VGA adapter will always function as the primary video
adapter. The other display adapter must be a digital monochrome display adap-
ter, or a special-purpose, non-IBM compatible, adapter card. One exception to
this rule is that the Super VGA adapter is compatible with 8514/A, TIGA and
most other coprocessor adapters.

If the Super VGA adapter is attached to a color monitor, the second adapter
must be a monochrome/printer adapter, not a graphics adapter, to avoid UNPRE-
DICTABLE RESULTS. UNPREDICTABLE RESULTS are usually caused by display adapters
using the same video memory addresses and/or attempting to perform functions
that have not been designed into the adapters.

NOTE: High Resolution display modes might not function with an early revision
of the Hercules Graphics Card (or compatible) installed. If you will be using
the Super VGA adapter in a system with a Hercules graphics adapter, configure
the Hercules card as a monochrome text adapter.

Other IBM PC/XT/AT Adapter Boards:

Some adapters might present potential memory addressing conflicts for users
when installed in a system with the Super VGA adapter. The Super VGA adapter
uses memory in segments A000-BFFF (Hex) for video buffer area. The entirety of
segment A000-AFFF is used in enhanced graphics display modes. All alphanumeric
(text) display modes use 32KB in segment B000-BFFF. Other video adapters and
some memory boards (including EMS and EEMS memory adapters) might also use me-
mory in these segments and might cause memory conflicts due to duplicate ad-
dressing. These memory conflicts can cause the Super VGA adapter to operate
incorrectly or cause a system hang up. Refer to the documentation of your
other equipment for alternative memory addressing if this condition is sus-
pected.