Released April 2008
XGA208 is a major improvement of the XGA206 display driver for the IBM XGA/XGA-2 display adapters. XGA208 enables coprocessor support for graphics operations at 16 colors and adds several new high resolution display modes up to 1600x1200 on the XGA-2 display adapter.
XGA208 introduces for the first time the 800x600 and 832x620 screen resolutions with 256 and 64K colors (High Color) on the original IBM XGA display adapter. These new XGA modes are supported driver-worldwide only by the XGA208, which is a truly remarkable and unique achievement.
XGA208 successfully passed Microsoft's Display Compatibility Test.
• Download XGA208 Display Driver for Windows 95/98.
Extended Graphics Modes
The IBM XGA and XGA-2 adapters do not contain built-in or BIOS-selectable Extended Graphics Modes. Such modes must be individually programmed by setting some 60 hardware registers to computed mode parameters. Under the DMQS (Display Mode Query and Set) mode of operation on the XGA-2, display mode parameters are read from a specific monitor definition file which was usually supplied by IBM or the monitor vendor. XGA208 does not implement or support the DMQS mode of operation and no monitor definition files are necessary.
The XGA-2 display adapter is a completely programmable device, while the XGA is limited by the fixed PEL rates. XGA208 uses manually computed monitor timings, or display mode settings, which require assumed monitor specifications. EIZO FlexScan T56S was used as a reference monitor. All XGA208 display modes do not require any adjustment on the EIZO FlexScan T56S. Your monitor, however, may eventually need some adjustment.
The XGA208 mode timings differ from the XGA206 timings, you may experience a change in the viewing comfort when you upgrade to XGA208. Display modes with resolutions above 1280x1024 are of course intended for the newer LCD monitors.
Supported Resolutions and Color Depths
The following table lists the specifications of the supported XGA208 display modes for the IBM XGA-2 Display Adapter. Video mode numbers above 160 designate the XGA208 non-VESA display modes. Where a specific monitor type is given, the mode is optimized for this specific monitor to provide the best viewing results on it.
* = Uses high PEL rate. Some XGA-2 adapters may not be
able to function without errors. Do not use the mode if you wish to strictly
comply with the IBM specifications published in 1992.
The following table lists the specifications of the supported XGA208 display modes for the IBM XGA Display Adapter. Video mode numbers above 160 designate the XGA208 non-VESA display modes.
* = Introduced for the first time with the XGA208
display driver. These mode and color depth combinations are totally absent in
the IBM technical specifications. The XGA technical reference specifies 65536
colors only for the 640x480 VGA resolution.
XGA208 Windows NT Miniport Display Driver
The XGA208 Windows NT Video Miniport Driver for the XGA/XGA-2 display adapters is intended to provide the video hardware interface services for the Windows NT XGA display driver. The XGA208 miniport supports all display modes as listed above and implemented by the XGA208 Windows 95/98 driver. However, the Windows NT XGA driver selects only the 256 color modes, apparently because it is not designed to support and work with 64K colors (High Color) modes.
The main benefit of using XGA208 on Windows NT are thus the higher refresh rates. The XGA208 Windows NT display driver is currently under development.
• Download XGA208 Miniport Driver for Windows NT.
I would like to express my best thanks to Jim Shorney and William R. Walsh for their enthusiastic support and invaluable work in testing the driver and validating the display modes. Special thanks to all members of comp.sys.ibm.ps2.hardware who participated in the discussion with constructive suggestions and opinions through public postings and private mails.
Very special thanks to Peter Wendt for providing the IBM XGA Technical Reference without which the XGA206/208 development would have been virtually impossible.
Authentic user reports and excerpts from the message exchanges are included in the download package.
The XGA208 Windows NT miniport does not currently support full screen DOS modes. Please report any other problems or bugs.