VGA Resources

This wiki
Google Search "VGA registers programming",
OSD: Graphics From Chris Giese, containing many code snippets.
Tutorial on VGA graphics including basis of font and line rendering, palette setting, unchained mode, etc.
FlingOS VGA Driver has a good (low-performance but easy to read, protected-mode) VGA driver supporting text and graphical modes

Graphics Registers -- control the way the CPU accesses video RAM.
Sequencer Registers -- control how video data is sent to the DAC.
Attribute Controller Registers -- selects the 16 color and 64 color palettes used for EGA/CGA compatibility.
CRT Controller Registers -- control how the video is output to the display.
Color Registers -- selects the 256 color palette from the maximum possible colors.
External Registers -- miscellaneous registers used to control video operation.

SVGA resources

The VESA home page: http://www.vesa.org
Emulating VESA calls from protected mode: Virtual 8086 Mode, or use a library like libx86emu. Xfree86 used this code to access VESA functions on Linux.

90x60 text mode from Chris Giese <geezer@execpc.com>
Changing text/graphic mode and fonts -- this also has code for switching video modes without bios