† Video Graphics Array (VGA): A standard 80x86 video architecture to properly display text and graphics on PCs, compatible with all modern BIOSs and graphics adapters/accelerators. It provides the following video modes:

Text (rows x columns):

• 40x25, 80x25 (CGA), 80x43 (EGA), 80x50 (VGA); 16 colors, indexed RGB/2 palette;

Graphics (pixel width x height):

• 640x350 (EGA); 16 colors, indexed RGB/2 palette;

• 640x480 (VGA); 16 colors, indexed RGB/6 palette;

• 320x200 (MCGA); 256 colors, indexed RGB/6 palette.

Tweaking with the VGA BIOS, other non-standard video modes can be achieved, like 80x28 text mode and Mode-X 320x240, 640x400 256-colors graphics modes.
Since all modern PCs support the aforementioned VGA BIOS modes, whereas higher-resolution, broader-palette video modes§ have to be set using additional, hardware-specific low-level code , currently up-to-date Operating Systems employ them for their installers and boot loaders/screens. This happens both for compatibility issues with every possible video hardware and for code compactness' sake of such delicate, early-execution programs.
For example, Windows^® 9x uses Mode-X 320x240x256 graphics mode; Windows^® 200x/ME/XP and most Linux distributions use VGA 640x480x16 graphics (used for the Linux FrameBuffer) and 80x50 text modes.


‡ e.g. consult [link] and [link]


* Technical note: Remember that such bitmaps, as they are stored within \ntoskrnl.exe, both have the palette set to “all black” (i.e. all 16 colours set to #000000₁₆), whereas their unique palette is stored in a separate object within the executable (cfr. previous note links for more information). The reason for that is because the boot screens fades in at the beginning from an all-black screen, so the bitmap palette is loaded separately.

§ Such as those video modes with more simultaneously-displayable colors, like HiColor or TrueColor RGB/8, RGBA/8 and better modes (with either 15, 16, 24 or 32 bits per pixel instead of 8bpp).