80x25 VGA Text Mode

80x25 VGA text mode is the standard video mode that all VGA-equipped x86 PC's start up in. It is the "default" mode in the x86 PC BIOS and is likely to be supported by any PC you come across.

This mode is great for PC's used as text terminals. It's fast, supports full ANSI color, and preserves that "old-school-PC" look.

80x25 VGA Text Mode is the default display mode for most (all?) PCs. In fact, I think it's the same as the 80x25 EGA Text Mode. It features 16 foreground colors and 8 background colors + blinking foreground text, or 16 foreground colors and 16 background colors.

The display memory is available on address b800h:0000h in 16-bit real mode. Every even byte is a 8-bit (extended) ascii character value and every odd byte is the corresponding attribute byte (4 bits for background color, 4 bits for foreground color).

The above writeup says the display supports ANSI color; this does not mean the display supports ANSI escape codes. The normal VGA BIOS does not have support for that, you need to load the ANSI.SYS device driver in DOS. Modern operating systems like Linux and FreeBSD's virtual consoles have built-in ANSI escape code support and operate in 80x25 by default.

Most of the VGA card hardware registers work even while in text mode, so you can do quite a bit of fancy stuff, such as using the VGA hardware split screen function, redefine the character set, reprogram various counters to boost the resolution, and so on.