I get what Turbo Vision is (was), but what's that B800 thing? Surely you aren't talking about a Celeron processor? Seems tricky to google, also no Wiki page on that. You got me curious, plz spill it! =)
0xb800 is the address of the framebuffer for text. Simply write characters to that address, using offset `((row * width) + col)` and they'll appear on screen.
In graphics mode it was, IIRC, 0xa000. I once wrote a pacman-type easter egg inside the point-of-sale system[1], because doing direct graphics straight to an address is so easy and simple.
[1] Was removed after pilot and before actual release.
In real mode addressing and graphic card in text mode, your video memory started at absolute address 0xb800:0x0000. It was an two-dimensional array, where you could poke and whatever you changed here, was reflected immediately on the display. Each element of the array was two bytes: character itself and color attributes.
