declaration

I'm a novice..now i'm learning how to write a graphic program in C. I've browsed through the Web http://www.brackeen.com/home/vga/basics.html
and got stuck with these declarations :

typedef unsigned char byte;

byte far *VGA = (byte far*)0xA0000000L;

please help me.........i got an assignment from my lecturer that is too hard for me

typedef unsigned char byte;

this tells the compiler that byte is an alias for an unsigned char.

byte far *VGA = (byte far*)0xA0000000L;

far means that the memory address is a segment:offset address rather than a near pointer which is just an offset address.

(byte far*) is a cast.

0xA0000000L is the start of the video memory on vga systems.