Format of XGA information buffer:
Offset	Size	Description	)
 00h  4 BYTEs	signature ("VESA")
 04h	WORD	VESA version number
 06h	DWORD	pointer to ASCIZ OEM string
 0Ah	DWORD	environment flags (see #00070)
 0Eh	WORD	number of XGA adapters installed (other VESA XGA functions
		  require a handle indicating which adapter to use)
 10h 240 BYTEs	reserved