I have not used this but as far as i can remember this is used for paging. 

Some one told me long time back that when u design games, u use video 
paging to speed up the display. what happens is u populate a page in the background
and u flip so as to avoid snowing and other assmebly lanauge 
related problems. 

I have not done it but if u get stuck send me a mail I will be more than happy to help u 
my email address is on the contact page. 

INT 10 - VIDEO -  SELECT ACTIVE DISPLAY PAGE
	AH = 05h
	AL = new page number (00h to number of pages - 1) (see #0009)
Desc:	specify which of possibly multiple display pages will be visible
Note:	to determine whether the requested page actually exists, use AH=0Fh
	  to query the current page after making this call
SeeAlso: AH=0Fh,AH=43h,AH=45h