A: Here is a simple 
outline for storing and restoring a text mode
screen in the standard 80 x 25 mode. Note that the code below is
incomplete in a sense that it works for a color monitor only,
because the monochrome screen address is $B000:$0000.
   For storing and restoring the graphics screen see Ohlsen & 
Stoker
(1989), Turbo Pascal Advanced Techniques, Que, pp 333-337.
  uses Crt;
  type ScreenType = array [1..4000] of byte;        (* 2 x 80 x 25 *)
  var ColorScreen : ScreenType Absolute $B800:$0000;
      SavedScreen : ScreenType;
      posx, posy : byte;
  begin
    SavedScreen := ColorScreen;      (* Save the screen *)
    posx := WhereX; posy := WhereY;  (* Save the cursor position *)
    writeln ('A simple demo storing and restoring the color text 
screen');
    writeln ('By Prof. Timo Salmi, ts@uwasa.fi');
    writeln; write ('Press <-'''); readln;
    ColorScreen := SavedScreen;   (* Restore the screen *)
    GotoXY(posx,posy);            (* Go to the stored cursor position *)
  end.
If you would prefer not using the Crt unit, you can apply 
WHEREXFN,
WHEREYFN, and GOATXY from TSUNTG.TPU from my units 
collection
ftp://garbo.uwasa.fi/pc/ts/tspa3470.zip.
   If you wish to test for the monitor type, that is choose between
$B800:$0000 and $B000:$0000 bases, you can use the following
function to test for the monochrome adapter.
  function MONOFN : boolean;
  var regs : registers;
  begin
    FillChar (regs, SizeOf(regs), 0);
    regs.ah := $0F;
    Intr ($10, regs);
    monofn := (regs.al = 7);
  end;  (* monofn *)