procedure errormsg( x : byte);
begin
   writeln;
   case x of
      0   : writeln('No error.');
      1   : writeln('Bad command.');
      2   : writeln('Bad address mark.');
      3   : writeln('Write-protected disk.');
      4   : writeln('Record not found.');
      5   : writeln('Controller reset failed.');
      7   : writeln('Controller won''t accept drive parameters.');
      8   : writeln('DMA overrun.');
      9   : writeln('DMA bounds error.');
      $0b : writeln('Bad track flag found.');
      $10 : writeln('Bad CRC on disk read.');
      $11 : writeln('Recoverable ECC error.');
      $20 : writeln('Disk controller chip failure.');
      $40 : writeln('Bad seek.');
      $80 : writeln('Time out error.');
      $BB : writeln('Undefined error.');
      $ff : writeln('Sense Drive Status failure.');
    end;
    writeln;
 end; { error msg }


procedure setparmptr( x : paramptr );
   var y : Registers;
begin
   y.ah:=setintrp ;
   y.al:=disktable;
   y.dx:=ofs( x^);
   y.ds:=seg(x^);
   msdos(Dos.Registers(y));  { set the interrupt  block to point to our block }
end; { set }

procedure getparmptr( var x : paramptr );
   var y : Registers;
begin
   y.ah:= getintrp;
   y.al:=disktable;
   msdos(Dos.Registers(y));
   x:= ptr(y.es,y.bx);
end; { getpar }

procedure smooth;
{ have to get this to be only exit }
{ and make sure it restores disk params to normal }
begin
  setparmptr(oldROMparms);
end; { smoothexit }