procedure set_dta;
begin
{-- Set DTA address --}
  pointer := addr(dta_area);
  r.ds := seg(pointer^);
  r.dx := ofs(pointer^);
  r.ax := $1A shl 8;
  MsDos(R);
end;

procedure get_dta;
begin
{-- Get DTA address in ES:BX --}
  r.ax := 0;
  r.es := 0;
  r.bx := 0;
  r.ax := $2F shl 8;
  MsDos(R);
  dta := ptr(r.es,r.bx);
end;

procedure set_fcb;
begin
{-- Set up an unopened FCB --}
  for x := -7 to 36 do fcb[x] := #0;
  fcb[-7] := #255;
  fcb[-1] := #0;
  filez := '*.*' + #0;
  pointer := addr(filez[1]);
  r.ds := seg(pointer^);
  r.si := ofs(pointer^);
  pointer := addr(fcb[0]);
  r.es := seg(pointer^);
  r.di := ofs(pointer^);
  r.ax := $29 shl 8;
  msdos(R);
  set_dta;
  get_dta;
end;

procedure msdos12;
begin
  set_dta;
  pointer := addr(fcb[-7]);
  r.ds := seg(pointer^);
  r.dx := ofs(pointer^);
  r.ax := $12 shl 8;         { go after the next matching entry }
  msdos(R);
end;

procedure msdos11(x : integer);
begin
  set_fcb;
  fcb[-7] := #255;
  fcb[-1] := chr(x);
  pointer := addr(fcb[-7]);
  r.ds := seg(pointer^);
  r.dx := ofs(pointer^);
  r.ax := $11 shl 8;
  msdos(R);
end;
  dta_area                      : array [1..130] of byte;
  fcb                           : array [-7..36] of char;
type  mem_ptr      = ^pointer_type;
  pointer_type = array [1..2] of integer;
var  pointer,dta,fcb_addr          : mem_ptr;
a