复制一个文件BlockRead,BlockWrite

procedure TForm1.Button1Click(Sender: TObject);
var
  FromF,ToF: file;
  NumRead,NumWritten: Integer;
  Buffer: array[1..2048] of Byte;
begin
  AssignFile(FromF, 'c:\temp\test1.dat'); //假定有这个文件
  Reset(FromF, 1);
  AssignFile(ToF, 'c:\temp\test2.dat');
  Rewrite(ToF, 1);

  repeat
    BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
    BlockWrite(ToF, Buffer, NumRead, NumWritten);
  until (NumRead = 0) or (NumWritten <> NumRead);
  { NumRead=0 表示读完了; NumWritten <> NumRead 表示磁盘空间不够了 }

  CloseFile(FromF);
  CloseFile(ToF);
end;