my @what = qw( bothChaff bothDegen oneChaff oneDegen );

open my $fh, ">", "data.data" or die;

for ( 10000000 .. 99999999 )
{
    next if rand(10) > 6.7;
    print $fh sprintf("11010%d\t11010%d\t%s\n",
                      $_, $_+3333, $what[rand@what]);
    last if -s $fh > 1_000 * 1_000 * 1_000;
}