Waiting after Yellow and Hard Cheese

Is it necessary to wait 6 hours after eating yellow or hard cheese before eating meat?

One must wait after yellow cheese, but there is no need to wait after hard cheese.

The Rema in Siman P"T S"B wrote: "There are those who are stringent even with meat after cheese (Mordechai in the name of Maharam and Beit Yosef in Orach Chaim Siman K"G), and it is customary that if the cheese is hard, they do not eat even poultry after it, like cheese after meat (and so it is in the Zohar). There are those who are lenient, and one should not protest, only that they should do rinsing and washing of hands, but it is good to be stringent, and this is that the Rema was stringent specifically with hard cheese, but with cheese that is not hard, he was not stringent about waiting at all, only rinsing and washing. In Beit Yosef, it is brought in the name of the Zohar not to eat cheese and meat in one meal and at one time, and the poskim wrote that one who wants to be concerned for the Zohar should wait about half an hour between milk and meat. Nevertheless, in the definition of hard cheese in Shach Yoreh Deah Siman PT S"K T"V, it is written that if it is old six months, it is considered hard, and in Taz there S"D it is written that hard cheese is cheese with worms. And they argue whether to be concerned for Rambam that it might get stuck between the teeth like meat, or like Rashi that it leaves a taste. Nevertheless, the opinion of our teacher, the Gaon Rabbi Ovadia Fried, shlita, is that yellow cheese should be considered hard cheese, and although its production does not take half a year, nevertheless, one should be concerned that due to the machines today, they manage to produce in a few hours what used to take six months, and one should be concerned that it might get stuck between the teeth, but with Tzfatit and Bulgarian cheese and the like, there is no such concern.