https://rein.kr/posts/2013-01-16-linux-%EB%8D%B0%EC%8A%A4%ED%81%AC%ED%83%91%EC%97%90-ssd-hdd-%EA%B5%AC%EC%84%B1%EC%9D%B4%EB%A9%B4-%ED%8C%8C%ED%8B%B0%EC%85%98%EC%9D%80-%EC%96%B4%EB%96%BB%EA%B2%8C/