How do hard drives work? - Kanawat Senanan

The modern hard drive boasts an impressive storage capacity, able to hold more information than many libraries combined. This is achieved through the use of high-speed spinning discs and a recording head that writes and reads data as magnetic patterns formed by tiny metal grains. Each group of grains represents either a zero or a one, and innovative techniques are employed to pack these bits closely together and filter out noise. Despite their small size, these grains can hold vast amounts of information, with the current limit being approximately 1 terabit per square inch.However, as hard drives continue to shrink, they face a new challenge known as the super-paramagnetic effect, which can cause bits to switch unintentionally due to heat energy. To overcome this limitation, scientists have altered the direction of recording from longitudinal to perpendicular, allowing aerial density to approach 20 terabits per square inch or more. Future advancements are expected with bit-patterned media, which could potentially allow for even higher storage capacities.