Levymuisti

Levymuisti refers to any data storage device that uses a physical medium to store information, typically in a magnetic or optical form. This contrasts with semiconductor memory, such as RAM, which relies on electronic circuits. Early forms of levymuisti included magnetic tape, which was sequential access, meaning data had to be read in order. The development of the hard disk drive (HDD) revolutionized storage by introducing random access, allowing the read/write head to move directly to any location on the disk.

Hard disk drives store data on rotating platters coated with magnetic material. A read/write head hovers just above the surface of these platters, magnetizing or detecting the magnetic orientation of tiny areas to represent binary data (0s and 1s). The speed of a hard drive is determined by factors like its rotational speed (RPM) and the data transfer rate.

Optical media, such as CDs, DVDs, and Blu-ray discs, are another form of levymuisti. These store data by burning microscopic pits and lands onto a reflective surface, which are then read by a laser. While offering high storage densities, optical drives are generally slower than HDDs and are becoming less common for primary storage due to the rise of solid-state drives (SSDs). SSDs, while not strictly levymuisti in the traditional sense as they have no moving parts, are often discussed alongside them as modern storage solutions, offering significantly faster access times.