In 1973, IBM introduced the IBM 3340 "Winchester" disk drive and the 3348 data module, the first significant commercial use of low mass and low load heads with lubricated platters and the last IBM disk drive with removable media. This technology and its derivatives remained the standard through 2011. Project head Kenneth Haughton named it after the Winchester 30-30 rifle because it was planned to have two 30 MB spindles; however, the actual product shipped with two spindles for data modules of either 35 MB or 70 MB.
A Winchester disk drive system, such as the one in your personal computer, is only one of a family of disk systems generally called hard disks. The disk itself is a carefully machined and polished nonmagnetic metal platter coated with a magnetic material, similar to that used by floppy disks and audio or video tape. Hard disks come in a variety of sizes, capacities, and configurations. Many have multiple disks and some even are removable, being enclosed in "disk packs," or "cartridges." The read/write head (which records and reads information to and from the surface of the disk) floats on a cushion of air above the disk as it turns. The distance between the head and the surface is so small that even a tiny smoke particle could cause irreparable damage to the disk. For this reason, most disks, including your Winchester disk system, are sealed against contamination.