Physical destruction is the premier option for data destruction on magnetic media, of which there are two methods: crushing and shredding. HDD crushers use powerful force applied to the drive chassis to buckle and/or pierce it. The internal platters and read/write heads are damaged beyond reasonable recovery methods, making the drive inoperable. HDD shredders utilize large, rugged cutting heads that rip drives to shreds as they enter the cutting mechanism. Resulting shred sizes depend on device specifications and regulatory requirements. Typically, crushers are used in lower volume applications of less than 100 drives per day. Shredders are larger, faster machines that can be operated continuously over a long period of time, making them ideal for higher volume destruction applications.
For most magnetic media, a crusher or shredder used on its own is acceptable. However, for classified information or additional security, drives must be degaussed prior to crushing or shredding. This two-step approach to data sanitization is mandated by the Department of Defense for classified data, and security-focused data centers also implement this best practice for end-of-life data destruction.