Final answer:
A head crash in a hard disk drive occurs when the read/write head touches the spinning platter, often causing data loss. Modern hard drives use giant magnetoresistance for reading data, a significant advancement in nanotechnology compared to the older induction-based read heads.
Step-by-step explanation:
A head crash refers to an event in computing where the read/write head of a hard disk drive touches the spinning platter, usually resulting in damage or data loss. In earlier hard drives, read heads operated based on the principle of magnetic induction, but modern drives commonly use giant magnetoresistance (GMR) for reading data. GMR is a phenomenon where weak changes in a magnetic field cause larger changes in electrical resistance, a breakthrough in nanotechnology.
Recorded data on hard drives are digital, in the form of a series of 0's and 1's written onto the spinning disk coated with a magnetic material. This process is similar to how the magnetic stripe on your credit card stores data, using the same principle of magnetic induction to read and write personal information. Figure 12.28 illustrates the inside of a hard drive, emphasizing the importance of the separation between the read/write head and the platter to avoid a head crash.