How Do Hard Drives Get 'Scratched'?

The latest news on ex-IRS official Lois Lerner's conveniently vanishing email records is that her computer hard drive was only scratched, reports Patrick Howley @ Daily Caller.

Ex-IRS official Lois Lerner’s computer hard drive was “scratched” and the data on it was still recoverable. But the IRS did not try to recover the data from Lerner’s hard drive, despite recommendations from in-house IRS IT experts to outsource the recovery project.

The hard drive was then “shredded,” according to a court filing the IRS made to House Ways and Means Committee investigators.

CDs get scratched, but how do computer hard drives cocooned inside hard-cased CPUs and protected from human handling get scratched?

Apparently that question is being pondered by members of the U.S. House Ways and Means Committee, which noted in its July 22 press release:

It is also unknown whether the scratch was accidental or deliberate ...