Magnetic imaging on a spin-stand

Abstract

A new technique of magnetic imaging on a spin stand has been developed. In this technique, raw image acquisition is performed by scanning a target area of a disk by a conventional magneto-resistive (MR) read head in two orthogonal (along- and cross-track) directions. Due to the nonlocalized nature of the MR reading head in the cross-track direction, image reconstruction is needed in order to retrieve the actual distribution of magnetization. It is demonstrated that the image reconstruction can be performed by using the response function characterization of the MR head and the specially designed deconvolution technique, which yields the curl-free (field producing) component of magnetization. The technique developed is illustrated by the sample examples of imaging of overwritten tracks with small misregistrations.

Extraction of the response function of GMR head for spin-stand imaging

“…R ECENTLY, a new technique of magnetic imaging on a spin-stand has been proposed [1]- [4]. The effectiveness of this technique has been demonstrated in a series of experiments.…”

A survey of confidential data storage and deletion methods

“…For example, when a zero overwrites a one, the actual value will become .95 and when a one overwrites a one it will be 1.05. Another approach is to use a spin-stand to collect several concentric and radial magnetic surface images, which can be processed to form a single surface image [Mayergoyz et al 2000]. A less well-funded attacker can resort to many drive-independent data recovery techniques [Sobey et al 2006], which may be used on most hard drives independently of their make.…”

Secure deletion for NAND flash file system

“…In the case of magnetic media such as a hard disk, a file can still be recovered even if the data of the file is overwritten [13]. Therefore, many secure deletion methods for magnetic media delete files by overwriting multiple times [2,10].…”