Erasing Data on Hard Disk Drives

Data erasure can at times be called data wiping or data cleaning, and is a software-based criteria for data overwriting which aims to totally destroy all electronic data on digital media such a hard disk drive (HDD). If one would like to delete all data residing on a HDD then they have to perform commands other than the basic ones for data deletion, for these just remove pointers that point to the HDD sectors and allow data recovery through use of software tools. As opposed to physical destruction and degaussing both of which completely make HDD unusable, data erasure completely removes data from a hard disk and allows reuse, thereby, saving resources and preserving the environment. The presence of new flash memories like USB flash drives and solid state drives may cause the data erasure techniques to terribly fail, thereby, allowing recovery of remnant data.

The software application for overwriting works by writing numerous meaningless pseudorandom data onto the entire hard disk. There are many differences between the other overwriting methods and data erasure, which is critical in determine that data is completely erased and cannot be retrieved no matter what. Most of the data eradication applications as well provide many overwrites to ensure they support the standards outlined by governments and the IT industry. If using good software, it will in the end verify that the data has been removed. Something required in order meet some special standards.

For a user to protect data on stolen or lost media they need data erasure applications to completely destroy the information on a hard disk provided they enter associated password and other personal data correctly. There is various data erasure tools targeting some type of data on your data for regular erasure, thus enabling protect sensitive information from getting hacked into, many users have found this efficient than software encryption. These days most HDD manufacturers inbuilt firmware/hardware encryption to their products, or/and integrated controllers and this has provided a perfect solution without compromising on performance.

Currently there are dedicated firmware or hardware encryption solutions which can do a 256-bit full AES encryption with sped higher that the ones with which drive electronics write data onto a hard disk. Drives with such capability are called self-encrypting drives (SEDs) and are common on the current enterprise-level laptops to protect data, most enterprises have adopted this new technology. If a user changes the encryption key, no other person can access any data stored on the associated SED, and this is the easiest and quickest method for erasing data. As much as theft of a SED results in loss of assets, the stored data is very secure as long as the key is changed or the one handling the SED does not know the key.

Many people users store a lot of sensitive information on the HDD or servers. Such information includes credit card numbers, medical records, social security numbers, classified information and bank details. Occasionally these may make their way onto media like REV drivers, USB, Jaz, flash, and Zip.

What creates a difference
Most of the software based data erasure technologies use special applications to write numerous zeroes and ones onto all hard drive sectors. The security level is dependent on the number of times the software writes over on the hard disk.

Full overwriting of a disk
There are so many overwriting programs in the market, however, a user can only be guaranteed if the software is able to completely destroy data written all over the hard drive. Good disk overwriting software should access the whole hard drive, including the locked or hidden areas such as device configuration overlay (DCO), host protected area (HPA), and mapped sectors, partially erase data, and leave some of the data intact. By accessing the whole HDD, data erasure completely eliminates chances of data remanence.

In some instances data erasure can bypass the OS and BIOS. Overwriting software programs operating through the OS and BIOS may not always completely erase data because of corrupted and altered BIOS data that may indicate a fully successful erasure even if they don’t fully access the hard disk, thus leaving data accessible.

Hardware support
If so many PCs are involves, the data erasure process can be deployed over an integrated network to help delete data simultaneously over many PCs as opposed to deleting theme separately. Compared to the DOS based overwriting software that may fail to detect the entire network hardware, Linux based erasure program supports storage area networks (SAN) and high-end-server environment that have hardware support for Serial Attached SCSI, Fiber Channel and Serial ATA remapped sectors and disks. It can directly operate with many vector sizes including 528, 524, and 520, thereby; eliminating need to first reformat to the usual 512 size.

Regulation and Standards
Governments and Industries have set standards for the software based overwriting for data removal. The major consideration for the standards is the number of times for rewriting the data. Some standards have a method for verifying the status of data removal and viewing the overwrite pattern.

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