Erase Methods

When using One Pass Zeros or One Pass Random standard, the number of passes is fixed and cannot be changed. When the write head passes through a sector, it writes only zeros or a series of random characters.

The write head passes over each sector three times. The first time with zeros 0x00, second time with 0xFF and the third time with random characters. There is one final pass to verify random characters by reading.

The write head passes over each sector, writing a random character. On the next pass, writes the compliment of previously written character. Final pass is random, proceeded by a verify.

The write head passes over each sector seven times (0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, random). There is one final pass to verify random characters by reading.

Baseline method overwrites disk's surface with just zeros 0x00. There is one final pass to verify random characters by reading.

Enhanced method - the write head passes over each sector three times. The first time with zeros 0x00, second time with 0xFF and the third time with random characters. There is one final pass to verify random characters by reading.

The write head passes over each sector two times: 0x00, Random. There is one final pass to verify random characters by reading.

The write head passes over each sector three times. The first time with 0xFF, second time with zeros 0x00 and the third time with random characters. There is one final pass to verify random characters by reading.

The write head passes over each sector three times. The first time with random characters, second time with zeros 0x00 and the third time with 0xFF. There is one final pass to verify random characters by reading.

RL method - the write head passes over each sector three times: 0x01, 0x27FFFFFF, Random. There is one final pass to verify random characters by reading.

The write head passes over each sector three times: 0x00, 0xFF, Random. There is one final pass to verify random characters by reading.

The write head passes over each sector two times: Random, Random. There is one final pass to verify random characters by reading.

Supported three NIST 800-88 media sanitation standards:

• 1. The write head passes over each sector one time (0x00).
• 2. The write head passes over each sector one time (Random).
• 3. The write head passes over each sector three times (0x00, 0xFF, Random).

For details about this,the most secure data clearing standard, you can read the original article at the link below: http://csrc.nist.gov/publications/nistpubs/800-88/NISTSP800-88_with-errata.pdf

The write head passes over each sector seven times.

The write head passes over each sector seven times: 0xFF, 0x00, Random, Random, Random, Random, Random. There is one final pass to verify random characters by reading.

The write head passes over each sector 35 times. For details about this, the most secure data clearing standard, you can read the original article: http://www.cs.auckland.ac.nz/%7Epgut001/pubs/se%0Acure_del.html

The write head passes over each sector once with random characters. There is one final pass to verify random characters by reading.

According to National Institute of Standards and Technology (NIST) Special Publication 800-88: Guidelines for Media Sanitation, Secure Erase is "An overwrite technology using firmware based process to overwrite a hard drive. Is a drive command defined in the ANSI ATA and SCSI disk drive interface specifications, which runs inside drive hardware. It completes in about 1/8 the time of 5220 block erasure." The guidelines also state that "degaussing and executing the firmware Secure Erase command (for ATA drives only) are acceptable methods for purging." ATA Secure Erase (SE) is designed for SSD controllers. The SSD controller resets all memory cells making them empty. In fact, this method restores the SSD to the factory state, not only deleting data but also returning the original performance. When implemented correctly, this standard processes all memory, including service areas and protected sectors.

User indicates the number of times the write head passes over each sector. Each overwriting pass is performed with a buffer containing user-defined or random characters. User Defined method allows to define any kind of new erase algorithms based on user requirements.