Disk Write Methods
February 22, 2010
| Writing method | Write / Read Passes | Description | Ref: |
| Overwriting with Zero data. | 1 | Write each byte to 0x00. | |
| Overwriting with Random data. | 1 | Write each byte to random data or pseudo-random data. | |
| U.S. Government DoD 5220.22-M | 4 | Pass 1, Random data; Pass 2, Bit-wise complement of 1st pass data; Pass 3, Random data again Pass 4, Read verify |
[xxx] |
| U.S. Government NAVSO P-5239-26 (RLL) | 4 | Pass 1, 0x01 to all bytes. Pass 2, 0x27FFFFFF byte pattern. Pass 3, Random data: Pass 4, Read verify |
[xxx] |
| U.S. Government NAVSO P-5239-26 (MFM) | 4 | Pass 1, 0x01 to all bytes. Pass 2, 0x7FFFFFFF byte pattern. Pass 3, Random data: Pass 4, Read verify |
[xxx] |
| German standard: VSITR | 7 | Pass 1 thru 6, alternate sequences of 0x00 and 0xFF. Pass 7, write to 0xAA |
[xxx] |
| Russian standard: GOST P50739-95 | 1 | Overwrite each byte with 0x00 or random data sequence. | [xxx] |
| B. Schneier method | 7 | Pass 1, 0xFF to all bytes Pass 2, 0x00 Pass 3 thru 7, separate passes with encrypted random data. |
[xxx] |