Method and apparatus for sanitization of fixed storage devices

A method for sanitization of a fixed storage device, the fixed storage device interfaced to a computer system, comprising:

• booting the computer system from a removable storage device, the removable storage device holding a bootable disk operating system and program code that is executed within the bootable disk operating system;
• taking control of the computer system by the bootable disk operating system,
• detecting the fixed storage device interfaced to the computer system;
• and
• overwriting writeable space of the fixed storage device with a plurality of overwrite layers;
• wherein overwriting is accomplished using a plurality of patterns, each layer having an associated pattern, to ensure that data can not be recovered even by destructive analysis;
• and
• wherein sanitizing comprises:
• addressing a last set of allocations on the fixed storage device;
• writing a current overwrite pattern to the addressed set of allocations;
• checking whether a write error occurred and, if so, adding the error to a list;
• reading data from the addressed set of allocations and comparing the data with expected data;
• if any of the data read is not accurate, adding bad sectors to a list of bad sectors;
• checking whether there are more allocations to be overwritten and, if so, addressing the next set of allocations and repeating writing, checking, reading and adding at the next set of allocations;
• and
• if there are no more allocations for a current overwrite layer, checking whether there are more overwrite layers to be performed and, if so, repeating writing, checking, reading, adding and checking.