Re: Wiping a disk clean

[Jeffrey Carter <spam@spam.com>]

Larry Hazel wrote:
> If I create a binary file, use sequential_io to write records of all 
> ones until Use_Error is raised.  Then, delete the file and repeat with 
> all zeros.
> Will the unused portion of the disk be wiped clean so that no one could 
> recover what was written there before?

Probably not. The US Govt requires 3 passes with specific patterns, and 
the most exhaustive study of the issue indicates that different 
approaches are required for different kinds of drives. For most modern 
disks, several passes with random data will suffice. "Several" is 
probably 5 or 6.

And that doesn't even get into the issues of whether Sequential_IO will 
write on all the unused portion of the disk, much less the unused parts 
of partially used sectors, and so on.

-- 
Jeff Carter
"You couldn't catch clap in a brothel, silly English K...niggets."
Monty Python & the Holy Grail
19