<s>
The	O
Gutmann	B-Algorithm
method	I-Algorithm
is	O
an	O
algorithm	O
for	O
securely	O
erasing	O
the	O
contents	O
of	O
computer	O
hard	B-Device
disk	I-Device
drives	I-Device
,	O
such	O
as	O
files	O
.	O
</s>
<s>
Most	O
of	O
the	O
patterns	O
in	O
the	O
Gutmann	B-Algorithm
method	I-Algorithm
were	O
designed	O
for	O
older	O
MFM/RLL	O
encoded	O
disks	O
.	O
</s>
<s>
Since	O
about	O
2001	O
,	O
some	O
ATA	B-Protocol
IDE	I-Protocol
and	O
SATA	O
hard	B-Device
drive	I-Device
manufacturer	O
designs	O
include	O
support	O
for	O
the	O
ATA	O
Secure	O
Erase	O
standard	O
,	O
obviating	O
the	O
need	O
to	O
apply	O
the	O
Gutmann	B-Algorithm
method	I-Algorithm
when	O
erasing	O
an	O
entire	O
drive	O
.	O
</s>
<s>
Each	O
of	O
patterns	O
5	O
to	O
31	O
was	O
designed	O
with	O
a	O
specific	O
magnetic	B-Architecture
media	I-Architecture
encoding	O
scheme	O
in	O
mind	O
,	O
which	O
each	O
pattern	O
targets	O
.	O
</s>
<s>
The	O
delete	O
function	O
in	O
most	O
operating	B-General_Concept
systems	I-General_Concept
simply	O
marks	O
the	O
space	O
occupied	O
by	O
the	O
file	B-Operating_System
as	O
reusable	O
(	O
removes	O
the	O
pointer	O
to	O
the	O
file	B-Operating_System
)	O
without	O
immediately	O
removing	O
any	O
of	O
its	O
contents	O
.	O
</s>
<s>
At	O
this	O
point	O
the	O
file	B-Operating_System
can	O
be	O
fairly	O
easily	O
recovered	O
by	O
numerous	O
recovery	O
applications	O
.	O
</s>
<s>
Gutmann	O
claims	O
that	O
intelligence	O
agencies	O
have	O
sophisticated	O
tools	O
,	O
including	O
magnetic	O
force	O
microscopes	O
,	O
which	O
together	O
with	O
image	B-General_Concept
analysis	I-General_Concept
,	O
can	O
detect	O
the	O
previous	O
values	O
of	O
bits	O
on	O
the	O
affected	O
area	O
of	O
the	O
media	O
(	O
for	O
example	O
hard	B-Device
disk	I-Device
)	O
.	O
</s>
