<s>
A	O
kernel	B-Operating_System
debugger	I-Operating_System
is	O
a	O
debugger	B-Application
present	O
in	O
some	O
operating	B-Operating_System
system	I-Operating_System
kernels	I-Operating_System
to	O
ease	O
debugging	O
and	O
kernel	B-Operating_System
development	O
by	O
the	O
kernel	B-Operating_System
developers	O
.	O
</s>
<s>
A	O
kernel	B-Operating_System
debugger	I-Operating_System
might	O
be	O
a	O
stub	O
implementing	O
low-level	O
operations	O
,	O
with	O
a	O
full-blown	O
debugger	B-Application
such	O
as	O
GNU	B-Language
Debugger	I-Language
(	O
gdb	B-Language
)	O
,	O
running	O
on	O
another	O
machine	O
,	O
sending	O
commands	O
to	O
the	O
stub	O
over	O
a	O
serial	B-Protocol
line	I-Protocol
or	O
a	O
network	O
connection	O
,	O
or	O
it	O
might	O
provide	O
a	O
command	O
line	O
that	O
can	O
be	O
used	O
directly	O
on	O
the	O
machine	O
being	O
debugged	O
.	O
</s>
<s>
Operating	O
systems	O
and	O
operating	B-Operating_System
system	I-Operating_System
kernels	I-Operating_System
that	O
contain	O
a	O
kernel	B-Operating_System
debugger	I-Operating_System
:	O
</s>
<s>
The	O
Windows	B-Device
NT	I-Device
family	I-Device
includes	O
a	O
kernel	B-Operating_System
debugger	I-Operating_System
named	O
KD	O
,	O
which	O
can	O
act	O
as	O
a	O
local	O
debugger	B-Application
with	O
limited	O
capabilities	O
(	O
reading	O
and	O
writing	O
kernel	B-Operating_System
memory	O
,	O
and	O
setting	O
breakpoints	O
)	O
and	O
can	O
attach	O
to	O
a	O
remote	O
machine	O
over	O
a	O
serial	B-Protocol
line	I-Protocol
,	O
IEEE	B-Protocol
1394	I-Protocol
connection	O
,	O
USB	B-Protocol
2.0	I-Protocol
or	O
USB	B-Protocol
3.0	O
connection	O
.	O
</s>
<s>
The	O
WinDbg	B-Application
GUI	B-Application
debugger	B-Application
can	O
also	O
be	O
used	O
to	O
debug	O
kernels	B-Operating_System
on	O
local	O
and	O
remote	O
machines	O
.	O
</s>
<s>
BeOS	B-Application
and	O
Haiku	B-Language
include	O
a	O
kernel	B-Operating_System
debugger	I-Operating_System
usable	O
with	O
either	O
an	O
on-screen	O
console	O
or	O
over	O
a	O
serial	B-Protocol
line	I-Protocol
.	O
</s>
<s>
It	O
features	O
various	O
commands	O
to	O
inspect	O
memory	O
,	O
threads	O
,	O
and	O
other	O
kernel	B-Operating_System
structures	O
.	O
</s>
<s>
Linux	B-Operating_System
kernel	I-Operating_System
;	O
No	B-Operating_System
kernel	B-Operating_System
debugger	I-Operating_System
was	O
included	O
in	O
the	O
mainline	O
Linux	B-Operating_System
tree	O
prior	O
to	O
version	O
2.6.26-rc1	O
because	O
Linus	O
Torvalds	O
did	O
n't	O
want	O
a	O
kernel	B-Operating_System
debugger	I-Operating_System
in	O
the	O
kernel	B-Operating_System
.	O
</s>
<s>
OpenBSD	B-Operating_System
includes	O
ddb	O
which	O
has	O
a	O
syntax	O
is	O
similar	O
to	O
GNU	B-Language
Debugger	I-Language
.	O
</s>
