<s>
KGDB	B-Application
is	O
a	O
debugger	B-Application
for	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
and	O
the	O
kernels	B-Operating_System
of	O
NetBSD	B-Device
and	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
The	O
serial	O
connection	O
may	O
either	O
be	O
an	O
RS-232	O
interface	O
using	O
a	O
null	O
modem	O
cable	O
,	O
or	O
via	O
the	O
UDP/IP	B-Protocol
networking	O
protocol	O
(	O
KGDB	B-Application
over	O
Ethernet	O
,	O
KGDBoE	O
)	O
.	O
</s>
<s>
The	O
target	O
machine	O
(	O
the	O
one	O
being	O
debugged	O
)	O
runs	O
the	O
patched	O
kernel	B-Operating_System
and	O
the	O
other	O
(	O
host	O
)	O
machine	O
runs	O
gdb	B-Language
.	O
</s>
<s>
The	O
GDB	B-Language
remote	O
protocol	O
is	O
used	O
between	O
the	O
two	O
machines	O
.	O
</s>
<s>
KGDB	B-Application
was	O
implemented	O
as	O
part	O
of	O
the	O
NetBSD	B-Device
kernel	I-Device
in	O
1997	O
,	O
and	O
FreeBSD	B-Operating_System
in	O
version	O
2.2	O
.	O
</s>
<s>
The	O
concept	O
and	O
existing	O
remote	O
gdb	B-Language
protocol	O
were	O
later	O
adapted	O
as	O
a	O
patch	O
to	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
A	O
scaled-down	O
version	O
of	O
the	O
Linux	B-Operating_System
patch	O
was	O
integrated	O
into	O
the	O
official	O
Linux	B-Operating_System
kernel	I-Operating_System
in	O
version	O
2.6.26	O
.	O
</s>
<s>
KGDB	B-Application
is	O
available	O
for	O
the	O
following	O
architectures	O
under	O
Linux	B-Operating_System
:	O
x86	B-Operating_System
,	O
x86-64	B-Device
,	O
PowerPC	B-Architecture
,	O
ARM	B-Architecture
,	O
MIPS	B-Device
,	O
and	O
S390	B-Device
.	O
</s>
<s>
It	O
is	O
available	O
on	O
all	O
supported	O
architectures	O
of	O
NetBSD	B-Device
and	O
FreeBSD	B-Operating_System
using	O
only	O
RS-232	O
connectivity	O
.	O
</s>
<s>
Amit	O
Kale	O
maintained	O
the	O
Linux	B-Operating_System
KGDB	B-Application
from	O
2000	O
to	O
2004	O
.	O
</s>
<s>
Ingo	O
Molnar	O
and	O
Jason	O
Wessel	O
created	O
a	O
slimmed-down	O
and	O
cleaned	O
up	O
version	O
of	O
KGDB	B-Application
which	O
was	O
called	O
"	O
kgdb	B-Application
light	O
"	O
(	O
without	O
Ethernet	O
support	O
and	O
many	O
other	O
hacks	O
)	O
.	O
</s>
<s>
This	O
was	O
the	O
one	O
merged	O
into	O
the	O
2.6.26	O
kernel	B-Operating_System
.	O
</s>
<s>
This	O
version	O
of	O
kgdb	B-Application
supports	O
only	O
RS-232	O
connectivity	O
,	O
using	O
a	O
special	O
driver	O
which	O
can	O
split	O
debugger	B-Application
inputs	O
and	O
console	O
inputs	O
such	O
that	O
only	O
a	O
single	O
serial	O
port	O
is	O
required	O
.	O
</s>
<s>
A	O
program	O
named	O
kgdb	B-Application
is	O
also	O
used	O
by	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
It	O
is	O
a	O
gdb	B-Language
based	O
utility	O
for	O
debugging	O
kernel	B-Operating_System
core	O
files	O
.	O
</s>
<s>
It	O
can	O
also	O
be	O
used	O
for	O
remote	O
"	O
live	O
"	O
kernel	B-Operating_System
debugging	O
,	O
much	O
in	O
the	O
same	O
way	O
as	O
the	O
Linux	B-Operating_System
KGDB	B-Application
,	O
over	O
either	O
a	O
serial	O
connection	O
or	O
a	O
firewire	O
link	O
.	O
</s>
