<s>
In	O
computing	O
,	O
a	O
core	B-Error_Name
dump	I-Error_Name
,	O
memory	B-Error_Name
dump	I-Error_Name
,	O
crash	B-Error_Name
dump	I-Error_Name
,	O
storage	B-Error_Name
dump	I-Error_Name
,	O
system	O
dump	O
,	O
or	O
ABEND	O
dump	O
consists	O
of	O
the	O
recorded	O
state	O
of	O
the	O
working	O
memory	B-General_Concept
of	O
a	O
computer	B-Application
program	I-Application
at	O
a	O
specific	O
time	O
,	O
generally	O
when	O
the	O
program	O
has	O
crashed	B-General_Concept
or	O
otherwise	O
terminated	O
abnormally	O
.	O
</s>
<s>
In	O
practice	O
,	O
other	O
key	O
pieces	O
of	O
program	B-Operating_System
state	I-Operating_System
are	O
usually	O
dumped	O
at	O
the	O
same	O
time	O
,	O
including	O
the	O
processor	B-General_Concept
registers	I-General_Concept
,	O
which	O
may	O
include	O
the	O
program	B-General_Concept
counter	I-General_Concept
and	O
stack	O
pointer	O
,	O
memory	B-General_Concept
management	I-General_Concept
information	O
,	O
and	O
other	O
processor	O
and	O
operating	B-General_Concept
system	I-General_Concept
flags	O
and	O
information	O
.	O
</s>
<s>
A	O
snapshot	O
dump	O
(	O
or	O
snap	O
dump	O
)	O
is	O
a	O
memory	B-Error_Name
dump	I-Error_Name
requested	O
by	O
the	O
computer	O
operator	O
or	O
by	O
the	O
running	O
program	O
,	O
after	O
which	O
the	O
program	O
is	O
able	O
to	O
continue	O
.	O
</s>
<s>
Core	B-Error_Name
dumps	I-Error_Name
are	O
often	O
used	O
to	O
assist	O
in	O
diagnosing	O
and	O
debugging	O
errors	O
in	O
computer	B-Application
programs	I-Application
.	O
</s>
<s>
On	O
many	O
operating	B-General_Concept
systems	I-General_Concept
,	O
a	O
fatal	B-Error_Name
exception	I-Error_Name
in	O
a	O
program	O
automatically	O
triggers	O
a	O
core	B-Error_Name
dump	I-Error_Name
.	O
</s>
<s>
By	O
extension	O
,	O
the	O
phrase	O
"	O
to	O
dump	B-Error_Name
core	I-Error_Name
"	O
has	O
come	O
to	O
mean	O
in	O
many	O
cases	O
,	O
any	O
fatal	O
error	O
,	O
regardless	O
of	O
whether	O
a	O
record	O
of	O
the	O
program	O
memory	B-General_Concept
exists	O
.	O
</s>
<s>
The	O
term	O
"	O
core	B-Error_Name
dump	I-Error_Name
"	O
,	O
"	O
memory	B-Error_Name
dump	I-Error_Name
"	O
,	O
or	O
just	O
"	O
dump	O
"	O
has	O
also	O
become	O
jargon	O
to	O
indicate	O
any	O
output	O
of	O
a	O
large	O
amount	O
of	O
raw	O
data	O
for	O
further	O
examination	O
or	O
other	O
purposes	O
.	O
</s>
<s>
The	O
name	O
comes	O
from	O
magnetic-core	O
memory	B-General_Concept
,	O
the	O
principal	O
form	O
of	O
random-access	B-Architecture
memory	I-Architecture
from	O
the	O
1950s	O
to	O
the	O
1970s	O
.	O
</s>
<s>
Earliest	O
core	B-Error_Name
dumps	I-Error_Name
were	O
paper	O
printouts	O
of	O
the	O
contents	O
of	O
memory	B-General_Concept
,	O
typically	O
arranged	O
in	O
columns	O
of	O
octal	O
or	O
hexadecimal	O
numbers	O
(	O
a	O
"	O
hex	O
dump	O
"	O
)	O
,	O
sometimes	O
accompanied	O
by	O
their	O
interpretations	O
as	O
machine	B-Language
language	I-Language
instructions	O
,	O
text	O
strings	O
,	O
or	O
decimal	B-Device
or	O
floating-point	O
numbers	O
(	O
cf	O
.	O
</s>
<s>
As	O
memory	B-General_Concept
sizes	O
increased	O
and	O
post-mortem	O
analysis	O
utilities	O
were	O
developed	O
,	O
dumps	O
were	O
written	O
to	O
magnetic	O
media	O
like	O
tape	O
or	O
disk	O
.	O
</s>
<s>
Instead	O
of	O
only	O
displaying	O
the	O
contents	O
of	O
the	O
applicable	O
memory	B-General_Concept
,	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
typically	O
generate	O
a	O
file	O
containing	O
an	O
image	O
of	O
the	O
memory	B-General_Concept
belonging	O
to	O
the	O
crashed	B-General_Concept
process	O
,	O
or	O
the	O
memory	B-General_Concept
images	O
of	O
parts	O
of	O
the	O
address	B-General_Concept
space	I-General_Concept
related	O
to	O
that	O
process	O
,	O
along	O
with	O
other	O
information	O
such	O
as	O
the	O
values	O
of	O
processor	B-General_Concept
registers	I-General_Concept
,	O
program	B-General_Concept
counter	I-General_Concept
,	O
system	O
flags	O
,	O
and	O
other	O
information	O
useful	O
in	O
determining	O
the	O
root	O
cause	O
of	O
the	O
crash	B-General_Concept
.	O
</s>
<s>
These	O
files	O
can	O
be	O
viewed	O
as	O
text	O
,	O
printed	O
,	O
or	O
analysed	O
with	O
specialised	O
tools	O
such	O
as	O
elfdump	O
on	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
objdump	B-Device
and	O
kdump	B-Application
on	O
Linux	B-Application
,	O
IPCS	O
(	O
Interactive	O
Problem	O
Control	O
System	O
)	O
on	O
IBM	B-Application
z/OS	I-Application
,	O
DVF	O
(	O
Dump	O
Viewing	O
Facility	O
)	O
on	O
IBM	O
z/VM	B-Application
,	O
WinDbg	B-Application
on	O
Microsoft	B-Application
Windows	I-Application
,	O
Valgrind	B-Application
,	O
or	O
other	O
debuggers	B-Application
.	O
</s>
<s>
In	O
some	O
operating	B-General_Concept
systems	I-General_Concept
an	O
application	O
or	O
operator	O
may	O
request	O
a	O
snapshot	O
of	O
selected	O
storage	O
blocks	O
,	O
rather	O
than	O
all	O
of	O
the	O
storage	O
used	O
by	O
the	O
application	O
or	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Core	B-Error_Name
dumps	I-Error_Name
can	O
serve	O
as	O
useful	O
debugging	O
aids	O
in	O
several	O
situations	O
.	O
</s>
<s>
On	O
early	O
standalone	O
or	O
batch-processing	B-General_Concept
systems	O
,	O
core	B-Error_Name
dumps	I-Error_Name
allowed	O
a	O
user	O
to	O
debug	O
a	O
program	O
without	O
monopolizing	O
the	O
(	O
very	O
expensive	O
)	O
computing	O
facility	O
for	O
debugging	O
;	O
a	O
printout	O
could	O
also	O
be	O
more	O
convenient	O
than	O
debugging	O
using	O
front	B-Device
panel	I-Device
switches	O
and	O
lights	O
.	O
</s>
<s>
On	O
shared	O
computers	O
,	O
whether	O
time-sharing	O
,	O
batch	B-General_Concept
processing	I-General_Concept
,	O
or	O
server	O
systems	O
,	O
core	B-Error_Name
dumps	I-Error_Name
allow	O
off-line	O
debugging	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
so	O
that	O
the	O
system	O
can	O
go	O
back	O
into	O
operation	O
immediately	O
.	O
</s>
<s>
Core	B-Error_Name
dumps	I-Error_Name
allow	O
a	O
user	O
to	O
save	O
a	O
crash	B-General_Concept
for	O
later	O
or	O
off-site	O
analysis	O
,	O
or	O
comparison	O
with	O
other	O
crashes	B-General_Concept
.	O
</s>
<s>
For	O
embedded	B-Architecture
computers	I-Architecture
,	O
it	O
may	O
be	O
impractical	O
to	O
support	O
debugging	O
on	O
the	O
computer	O
itself	O
,	O
so	O
analysis	O
of	O
a	O
dump	O
may	O
take	O
place	O
on	O
a	O
different	O
computer	O
.	O
</s>
<s>
Some	O
operating	B-General_Concept
systems	I-General_Concept
such	O
as	O
early	O
versions	O
of	O
Unix	B-Application
did	O
not	O
support	O
attaching	O
debuggers	B-Application
to	O
running	O
processes	O
,	O
so	O
core	B-Error_Name
dumps	I-Error_Name
were	O
necessary	O
to	O
run	O
a	O
debugger	B-Application
on	O
a	O
process	O
's	O
memory	B-General_Concept
contents	O
.	O
</s>
<s>
Core	B-Error_Name
dumps	I-Error_Name
can	O
be	O
used	O
to	O
capture	O
data	O
freed	O
during	O
dynamic	B-General_Concept
memory	I-General_Concept
allocation	I-General_Concept
and	O
may	O
thus	O
be	O
used	O
to	O
retrieve	O
information	O
from	O
a	O
program	O
that	O
is	O
no	O
longer	O
running	O
.	O
</s>
<s>
In	O
the	O
absence	O
of	O
an	O
interactive	O
debugger	B-Application
,	O
the	O
core	B-Error_Name
dump	I-Error_Name
may	O
be	O
used	O
by	O
an	O
assiduous	O
programmer	O
to	O
determine	O
the	O
error	O
from	O
direct	O
examination	O
.	O
</s>
<s>
A	O
core	B-Error_Name
dump	I-Error_Name
generally	O
represents	O
the	O
complete	O
contents	O
of	O
the	O
dumped	O
regions	O
of	O
the	O
address	B-General_Concept
space	I-General_Concept
of	O
the	O
dumped	O
process	O
.	O
</s>
<s>
Depending	O
on	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
the	O
dump	O
may	O
contain	O
few	O
or	O
no	O
data	O
structures	O
to	O
aid	O
interpretation	O
of	O
the	O
memory	B-General_Concept
regions	O
.	O
</s>
<s>
In	O
these	O
systems	O
,	O
successful	O
interpretation	O
requires	O
that	O
the	O
program	O
or	O
user	O
trying	O
to	O
interpret	O
the	O
dump	O
understands	O
the	O
structure	O
of	O
the	O
program	O
's	O
memory	B-General_Concept
use	O
.	O
</s>
<s>
A	O
debugger	B-Application
can	O
use	O
a	O
symbol	B-Application
table	I-Application
,	O
if	O
one	O
exists	O
,	O
to	O
help	O
the	O
programmer	O
interpret	O
dumps	O
,	O
identifying	O
variables	O
symbolically	O
and	O
displaying	O
source	O
code	O
;	O
if	O
the	O
symbol	B-Application
table	I-Application
is	O
not	O
available	O
,	O
less	O
interpretation	O
of	O
the	O
dump	O
is	O
possible	O
,	O
but	O
there	O
might	O
still	O
be	O
enough	O
possible	O
to	O
determine	O
the	O
cause	O
of	O
the	O
problem	O
.	O
</s>
<s>
There	O
are	O
also	O
special-purpose	O
tools	O
called	O
dump	B-General_Concept
analyzers	I-General_Concept
to	O
analyze	O
dumps	O
.	O
</s>
<s>
One	O
popular	O
tool	O
,	O
available	O
on	O
many	O
operating	B-General_Concept
systems	I-General_Concept
,	O
is	O
the	O
GNU	O
binutils	O
 '	O
objdump	B-Device
.	O
</s>
<s>
On	O
modern	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
administrators	O
and	O
programmers	O
can	O
read	O
core	B-Error_Name
dump	I-Error_Name
files	O
using	O
the	O
GNU	O
Binutils	O
Binary	B-Application
File	I-Application
Descriptor	I-Application
library	I-Application
(	O
BFD	O
)	O
,	O
and	O
the	O
GNU	B-Language
Debugger	I-Language
(	O
gdb	B-Language
)	O
and	O
objdump	B-Device
that	O
use	O
this	O
library	O
.	O
</s>
<s>
This	O
library	O
will	O
supply	O
the	O
raw	O
data	O
for	O
a	O
given	O
address	O
in	O
a	O
memory	B-General_Concept
region	O
from	O
a	O
core	B-Error_Name
dump	I-Error_Name
;	O
it	O
does	O
not	O
know	O
anything	O
about	O
variables	O
or	O
data	O
structures	O
in	O
that	O
memory	B-General_Concept
region	O
,	O
so	O
the	O
application	O
using	O
the	O
library	O
to	O
read	O
the	O
core	B-Error_Name
dump	I-Error_Name
will	O
have	O
to	O
determine	O
the	O
addresses	O
of	O
variables	O
and	O
determine	O
the	O
layout	O
of	O
data	O
structures	O
itself	O
,	O
for	O
example	O
by	O
using	O
the	O
symbol	B-Application
table	I-Application
for	O
the	O
program	O
undergoing	O
debugging	O
.	O
</s>
<s>
Analysts	O
of	O
crash	B-Error_Name
dumps	I-Error_Name
from	O
Linux	B-Application
systems	O
can	O
use	O
kdump	B-Application
or	O
the	O
Linux	B-Application
Kernel	O
Crash	B-Error_Name
Dump	I-Error_Name
(	O
LKCD	O
)	O
.	O
</s>
<s>
Core	B-Error_Name
dumps	I-Error_Name
can	O
save	O
the	O
context	O
(	O
state	O
)	O
of	O
a	O
process	O
at	O
a	O
given	O
state	O
for	O
returning	O
to	O
it	O
later	O
.	O
</s>
<s>
Systems	O
can	O
be	O
made	O
highly	O
available	O
by	O
transferring	O
core	O
between	O
processors	O
,	O
sometimes	O
via	O
core	B-Error_Name
dump	I-Error_Name
files	O
themselves	O
.	O
</s>
<s>
In	O
older	O
and	O
simpler	O
operating	B-General_Concept
systems	I-General_Concept
,	O
each	O
process	O
had	O
a	O
contiguous	O
address-space	O
,	O
so	O
a	O
dump	B-Error_Name
file	I-Error_Name
was	O
sometimes	O
simply	O
a	O
file	O
with	O
the	O
sequence	O
of	O
bytes	O
,	O
digits	O
,	O
characters	O
or	O
words	O
.	O
</s>
<s>
On	O
other	O
early	O
machines	O
a	O
dump	B-Error_Name
file	I-Error_Name
contained	O
discrete	O
records	O
,	O
each	O
containing	O
a	O
storage	O
address	O
and	O
the	O
associated	O
contents	O
.	O
</s>
<s>
On	O
early	O
machines	O
,	O
the	O
dump	O
was	O
often	O
written	O
by	O
a	O
stand-alone	O
dump	O
program	O
rather	O
than	O
by	O
the	O
application	O
or	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
On	O
the	O
IBM	B-Application
System/360	I-Application
,	O
the	O
standard	O
operating	B-General_Concept
systems	I-General_Concept
wrote	O
formatted	O
ABEND	O
and	O
SNAP	O
dumps	O
,	O
with	O
the	O
addresses	O
,	O
registers	B-General_Concept
,	O
storage	O
contents	O
,	O
etc.	O
,	O
all	O
converted	O
into	O
printable	O
forms	O
.	O
</s>
<s>
In	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
,	O
a	O
process	O
address	B-General_Concept
space	I-General_Concept
may	O
contain	O
gaps	O
,	O
and	O
it	O
may	O
share	O
pages	O
with	O
other	O
processes	O
or	O
files	O
,	O
so	O
more	O
elaborate	O
representations	O
are	O
used	O
;	O
they	O
may	O
also	O
include	O
other	O
information	O
about	O
the	O
state	O
of	O
the	O
program	O
at	O
the	O
time	O
of	O
the	O
dump	O
.	O
</s>
<s>
In	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
core	B-Error_Name
dumps	I-Error_Name
generally	O
use	O
the	O
standard	O
executable	B-Application
image-format	O
:	O
</s>
<s>
a.out	O
in	O
older	O
versions	O
of	O
Unix	B-Application
,	O
</s>
<s>
ELF	O
in	O
modern	O
Linux	B-Application
,	O
System	B-Operating_System
V	I-Operating_System
,	O
Solaris	B-Application
,	O
and	O
BSD	B-Operating_System
systems	O
,	O
</s>
<s>
Mach-O	B-Operating_System
in	O
macOS	B-Application
,	O
etc	O
.	O
</s>
<s>
In	O
OS/360	B-Application
and	I-Application
successors	I-Application
,	O
a	O
job	O
may	O
assign	O
arbitrary	O
data	O
set	O
names	O
(	O
DSNs	O
)	O
to	O
the	O
ddnames	O
SYSABEND	O
and	O
SYSUDUMP	O
for	O
a	O
formatted	O
ABEND	O
dump	O
and	O
to	O
arbitrary	O
ddnames	O
for	O
SNAP	O
dumps	O
,	O
or	O
define	O
those	O
ddnames	O
as	O
SYSOUT	O
.	O
</s>
<s>
Since	O
Solaris8	O
,	O
system	O
utility	O
coreadm	O
allows	O
the	O
name	O
and	O
location	O
of	O
core	B-Error_Name
files	I-Error_Name
to	O
be	O
configured	O
.	O
</s>
<s>
On	O
Linux	B-Application
(	O
since	O
versions	O
2.4.21	O
and	O
2.6	O
of	O
the	O
Linux	B-Application
kernel	O
mainline	O
)	O
,	O
a	O
different	O
name	O
can	O
be	O
specified	O
via	O
procfs	B-Application
using	O
the	O
/proc/sys/kernel/core_pattern	O
configuration	O
file	O
;	O
the	O
specified	O
name	O
can	O
also	O
be	O
a	O
template	O
that	O
contains	O
tags	O
substituted	O
by	O
,	O
for	O
example	O
,	O
the	O
executable	B-Application
filename	O
,	O
the	O
process	O
ID	O
,	O
or	O
the	O
reason	O
for	O
the	O
dump	O
.	O
</s>
<s>
System-wide	O
dumps	O
on	O
modern	O
Unix-like	B-Operating_System
systems	I-Operating_System
often	O
appear	O
as	O
vmcore	O
or	O
vmcore.incomplete	O
.	O
</s>
<s>
Systems	O
such	O
as	O
Microsoft	B-Application
Windows	I-Application
,	O
which	O
use	O
filename	O
extensions	O
,	O
may	O
use	O
extension	O
.dmp	O
;	O
for	O
example	O
,	O
core	B-Error_Name
dumps	I-Error_Name
may	O
be	O
named	O
memory.dmp	O
or	O
\Minidump\Mini051509-01.dmp	O
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
supports	O
two	O
memory	B-Error_Name
dump	I-Error_Name
formats	O
,	O
described	O
below	O
.	O
</s>
<s>
Complete	O
memory	B-Error_Name
dump	I-Error_Name
contains	O
full	O
physical	O
memory	B-General_Concept
for	O
the	O
target	O
system	O
.	O
</s>
<s>
Kernel	O
memory	B-Error_Name
dump	I-Error_Name
contains	O
all	O
the	O
memory	B-General_Concept
in	O
use	O
by	O
the	O
kernel	O
at	O
the	O
time	O
of	O
the	O
crash	B-General_Concept
.	O
</s>
<s>
Small	O
memory	B-Error_Name
dump	I-Error_Name
contains	O
various	O
info	O
such	O
as	O
the	O
stop	O
code	O
,	O
parameters	O
,	O
list	O
of	O
loaded	O
device	O
drivers	O
,	O
etc	O
.	O
</s>
<s>
Automatic	O
Memory	B-Error_Name
Dump	I-Error_Name
(	O
Windows	O
8	O
and	O
later	O
)	O
same	O
as	O
Kernel	O
memory	B-Error_Name
dump	I-Error_Name
,	O
but	O
if	O
the	O
paging	O
file	O
is	O
both	O
System	O
Managed	O
and	O
too	O
small	O
to	O
capture	O
the	O
Kernel	O
memory	B-Error_Name
dump	I-Error_Name
,	O
it	O
will	O
automatically	O
increase	O
the	O
paging	O
file	O
to	O
at	O
least	O
the	O
size	O
of	O
RAM	B-Architecture
for	O
four	O
weeks	O
,	O
then	O
reduce	O
it	O
to	O
the	O
smaller	O
size	O
.	O
</s>
<s>
Active	O
memory	B-Error_Name
dump	I-Error_Name
(	O
Windows	O
10	O
and	O
later	O
)	O
contains	O
most	O
of	O
the	O
memory	B-General_Concept
in	O
use	O
by	O
the	O
kernel	O
and	O
user	O
mode	O
applications	O
.	O
</s>
<s>
To	O
analyze	O
the	O
Windows	O
kernel-mode	O
dumps	O
Debugging	B-Application
Tools	I-Application
for	I-Application
Windows	I-Application
are	O
used	O
.	O
</s>
<s>
User-mode	O
memory	B-Error_Name
dump	I-Error_Name
,	O
also	O
known	O
as	O
minidump	O
,	O
is	O
a	O
memory	B-Error_Name
dump	I-Error_Name
of	O
a	O
single	O
process	O
.	O
</s>
<s>
It	O
contains	O
selected	O
data	O
records	O
:	O
full	O
or	O
partial	O
(	O
filtered	O
)	O
process	O
memory	B-General_Concept
;	O
list	O
of	O
the	O
threads	B-Operating_System
with	O
their	O
call	B-General_Concept
stacks	I-General_Concept
and	O
state	O
(	O
such	O
as	O
registers	B-General_Concept
or	O
TEB	B-Operating_System
)	O
;	O
information	O
about	O
handles	O
to	O
the	O
kernel	O
objects	O
;	O
list	O
of	O
loaded	O
and	O
unloaded	O
libraries	O
.	O
</s>
<s>
The	O
NASA	O
Voyager	O
program	O
was	O
probably	O
the	O
first	O
craft	O
to	O
routinely	O
utilize	O
the	O
core	B-Error_Name
dump	I-Error_Name
feature	O
in	O
the	O
Deep	O
Space	O
segment	O
.	O
</s>
<s>
The	O
core	B-Error_Name
dump	I-Error_Name
feature	O
is	O
a	O
mandatory	O
telemetry	O
feature	O
for	O
the	O
Deep	O
Space	O
segment	O
as	O
it	O
has	O
been	O
proven	O
to	O
minimize	O
system	O
diagnostic	O
costs	O
.	O
</s>
<s>
The	O
Voyager	O
craft	O
uses	O
routine	O
core	B-Error_Name
dumps	I-Error_Name
to	O
spot	O
memory	B-General_Concept
damage	O
from	O
cosmic	O
ray	O
events	O
.	O
</s>
<s>
Space	O
Mission	O
core	B-Error_Name
dump	I-Error_Name
systems	O
are	O
mostly	O
based	O
on	O
existing	O
toolkits	O
for	O
the	O
target	O
CPU	O
or	O
subsystem	O
.	O
</s>
<s>
However	O
,	O
over	O
the	O
duration	O
of	O
a	O
mission	O
the	O
core	B-Error_Name
dump	I-Error_Name
subsystem	O
may	O
be	O
substantially	O
modified	O
or	O
enhanced	O
for	O
the	O
specific	O
needs	O
of	O
the	O
mission	O
.	O
</s>
