<s>
Computer-aided	B-General_Concept
maintenance	I-General_Concept
(	O
not	O
to	O
be	O
confused	O
with	O
CAM	O
which	O
usually	O
stands	O
for	O
Computer	O
Aided	O
Manufacturing	O
)	O
refers	O
to	O
systems	O
that	O
utilize	O
software	O
to	O
organize	O
planning	O
,	O
scheduling	O
,	O
and	O
support	O
of	O
maintenance	O
and	O
repair	O
.	O
</s>
<s>
The	O
first	O
computer-aided	B-General_Concept
maintenance	I-General_Concept
software	O
came	O
from	O
DEC	O
in	O
the	O
1980s	O
to	O
configure	O
VAX	B-Device
computers	O
.	O
</s>
<s>
The	O
software	O
was	O
built	O
using	O
the	O
techniques	O
of	O
artificial	B-Application
intelligence	I-Application
expert	B-Application
systems	I-Application
,	O
because	O
the	O
problem	O
of	O
configuring	O
a	O
VAX	B-Device
required	O
expert	O
knowledge	O
.	O
</s>
<s>
During	O
the	O
research	O
,	O
the	O
software	O
was	O
called	O
R1	B-Application
and	O
was	O
renamed	O
XCON	B-Application
when	O
placed	O
in	O
service	O
.	O
</s>
<s>
Fundamentally	O
,	O
XCON	B-Application
was	O
a	O
rule-based	O
configuration	O
database	O
written	O
as	O
an	O
expert	B-Application
system	I-Application
using	O
forward	O
chaining	O
rules	O
.	O
</s>
<s>
As	O
one	O
of	O
the	O
first	O
expert	B-Application
systems	I-Application
to	O
be	O
pressed	O
into	O
commercial	O
service	O
it	O
created	O
high	O
expectations	O
,	O
which	O
did	O
not	O
materialize	O
,	O
as	O
DEC	O
lost	O
commercial	O
pre-eminence	O
.	O
</s>
<s>
Help	O
desks	O
frequently	O
use	O
help	O
desk	O
software	O
that	O
captures	O
symptoms	O
of	O
a	O
bug	B-Error_Name
and	O
relates	O
them	O
to	O
fixes	O
,	O
in	O
a	O
fix	O
database	O
.	O
</s>
<s>
Oddly	O
enough	O
,	O
shutting	O
down	O
and	O
booting	B-Operating_System
up	I-Operating_System
again	O
manages	O
to	O
'	O
fix	O
,	O
'	O
or	O
at	O
least	O
'	O
mask	O
,	O
'	O
a	O
bug	B-Error_Name
in	O
many	O
computer-based	O
systems	O
;	O
thus	O
reboot	O
is	O
the	O
remedy	O
for	O
distressingly	O
many	O
symptoms	O
in	O
a	O
'	O
fix	O
database.	O
'	O
</s>
<s>
The	O
reason	O
a	O
reboot	O
often	O
works	O
is	O
that	O
it	O
causes	O
the	O
RAM	B-Architecture
to	O
be	O
flushed	O
.	O
</s>
