<s>
A	O
component	O
of	O
a	O
job	O
(	O
as	O
a	O
unit	O
of	O
work	O
)	O
is	O
called	O
a	O
task	B-General_Concept
or	O
a	O
step	O
(	O
if	O
sequential	O
,	O
as	O
in	O
a	O
job	B-Application
stream	I-Application
)	O
.	O
</s>
<s>
As	O
a	O
unit	O
of	O
execution	O
,	O
a	O
job	O
may	O
be	O
concretely	O
identified	O
with	O
a	O
single	O
process	B-Operating_System
,	O
which	O
may	O
in	O
turn	O
have	O
subprocesses	O
(	O
child	O
processes	O
;	O
the	O
process	B-Operating_System
corresponding	O
to	O
the	O
job	O
being	O
the	O
parent	B-Operating_System
process	I-Operating_System
)	O
which	O
perform	O
the	O
tasks	O
or	O
steps	O
that	O
comprise	O
the	O
work	O
of	O
the	O
job	O
;	O
or	O
with	O
a	O
process	B-Operating_System
group	I-Operating_System
;	O
or	O
with	O
an	O
abstract	O
reference	O
to	O
a	O
process	B-Operating_System
or	O
process	B-Operating_System
group	I-Operating_System
,	O
as	O
in	O
Unix	B-Operating_System
job	I-Operating_System
control	I-Operating_System
.	O
</s>
<s>
Jobs	O
can	O
be	O
started	O
interactively	O
,	O
such	O
as	O
from	O
a	O
command	B-Application
line	I-Application
,	O
or	O
scheduled	O
for	O
non-interactive	O
execution	O
by	O
a	O
job	B-General_Concept
scheduler	I-General_Concept
,	O
and	O
then	O
controlled	O
via	O
automatic	O
or	O
manual	O
job	B-General_Concept
control	I-General_Concept
.	O
</s>
<s>
By	O
contrast	O
,	O
online	O
processing	O
such	O
as	O
by	O
servers	B-Application
has	O
open-ended	O
input	O
(	O
they	O
service	O
requests	O
as	O
long	O
as	O
they	O
run	O
)	O
,	O
and	O
thus	O
never	O
complete	O
,	O
only	O
stopping	O
when	O
terminated	O
(	O
sometimes	O
called	O
"	O
canceled	O
"	O
)	O
:	O
a	O
server	O
's	O
job	O
is	O
never	O
done	O
.	O
</s>
<s>
Note	O
that	O
these	O
distinctions	O
have	O
become	O
blurred	O
in	O
computing	O
,	O
where	O
the	O
oxymoronic	O
term	O
"	O
batch	B-General_Concept
job	I-General_Concept
"	O
is	O
found	O
,	O
and	O
used	O
either	O
for	O
a	O
one-off	O
job	O
or	O
for	O
a	O
round	O
of	O
"	O
batch	B-General_Concept
processing	I-General_Concept
"	O
(	O
same	O
processing	O
step	O
applied	O
to	O
many	O
items	O
at	O
once	O
,	O
originally	O
punch	B-Architecture
cards	I-Architecture
)	O
.	O
</s>
<s>
The	O
term	O
"	O
job	O
"	O
is	O
also	O
common	O
in	O
operations	O
research	O
,	O
predating	O
its	O
use	O
in	O
computing	O
,	O
in	O
such	O
uses	O
as	O
job	B-Algorithm
shop	I-Algorithm
scheduling	I-Algorithm
(	O
see	O
,	O
for	O
example	O
and	O
references	O
thereof	O
from	O
throughout	O
the	O
1950s	O
,	O
including	O
several	O
"	O
System	O
Research	O
Department	O
Reports	O
"	O
from	O
IBM	O
Research	O
Center	O
)	O
.	O
</s>
<s>
This	O
analogy	O
is	O
applied	O
to	O
computer	O
systems	O
,	O
where	O
the	O
system	B-General_Concept
resources	I-General_Concept
are	O
analogous	O
to	O
machines	O
in	O
a	O
job	O
shop	O
,	O
and	O
the	O
goal	O
of	O
scheduling	O
is	O
to	O
minimize	O
the	O
total	O
time	O
from	O
beginning	O
to	O
end	O
(	O
makespan	B-Algorithm
)	O
.	O
</s>
<s>
The	O
term	O
continued	O
in	O
occasional	O
use	O
,	O
such	O
as	O
for	O
the	O
IBM	B-Device
709	I-Device
(	O
1958	O
)	O
,	O
and	O
in	O
wider	O
use	O
by	O
early	O
1960s	O
,	O
such	O
as	O
for	O
the	O
IBM	B-Device
7090	I-Device
,	O
with	O
widespread	O
use	O
from	O
the	O
Job	B-Application
Control	I-Application
Language	I-Application
of	O
OS/360	B-Application
(	O
announced	O
1964	O
)	O
.	O
</s>
<s>
A	O
standard	O
early	O
use	O
of	O
"	O
job	O
"	O
is	O
for	O
compiling	O
a	O
program	O
from	O
source	O
code	O
,	O
as	O
this	O
is	O
a	O
one-off	O
task	B-General_Concept
.	O
</s>
