<s>
In	O
computing	O
system	B-Application
generation	I-Application
or	O
sysgen	B-Application
is	O
the	O
process	O
of	O
creating	O
a	O
particular	O
unique	O
instance	O
of	O
an	O
operating	B-General_Concept
system	I-General_Concept
by	O
combining	O
user-specified	O
options	O
and	O
parameters	O
with	O
manufacturer-supplied	O
general-purpose	O
program	O
code	O
to	O
produce	O
an	O
operating	B-General_Concept
system	I-General_Concept
tailored	O
for	O
a	O
particular	O
hardware	O
and	O
software	O
environment	O
.	O
</s>
<s>
Some	O
other	O
programs	O
have	O
similar	O
processes	O
,	O
although	O
not	O
usually	O
called	O
"	O
sysgen.	O
"	O
</s>
<s>
For	O
example	O
,	O
IBM	O
's	O
Customer	B-Application
Information	I-Application
Control	I-Application
System	I-Application
(	O
CICS	B-Application
)	O
was	O
installed	O
through	O
a	O
process	O
called	O
CICSGEN	O
.	O
</s>
<s>
A	O
large	O
general-purpose	O
program	O
such	O
as	O
an	O
operating	B-General_Concept
system	I-General_Concept
has	O
to	O
provide	O
support	O
for	O
all	O
variations	O
of	O
Central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
(	O
CPU	O
)	O
that	O
it	O
might	O
be	O
run	O
on	O
,	O
for	O
all	O
supported	O
main	O
memory	O
sizes	O
,	O
and	O
for	O
all	O
possible	O
configurations	O
of	O
input/output	B-General_Concept
(	O
I/O	B-General_Concept
)	O
equipment	O
.	O
</s>
<s>
No	O
one	O
installation	O
requires	O
all	O
this	O
support	O
,	O
so	O
system	B-Application
generation	I-Application
provides	O
a	O
process	O
for	O
selecting	O
the	O
options	O
and	O
features	O
actually	O
required	O
on	O
any	O
one	O
system	O
.	O
</s>
<s>
Sysgen	B-Application
produces	O
a	O
system	O
that	O
is	O
most	O
efficient	O
in	O
terms	O
of	O
CPU	O
time	O
,	O
main	O
memory	O
requirements	O
,	O
I/O	B-General_Concept
activity	O
,	O
and/or	O
disk	O
space	O
.	O
</s>
<s>
Often	O
these	O
parameters	O
can	O
be	O
traded	O
off	O
,	O
for	O
example	O
to	O
generate	O
a	O
system	O
that	O
requires	O
less	O
memory	O
at	O
the	O
expense	O
of	O
increased	O
disk	O
I/O	B-General_Concept
operations	I-General_Concept
.	O
</s>
