<s>
On	O
many	O
computing	B-Device
platforms	I-Device
everything	B-Application
is	I-Application
a	I-Application
file	I-Application
,	O
but	O
in	O
contrast	O
in	O
IBM	B-Application
i	I-Application
everything	O
is	O
an	O
object	O
.	O
</s>
<s>
IBM	B-Application
i	I-Application
objects	O
share	O
similarities	O
with	O
objects	O
in	O
object-oriented	B-Language
programming	I-Language
,	O
but	O
there	O
are	O
differences	O
as	O
well	O
.	O
</s>
<s>
There	O
are	O
similarities	O
in	O
that	O
when	O
storage	B-General_Concept
is	O
allocated	O
for	O
something	O
,	O
that	O
something	O
is	O
of	O
a	O
specific	O
type	O
,	O
and	O
only	O
a	O
specific	O
set	O
of	O
programs	O
are	O
allowed	O
to	O
act	O
upon	O
that	O
object	O
.	O
</s>
<s>
There	O
are	O
differences	O
in	O
that	O
IBM	B-Application
i	I-Application
objects	O
cannot	O
be	O
inherited	O
,	O
and	O
the	O
set	O
of	O
object	O
types	O
is	O
fixed	O
,	O
and	O
only	O
IBM	O
has	O
the	O
ability	O
to	O
create	O
new	O
ones	O
.	O
</s>
<s>
*	O
LIB	O
:	O
Library	B-Device
(	O
where	O
everything	O
below	O
,	O
except	O
directories	O
and	O
stream	O
files	O
,	O
is	O
stored	O
;	O
libraries	B-Device
cannot	O
exist	O
within	O
other	O
libraries	B-Device
)	O
.	O
</s>
<s>
*	O
PGM	O
:	O
Program	O
(	O
for	O
compiled	O
languages	O
:	O
CL	B-Operating_System
,	O
RPG-IV	O
,	O
C	O
,	O
C++	O
,	O
COBOL	O
,	O
etc	O
.	O
</s>
<s>
*	O
SRVPGM	O
:	O
Service	O
program	O
(	O
dynamic	O
set	O
of	O
one	O
or	O
more	O
modules	O
,	O
akin	O
to	O
a	O
DLL	O
file	O
in	O
Microsoft	B-Application
Windows	I-Application
)	O
.	O
</s>
<s>
*	O
CMD	O
:	O
Command	B-Operating_System
(	O
an	O
object	O
used	O
for	O
calling	O
programs	O
that	O
allows	O
users	O
to	O
prompt	O
for	O
their	O
parameters	O
;	O
can	O
be	O
created	O
with	O
the	O
Command	B-Operating_System
Definition	O
language	O
)	O
.	O
</s>
<s>
See	O
Control	B-Operating_System
Language	I-Operating_System
for	O
more	O
information	O
.	O
</s>
<s>
*	O
MENU	O
:	O
Menu	O
(	O
accessed	O
with	O
the	O
GO	O
command	B-Operating_System
)	O
.	O
</s>
<s>
*	O
FILE	O
:	O
File	O
(	O
IBM	B-Application
i	I-Application
files	O
can	O
be	O
used	O
for	O
data	O
,	O
input/output	O
devices	O
,	O
and	O
source	O
code	O
,	O
depending	O
on	O
sub	O
type	O
)	O
.	O
</s>
<s>
*	O
DTAARA	O
:	O
Data	O
area	O
(	O
small	O
bits	O
of	O
storage	B-General_Concept
used	O
to	O
store	O
tiny	O
items	O
of	O
data	O
for	O
fast	O
access	O
)	O
.	O
</s>
<s>
*	O
DIR	O
:	O
Directory	O
(	O
part	O
of	O
the	O
Integrated	O
File	O
System	O
that	O
is	O
equivalent	O
to	O
Unix	B-Application
and	O
Microsoft	B-Application
Windows	I-Application
hierarchical	O
file	O
systems	O
)	O
.	O
</s>
<s>
*	O
STMF	O
:	O
Stream	O
file	O
(	O
traditional	O
file	O
that	O
would	O
be	O
familiar	O
to	O
most	O
Unix	B-Application
and	O
Microsoft	B-Application
Windows	I-Application
users	O
and	O
only	O
stored	O
in	O
directories	O
)	O
.	O
</s>
<s>
A	O
library	B-Device
( *	O
LIB	O
)	O
on	O
IBM	B-Application
i	I-Application
is	O
an	O
object	O
that	O
is	O
used	O
as	O
a	O
system	O
directory	O
to	O
keep	O
track	O
of	O
other	O
objects	O
.	O
</s>
<s>
Objects	O
are	O
not	O
stored	O
inside	O
libraries	B-Device
,	O
but	O
rather	O
libraries	B-Device
are	O
used	O
as	O
namespaces	O
for	O
objects	O
.	O
</s>
<s>
Libraries	B-Device
are	O
a	O
"	O
system	O
"	O
object	O
,	O
and	O
therefore	O
only	O
one	O
instance	O
of	O
any	O
given	O
Library	B-Device
"	O
name	O
"	O
is	O
possible	O
.	O
</s>
<s>
They	O
're	O
made	O
to	O
appear	O
as	O
if	O
they	O
're	O
stored	O
in	O
the	O
QSYS	O
library	B-Device
.	O
</s>
<s>
Generally	O
speaking	O
all	O
libraries	B-Device
created	O
by	O
IBM	O
for	O
use	O
by	O
the	O
operating	B-Application
system	I-Application
begin	O
with	O
the	O
letter	O
'	O
Q	O
 '	O
.	O
</s>
<s>
IBM	O
Standard	O
Libraries	B-Device
:	O
</s>
<s>
A	O
library	B-Device
list	O
( *	O
LIBL	O
)	O
is	O
an	O
object	O
which	O
specifies	O
a	O
default	O
set	O
of	O
locations	O
to	O
look	O
for	O
an	O
object	O
(	O
similar	O
to	O
the	O
PATH	B-Application
mechanism	O
of	O
other	O
operating	O
systems	O
)	O
.	O
</s>
<s>
Some	O
job	O
descriptions	O
specify	O
the	O
special	O
value	O
*	O
SYSVAL	O
which	O
means	O
that	O
the	O
library	B-Device
list	O
can	O
be	O
found	O
in	O
the	O
system	O
value	O
QUSRLIBL	O
.	O
</s>
<s>
As	O
of	O
OS/400	B-Application
V5R1	O
,	O
the	O
user	O
portion	O
of	O
the	O
Library	B-Device
List	O
can	O
contain	O
up	O
to	O
250	O
library	B-Device
names	O
.	O
</s>
<s>
Prior	O
to	O
that	O
it	O
could	O
only	O
have	O
25	O
libraries	B-Device
.	O
</s>
<s>
A	O
job	O
's	O
library	B-Device
list	O
consists	O
of	O
four	O
sections	O
:	O
</s>
<s>
System	O
portion	O
:	O
Always	O
at	O
the	O
top	O
and	O
contains	O
system	O
libraries	B-Device
like	O
QSYS	O
,	O
QHLPSYS	O
,	O
QUSRSYS	O
,	O
etc	O
.	O
</s>
<s>
The	O
system	O
portion	O
can	O
hold	O
up	O
to	O
15	O
library	B-Device
names	O
.	O
</s>
<s>
The	O
contents	O
of	O
the	O
system	O
portion	O
can	O
be	O
changed	O
for	O
the	O
current	O
job	O
to	O
differ	O
from	O
QSYSLIBL	O
by	O
using	O
the	O
CHGSYSLIBL	O
command	B-Operating_System
.	O
</s>
<s>
Product	O
portion	O
:	O
When	O
a	O
CL	B-Operating_System
command	B-Operating_System
is	O
executed	O
that	O
specifies	O
a	O
production	O
library	B-Device
,	O
that	O
library	B-Device
will	O
be	O
added	O
to	O
the	O
product	O
portion	O
of	O
the	O
library	B-Device
list	O
for	O
the	O
duration	O
of	O
the	O
command	B-Operating_System
.	O
</s>
<s>
It	O
follows	O
the	O
system	O
portion	O
and	O
the	O
O/S	O
will	O
maintain	O
up	O
to	O
two	O
libraries	B-Device
in	O
it	O
.	O
</s>
<s>
Current	O
library	B-Device
:	O
Is	O
a	O
special	O
library	B-Device
associated	O
with	O
a	O
user	O
profile	O
and	O
there	O
can	O
only	O
be	O
one	O
in	O
the	O
list	O
at	O
a	O
time	O
.	O
</s>
<s>
This	O
library	B-Device
is	O
useful	O
for	O
programmers	O
to	O
have	O
their	O
personal	O
library	B-Device
at	O
the	O
top	O
of	O
the	O
list	O
regardless	O
of	O
what	O
the	O
user	O
portion	O
is	O
changed	O
to	O
.	O
</s>
<s>
It	O
can	O
be	O
changed	O
locally	O
using	O
the	O
CHGCURLIB	O
command	B-Operating_System
.	O
</s>
<s>
To	O
change	O
it	O
for	O
the	O
user	O
on	O
all	O
future	O
jobs	O
use	O
the	O
CHGUSRPRF	O
command	B-Operating_System
.	O
</s>
<s>
User	O
portion	O
:	O
The	O
last	O
part	O
of	O
the	O
library	B-Device
list	O
that	O
contains	O
all	O
of	O
the	O
application	O
libraries	B-Device
.	O
</s>
<s>
The	O
list	O
is	O
normally	O
assigned	O
to	O
the	O
job	O
from	O
the	O
job	O
description	O
but	O
for	O
batch	O
jobs	O
this	O
can	O
be	O
overridden	O
using	O
the	O
SBMJOB	O
command	B-Operating_System
's	O
INLLIBL	O
parameter	O
.	O
</s>
<s>
A	O
job	O
's	O
library	B-Device
list	O
can	O
be	O
changed	O
locally	O
with	O
the	O
EDTLIBL(Edit Library List )	O
,	O
CHGLIBL(Change Library List )	O
,	O
ADDLIBLE(Add Library List Entry )	O
,	O
and	O
RMVLIBLE(Remove Library List Entry )	O
command	B-Operating_System
.	O
</s>
