<s>
Any	O
change	O
in	O
a	O
computing	O
system	O
,	O
such	O
as	O
a	O
new	O
feature	O
or	O
new	O
component	O
,	O
is	O
transparent	O
if	O
the	O
system	O
after	O
change	O
adheres	O
to	O
previous	O
external	B-Application
interface	I-Application
as	O
much	O
as	O
possible	O
while	O
changing	O
its	O
internal	O
behaviour	O
.	O
</s>
<s>
Confusingly	O
,	O
the	O
term	O
refers	O
to	O
overall	O
invisibility	O
of	O
the	O
component	O
,	O
it	O
does	O
not	O
refer	O
to	O
visibility	B-Application
of	O
component	O
's	O
internals	O
(	O
as	O
in	O
white	B-General_Concept
box	I-General_Concept
or	O
open	B-Operating_System
system	I-Operating_System
)	O
.	O
</s>
<s>
The	O
term	O
is	O
used	O
particularly	O
often	O
with	O
regard	O
to	O
an	O
abstraction	B-Architecture
layer	I-Architecture
that	O
is	O
invisible	O
either	O
from	O
its	O
upper	O
or	O
lower	O
neighbouring	O
layer	O
.	O
</s>
<s>
Also	O
temporarily	O
used	O
later	O
around	O
1969	O
in	O
IBM	O
and	O
Honeywell	O
programming	O
manuals	O
the	O
term	O
referred	O
to	O
a	O
certain	O
computer	B-General_Concept
programming	I-General_Concept
technique	O
.	O
</s>
<s>
It	O
was	O
achieved	O
through	O
encapsulation	B-Application
–	O
putting	O
the	O
code	O
into	O
modules	O
that	O
hid	B-Application
internal	O
details	O
,	O
making	O
them	O
invisible	O
for	O
the	O
main	O
application	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Network	B-Protocol
File	I-Protocol
System	I-Protocol
is	O
transparent	O
,	O
because	O
it	O
introduces	O
the	O
access	O
to	O
files	O
stored	O
remotely	O
on	O
the	O
network	O
in	O
a	O
way	O
uniform	O
with	O
previous	O
local	O
access	O
to	O
a	O
file	B-Application
system	I-Application
,	O
so	O
the	O
user	O
might	O
even	O
not	O
notice	O
it	O
while	O
using	O
the	O
folder	O
hierarchy	O
.	O
</s>
<s>
The	O
early	O
File	B-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
FTP	O
)	O
is	O
considerably	O
less	O
transparent	O
,	O
because	O
it	O
requires	O
each	O
user	O
to	O
learn	O
how	O
to	O
access	O
files	O
through	O
an	O
ftp	O
client	O
.	O
</s>
<s>
Similarly	O
,	O
some	O
file	B-Application
systems	I-Application
allow	O
transparent	O
compression	B-General_Concept
and	O
decompression	O
of	O
data	O
,	O
enabling	O
users	O
to	O
store	O
more	O
files	O
on	O
a	O
medium	O
without	O
any	O
special	O
knowledge	O
;	O
some	O
file	B-Application
systems	I-Application
encrypt	O
files	O
transparently	O
.	O
</s>
<s>
This	O
approach	O
does	O
not	O
require	O
running	O
a	O
compression	B-General_Concept
or	O
encryption	O
utility	O
manually	O
.	O
</s>
<s>
In	O
software	B-General_Concept
engineering	I-General_Concept
,	O
it	O
is	O
also	O
considered	O
good	O
practice	O
to	O
develop	O
or	O
use	O
abstraction	B-Architecture
layers	I-Architecture
for	O
database	O
access	O
,	O
so	O
that	O
the	O
same	O
application	O
will	O
work	O
with	O
different	O
databases	O
;	O
here	O
,	O
the	O
abstraction	B-Architecture
layer	I-Architecture
allows	O
other	O
parts	O
of	O
the	O
program	O
to	O
access	O
the	O
database	O
transparently	O
(	O
see	O
Data	O
Access	O
Object	O
,	O
for	O
example	O
)	O
.	O
</s>
<s>
In	O
object-oriented	B-Language
programming	I-Language
,	O
transparency	B-Operating_System
is	O
facilitated	O
through	O
the	O
use	O
of	O
interfaces	B-Application
that	O
hide	O
actual	O
implementations	O
done	O
with	O
different	O
underlying	O
classes	O
.	O
</s>
<s>
Transparency	B-Operating_System
means	O
that	O
any	O
form	O
of	O
distributed	B-Architecture
system	I-Architecture
should	O
hide	O
its	O
distributed	O
nature	O
from	O
its	O
users	O
,	O
appearing	O
and	O
functioning	O
as	O
a	O
normal	O
centralized	O
system	O
.	O
</s>
<s>
There	O
are	O
many	O
types	O
of	O
transparency	B-Operating_System
:	O
</s>
<s>
Access	O
transparency	B-Operating_System
–	O
Regardless	O
of	O
how	O
resource	O
access	O
and	O
representation	O
has	O
to	O
be	O
performed	O
on	O
each	O
individual	O
computing	O
entity	O
,	O
the	O
users	O
of	O
a	O
distributed	B-Architecture
system	I-Architecture
should	O
always	O
access	O
resources	O
in	O
a	O
single	O
,	O
uniform	O
way	O
.	O
</s>
<s>
Location	B-Protocol
transparency	I-Protocol
–	O
Users	O
of	O
a	O
distributed	B-Architecture
system	I-Architecture
should	O
not	O
have	O
to	O
be	O
aware	O
of	O
where	O
a	O
resource	O
is	O
physically	O
located	O
.	O
</s>
<s>
Migration	O
transparency	B-Operating_System
–	O
Users	O
should	O
not	O
be	O
aware	O
of	O
whether	O
a	O
resource	O
or	O
computing	O
entity	O
possesses	O
the	O
ability	O
to	O
move	O
to	O
a	O
different	O
physical	O
or	O
logical	O
location	O
.	O
</s>
<s>
Relocation	O
transparency	B-Operating_System
–	O
Should	O
a	O
resource	O
move	O
while	O
in	O
use	O
,	O
this	O
should	O
not	O
be	O
noticeable	O
to	O
the	O
end	O
user	O
.	O
</s>
<s>
Replication	B-Architecture
transparency	B-Operating_System
–	O
If	O
a	O
resource	O
is	O
replicated	O
among	O
several	O
locations	O
,	O
it	O
should	O
appear	O
to	O
the	O
user	O
as	O
a	O
single	O
resource	O
.	O
</s>
<s>
Concurrent	B-Operating_System
transparency	B-Operating_System
–	O
While	O
multiple	O
users	O
may	O
compete	O
for	O
and	O
share	O
a	O
single	O
resource	O
,	O
this	O
should	O
not	O
be	O
apparent	O
to	O
any	O
of	O
them	O
.	O
</s>
<s>
Failure	B-Operating_System
transparency	I-Operating_System
–	O
Always	O
try	O
to	O
hide	O
any	O
failure	O
and	O
recovery	O
of	O
computing	O
entities	O
and	O
resources	O
.	O
</s>
<s>
Persistence	B-Application
transparency	B-Operating_System
–	O
Whether	O
a	O
resource	O
lies	O
in	O
volatile	O
or	O
permanent	O
memory	O
should	O
make	O
no	O
difference	O
to	O
the	O
user	O
.	O
</s>
<s>
Security	O
transparency	B-Operating_System
–	O
Negotiation	O
of	O
cryptographically	O
secure	O
access	O
of	O
resources	O
must	O
require	O
a	O
minimum	O
of	O
user	O
intervention	O
,	O
or	O
users	O
will	O
circumvent	O
the	O
security	O
in	O
preference	O
of	O
productivity	O
.	O
</s>
<s>
Formal	O
definitions	O
of	O
most	O
of	O
these	O
concepts	O
can	O
be	O
found	O
in	O
RM-ODP	B-Operating_System
,	O
the	O
Open	B-Operating_System
Distributed	I-Operating_System
Processing	I-Operating_System
Reference	O
Model	O
(	O
ISO	B-Operating_System
10746	I-Operating_System
)	O
.	O
</s>
<s>
If	O
one	O
expects	O
real-time	O
interaction	O
with	O
the	O
distributed	B-Architecture
system	I-Architecture
,	O
this	O
may	O
be	O
very	O
noticeable	O
.	O
</s>
