<s>
SDXF	B-Protocol
(	O
Structured	B-Application
Data	I-Application
eXchange	O
Format	O
)	O
is	O
a	O
data	B-Application
serialization	I-Application
format	O
defined	O
by	O
RFC	O
3072	O
.	O
</s>
<s>
It	O
allows	O
arbitrary	O
structured	B-Application
data	I-Application
of	O
different	O
types	O
to	O
be	O
assembled	O
in	O
one	O
file	O
for	O
exchanging	B-General_Concept
between	O
arbitrary	O
computers	O
.	O
</s>
<s>
The	O
ability	O
to	O
arbitrarily	O
serialize	B-Application
data	O
into	O
a	O
self-describing	O
format	O
is	O
reminiscent	O
of	O
XML	B-Protocol
,	O
but	O
SDXF	B-Protocol
is	O
not	O
a	O
text	O
format	O
(	O
as	O
XML	B-Protocol
)	O
—	O
SDXF	B-Protocol
is	O
not	O
compatible	O
with	O
text	O
editors	O
.	O
</s>
<s>
The	O
maximal	O
length	O
of	O
a	O
datum	O
(	O
composite	O
as	O
well	O
as	O
elementary	O
)	O
encoded	O
using	O
SDXF	B-Protocol
is	O
16777215	O
bytes	O
(	O
one	O
less	O
than	O
16MB	O
)	O
.	O
</s>
<s>
SDXF	B-Protocol
data	O
can	O
express	O
arbitrary	O
levels	O
of	O
structural	O
depth	O
.	O
</s>
<s>
The	O
design	O
of	O
this	O
format	O
is	O
simple	O
and	O
transparent	O
:	O
computer	O
programs	O
access	O
SDXF	B-Protocol
data	O
with	O
the	O
help	O
of	O
well-defined	O
functions	O
,	O
exempting	O
programmers	O
from	O
learning	O
the	O
precise	O
data	O
layout	O
.	O
</s>
<s>
The	O
word	O
"	O
exchange	O
"	O
in	O
the	O
name	O
reflects	O
another	O
kind	O
of	O
transparency	O
:	O
the	O
SDXF	B-Protocol
functions	O
provide	O
a	O
computer	O
architecture	O
independent	O
conversion	O
of	O
the	O
data	O
.	O
</s>
<s>
Serializations	B-Application
can	O
be	O
exchanged	O
among	O
computers	O
(	O
via	O
direct	O
network	O
,	O
file	O
transfer	O
or	O
CD	O
)	O
without	O
further	O
measures	O
.	O
</s>
<s>
The	O
SDXF	B-Protocol
functions	O
on	O
the	O
receiving	O
side	O
handle	O
architectural	O
adaptation	O
.	O
</s>
<s>
Structured	B-Application
data	I-Application
is	O
data	O
with	O
patterns	O
predictable	O
more	O
complex	O
than	O
strings	O
of	O
text	O
.	O
</s>
<s>
An	O
SDXF	B-Protocol
serialization	B-Application
is	O
itself	O
a	O
chunk	O
.	O
</s>
<s>
Structured	O
chunks	O
enable	O
the	O
programmer	O
to	O
pack	O
hierarchical	O
constructions	O
such	O
as	O
the	O
INVOICE	O
above	O
into	O
an	O
SDXF	B-Protocol
structure	O
as	O
follow	O
:	O
</s>
<s>
SDXF	B-Protocol
allows	O
programmer	O
to	O
work	O
on	O
SDXF	B-Protocol
structures	O
with	O
a	O
compact	O
function	O
set	O
.	O
</s>
<s>
The	O
following	O
pseudocode	B-Language
creates	O
invoices	O
:	O
</s>
<s>
Pseudocode	B-Language
to	O
extract	O
the	O
INVOICE	O
structure	O
could	O
look	O
like	O
:	O
</s>
<s>
SDXF	B-Protocol
is	O
not	O
designed	O
for	O
readability	O
or	O
to	O
be	O
modified	O
by	O
text	O
editors	O
.	O
</s>
<s>
A	O
related	O
editable	O
structure	O
is	O
SDEF	O
-	O
Structured	B-Application
Data	I-Application
Editable	O
Format	O
.	O
</s>
