<s>
A	O
relative	B-Application
record	I-Application
data	I-Application
set	I-Application
(	O
RRDS	B-Application
)	O
is	O
a	O
type	O
of	O
data	B-Application
set	I-Application
organization	O
used	O
by	O
IBM	O
's	O
VSAM	O
computer	O
data	O
storage	O
system	O
.	O
</s>
<s>
Records	O
are	O
accessed	O
based	O
on	O
their	O
ordinal	O
position	O
in	O
the	O
file	O
(	O
relative	B-Application
record	I-Application
number	I-Application
,	O
RRN	O
)	O
.	O
</s>
<s>
The	O
concept	O
of	O
RRDS	B-Application
is	O
similar	O
to	O
sequential	B-General_Concept
access	I-General_Concept
method	I-General_Concept
,	O
but	O
it	O
can	O
access	O
with	O
data	O
in	O
random	B-General_Concept
access	I-General_Concept
and	O
dynamic	O
access	O
.	O
</s>
<s>
An	O
RRDS	B-Application
consists	O
of	O
data	O
records	O
in	O
sequence	O
,	O
with	O
the	O
record	O
number	O
indicating	O
the	O
record	O
's	O
logical	O
position	O
in	O
the	O
data	B-Application
set	I-Application
.	O
</s>
<s>
But	O
unlike	O
a	O
Key	B-Application
Sequenced	I-Application
Data	I-Application
Set	I-Application
,	O
an	O
RRDS	B-Application
has	O
no	O
keys	O
,	O
so	O
the	O
program	O
cannot	O
access	O
records	O
by	O
key	O
value	O
.	O
</s>
